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Background Colchicine is an available, safe, and effective anti-inflammatory drug and has been suggested as a COVID-19 treatment, but its usefulness in hospitalized severe COVID-19 patients has not been thoroughly demonstrated. Objective To address the safety and efficacy of colchicine in hospitalized patients with severe COVID-19. Design We conducted a triple-blind parallel non-stratified placebo-controlled clinical trial. Participants We recruited 116 hospitalized patients with severe COVID-19 in Mexico. Interventions Patients were randomized to receive 1.5 mg of colchicine or placebo at the time of the recruitment in the study (baseline) and 0.5 mg BID PO to complete 10 days of treatment. Main Measures The primary composite outcome was the progression to critical disease or death. Besides, we evaluated immunological features at baseline and after recovery or disease progression in 20 patients. Key Results Fifty-six patients were allocated to colchicine and 60 patients received placebo. The study was suspended after the second interim analysis demonstrated colchicine had no effect on the primary outcome (OR 0.83, 95%CI 0.35–1.93, P = 0.67), nor in the days of ICU and hospital stays. Adverse events were similar between groups (OR 1.63, 95% CI 0.66–3.88, P = 0.37). After colchicine treatment, patients had higher BUN and lower serum levels of IL-8, IL-12p70, and IL-17A. Conclusions Colchicine is safe but not effective in the treatment of severe COVID-19. Trial Registration ClinicalTrials.gov Identifier: NCT04367168.

Objectives The role of B cells in COVID‐19, beyond the production of specific antibodies against SARS-CoV-2, is still not well understood. Here, we describe the novel landscape of circulating double-negative (DN) CD27− IgD− B cells in COVID‐19 patients, representing a group of atypical and neglected subpopulations of this cell lineage. Methods Using multiparametric flow cytometry, we determined DN B cell subset amounts from 91 COVID-19 patients, correlated those with cytokines, clinical and laboratory parameters, and segregated them by principal components analysis. Results We detected significant increments in the DN2 and DN3 B cell subsets, while we found a relevant decrease in the DN1 B cell subpopulation, according to disease severity and patient outcomes. These DN cell numbers also appeared to correlate with pro- or anti-inflammatory signatures, respectively, and contributed to the segregation of the patients into disease severity groups. Conclusion This study provides insights into DN B cell subsets’ potential role in immune responses against SARS‐CoV‐2, particularly linked to the severity of COVID‐19. Supplementary Information The online version contains supplementary material available at 10.1007/s00011-021-01525-3.

We identified the main changes in serum metabolites associated with severe (n = 46) and mild (n = 19) COVID-19 patients by gas chromatography coupled to mass spectrometry. The modified metabolic profiles were associated to an altered amino acid catabolism in hypoxic conditions. Noteworthy, three α-hydroxyl acids of amino acid origin increased with disease severity and correlated with altered oxygen saturation levels and clinical markers of lung damage. We hypothesize that the enzymatic conversion of α-keto-acids to α- hydroxyl-acids helps to maintain NAD recycling in patients with altered oxygen levels, highlighting the potential relevance of amino acid supplementation during SARS-CoV-2 infection.

Background Monocytes and toll-like receptors (TLR) have been found in the inflammatory infiltrate of muscle biopsies in patients with idiopathic inflammatory myopathies (IIM), suggesting an important role of these cells in the pathogenesis of myositis. The monocyte subsets, their TLR expression in peripheral blood and their relationship with the clinical characteristics of patients with IIM has not been addressed. Methods We recruited 45 patients with IIM diagnosis and 15 age and sex-adjusted healthy controls. We assessed the disease activity and damage, performed a nailfold capillaroscopy and registered the cardio-pulmonary parameters from the medical charts. Monocyte subsets, their expression of TLR2 and TLR4 and the serum Th1/Th2/Th17 cytokines levels were evaluated by flow cytometry. We expressed quantitative variables as medians and interquartile ranges (IQR) or minimum and maximum (min–max). Differences between groups were assessed with Mann–Whitney U and the Kruskal–Wallis tests. Correlation between quantitative variables was assessed with Spearman Rho. Results Twenty-nine patients were women (64.4%) and 32 (71.1%) had dermatomyositis. In comparison to healthy controls, patients with active IIM had a higher percentage of intermediate monocytes and lower amounts of classical monocytes. Patients with IIM had a higher expression of TLR4 in all their monocyte subsets, regardless of disease activity and prednisone treatment. Serum IL-6 correlated with the TLR2 expression in every monocyte subset and the expression of TLR2 in intermediate monocytes was higher among patients with dysphagia. Subjects with nailfold capillaroscopy abnormalities had a higher amount of TLR2+ classical and non-classical monocytes and those with interstitial lung disease (ILD) had a higher percentage of TLR4+ non-classical monocytes. The classical and intermediate monocytes from patients with anti Mi2 antibodies had a higher expression of TLR4. The percentage of intermediate monocytes and the expression of TLR4 in all monocyte subsets showed a good diagnostic capacity in patients with IIM. Conclusion Patients with IIM have a differential pool of monocyte subsets with an enhanced expression of TLR2 and TLR4, which correlates with disease activity and distinctive clinical features including dysphagia, ILD, vasculopathy, and pro-inflammatory cytokines. These immunological features might be useful as a potential diagnostic tool as well as novel disease activity biomarkers in IIM.

Background/objective Biomarkers for disease activity and damage accrual in idiopathic inflammatory myopathies (IIMs) are currently lacking. The purpose of this cross-sectional study is to analyze the relationship among low-density granulocytes (LDGs), neutrophil extracellular traps (NETs), and clinical and immunological features of patients with IIM. Methods We assessed disease activity, damage accrual, amount of LDGs, NETs, expression of LL-37, and serum cytokines in 65 adult patients with IIM. Differences between groups and correlations were assessed by Kruskal-Wallis, Mann-Whitney U, and Spearman [rho] tests. The association between LDGs, NETs, disease activity, calcinosis, and cutaneous ulcers was assessed by logistic regression. To address the capacity of LDGs and NETs to diagnose disease activity, we used receiving operating characteristic curves. Results Low-density granulocytes were higher in patients with active disease, ulcers, calcinosis, and anti-MDA5 antibodies, which correlated with serum levels of IL-17A and IL-18. Neutrophil extracellular traps were higher in patients with calcinosis, elevated titers of antinuclear antibodies, and positive anti-PM/Scl75 tests. The combination of a high proportion of both total LDGs and NETs was associated with the presence of calcinosis and cutaneous ulcers. LL-37 was higher in NETs originating from LDGs. Normal-density neutrophils were elevated in patients with active dermatomyositis. Conclusions Low-density granulocytes and NETs containing LL-37 are increased in patients with IIM and active disease, and correlate with proinflammatory cytokines. Both total and CD10+ LDGs are potential biomarkers for disease activity and, in combination with NETs, have the potential to detect patients who are at risk for cutaneous ulcers and calcinosis.

BackgroundMost of the explanatory and prognostic models of COVID-19 lack of a comprehensive assessment of the wide COVID-19 spectrum of abnormalities. The aim of this study was to unveil novel biological features to explain COVID-19 severity and prognosis (death and disease progression).MethodsA predictive model for COVID-19 severity in 121 patients was constructed by ordinal logistic regression calculating odds ratio (OR) with 95% confidence intervals (95% CI) for a set of clinical, immunological, metabolomic, and other biological traits. The accuracy and calibration of the model was tested with the area under the curve (AUC), Somer’s D, and calibration plot. Hazard ratios with 95% CI for adverse outcomes were calculated with a Cox proportional-hazards model.ResultsThe explanatory variables for COVID-19 severity were the body mass index (BMI), hemoglobin, albumin, 3-Hydroxyisovaleric acid, CD8+ effector memory T cells, Th1 cells, low-density granulocytes, monocyte chemoattractant protein-1, plasma TRIM63, and circulating neutrophil extracellular traps. The model showed an outstanding performance with an optimism-adjusted AUC of 0.999, and Somer’s D of 0.999. The predictive variables for adverse outcomes in COVID-19 were severe and critical disease diagnosis, BMI, lactate dehydrogenase, Troponin I, neutrophil/lymphocyte ratio, serum levels of IP-10, malic acid, 3, 4 di-hydroxybutanoic acid, citric acid, myoinositol, and cystine.ConclusionsHerein, we unveil novel immunological and metabolomic features associated with COVID-19 severity and prognosis. Our models encompass the interplay among innate and adaptive immunity, inflammation-induced muscle atrophy and hypoxia as the main drivers of COVID-19 severity.

Objective This study aimed to analyze the expression of the high mobility group box-1 (HMGB1) protein in neutrophil extracellular traps (NETs) of patients with lupus nephritis (LN) and its association with clinical and histopathological features of the disease. Methods Twenty-three patients with biopsy-confirmed LN and 14 systemic lupus erythematosus (SLE) patients with active disease (SLE Disease Activity Index (SLEDAI) score ≥ 6) and no evidence of LN were included. Clinical and laboratory features were recorded. NETs and the expression of HMGB1 were assessed by confocal microscopy, and serum HMGB1 levels were measured by ELISA. Results In comparison to patients without kidney disease, patients with LN had a higher expression of HMGB1 in spontaneous (57 vs. 30.4; p = 0.027) and lipopolysaccharide (LPS)-induced (55.8 vs. 24.9; p = 0.005) NETs. We found a positive correlation between serum HMGB1 and the expression of HMGB1 in LPS-induced NETs ( r = 0.447, p = 0.017). The expression of HMGB1 in spontaneous NETs correlated with SLEDAI score ( r = 0.514, p = 0.001), anti-dsDNA antibodies ( r = 0.467, p = 0.004), the rate of glomerular filtration descent ( r = 0.543, p = 0.001), and diverse histopathological components of active nephritis in the kidney biopsy, such as the activity index ( r = 0.581, p = 0.004), fibrinoid necrosis ( r = 0.603, p = 0.002), and cellular crescents ( r = 0.486, p = 0.019). Conclusions In patients with SLE, NETs are a source of extracellular HMGB1. The expression of HMGB1 in NETs is higher among patients with LN, which correlates with clinical and histopathological features of active nephritis and suggest a possible role of this alarmin in the pathophysiology of kidney damage in SLE.

