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The number of kidney transplant recipients has grown incrementally over the years. These patients have a high comorbidity index and require special attention to immunosuppression management. In addition, this population has an increased risk for cardiovascular events, electrolyte abnormalities, allograft dysfunction, and infectious complications. It is vital for hospitalists and internists to understand the risks and nuances in the care of this increasingly prevalent, but also high-risk, population.

As the severe acute respiratory syndrome coronavirus 2 pandemic evolved and became a global health threat, the safety of immunosuppression in antineutrophil cytoplasmic antibody-associated vasculitis (AAV) became of utmost important for clinicians and patients. Although timely initiation of immunosuppressive therapy is critical to quell the acute inflammation and prevent AAV-associated mortality and morbidity, concerns for increased susceptibility to Coronavirus Disease 2019 (COVID-19), delayed viral clearance, and decreased humoral response to infection led to speculation about modification in induction therapy practices may be deployed by physicians caring for patients with AAV. This international retrospective cohort study investigated the influence of the COVID-19 pandemic on AAV induction therapy and patient outcomes in different parts of the world by studying differences in treatment regimens in the United States, United Kingdom, and Europe.

It has been recognized that T cells have a pathogenic role in anti-neutrophil cytoplasmic antibody- (ANCA) associated vasculitis, in addition to being dominant cells in the interstitium in ANCA glomerulonephritis (GN). Given there are differences in renal outcomes based on ANCA type, we sought to characterize the interstitial infiltrate in ANCA GN to determine differences in relation to ANCA type and renal function. Immunohistochemistry stains for CD3, CD4, CD20, C4d and FOXP3 were done in renal biopsies of patients with ANCA GN. Light microscopy was used to determine the percentage of cortical interstitium containing positive cells. Demographics, ANCA type and entry eGFR were recorded. The level of staining was compared between ANCA type and entry eGFR using Wilcoxon rank-sum test. Renal biopsies of 16 patients with MPO and 14 with PR3 ANCA GN were studied. CD3 cells were the predominant cells, with all biopsies staining positive for CD4 and FOXP3. C4d staining was negative in all biopsies, with no significant difference in staining between MPO and PR3 groups for any of the identified cell types. However, regardless of ANCA type, FOXP3 staining was significantly higher in patients with baseline GFR 10 mL/min/1.73 m2(mean 7.54, SD 6.6 versus mean 2.67, SD 3.6; p = 0.04). These data confirm the role of T cells in ANCA GN and demonstrate no differences in interstitial T and B cell infiltrates between PR3 and MPO ANCA GN. Higher FOXP3 signal associates with lower renal function, suggesting a role for regulatory T cells. Further characterization of this T cell subset should be explored in future studies.

Renal biopsy is currently the gold standard for diagnosing active renal vasculitis. In this pilot study, metabolomics analysis was used to investigate the differences in metabolic profiles between paired patients’ serum and urine samples collected during both the active and the remission phase of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). Ten patients with AAV renal disease were included. Mean age was 61 years, with 6 patients each being male and Caucasian. Mean Birmingham Vasculitis Activity Score (BVAS) and mean glomerular filtration rate (GFR) were 17 and 28, respectively. We found that while the citric acid cycle intermediates citrate, iso-citrate and oxaloacetate had lower intensities in the active phase samples as compared to the remission phase samples. The intensities of other metabolites of carbohydrate metabolism, amino acid metabolism, and nucleotide synthesis were significantly higher in the active phase samples, indicating the upregulation of these pathways for the production of energy and other biomolecules such as proteins and nucleic acids during the active phase of AAV. This pilot study suggests that serum and urinary metabolomic profiling may be useful to monitor disease activity in renal AAV.

Kidney involvement is common in patients with systemic lupus erythematosus (SLE). This study investigates the clinical and prognostic characteristics of thrombotic microangiopathy (TMA) compared to class IV lupus nephritis in SLE patients. A retrospective review of patients who underwent kidney biopsy, with a primary diagnosis of SLE and TMA between June 2006 and September 2018 was conducted. Those patients were subsequently compared to patients with class IV lupus nephritis between January 2018 and December 2018. Demographics, laboratory, and serological data at the time of biopsy were abstracted. Among 214 SLE patients records screened, 27 were included in the final analysis. Eight patients had lupus-related TMA without evidence of active lupus nephritis, while 19 patients had class IV lupus nephritis without evidence of TMA. TMA patients had significantly higher lactate dehydrogenase levels (718 ± 499 vs. 264 ± 107.7 U/L, p = 0.009), serum C3 (100.6 ± 39.3 vs. 65.8 ± 27 mg/dL, p = 0.049), white blood cell count (14743.8 ± 7933.3 vs. 5807.9 ± 2053.2 × 10E3/uL, p