The immune response plays a critical role in the pathophysiology of SARS‐CoV‐2 infection ranging from protection to tissue damage and all occur in the development of acute respiratory distress syndrome (ARDS). ARDS patients display elevated levels of inflammatory cytokines and innate immune cells, and T and B cell lymphocytes have been implicated in this dysregulated immune response. Mast cells are abundant resident cells of the respiratory tract and are able to release different inflammatory mediators rapidly following stimulation. Recently, mast cells have been associated with tissue damage during viral infections, but their role in SARS‐CoV‐2 infection remains unclear. In this study, we examined the profile of mast cell activation markers in the serum of COVID‐19 patients. We noticed that SARS‐CoV‐2‐infected patients showed increased carboxypeptidase A3 (CPA3) and decreased serotonin levels in their serum when compared with symptomatic SARS‐CoV‐2‐negative patients. CPA3 levels correlated with C‐reactive protein, the number of circulating neutrophils, and quick SOFA. CPA3 in serum was a good biomarker for identifying severe COVID‐19 patients, whereas serotonin was a good predictor of SARS‐CoV‐2 infection. In summary, our results show that serum CPA3 and serotonin levels are relevant biomarkers during SARS‐CoV‐2 infection. This suggests that mast cells and basophils are relevant players in the inflammatory response in COVID‐19 and may represent targets for therapeutic intervention., Graphical Abstract Serum levels of CPA3 and serotonin are affected during SARS‐CoV‐2 infection and can be considered as biomarkers during COVID‐19.

BACKGROUNDPrognostic biomarkers are needed to identify patients at high-risk for severe COVID-19. Galectin-3 is known to drive neutrophil infiltration and release of pro-inflammatory cytokines contributing to airway inflammation.METHODSIn this prospective cohort, we assessed galectin-3 levels in 156 hospitalized patients with confirmed COVID-19. COVID-19 patients were diagnosed as eithercritical(>50% lung damage) ormoderate(severe outcome, and anon-severe outcomeif they were discharged and none of the former occurred.RESULTSElevated serum galectin-3 was significantly higher in critical patients compared to moderate ones (35.91 ± 19.37 ng/mL vs. 25 ± 14.85 ng/mL, psevere outcomeincluding IMV and/or in-hospital death, presented higher galectin-3 levels (41.17 ng/mL [IQR 29.71 – 52.25] vs. 23.76 ng/mL [IQR 15.78 – 33.97] compared to those of a non-severe outcome, pCONCLUSIONCirculating galectin-3 levels can be used to predict severe outcomes in COVID-19 patients, including the requirement of mechanical ventilation and/or death, regardless of the initial severity of the disease.

BackgroundSARS-CoV-2 infection represents a global health problem that has affected millions of people. The fine host immune response and its association with the disease course have not yet been fully elucidated. Consequently, we analyze circulating B cell subsets and their possible relationship with COVID-19 features and severity.MethodsUsing a multiparametric flow cytometric approach, we determined B cell subsets frequencies from 52 COVID-19 patients, grouped them by hierarchical cluster analysis, and correlated their values with clinical data.ResultsThe frequency of CD19+ B cells is increased in severe COVID-19 compared to mild cases. Specific subset frequencies such as transitional B cell subsets increase in mild/moderate cases but decrease with the severity of the disease. Memory B compartment decreased in severe and critical cases, and antibody-secreting cells are increased according to the severity of the disease. Other non-typical subsets such as double-negative B cells also showed significant changes according to disease severity. Globally, these differences allow us to identify severity-associated patient clusters with specific altered subsets. Finally, respiratory parameters, biomarkers of inflammation, and clinical scores exhibited correlations with some of these subpopulations.ConclusionsThe severity of COVID-19 is accompanied by changes in the B cell subpopulations, either immature or terminally differentiated. Furthermore, the existing relationship of B cell subset frequencies with clinical and laboratory parameters suggest that these lymphocytes could serve as potential biomarkers and even active participants in the adaptive antiviral response mounted against SARS-CoV-2.

We identified the main changes in serum metabolites associated with severe (n=46) and mild (n=19) COVID-19 patients by gas chromatography coupled to mass spectrometry. The modified metabolic profiles were associated to an altered amino acid catabolism in hypoxic conditions. Noteworthy, three 𝛼-hydroxyl acids of amino acid origin increased with disease severity and correlated with altered oxygen saturation levels and clinical markers of lung damage. We hypothesize that the enzymatic conversion of 𝛼-keto-acids to 𝛼- hydroxyl-acids helps to maintain NAD recycling in patients with altered oxygen levels, highlighting the potential relevance of amino acid supplementation during SARS-CoV-2 infection.

Background: Neutrophil extracellular traps (NETs) from patients with Systemic Lupus Erythematosus (SLE) are characterized by lower ubiquitylation and myeloperoxidase (MPO) as a substrate. The structural and functional effect of such modification and if there are additional post-translational modifications (PTMs) are unknown.Methods: To assess the expression and functional role of PTMs in NETs of patients with SLE; reactivation, proliferation and cytokine production was evaluated by flow cytometry using co-cultures with dendritic cells (DC) and CD4+ from SLE patients and healthy controls. The impact of ubiquitylation on MPO was assessed by molecular dynamics. The expression of ISG15 in NETs was evaluated by immunofluorescence and Western Blot.Results: Fifteen patients with SLE and 10 healthy controls were included. In the co-cultures of CD4+ lymphocytes with DC stimulated with ubiquitylated MPO or recombinant MPO, a higher expression of IFNγ and IL17A was found in CD4+ from SLE patients (p + lymphocytes, while the opposite was documented in controls (p Conclusion: The ubiquitylated MPO has a differential effect on the induction of reactivation and proliferation of CD4+ lymphocytes in patients with SLE, which may be related to structural changes by ubiquitylation at the catalytic site of MPO. Besides a lower ubiquitylation pattern, NETs of patients with SLE are characterized by the expression of H2B conjugated with ISG15, and the induction of IFNγ by Th1 cells.

Objectives Psoriasis (PsO) is a chronic, inflammatory, multisystem disease with predominantly skin and joint manifestations. The disease is also associated with lower quality of life, lower work productivity, and higher healthcare costs. The objective of this study was to conduct a systematic literature review of the disease burden for PsO in Argentina, Brazil, Colombia, and Mexico. Methods PubMed/MEDLINE, Web of Science, SciELO, and LILACS were searched for publications in English, Spanish, or Portuguese from 2003 to July 2018. Results A total of 680 records were retrieved and 13 articles were included. In Latin America, PsO has a negative impact on the physical and mental well-being as shown by substantially lower scores on measures of quality of life (eg, 12-item Short-Form Health Survey) for patients than the general population. Patients with PsO reported higher levels of presenteeism, activity impairment, and work productivity loss. The estimated annual costs per patient with PsO in Colombia were $3497.58 and $2160.92 for the private sector and public scenario, respectively. Conclusions Although evidence on the full cost and impact of PsO in Latin America is scarce and further research is needed, the burden in these regions is significant and comparable with that in other parts of the world.

Background: Acute graft-versus-host disease (aGVHD) is an important cause of death following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The association between cholesterol and aGVHD was previously described potentially resulting from pro-inflammatory responses associated with hypercholesterolemia. The aim of this study was to correlate T-cell subsets in donor bone marrow (BM) samples with their levels of cholesterol and associate these results with recipients who developed aGVHD and those who did not. Materials and Methods: A prospective study was performed in 39 donor samples. T-cell subsets were analyzed by flow cytometry. Results: Eleven (28%) donors had hypercholesterolemia. Donor samples with hypercholesterolemia had less Tregs compared to donors with normal levels of cholesterol (22.69 (IQR=30.6) cells/µL vs 52.62 (IQR=44.68) cells/µL, p=0.04). Among all individuals in the cohort, aGVHD was observed in 21%: 36% from donors with hypercholesterolemia versus 14% from donors with normal levels of cholesterol. Conclusion: As we described the association between hypercholesterolemia and diminished Tregs, our results might suggest that normalizing the levels of total cholesterol in the donor, prior performing allo-HSCT, might be an effective approach to diminish the risk of the receptor to develop aGVHD.

The coronavirus disease 2019 (COVID-19) is related to enhanced production of NETs, and autoimmune/autoinflammatory phenomena. We evaluated the proportion of low-density granulocytes (LDG) by flow cytometry, and their capacity to produce NETs was compared with that of conventional neutrophils. NETs and their protein cargo were quantified by confocal microscopy and ELISA. Antinuclear antibodies (ANA), anti-neutrophil cytoplasmic antibodies (ANCA) and the degradation capacity of NETs were addressed in serum. MILLIPLEX assay was used to assess the cytokine levels in macrophages’ supernatant and serum. We found a higher proportion of LDG in severe and critical COVID-19 which correlated with severity and inflammatory markers. Severe/critical COVID-19 patients had higher plasmatic NE, LL-37 and HMGB1-DNA complexes, whilst ISG-15-DNA complexes were lower in severe patients. Sera from severe/critical COVID-19 patients had lower degradation capacity of NETs, which was reverted after adding hrDNase. Anti-NET antibodies were found in COVID-19, which correlated with ANA and ANCA positivity. NET stimuli enhanced the secretion of cytokines in macrophages. This study unveils the role of COVID-19 NETs as inducers of pro-inflammatory and autoimmune responses. The deficient degradation capacity of NETs may contribute to the accumulation of these structures and anti-NET antibodies are related to the presence of autoantibodies.

Summary Natural killer (NK) cells participate in the regulation of the immune response. However, the immunomodulatory function of NK cells in systemic lupus erythematosus (SLE) is not well understood. The aim of this study was to evaluate the regulatory function of NK cells in SLE patients and to identify the NK cells involved in the pathogenesis of this complex disease. We analysed the expression of NK receptors and co-stimulatory molecules in peripheral NK cells (CD3−CD56+) from SLE patients, as well as the numbers of human leucocyte antigen D-related (HLA-DR)/CD11c+ NK cells. In addition, NK cell regulatory function was assessed by the detection of NK cell-mediated dendritic cell (DC) lysis. We found that SLE patients showed increased numbers of immunoglobulin-like transcript 2 (ILT2)+, CD86+ and CD134+ NK cells. Furthermore, NK cells from SLE patients induced higher levels of DC lysis. We were able to identify a new subset of NK cells co-expressing CD11c and HLA-DR. These atypical NK cells were increased in SLE patients when compared with controls. We have identified an expanded new subset of NK cells in SLE patients. This is the first study, to our knowledge, which demonstrates that NK cells in SLE patients have an altered phenotype with a high expression of receptors characteristic of dendritic cells. Our results suggest that the impairment in the regulatory function of NK cells, together with the increased number of DC-like NK cells, could play an important role in the development of SLE and highlight the importance of NK cells as a future therapeutic target.

In patients with systemic lupus erythematosus (SLE), persistent joint activity and treatment with glucocorticoids are associated with musculoskeletal complications. About 30% of these patients become candidates for surgical treatment. The aim of this study was to evaluate postoperative outcomes after total hip arthroplasty (THA) in SLE patients.We performed a retrospective cohort study at a tertiary care center in Mexico City between 1995 and 2013. All patients with SLE who underwent THA during that period were included (n = 58). They were compared with 2 control groups, one from another inflammatory arthropathy (rheumatoid arthritis, n = 58) and other noninflammatory (osteoarthritis, n = 58), matched by gender and date of surgery. The primary outcome was the frequency of postoperative complications during follow-up.We included 174 patients who underwent THA during the study period. Patients with SLE were younger (P.0001), had a longer hospitalization stay (P = .001), and required more transfusions (P = .004). Global complications in THA in patients with SLE were more prevalent than rheumatoid arthritis (36.2% vs 15.5%, P = .029) and osteoarthritis (36.2% vs 5.1%, P.0001) patients. After multivariate analysis, risk factors for THA complications were: SLE (hazard ratio 2.8, 95% confidence interval 1.2-6.8; P = .018) and low postoperative hemoglobin (hazard ratio 0.77, 95% confidence interval 0.73-0.83; P .0001). Long-term complications after THA were similar among groups.This is the largest single-center study regarding clinical outcomes after THA in SLE patients. Our data suggest that SLE is an independent risk factor for adverse postoperative outcomes, mainly immediate complications, but the long-term outcome is good enough to offer surgical treatment that will improve quality of life.

Summary T cells from systemic lupus erythematosus (SLE) patients display a wide array of anomalies in peripheral immune tolerance mechanisms. The role of ubiquitin ligases such as Cbl-b has been described recently in these phenomena. However, its role in resistance to suppression phenotype in SLE has not been characterized, which was the aim of the present study. Thirty SLE patients (20 with active disease and 10 with complete remission) and 30 age- and sex-matched healthy controls were recruited. Effector (CD4+CD25–) and regulatory (CD4+CD25+) T cells (Tregs) were purified from peripheral blood mononuclear cells (PBMCs) by magnetic selection. Suppression assays were performed in autologous and allogeneic co-cultures and analysed by a flow cytometry assay. Cbl-b expression and lysine-63 (K63)-specific polyubiquitination profile were assessed by Western blotting. We found a defective Cbl-b expression in Tregs from lupus patients in contrast to healthy controls (1·1 ± 0·9 versus 2·5 ± 1·8, P = 0·003), which was related with resistance to suppression (r = 0·633, P = 0·039). Moreover, this feature was associated with deficient K63 polyubiquitination substrates and enhanced expression of phosphorylated signal transducer and activation of transcription 3 (pSTAT-3) in Tregs from lupus patients. Our findings support that Cbl-b modulates resistance to suppression by regulating the K63 polyubiquitination profile in lupus Tregs. In addition, defective K63 polyubiquitination of STAT-3 is related to increased pSTAT-3 expression, and might promote the loss of suppressive capacity of Tregs in lupus patients.

Background This study aimed to address whether bloodstream infections are a risk factor for the development of severe lupus flares, as well as clinical, immunological and microbiological features of patients with bloodstream infections that develop severe lupus flares. Methods We performed a retrospective cohort study comparing 87 systemic lupus erythematosus (SLE) patients with bloodstream infections and 87 hospitalized SLE patients without bloodstream infections as a comparison group. All patients were followed up for at least 3 months or until one of the primary outcomes was developed (severe SLE flare according to SELENA/SLEDAI score or death). Microbiological features of all bloodstream infections were recorded. The disease status at the end of follow up was registered. Results A total of 23 patients (13.2%) developed a severe flare during follow up; among them, 20 (87%) had an associated episode of bloodstream infection ( p 0.001). The most frequent flares were renal (43.4%) and severe thrombocytopenia (26%). After multivariate analysis, baseline-independent factors associated with severe SLE flare were bloodstream infection [hazard ratio (HR) 7.3, 95% confidence interval (CI) 2.13-24.95; p = 0.002]. Among patients with bloodstream infections, low C4 levels (HR 2.43, 95% CI 1.04-5.69: p = 0.04) and Streptococcus pneumoniae were associated with severe SLE flare (HR 3.41, 95% CI 1.68-6.91; p = 0.012). Conclusions SLE patients with bloodstream infections, especially due to S. pneumoniae, and low C4 levels, are at higher risk for development of severe SLE flares.

Idiopathic inflammatory myopathies (IIM) are characterized by muscle inflammation and weakness, myositis-specific autoantibodies (MSAs), and extramuscular organ damage. The role of neutrophil dysregulation and neutrophil extracellular traps (NETs) in IIM is unclear. We assessed whether pathogenic neutrophil subsets (low-density granulocytes [LDGs]) and NETs were elevated in IIM, associated with clinical presentation and MSAs, and their effect on skeletal myoblasts and myotubes. Circulating NETs and LDGs were quantified and correlated with clinical measures. Specific MSAs were tested for their ability to induce NETs. NETs and neutrophil gene expression were measured in IIM biopsies. Whether NETs damage skeletal myoblasts and myotubes was tested. Circulating LDGs and NETs were increased in IIM. IIM LDGs had an enhanced ability to form NETs. LDGs and NETs correlated with IIM disease activity and muscle damage. The serum MSA anti-MDA5 correlated with circulating and tissue NETs and directly enhanced NET formation. An enhanced neutrophil gene signature was present in IIM muscle and associated with muscle injury and tissue IFN gene signatures. IIM NETs decreased the viability of myotubes in a citrullinated histone-dependent manner. Dysregulated neutrophil pathways may play pathogenic roles in IIM through their ability to directly injure muscle cells and other affected tissues.

Recently, neutrophil extracellular traps (NETs), three-dimensional structures formed of neutrophil enzymes such as neutrophil elastase (NE) and nuclear components (DNA), have been associated with progression in different types of cancer. However, data remain scarce in breast cancer. Thus, the aim of this study was to associate NETs with clinical stages of breast cancer. A prospective analysis was performed in 45 plasma samples of female patients with newly diagnosed breast cancer. NE-DNA complexes were evaluated by ELISA. Optical density was dichotomized at the median for comparisons (low and high levels of NE-DNA). The most frequent clinical stage was localized (n = 28, 62%) followed by regional (n = 13, 29%) and distant (n = 4, 9%). Higher levels of NE-DNA complexes were observed in regional and distant stages compared to localized disease (68% vs 32%, p = 0.034). No differences were observed when comparing other clinical characteristics between both groups. We demonstrated that the levels of NETs increase in proportion to the stage of the disease, observing higher levels of NE-DNA complexes in regional and metastatic disease, which coincides with the proposed mechanism by which cancer progression and metastasis might result from the formation of NETs.