Background: Dyspnea is a common symptom in patients with end-stage kidney disease being treated with dialysis. This study aimed to ascertain the level of respiratory disability in patients after kidney transplantation through assessing a cohort of kidney allograft recipients for respiratory compromise and thereby identifying a potential target for therapeutic intervention. Methods: Kidney transplant recipients who were under active observation in a single tertiary referral center were invited to take part in this prevalence study at the time of clinic follow-up. All patients agreed to take part in the study, which involved completing a Medical Research Council (MRC) dyspnea scale, completing the St George's Respiratory Questionnaire, and performing basic spirometry. An MRC score of ≥2 and/or a forced expiratory volume in 1 second

The management of immunosuppression utilized in glomerular diseases requires highly nuanced care. Timely recognition and management of these disorders is essential to mitigate the extent of kidney damage. This involves being cognizant of the various classes of immunosuppression, which includes alkylating agents, antimetabolites, calcineurin inhibitors, anti-CD20 therapy, complement inhibitors, corticosteroids, and intravenous immunoglobulin. The mechanisms of action of these drugs, along with associated pharmacokinetics and pharmacodynamics, facets of monitoring, and adverse effects are important aspects with which nephrologists are required to be well versed. In addition, an understanding of therapeutic decisions such as induction and maintenance regimens in the setting of glomerular disease and alteration based on trajectory of disease and subsequent response is imperative. The overarching principle of these strategies of immunosuppression is to achieve a balance of disease mitigation without exposure to inadvertent harm. Special groups such as pregnant women, elderly patients, and patients treated with dialysis are especially susceptible to immunosuppression and thus need highly weighed therapeutic strategies and enhanced surveillance of adverse effects.

SARS-CoV-2 vaccination elicited high levels of immunogenicity in immunocompetent people in the original vaccine trials1 2 though recent studies have shown blunted immunogenicity in patients with rheumatic diseases treated with lymphocyte depleting agents.3 4 B-lymphocytes have been implicated in the pathogenesis of anti-neutrophil cytoplasmic antibidy (ANCA)-associated vasculitis (AAV) and B-cell-targeted therapy with rituximab is recognised as an established induction and maintenance strategy in management.5 6 SARS-CoV-2 infection in patients with AAV has been associated with severe outcomes,7 while rituximab has been associated with worse outcomes among patients infected with SARS-CoV-2.8 9 A recent study by Bonelli et al found evidence of an ameliorated humoral response but possible inducible cellular response in five patients treated with rituximab.10 We studied the tolerability and humoral response to the SARS-CoV-2 vaccine series in 48 patients with a diagnosis of AAV. Patients underwent SARS-CoV-2 antispike antibody testing to assess humoral response. Antibody testing was performed using antispike IgG enzyme immunoassay (Roche Elecsys via Quest, DiaSorin Liaison assay via LabCorp or Euroimmun via Hopkins lab). Demographics, clinical information including immunosuppressive therapy were extracted from medical records. Time from last rituximab administration to receipt of the first dose of the vaccine was recorded. We recorded serum creatinine, white blood cell count, serum immunoglobulins, Cluster of CD19 and …

Angiotensin converting-enzyme (ACE) inhibitors are commonly prescribed drugs with multiple indications including congestive heart failure, hypertension, and diabetic nephropathy. ACE inhibitor induced angioedema is commonly seen across emergency departments and clinics, with transient swelling of lips, tongue, and other facial structures being the common presentation. Isolated airway obstruction as a result of pharyngeal and laryngeal swelling without facial swelling is a rare presentation. We present a case of a patient on lisinopril therapy for one year who experienced severe airway compromise without the classic symptoms of ACE inhibitor induced angioedema. He required emergent cricothyroidotomy to secure his airway, as fiberoptic laryngoscopy showed 90% obstruction and inability to visualize true vocal cords. His ACE inhibitor therapy was discontinued, and he was discharged home within a few days with no residual symptoms.