Daniel Toro is at present supported by structural funds to MEAR from the Fundación Pública Andaluza Progreso y Salud of the Junta de Andalucía, Supplementary information is available for this paper at https://doi.org/10.1038/s41598-019-51616-9., Systemic lupus erythematosus (SLE) is a heterogeneous disease with unpredictable patterns of activity. Patients with similar activity levels may have different prognosis and molecular abnormalities. In this study, we aimed to measure the main differences in drug-induced gene expression signatures across SLE patients and to evaluate the potential for clinical data to build a machine learning classifier able to predict the SLE subset for individual patients. SLE transcriptomic data from two cohorts were compared with drug-induced gene signatures from the CLUE database to compute a connectivity score that reflects the capability of a drug to revert the patient signatures. Patient stratification based on drug connectivity scores revealed robust clusters of SLE patients identical to the clusters previously obtained through longitudinal gene expression data, implying that differential treatment depends on the cluster to which patients belongs. The best drug candidates found, mTOR inhibitors or those reducing oxidative stress, showed stronger cluster specificity. We report that drug patterns for reverting disease gene expression follow the cell-specificity of the disease clusters. We used 2 cohorts to train and test a logistic regression model that we employed to classify patients from 3 independent cohorts into the SLE subsets and provide a clinically useful model to predict subset assignment and drug efficacy., This work has been partially supported by Junta de Andalucía through grant PI-0173–2017. The Hopkins Lupus Cohort is supported by NIH AR RO1069572.

Background The aim of this study was to evaluate neutrophil extracellular traps (NETs) in kidney transplant recipients (KTR) and their potential involvement in acute antibody-mediated rejection (AAMR). Methods We studied 3 groups: KTR with AAMR (KTR-Cases, n = 14); KTR without any immunologic event (KTR-Controls, n = 14) and donors (n = 12). Spontaneous and lipopolysaccharide-induced NETosis were evaluated by immunofluorescence indirect (IFI) (NET/cells ratio). Plasmatic cH3-DNA complexes were evaluated by ELISA, (Optic Density Index - ODI). The expression of MPO and citrullinated histone 4 (cH4) was evaluated in renal biopsies. Results We found an enhanced spontaneous NETosis in KTR regardless of whether they had rejection. The Nets/cells ratio in spontaneous NETosis was 0.203 (IQR 0.12–0.34) in Total-KTR and 0.094 (IQR 0.01–0.17) in donors, p = .011. Likewise, the ODI of cH3-DNA was 1.41 (IQR 0.94–1.72) in Total-KTR, and 0.95 (IQR 0.83–1.27) in donors, p = .019. KTR-Cases had the higher amount of NETs 1.70 (IQR 1.19–1.91). In two KTR-Cases, expression of MPO and cH4 was found in biopsies. Conclusions KTR show enhanced NETosis. This may indicate a permanent activation of neutrophils. Although more studies are needed, the higher amount of NETs and netting neutrophils in biopsies of KTR-Cases suggest a role of NETosis in AAMR.

Background: Whereas SLE is uncommon in men, the disease is usually more severe and requires more aggressive immunosuppression in male patients. There are multiple studies regarding sexual aspects in women with SLE, but information about sexual function in male patients is quite scant. Objectives: To determine the relationship between SLE and sexual function alterations in men, through the application of validated questionnaires. Methods: We performed a longitudinal study in a third-level referral center in Mexico City. We included men aged ≥16 years who fulfilled ACR criteria for SLE and who were sexually active. All subjects answered the International Index of Erectile Function-15 (IIEF-15), the SF-36 and the HAQ in two visits. Other clinical, serological and demographic variables were measured. Oxidized LDL was quantified by ELISA. Results: We included 108 male SLE patients. Mean age was 37.2±1.1 years and most patients (87%) were taking immunosuppressive therapy. Comorbidities were present in 58% of subjects, with dyslipidemia and hypertension being the most prevalent (34% and 28%, respectively). The prevalence of sexual dysfunction (SD) was 53%. In the basal visit, the only significant differences between the patients with SD and those without SD were a lower education degree (p=0.007) and persistent lymphopenia (p=0.01). There was a positive correlation between global IIEF-15 score and SF-36 score (r=0.46, p=0.001). The physical function domain had the highest correlation (r=0.50, p=0.001). Likewise, there was a weak negative correlation between IIEF-15 and HAQ score (r=-0.25, p=0.012). Also, the IIEF-15 had a weak correlation with the absolute lymphocyte count (r=0.27, p=0.005) and oxidized LDL (r=0.31, p=0.04). In the follow-up visit the only significant differences between the patients with SD when compared with subjects without SD was a low absolute lymphocyte count (1031±89 vs 1458±119, p=0.005); the correlations mentioned in the baseline visit remained significant. Regarding erectile function, 44% of the subjects had some degree of dysfunction. The rest of the variables are shown in Table 1. Conclusion: Sexual function is affected in men with lupus, regardless of comorbidities and treatment. Interestingly, lymphopenia is persistently associated with an impaired sexual function, which could be related to the role it plays in endothelial dysfunction and atherosclerosis. The patients’ disease perception, which is influenced by their academic level and physical role in their daily activities, seems to affect their sexual performance and quality of life. Disclosure of Interests: Jonathan Campos-Guzman: None declared, Ana Barrera-Vargas: None declared, Samuel Govea-Pelaez: None declared, Diana Gomez-Martin: None declared, Jorge Alcocer-Varela: None declared, Diana Padilla-Ortiz: None declared, Javier Merayo-Chalico Speakers bureau: Pfizer

Background Whereas SLE is uncommon in men, the disease is usually more severe and requires more aggressive immunosuppression in male patients. There are multiple studies regarding sexual aspects in women with SLE, but information about sexual function in male patients is quite scant. Methods We performed a longitudinal study in a third-level referral center in Mexico City (January–November 2018). We included men aged 16 years who fulfilled ACR criteria for SLE and who were sexually active in the previous six months. All subjects answered the International Index of Erectile Function-15 (IIEF-15), the SF-36 (which determines generic health-related quality of life) and the HAQ in two visits. Other clinical, serological and demographic variables were measured. Oxidized LDL was quantified by ELISA. Results We included 108 male SLE patients. Mean age was 37.2±1.1 years and most patients (87.9%) were taking immunosuppressive therapy. Comorbidities were present in 58.3% of subjects, with dyslipidemia and hypertension being the most prevalent (34.2% and 28.7%, respectively). The prevalence of sexual dysfunction (SD) was 53.7%. In the basal visit, the only significant differences between the patients with SD and those without SD were a lower education degree (p=0.007) and persistent lymphopenia (p=0.01). There was a positive correlation between global IIEF-15 score (gsIIEF-15) and global SF-36 score (r=0.459, p=0.0001). The physical function domain had the highest correlation (r=0.509, p=0.0001). Likewise, there was a weak negative correlation between gsIIEF-15 and HAQ score (r=−0.252, p=0.012). Also, the gsIIEF-15 had a weak correlation with the absolute lymphocyte count (r=0.273, p=0.005) and oxidized LDL (r=0.310, p=0.04). In the follow-up visit the only significant differences between the patients with SD when compared with subjects without SD was a low absolute lymphocyte count (1031±89 vs 1458±119, p=0.005); the correlations mentioned in the baseline visit remained significant. Regarding erectile function, 44% of the subjects had some degree of dysfunction. The rest of the variables are shown in table 1. Conclusions Sexual function is affected in men with lupus (mostly young and with adequate functional capacity), regardless of comorbidities and treatment. Interestingly, lymphopenia is persistently associated with an impaired sexual function, which could be related to the role it plays in endothelial dysfunction and atherosclerosis. The patients disease perception, which is influenced by their academic level and physical role in their daily activities, seems to affect their sexual performance and quality of life. These findings reinforce the need of a multidisciplinary approach for male SLE patients with sexual dysfunction. Funding Source(s): None

Among autoimmune diseases, systemic lupus erythematosus (SLE) patients have a unique predisposition to develop infections, which represents one of their main causes of morbidity and mortality. Many infections occur at disease diagnosis in the absence of immunosuppressive therapy, suggesting that the immunological abnormalities in SLE patients might be fundamental for the development of this complication. The aim of this study was to address the main clinical and immunological features associated with the development of infection and to create and validate a compound clinical-immunological infection predictive index in a cohort of SLE patients. We included 55 SLE patients with < 5 years since diagnosis. The clinical and immunological features were evaluated periodically and patients were followed-up during 1 year, searching for the development of infection. Immunophenotyping was performed by multiparametric flow cytometry and neutrophil extracellular traps (NETs) were assessed by confocal microscopy. Eighteen patients (32.7%) presented 19 infectious events, 5 (26.3%) were severe. For the construction of the index, we performed a logistic regression analysis and the cutoff points were determined with ROC curves. Increased numbers of peripheral Th17 cells, B cell lymphopenia, and lower TLR2 expression in monocytes, as well as the use of cyclophosphamide were the major risk factors for the development of infection and thus were included in the index. Besides, patients that developed infection were characterized by increased numbers of low-density granulocytes (LDGs) and higher expression of LL-37 in NETs upon infection. Finally, we validated the index retrospectively in a nested case-control study. A score >1.5 points was able to predict infection in the following year (AUC = 0.97; LR– = 0.001, specificity 100%, P = 0.0003). Our index encompasses novel immunological features able to prospectively predict the risk of infection in SLE patients.

Lymphopenia is strongly associated with autoimmune diseases. The molecular mechanisms that link both phenomena are still unclear, but certain key pathways have been described. Central tolerance is as important as peripheral. In the earlier, epithelial and dendritic cells play a crucial role in the selection of clones. In the latter, regulatory T cells (Tregs) rise as inductors of anergy in order to prevent the development of autoimmune pathology. In lymphopenic conditions, T cells develop the process of lymphopenia-induced proliferation (LIP). A complex interaction between the major histocompatibility complex (MHC) and the T cell receptor (TCR) makes this process possible. Furthermore, IL-7 can act synergistically or in an independent manner to promote LIP. A lack of Transforming Growth Factor-β (TGF-β) was recently described as the second hit needed to develop autoimmunity in a lymphopenic microenvironment, given its actions in Tregs and its interaction with CTLA-4. Regarding autoimmune clinical scenarios, lymphopenia is related to both, systemic and organ-specific diseases. Thus, the molecular study of such patients has been limited and needs to be widened to the pathways shown here to be involved in the development of lymphopenia and autoimmunity.

Background Renal thrombotic microangiopathy (TMA) may be associated with lupus nephritis. Its relationship to other disease factors and its specific effect on prognosis are not precisely known. Evidence regarding these aspects is controversial, and information focusing on kidney-limited TMA in systemic lupus erythematosus (SLE) patients is scarce. Objectives The aims of this study were to identify risk factors for renal TMA in patients with lupus nephritis and to determine its impact on clinical outcomes. Methods A case-control study was performed. We studied 245 renal biopsies from SLE patients. We included patients with renal TMA, as well as control subjects adjusted for glomerulonephritis class, estimated glomerular filtration rate, activity and chronicity indices, and follow-up time. Serological and clinical features were measured at the time of the biopsy and during follow-up. Results Twenty-three patients with renal TMA and 21 control subjects were included. There were no differences in Systemic Lupus Erythematosus Disease Activity Index score, end-stage renal disease, or mortality between groups during follow-up. After multivariate analysis, lymphopenia (odds ratio, 10.69; 95% CI, 1.35-84.74) and anti-Ro antibody positivity (odds ratio, 8.96; 95% CI, 1.49-53.57) remained significantly associated with renal TMA. Conclusions Lymphopenia and anti-Ro positivity are independent risk factors for renal TMA in SLE patients. This increased risk could be a consequence of the potential role of these factors in endothelial dysfunction and damage. Outcomes were similar for patients with the same estimated glomerular filtration rate and biopsy characteristics, regardless of the presence of TMA.

Objective.The aim of this study was to describe the prevalence of erectile dysfunction (ED), as well as associated demographic and clinical features, in men with systemic lupus erythematosus (SLE), by means of a systematic, standardized evaluation.Methods.We performed a transversal study in 8 tertiary care centers in Latin America. We included male patients ≥ 16 years who fulfilled ≥ 4 American College of Rheumatology criteria for SLE and had regular sexual activity, and evaluated them with the International Index of Erectile Function-5 questionnaire. Relevant demographic, clinical, and serological characteristics were recorded. We included 2 control groups: the first was made up of healthy men and the second of men with autoimmune diseases other than SLE (non-SLE group).Results.We included 590 subjects (174 SLE, 55 non-SLE, and 361 healthy controls). The prevalence of ED in the SLE group was 69%. Mean age in that group was 36.3 ± 1.03 years. Among SLE patients with and without ED, these factors were significantly different: the presence of persistent lymphopenia (p = 0.006), prednisone dose (9.3 ± 1.2 vs 5.3 ± 1.3 mg, p = 0.026), and the Systemic Lupus International Collaborating Clinics damage score (1.25 ± 0.14 vs 0.8 ± 0.16 points, p = 0.042). Independent risk factors for ED in patients with SLE were persistent lymphopenia (OR 2.79, 95% CI 1.37–5.70, p = 0.001) and corticosteroid use in the previous year (OR 2.15, 95% CI 1.37–3.37, p = 0.001).Conclusion.Regardless of comorbidities, treatment (excluding steroids), and type of disease activity, patients with SLE have a high prevalence of ED, especially considering that most patients are young. Recent corticosteroid use and persistent lymphopenia, which could be related to endothelial dysfunction, are risk factors for this complication in men with SLE.

Background SLE patients display an elevated cardiovascular risk when compared to the general population.1 Interferon-alpha (IFN-α) appears to drive atherogenesis in SLE at least in part, by promoting abnormal phenotype and function of EPCs.1 S1P1 is considered crucial for vasculogenesis and has been shown to attenuate IFN-α autoamplification by promoting IFN receptor 1 (IFNAR1) degradation.2,3 Objectives To characterise S1P1 expression in EPCs from SLE patients and its putative association to type I IFNs effects on vasculogenesis. Methods SLE subjects that fulfilled SLE ACR classification criteria were recruited. Healthy controls were selected based on age and gender. Disease activity was assessed by SLEDAI-2K index. EPCs were quantified by flow cytometry in PBMC subsets as those cells that coexpress CD133+/CD34+ in the CD3-/CD56-/CD79b- gate.1 S1P1 expression was quantified in that subset. Control PBMCs were cultured in endothelial cell (EC)-enrichment medium for 2 weeks. Differentiated ECs were characterised by immunofluorescence (IF) as those cells that coexpress UEA-1 lectin and take up acetylated LDL.1 These cells were stimulated with recombinant IFN-α in the presence or absence of the S1P1 agonist CYM-5442 and the S1P1 antagonist W-146 to assess the effect of this pathway on EC differentiation and type I IFN induced gene expression.3 Results SLE and matched healthy controls (n=36/group) were compared. Demographic and clinical characteristics are depicted in table 1. Conclusions The S1P1 pathway is involved in the regulation of EPC differentiation by type I IFNs. Defects in S1P1 signalling pathway in lupus EPCs may contribute to the development of endothelial dysfunction in SLE. References [1] Denny MF. Interferon-alpha promotes abnormal vasculogenesis in lupus: a potential pathway for premature atherosclerosis. Blood2007;110:2907–2915. [2] Liu Y. Edg-1, the G protein-coupled receptor for sphingosine-1-phosphate, is essential for vascular maturation. J Clin Invest2000;106:951–961. [3] Teijaro JR. S1PR1-mediated IFNAR1 degradation modulates plasmacytoid dendritic cell interferon-alpha autoamplification. Proc Natl Acad Sci USA2016;113:1351–1356. Acknowledgements This work was supported by a grant from the Colegio Mexicano de Reumatologia to DGM. Disclosure of Interest None declared

The primary aim of this study was to assess demographic, clinical, and serological factors associated with remission in systemic lupus erythematosus (SLE). A retrospective cohort study was performed. We examined relevant features in patients with SLE with a follow-up of at least 8 years from active disease (SLE Disease Activity Index-2000 [SLEDAI-2K] ≥6). The primary outcome was to assess various remission states in SLE according to disease activity and treatment. Differences between groups were assessed by Student’s t test and chi-square test for continuous and categorical variables, respectively. Multivariate Cox proportional hazard analysis was used to assess association between variables, and we performed a Kaplan-Meier analysis with log rank test to evaluate time to remission. One hundred twenty-four patients fulfilled our inclusion criteria: 116 (93.54%) were women with a mean age of 30.23 ± 8.52 years. Twenty-four patients (19.35%), 25 patients (20.16%), and 16 patients (12.9%) achieved complete remission, clinical remission on corticosteroids, and clinical remission off corticosteroids, respectively. SLEDAI-2K at 3rd month of follow-up (HR = 0.85, 95% CI = 0.73–0.98, p = 0.029) and total number of disease flares (HR = 0.73, 95% CI = 0.56–0.95, p = 0.024) were associated with complete remission, and total number of disease flares (HR = 0.80, 95% CI = 0.67–0.95, p = 0.011) was associated with clinical remission on corticosteroids. Our findings are clinically relevant to encourage an intensive immunosuppressive treatment and close monitoring early after active disease.

espanolObjetivo: Se investigo la proporcion de la expresion genica del receptor variable beta de celulas T (Vβ TCR) en linfocitos perifericos CD3+ en pacientes con lupus eritematoso generalizado (LEG) familiar y no familiar. Metodo: El repertorio de Vβ TCR se estudio en 14 familias que presentaban mas de un miembro con LEG. El uso de Vβ TCR en pacientes con LEG (n = 27) se comparo con el de los miembros sanos de estas familias (n = 47), con 37 pacientes con LEG esporadico y con 15 controles sanos. La expresion del repertorio de Vβ TCR se estudio por citometria de flujo multiparametrica utilizando un arreglo de 24 diferentes anticuerpos monoclonales especificos de genes familiares para Vβ TCR. Resultados: Se encontro el mismo perfil de expresion en las comparaciones entre los casos de LEG esporadico y familiar, asi como en los consanguineos sanos de las familias multicasos, que incluia una expresion incrementada de Vβ 5.2, Vβ 11 y Vβ 16, y una menor expresion de Vβ 3, Vβ4, Vβ 7.1 y Vβ 7. De manera interesante, solo Vβ 17 se expreso de modo diferente entre casos familiares y esporadicos de LEG. Igualmente, la expresion incrementada de Vβ 9 fue el distintivo entre los casos de LEG familiar (casos y consanguineos sanos) y los controles sanos. Conclusiones: Estos resultados refuerzan la nocion de que el perfil final del repertorio Vβ TCR observado en LEG familiar y no familiar parece surgir de la interaccion de factores geneticos, ambientales e inmunorreguladores, ademas de que pueden explicar las alteraciones inmunitarias que se observan en los consanguineos sanos de pacientes con LEG. EnglishObjective: We investigated the proportion of Vβ T cell receptor (TCR) gene expression in peripheral CD3+ lymphocytes in familial and non-familial systemic lupus erythematosus (SLE) patients. Method: The Vβ TCR repertoire was studied in 14 families in which several members had SLE. The Vβ TCR usage in SLE patients (n = 27) was compared with that in healthy members of these multiplex families (n = 47), in 37 sporadic SLE patients who had no relatives with SLE, and in 15 healthy unrelated controls. Vβ TCR repertoire expression was studied by multiparameter flow cytometry with the use of an array of 24 different Vβ TCR gene family-specific monoclonal antibodies. Results: We found the same Vβ TCR expression profile in the comparisons between sporadic SLE and familial SLE cases and healthy relatives, which included increased expression of Vβ 5.2, Vβ 11 and Vβ 16, and lower expression of Vβ 3, Vβ 4, Vβ 7.1 and Vβ 17. Interestingly, solely Vβ 17 was differentially expressed among sporadic and familial SLE. Also, increased expression of Vβ 9 was the hallmark among familial SLE (cases and healthy relatives) in comparison to controls. Conclusion: These results highlight the notion that the final profile of the Vβ TCR repertoire seen in familial and non-familial SLE seems to arise from the interaction of genetic, environmental, and immunoregulatory factors. Furthermore, it may contribute to the immunologic abnormalities affecting relatives of SLE patients.