Background: The introduction of combination therapy with glucocorticoids (GC) and cyclophosphamide (CYC) or rituximab (RTX) has resulted in remission rates exceeding 90% in patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). However, early treatment-related mortality remains a major concern and has driven the search for safer induction regimens exploring minimization or avoidance of GC and CYC. Most trials have excluded patients with severe renal disease. We report the outcomes of AAV patients with severe renal disease treated with sequential therapy (ST) starting with (GC) and oral (CYC) followed by transition to (RTX). Methods: Patients with new or relapsing severe AAV who presented with severe renal disease and/or rapidly progressive glomerulonephritis (RPGN) were identified. RPGN was defined as at least a 20% decrease in estimated glomerular filtration rate (eGFR) over a 2-week period along with hematuria and proteinuria. Induction treatment included pulse (GC) for 3 days followed by oral prednisone tapered to 5 mg by month 6, oral (CYC) adjusted for GFR until improvement in Birmingham Vasculitis Activity Score (BVAS), and serum creatinine at which point (CYC) was stopped and induction dose of (RTX) was given. Use of plasmapheresis (PLEX) was allowed. The primary outcome was complete remission defined as BVAS of zero by 6 months. Descriptive data are presented as median with range and mean with SD. Results: Nine patients met the inclusion criteria. Median age at diagnosis was 63 years. The majority were females, myeloperoxidase ANCA positive, and had a new diagnosis. The mean nadir (SD) eGFR was 12 (5) with 3 requiring dialysis. The median BVAS at the time of diagnosis was 15. All patients received ST and 3 received PLEX. The median exposure to oral CYC was 35 days. The mean (SD) eGFR and median BVAS were 26 (12) and 3, respectively, at the time of switching to RTX. The median prednisone dose at 6M was 5 mg. The median follow-up was 44 months. All patients achieved remission. One patient with relapsing disease reached ESRD. The mean (SD) eGFR in the remaining 8 patients at last FU was 37 (27), and the mean (SD) eGFR rise at 1 year was 26 (25). Adverse events included 2 patients with pneumonia and 3 with bone marrow suppression. There were no deaths. Conclusion: ST with GC and CYC followed by RTX is effective for in AAV patients with severe renal disease. Therapy-related adverse events are comparable to other studies, and further modification in ST with decrease in GC dosage should be explored.

Aims Overlap syndrome of ANCA-associated vasculitis (AAV) and scleroderma (SSc) is rare with conflicting data on renal outcomes. We describe the clinical characteristics and treatment outcome of ANCA-associated glomerulonephritis (AAG) in SSc patients followed at a single center. Materials and methods We conducted a retrospective study of 3,570 patients in our SSc database to identify SSc patients who subsequently developed AAV with renal involvement. Patient demographics, serology, renal function, renal histology, and treatment outcomes were assessed. Results Of the 3,570 patients, we identified 7 patients who developed acute glomerulonephritis, and all were ANCA positive. The mean age at SSc diagnosis was 47 years, 4 patients were female, and 6 had diffuse SSc. Anti-nuclear antibody (ANA) was positive in all. Mean time of onset of AAV from time of diagnosis of SSc was 6 years, and all were myeloperoxidase (MPO) positive. Patients presented with hematuria, proteinuria, with or without rise in serum creatinine, and all patients had biopsy-proven crescentic glomerulonephritis. One patient required dialysis at presentation. Five patients were treated with cyclophosphamide and steroids, and 2 were treated with rituximab and steroids. Of the 7 patients, 4 did not receive maintenance immunosuppression. Three patients died, and 1 of them experienced relapse with fulminant alveolar hemorrhage. Conclusion AAG in SSc is rare, with disease manifestation and course similar to that of AAV. This case series demonstrates that disease remission can be achieved with standard induction therapy. Vasculitis relapse can occur, and similar to idiopathic AAV, maintenance immunosuppression should be initiated to maintain remission. .

Scleroderma Renal Crisis (SRC) is the most common cause of Acute Kidney Injury (AKI) in scleroderma and occurs early during the disease course while ANCA Associated Vasculitis (AAV) is a rare cause of acute kidney injury occurring late in the disease course. We report a case of AKI with positive PR3 ANCA serology late in the disease course with a renal biopsy revealing findings of SRC.

There continues to be rapid advancement in our understanding of the pathogenesis of immune-mediated kidney disease. This progress has culminated in the development of multiple therapeutic agents that have consistently improved renal and patient outcomes. The focus of this review is to discuss these recent advancements in immune-mediated kidney disease via the lens of direct and indirect immune-mediated mechanisms. In the direct immune-mediated disease, recently described antigens in anti-glomerular basement membrane (GBM) disease and membranous nephropathy are discussed, along with new therapeutic regimens in membranous nephropathy and focal segmental glomerulosclerosis. From an indirect immune-mediated disease standpoint, recent pivotal trials in antineutrophil cytoplasmic antibody vasculitis, lupus nephritis, and IgA nephropathy are examined from a real-world practice perspective. New molecular pathways in various disorders of alternate complement pathway are described, which in turn have led to development of various experimental therapies. In addition, pivotal and ongoing therapeutic trials in the aforementioned diseases are presented.