Summary Systemic lupus erythematosus (SLE) patients are susceptible to the development of posterior reversible encephalopathy syndrome (PRES). The main theory concerning the physiopathology of PRES suggests that there is brain–blood barrier damage, which is associated with endothelial dysfunction, and characterized by vasogenic oedema. However, current evidence regarding its physiopathogenic mechanisms is quite scant. The aim of this study was to analyse the expression of different serum cytokines, as well as vascular endothelial growth factor (VEGF) and soluble CD40 ligand (sCD40L), in patients with PRES/systemic lupus erythematosus (SLE) and to compare them with levels in SLE patients without PRES and in healthy controls. We performed a transversal study in a tertiary care centre in México City. We included 32 subjects (healthy controls, n = 6; remission SLE, n = 6; active SLE, n = 6 and PRES/SLE patients, n = 14). PRES was defined as reversible neurological manifestations (seizures, visual abnormalities, acute confusional state), associated with compatible changes by magnetic resonance imaging (MRI). Serum samples were obtained during the first 36 h after the PRES episode and were analysed by cytometric bead array, Luminex multiplex assay or enzyme-linked immunosorbent assay (ELISA). Interleukin (IL)-6 and IL-10 levels were significantly higher in PRES/SLE patients (P = 0·013 and 0·025, respectively) when compared to the other groups. Furthermore, IL-6 and IL-10 levels displayed a positive correlation (r = 0·686, P = 0·007). There were no differences among groups regarding other cytokines, sCD40L or VEGF levels. A differential serum cytokine profile was found in PRES/SLE patients, with increased IL-6 and IL-10 levels. Our findings, which are similar to those described in other neurological manifestations of SLE, support the fact that PRES should be considered among the SLE-associated neuropsychiatric syndromes.

Systemic lupus erythematosus (SLE), a complex and heterogeneous autoimmune disease, represents a significant challenge for both diagnosis and treatment. Patients with SLE in Latin America face special problems that should be considered when therapeutic guidelines are developed. The objective of the study is to develop clinical practice guidelines for Latin American patients with lupus. Two independent teams (rheumatologists with experience in lupus management and methodologists) had an initial meeting in Panama City, Panama, in April 2016. They selected a list of questions for the clinical problems most commonly seen in Latin American patients with SLE. These were addressed with the best available evidence and summarised in a standardised format following the Grading of Recommendations Assessment, Development and Evaluation approach. All preliminary findings were discussed in a second face-to-face meeting in Washington, DC, in November 2016. As a result, nine organ/system sections are presented with the main findings; an 'overarching' treatment approach was added. Special emphasis was made on regional implementation issues. Best pharmacologic options were examined for musculoskeletal, mucocutaneous, kidney, cardiac, pulmonary, neuropsychiatric, haematological manifestations and the antiphospholipid syndrome. The roles of main therapeutic options (ie, glucocorticoids, antimalarials, immunosuppressant agents, therapeutic plasma exchange, belimumab, rituximab, abatacept, low-dose aspirin and anticoagulants) were summarised in each section. In all cases, benefits and harms, certainty of the evidence, values and preferences, feasibility, acceptability and equity issues were considered to produce a recommendation with special focus on ethnic and socioeconomic aspects. Guidelines for Latin American patients with lupus have been developed and could be used in similar settings. Fil: Pons Estel, Bernardo A.. Centro Regional de Enfermedades Autoinmunes y Reumáticas; Argentina Fil: Bonfa, Eloisa. Universidade de Sao Paulo; Brasil Fil: Soriano, Enrique R.. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; Argentina Fil: Cardiel, Mario H.. Centro de Investigación Clínica de Morelia; México Fil: Izcovich, Ariel. Hospital Alemán; Argentina Fil: Popoff, Federico. Hospital Aleman; Argentina Fil: Criniti, Juan M.. Hospital Alemán; Argentina Fil: Vásquez, Gloria. Universidad de Antioquia; Colombia Fil: Massardo, Loreto. Universidad San Sebastián; Chile Fil: Duarte, Margarita. Hospital de Clínicas; Paraguay Fil: Barile Fabris, Leonor A.. Hospital Angeles del Pedregal; México Fil: García, Mercedes A.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina Fil: Amigo, Mary Carmen. Centro Médico Abc; México Fil: Espada, Graciela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina Fil: Catoggio, Luis J.. Hospital Italiano. Instituto Universitario. Escuela de Medicina; Argentina Fil: Sato, Emilia Inoue. Universidade Federal de Sao Paulo; Brasil Fil: Levy, Roger A.. Universidade do Estado de Rio do Janeiro; Brasil Fil: Acevedo Vásquez, Eduardo M.. Universidad Nacional Mayor de San Marcos; Perú Fil: Chacón Díaz, Rosa. Policlínica Méndez Gimón; Venezuela Fil: Galarza Maldonado, Claudio M.. Corporación Médica Monte Sinaí; Ecuador Fil: Iglesias Gamarra, Antonio J.. Universidad Nacional de Colombia; Colombia Fil: Molina, José Fernando. Centro Integral de Reumatología; Colombia Fil: Neira, Oscar. Universidad de Chile; Chile Fil: Silva, Clóvis A.. Universidade de Sao Paulo; Brasil Fil: Vargas Peña, Andrea. Hospital Pasteur Montevideo; Uruguay Fil: Gómez Puerta, José A.. Hospital Clinic Barcelona; España Fil: Scolnik, Marina. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; Argentina Fil: Pons Estel, Guillermo J.. Centro Regional de Enfermedades Autoinmunes y Reumáticas; Argentina. Hospital Provincial de Rosario; Argentina Fil: Ugolini Lopes, Michelle R.. Universidade de Sao Paulo; Brasil Fil: Savio, Verónica. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; Argentina Fil: Drenkard, Cristina. University of Emory; Estados Unidos Fil: Alvarellos, Alejandro J.. Hospital Privado Universitario de Córdoba; Argentina Fil: Ugarte Gil, Manuel F.. Universidad Cientifica del Sur; Perú. Hospital Nacional Guillermo Almenara Irigoyen; Perú Fil: Babini, Alejandra. Instituto Universitario Hospital Italiano de Buenos Aires. Rectorado.; Argentina Fil: Cavalcanti, André. Universidade Federal de Pernambuco; Brasil Fil: Cardoso Linhares, Fernanda Athayde. Hospital Pasteur Montevideo; Uruguay Fil: Haye Salinas, Maria Jezabel. Hospital Privado Universitario de Córdoba; Argentina Fil: Fuentes Silva, Yurilis J.. Universidad de Oriente - Núcleo Bolívar; Venezuela Fil: Montandon De Oliveira E Silva, Ana Carolina. Universidade Federal de Goiás; Brasil Fil: Eraso Garnica, Ruth M.. Universidad de Antioquia; Colombia Fil: Herrera Uribe, Sebastián. Hospital General de Medellin Luz Castro de Gutiérrez; Colombia Fil: Gómez Martín, DIana. Instituto Nacional de la Nutrición Salvador Zubiran; México Fil: Robaina Sevrini, Ricardo. Universidad de la República; Uruguay Fil: Quintana, Rosana M.. Hospital Provincial de Rosario; Argentina. Centro Regional de Enfermedades Autoinmunes y Reumáticas; Argentina Fil: Gordon, Sergio. Hospital Interzonal General de Agudos Dr Oscar Alende. Unidad de Reumatología y Enfermedades Autoinmunes Sistémicas; Argentina Fil: Fragoso Loyo, Hilda. Instituto Nacional de la Nutrición Salvador Zubiran; México Fil: Rosario, Violeta. Hospital Docente Padre Billini; República Dominicana Fil: Saurit, Verónica. Hospital Privado Universitario de Córdoba; Argentina Fil: Appenzeller, Simone. Universidade Estadual de Campinas; Brasil Fil: Dos Reis Neto, Edgard Torres. Universidade Federal de Sao Paulo; Brasil Fil: Cieza, Jorge. Hospital Nacional Edgardo Rebagliati Martins; Perú Fil: González Naranjo, Luis A.. Universidad de Antioquia; Colombia Fil: González Bello, Yelitza C.. Ceibac; México Fil: Collado, María Victoria. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: Sarano, Judith. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: Retamozo, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; Argentina Fil: Sattler, María E.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; Argentina Fil: Gamboa Cárdenas, Rocio V.. Hospital Nacional Guillermo Almenara Irigoyen; Perú Fil: Cairoli, Ernesto. Universidad de la República; Uruguay Fil: Conti, Silvana M.. Hospital Provincial de Rosario; Argentina Fil: Amezcua Guerra, Luis M.. Instituto Nacional de Cardiologia Ignacio Chavez; México Fil: Silveira, Luis H.. Instituto Nacional de Cardiologia Ignacio Chavez; México Fil: Borba, Eduardo F.. Universidade de Sao Paulo; Brasil Fil: Pera, Mariana A.. Hospital Interzonal General de Agudos General San Martín; Argentina Fil: Alba Moreyra, Paula B.. Universidad Nacional de Córdoba. Facultad de Medicina; Argentina Fil: Arturi, Valeria. Hospital Interzonal General de Agudos General San Martín; Argentina Fil: Berbotto, Guillermo A.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; Argentina Fil: Gerling, Cristian. Hospital Interzonal General de Agudos Dr Oscar Alende. Unidad de Reumatología y Enfermedades Autoinmunes Sistémicas; Argentina Fil: Gobbi, Carla Andrea. Universidad Nacional de Córdoba. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Gervasoni, Viviana L.. Hospital Provincial de Rosario; Argentina Fil: Scherbarth, Hugo R.. Hospital Interzonal General de Agudos Dr Oscar Alende. Unidad de Reumatología y Enfermedades Autoinmunes Sistémicas; Argentina Fil: Brenol, João C. Tavares. Hospital de Clinicas de Porto Alegre; Brasil Fil: Cavalcanti, Fernando. Universidade Federal de Pernambuco; Brasil Fil: Costallat, Lilian T. Lavras. Universidade Estadual de Campinas; Brasil Fil: Da Silva, Nilzio A.. Universidade Federal de Goiás; Brasil Fil: Monticielo, Odirlei A.. Hospital de Clinicas de Porto Alegre; Brasil Fil: Seguro, Luciana Parente Costa. Universidade de Sao Paulo; Brasil Fil: Xavier, Ricardo M.. Hospital de Clinicas de Porto Alegre; Brasil Fil: Llanos, Carolina. Universidad Católica de Chile; Chile Fil: Montúfar Guardado, Rubén A.. Instituto Salvadoreño de la Seguridad Social; El Salvador Fil: Garcia De La Torre, Ignacio. Hospital General de Occidente; México Fil: Pineda, Carlos. Instituto Nacional de Rehabilitación; México Fil: Portela Hernández, Margarita. Umae Hospital de Especialidades Centro Medico Nacional Siglo Xxi; México Fil: Danza, Alvaro. Hospital Pasteur Montevideo; Uruguay Fil: Guibert Toledano, Marlene. Medical-surgical Research Center; Cuba Fil: Reyes, Gil Llerena. Medical-surgical Research Center; Cuba Fil: Acosta Colman, Maria Isabel. Hospital de Clínicas; Paraguay Fil: Aquino, Alicia M.. Hospital de Clínicas; Paraguay Fil: Mora Trujillo, Claudia S.. Hospital Nacional Edgardo Rebagliati Martins; Perú Fil: Muñoz Louis, Roberto. Hospital Docente Padre Billini; República Dominicana Fil: García Valladares, Ignacio. Centro de Estudios de Investigación Básica y Clínica; México Fil: Orozco, María Celeste. Instituto de Rehabilitación Psicofísica; Argentina Fil: Burgos, Paula I.. Pontificia Universidad Católica de Chile; Chile Fil: Betancur, Graciela V.. Instituto de Rehabilitación Psicofísica; Argentina Fil: Alarcón, Graciela S.. Universidad Peruana Cayetano Heredia; Perú. University of Alabama at Birmingahm; Estados Unidos

Posterior reversible encephalopathy syndrome (PRES) is a well-known but rare complication in patients (1%) with systemic lupus erythematosus (SLE). However, current epidemiological data are quite scant. The aim of the present study was to describe potentially unrecognised risk factors.We performed a multicentre, retrospective case-control study in Mexico between 1999 and 2014. We included a total of 168 patients who accounted for 77 episodes of PRES, as follows: SLE/PRES, 43 patients with 48 episodes; SLE without PRES, 96 patients; and PRES without SLE, 29 patients. SLE diagnosis was considered when patients fulfilled ≥4 American College of Rheumatology criteria. PRES was defined by reversible neurological manifestations and MRI changes.Patients with SLE/PRES were younger, presented with seizures as the most common manifestation (81%) and 18% had the typical occipital MRI finding. Hypertension (OR=16.3, 95% CI 4.03 to 65.8), renal dysfunction (OR=6.65, 95% CI 1.24 to 35.6), lymphopenia (OR=5.76, 95% CI 1.36 to 24.4), Systemic Lupus Erythematosus Activity Index ≥ 6 points (OR=1.11, 95% CI 1.01 to 1.22) and younger age (OR=0.86, 95% CI 0.81 to 0.91, p0.001) were independent risk factors for development of PRES in SLE. Furthermore, dyslipidemia also characterised the association between PRES and SLE (OR=10.6, 95% CI 1.17 to 96.4).This is the largest reported series of patients with SLE and PRES. We were able to corroborate the known risk factors for of PRES, and found two previously undescribed factors (lymphopenia and dyslipidemia), which suggests that endothelial dysfunction is a key element in PRES pathogenesis in lupus patients.

Summary The role of T cells in idiopathic inflammatory myopathies (IIM) is not yet clear. Some alterations in certain subsets have been reported in inflamed muscle cells. However, a broad quantitative assessment of peripheral T cell subsets has not been evaluated. The aim of this study was to address the quantitative profile of potential pathogenic T cell subsets, namely follicular helper T cells (Tfh), T helper type 17 (Th17), CD28null and regulatory T cells (Tregs) in peripheral blood from IIM patients. Thirty IIM patients and 30 age- and gender-matched healthy donors were included. Peripheral blood mononuclear cells were isolated. T cell subsets were evaluated by flow cytometry, as follows: Tfh (CD4+ CXCR5+) and its subsets Tfh1 (CXCR3+ CCR6−), Tfh2 (CXCR3− CCR6−), Tfh17 (CXCR3− CCR6+), Th17 (CD4+ IL17A+), CD28null (CD4+ CD28− CD244+) and Tregs (CD4+ CD25high forkhead box protein 3 (FoxP3+); CD8+ CD25high FoxP3+). Percentage, absolute numbers and mean fluorescence intensity were analysed. We found increased numbers of total Tfh cells (28 ± 8·16 versus 6·64 ± 1·29, P = 0·031) in IIM patients when compared to healthy controls. Moreover, this increment was dependent upon Tfh2 and Tfh17 (Tfh2:9·49 ± 2·19 versus 1·66 ± 0·46, P = 0·005; Tfh17 9·48 ± 2·83 versus 1·18 ± 0·21, P = 0·014). Also, IIM patients showed higher numbers of Th17 cells (30·25 ± 6·49 versus 13·46 ± 2·95, P = 0·031) as well as decreased number of Tregs (5·98 ± 1·61 versus 30·82 ± 8·38, P = 0·009). We also found an expansion of CD28null cells (162·88 ± 32·29 versus 64 ± 17·35, P = 0·015). Our data suggest that IIM patients are characterized by an expansion of peripheral proinflammatory T cells, such as Tfh and Th17, as well as pro-apoptotic CD28 null cells and a deficiency of suppressor populations of Tregs (CD4+ and CD8+).

To assess if ubiquitinated proteins potentially present in neutrophil extracellular traps (NETs) can modify cellular responses and induce inflammatory mechanisms in patients with systemic lupus erythematosus (SLE) and healthy subjects.We studied 74 subjects with SLE and 77 healthy controls. Neutrophils and low-density granulocytes were isolated, and NETs were induced. Ubiquitin content was quantified in NETs by western blot analysis, ELISA and immunofluorescence microscopy, while ubiquitination of NET proteins was assessed by immunoprecipitation. Monocyte-derived macrophages from SLE and controls were isolated and stimulated with NETs or ubiquitin. Calcium flux and cytokine synthesis were measured following these stimuli.NETs contain ubiquitinated proteins, with a lower expression of polyubiquitinated proteins in subjects with SLE than in controls. Myeloperoxidase (MPO) is present in ubiquitinated form in NETs. Patients with SLE develop antiubiquitinated MPO antibodies, and titres positively correlate with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score (P0.01), and negatively correlate with complement components (P0.01). Stimulation of monocyte-derived macrophages with NETs or with ubiquitin led to enhanced calcium flux. In addition, stimulation with NETs led to enhanced cytokine (tumour necrosis factor-α and interleukin-10) production in macrophages from patients with SLE when compared with controls, which was hampered by inhibition of NET internalisation by macrophages.This is the first study to find ubiquitinated proteins in NETs, and evidence for adaptive immune responses directed towards ubiquitinated NET proteins in SLE. The distinct differences in ubiquitin species profile in NETs compared with healthy controls may contribute to dampened anti-inflammatory responses observed in SLE. These results also support a role for extracellular ubiquitin in inflammation in SLE.