Renal biopsy is currently the gold standard for diagnosing active renal vasculitis. In this pilot study, metabolomics analysis was used to investigate the differences in metabolic profiles between paired patients' serum and urine samples collected during both the active and the remission phase of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). Ten patients with AAV renal disease were included. Mean age was 61 years, with 6 patients each being male and Caucasian. Mean Birmingham Vasculitis Activity Score (BVAS) and mean glomerular filtration rate (GFR) were 17 and 28, respectively. We found that while the citric acid cycle intermediates citrate, iso-citrate and oxaloacetate had lower intensities in the active phase samples as compared to the remission phase samples. The intensities of other metabolites of carbohydrate metabolism, amino acid metabolism, and nucleotide synthesis were significantly higher in the active phase samples, indicating the upregulation of these pathways for the production of energy and other biomolecules such as proteins and nucleic acids during the active phase of AAV. This pilot study suggests that serum and urinary metabolomic profiling may be useful to monitor disease activity in renal AAV.

Introduction The coronavirus 2019 (COVID-19) pandemic has brought on challenges not only to acute care, but also chronic care of patients. Individuals maintained on immunosuppression appear to be especially susceptible to COVID-19 infection. Patients with ANCA-associated vasculitis (AAV) frequently require immunosuppression and may be at increased risk for developing COVID-19. The incidence and impact of COVID-19 on patients with AAV is currently not known. We aimed to investigate this impact via a telephone questionnaire-based patient survey and chart review. Methods A cross-sectional study of AAV patients followed at two centers was conducted. Data regarding demographics, disease characteristics and therapy were confirmed by chart review. A telephone survey was conducted to ascertain symptoms and contact exposure related to COVID-19, as well as changes in health care delivery during the pandemic period between January and July, 2020. Results Of the 206 patients surveyed, the median age was 64 years, 51% were female and mean (SD) disease duration was 7 (5) years. The majority had kidney (n = 160) and lung (n = 108) involvement. Seventy-five percent (n = 155) were receiving immunosuppression, with 77 patients (50%) receiving rituximab during the pandemic period. Of the 10 patients tested for severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) by PCR, three were positive. Patients had a significant disruption in care; none had an in-person visit and 69% had a telemedicine consultation. Rituximab maintenance was postponed in 21 patients. Twelve patients experienced disease relapse. Conclusion The incidence of COVID-19 in patients with AAV appears to be similar to that of the general population. For a patient population that requires active clinical surveillance, there is significant disruption in care as a result of the pandemic. Reduction of immunosuppression may not be indicated, and the risk of relapse likely far outweighs the risk of COVID-19. Electronic supplementary material The online version of this article (10.1007/s40620-020-00881-3) contains supplementary material, which is available to authorized users.

Background: Kidney disease associated with cancer and anti-cancer therapies has been increasingly recognized in the field of onco-nephrology. In particular, drug-induced nephrotoxicity has important implications since most chemotherapeutic agents have a nephrotoxic potential. Also, standard creatinine clearance methods used for the measurement of kidney function have been questioned in cancer patients due to factors like low muscle mass and poor nutritional status. Overestimations of the glomerular filtration rate, not only can increase the nephrotoxic potential of different agents, but also further limit the use of first-line therapies. Objective: This review covers specifically the drug-induced thrombotic microangiopathy and its two pathophysiologic mechanisms which include immune or idiosyncratic reactions, and non-immune or dose-dependent ones. Conclusion: As novel cancer therapies are developed, it is paramount to pursue a better understanding of conventional and novel chemotherapeutic agents and their role in kidney disease.

The pandemic of coronavirus disease 2019 (CoVID-19) has been an unprecedented period. The disease afflicts multiple organ systems, with acute kidney injury (AKI) a major complication in seriously ill patients. The incidence of AKI in patients with CoVID-19 is variable across numerous international studies, but the high incidence of AKI and its associated worse outcomes in the critical care setting are a consistent finding. A multitude of patterns and mechanisms of AKI have been elucidated, and novel strategies to address shortage of renal replacement therapy equipment have been implemented. The disease also has had consequences on longitudinal management of patients with chronic kidney disease and end stage kidney disease. Kidney transplant recipients may be especially susceptible to CoVID-19 as a result of immunosuppression, with preliminary studies demonstrating high mortality rates. Increased surveillance of disease with low threshold for testing and adjustment of immunosuppression regimen during acute periods of illness have been recommended.