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). At our Institution, patients transplanted using G-CSF-primed bone marrow (G-BM), have a lower incidence of GVHD when compared to other sources. The objective of this study was to analyze and compare T cell subsets and cytokines in donor G-BM and steady-state BM (SS-BM). A prospective study was performed in 48 donor samples. Mononuclear cells were isolated by gradient density. T cell subsets and cytokine production in supernatants were analyzed by multiparametric flow cytometry. Six and 16 patients developed acute and chronic GVHD, respectively. Patients who developed GVHD were characterized by a predominant pro-inflammatory response (IL-17A (10.02 vs 0.43pg/mL, p=0.006), TNF-α (54.57 vs 0.81pg/mL, p=0.001)), in contrast to a deficient suppressor profile (IL-10 (7.87 vs 41.37pg/mL, p=0.003)) and Tregs (0.95% vs 1.52%, p=0.004). G-BM showed an enhanced suppressive phenotype (increased Th2 and Tregs) in comparison to SS-BM. GVHD is associated with an imbalance between pro-inflammatory and suppressor immune responses. G-BM showed a more favorable immunologic profile characterized by diminished pro-inflammatory cytokine production, which was associated with a lower frequency of GVHD in our cohort.

Background and aims Although SLE has a higher prevalence in women, the disease usually has a more aggressive course in men. Therefore, the aim of this study was to describe the prevalence of erectile dysfunction (ED), as well as associated demographic and clinical features in men with SLE, by means of a systematic, standardised evaluation. Methods We performed a transversal study in six tertiary care centres in Latin America. We included male patients≥16 years who fulfilled ≥4 ACR criteria for SLE, and had regular sexual activity in ≤6 months. Patients with other rheumatic diseases (except for APS), chronic viral infections and late-onset SLE were excluded. All patients answered the IIEF-5 Questionnaire, which has been validated in Spanish. Other relevant demographic, clinical and serological characteristics were documented. Results We included 157 subjects. The prevalence of ED in our study population was 68%, the majority were classified as mild to moderate (17.3±0.36 points; normal score: 22–25 points). The mean age of patients with ED was 35.3±1, while in patients without ED it was 32.9±1.3 (p=0.17). The only significant differences were regarding corticosteroid usage in the past year; the rest of the demographic and clinical variables were similar between both groups. (Table 1). After multivariate analysis, independent risk factors for ED were: persistent lymphopenia, age and corticosteroid use in the past year (Table 2). Conclusions Regardless of comorbidities, medication (excluding corticosteroids) and disease duration, SLE patients, who are mostly young and sexually active, have a high ED prevalence.

Summary The presence of anti-Ro52/tripartite motif 21 (Trim21) autoantibodies has been associated with a distinctive clinical profile and has gained value as a prognostic marker in idiopathic inflammatory myopathies (IIM). The aim of the present work was to analyse Ro52/Trim21 expression in different subsets of peripheral blood mononuclear cells (PBMCs) of patients with IIM, as well as the ubiquitination profile and its association with proinflammatory cytokine production. We included 18 patients with recent-onset IIM and 18 age- and gender-matched healthy donors. PBMCs were isolated and different subsets (CD4+, CD8+, CD14+) were purified by magnetic selection. The expression of Ro52/Trim21 in different PBMC subsets of patients with IIM and healthy donors was analysed by Western blot. We assessed the presence of myositis-specific and associated autoantibodies by enzyme-linked immunosorbent assay (ELISA). Cytokine levels were measured by cytometric bead array. Patients with IIM showed decreased protein expression of Ro52/Trim21 in comparison to healthy controls in PBMC (0·97 ± 0·60 versus 1·84 ± 0·92, P = 0·016), CD4+ lymphocytes (0·79 ± 0·54 versus 2·41 ± 0·78, P = 0·017), and monocytes (0·87 ± 0·35 versus 1·89 ± 0·20, P

Key Clinical Message The scenario of a renal transplant recipient who is diagnosed with HIV infection in the late post transplant period is very uncommon. The viral infection effect on immunologic stability, regulatory cells, and allogeneic response during immune quiescence and graft acceptance provides a fertile ground in organ transplantation research and translational immunology.

Cytotoxic T-Lymphocye Antigen 4 (CTLA-4) or CD152 is an inhibitory molecule that plays a critical role in maintenance of tolerance to self-antigens. CTLA-4 is structurally as well as functionally related to CD28, since it shares 31% of homology and binds the B7 family molecules CD80 and CD86 with higher affinity. Nevertheless, CTLA-4 has opposing effects on T cell activation and current evidence shows that its inhibitory role goes beyond the ligand-binding interaction. CTLA-4 competes with CD28 in binding to B7, interacts within the immunological synapsis elements and with clathrin adaptor proteins and tyrosine phosphatases through its cytoplasmic domain to regulate cell trafficking and to set the activation threshold within T cells. Moreover, we have learned from the knock out model that CTLA-4 plays a key role in regulatory T cells and in central tolerance. Because of its importance in maintenance of peripheral tolerance, CTLA-4 has been implicated in several autoimmune diseases, such as systemic lupus erythematosus. Multiple single-nucleotide polymorphisms have been located to human Ctla-4 gene, and their association with autoimmune disease is still a matter of controversy. Despite the promising results of abatacept or CTLA-4-Ig in rheumatoid arthritis and murine lupus nephritis, more clinical randomized trials and standardization of outcomes are needed to prove its efficacy and safety in human lupus nephritis.

Dendritic cells (DCs) play an important role in inducing immune tolerance. Inhibitory receptors, such as ILT2/CD85j, are involved in the tolerogenic effect of DCs and previous studies have indicated the important role of these receptors on the pathogenesis of autoimmune diseases. The aim of this study was to evaluate the expression and function of ILT2 in DCs from SLE patients. Peripheral blood from fifty patients with SLE and 38 healthy volunteers was obtained. ILT2 expression was assessed by flow cytometry. DCs were generated in the absence or presence of an anti-ILT2 antibody. The effect of ILT2 in the immunogenic ability of SLE DCs was also evaluated. We observed that SLE patients had significant higher levels of circulating plasmacytoid DCs (pDCs), and that these levels correlated with disease activity. In contrast, the expression of ILT2 was diminished in both pDCs and myeloid DCs (mDCs) from these patients. However, under our experimental conditions, the in vitro differentiation of DCs was not apparently affected by ILT2 engagement. In contrast, the immunogenic capability of monocyte-derived DCs was not down-regulated by ILT2 cross-linking in a significant proportion of SLE patients. Our results suggest that ILT2 participates in the defective immune-regulation observed in patients with SLE.

Objective To analyze whether the expression and modulation of T cell receptor (TCR) signaling is dependent on Casitas B lineage lymphoma b (Cbl-b) in T cells from patients with systemic lupus erythematosus (SLE) upon stimulation with a tolerogenic substance. Methods Peripheral blood mononuclear cells were obtained from 20 patients with SLE (active disease or in remission) and 20 healthy controls. Levels of Cbl-b expression were measured using reverse transcription–polymerase chain reaction and Western blotting in peripheral CD4+ T cells from SLE patients and healthy controls upon anergy induction. Cell proliferation was measured using the carboxyfluorescein diacetate succinimidyl ester dilution method. Cytokine production was analyzed by luminometry, and surface expression of activation markers was assessed by flow cytometry. Transfection assays were performed to induce overexpression of Cbl-b, and phosphorylation of TCR-associated kinases was evaluated. Results CD4+ T cells from SLE patients displayed resistance to anergy (as evidenced by increased cell proliferation, interleukin-2 production, and expression of activation and costimulatory markers), and this was associated with altered Cbl-b expression. Upon ionomycin treatment, primary T cells showed enhanced MAPK activity and decreased Akt phosphorylation, which was representative of the anergic state. In T cells from lupus patients, Cbl-b overexpression led to increased expression of phosphorylated MAPK, thus indicating the reversibility of anergy resistance. Conclusion These findings suggest that abnormal peripheral tolerance in SLE is caused by a deficiency in Cbl-b, and that this ubiquitin ligase plays a key role in regulating TCR signaling during the induction of peripheral tolerance.

Systemic lupus erythematosus (SLE) is a chronic, multiorgan inflammatory autoimmune disorder associated with high levels of circulating autoantibodies and immune complexes. We report that passive transfer of human SLE sera into mice expressing the uniquely human FcγRIIA and FcγRIIIB on neutrophils induces lupus nephritis and in some cases arthritis only when the mice additionally lack the CD18 integrin, Mac-1. The prevailing view is that Mac-1 on macrophages is responsible for immune complex clearance. However, disease permitted by the absence of Mac-1 is not related to enhanced renal immune complex deposition or in situ C1q/C3 complement activation and proceeds even in the absence of macrophages. Instead, disease is associated with increased FcγRIIA-induced neutrophil accumulation that is enabled by Mac-1 deficiency. Intravital microscopy in the cremasteric vasculature reveals that Mac-1 mitigates FcγRIIA-dependent neutrophil recruitment in response to deposited immune complexes. Our results provide direct evidence that human SLE immune complexes are pathogenic, demonstrate that neutrophils are primary mediators of end organ damage in a novel humanized lupus mouse model, and identify Mac-1 regulation of FcγRIIA-mediated neutrophil recruitment as a key step in development of target organ damage.