Background Atypical hemolytic uremic syndrome (aHUS) can result in severe kidney dysfunction, secondary to thrombotic microangiopathy. Eculizumab has been used to treat this disorder, and has resulted in favourable outcomes in both, native and transplanted kidneys. There is limited long term follow up data in kidney transplant recipients (KTRs) who received prevention and treatment with Eculizumab. We report our long term follow up data from our center to address safety and efficacy of this therapy in KTRs. Methods We performed a retrospective analysis of KTRs between January 2009 and December 2018. Clinical diagnosis of aHUS established with presence of thrombotic microangiopathy, acute kidney injury, absence of alternate identifiable etiology. We reviewed clinical data, including genetic testing for complement factor mutations, post-transplant course, and response to therapy including therapeutic and prophylactic use of eculizumab. Results Nineteen patients with aHUS received a total of 36 kidney transplants; 10 of them had 2 or more prior kidney transplants. Median age at time of last transplant was 37 years (range 27–59), 72% were female (n = 14), 78% Caucasian (n = 15), with 61% had live donor transplant (n = 12) as the last transplant. Eculizumab prophylaxis was given to 10/19 (56%) at the time of transplantation, with no aHUS recurrence during the follow up. Median duration of follow up was 46 (range 6–237) months. Mean estimated glomerular filtration rate (eGFR) at the time of last follow up was 59.5 ml/min/m2. No infections secondary to encapsulated organisms or other major infectious complications occurred during the follow up. Conclusions Eculizumab prophylaxis is safe and effective in KTRs with aHUS. Long term follow up demonstrates that it may be possible to discontinue prophylaxis carefully in selected patients with no evidence of complement mutations.

BACKGROUNDPreclinical experiments have shown that donor blood cells, modified in vitro by an alkylating agent (modified immune cells [MICs]), induced long-term specific immunosuppression against the allogeneic donor.METHODSIn this phase I trial, patients received either 1.5 × 106 MICs per kg BW on day -2 (n = 3, group A), or 1.5 × 108 MICs per kg BW on day -2 (n = 3, group B) or day -7 (n = 4, group C) before living donor kidney transplantation in addition to post-transplantation immunosuppression. The primary outcome measure was the frequency of adverse events (AEs) until day 30 (study phase) with follow-up out to day 360.RESULTSMIC infusions were extremely well tolerated. During the study phase, 10 treated patients experienced a total of 69 AEs that were unlikely to be related or not related to MIC infusion. No donor-specific human leukocyte antigen Abs or rejection episodes were noted, even though the patients received up to 1.3 × 1010 donor mononuclear cells before transplantation. Group C patients with low immunosuppression during follow-up showed no in vitro reactivity against stimulatory donor blood cells on day 360, whereas reactivity against third-party cells was still preserved. Frequencies of CD19+CD24hiCD38hi transitional B lymphocytes (Bregs) increased from a median of 6% before MIC infusion to 20% on day 180, which was 19- and 68-fold higher, respectively, than in 2 independent cohorts of transplanted controls. The majority of Bregs produced the immunosuppressive cytokine IL-10. MIC-treated patients showed the Immune Tolerance Network operational tolerance signature.CONCLUSIONMIC administration was safe and could be a future tool for the targeted induction of tolerogenic Bregs.TRIAL REGISTRATIONEudraCT number: 2014-002086-30; ClinicalTrials.gov identifier: NCT02560220.FUNDINGFederal Ministry for Economic Affairs and Technology, Berlin, Germany, and TolerogenixX GmbH, Heidelberg, Germany.

Levamisole is an antihelminth drug and a common cocaine contaminant, present in an estimated 71% of cocaine samples in the US. Levamisole-contaminated cocaine has been linked to an ANCA-associated vasculitis with cutaneous, renal, and pulmonary manifestations. We report the case of a 46 year old woman with known cocaine exposure who presents with recurrent, large purpuric and maculopapular rash of the extremities and face and review existing cases of levamisole/cocaine-associated ANCA vasculitis, We summarize the clinical presentation, treatment, and outcomes of levamisole induced vasculitis. There is emerging research on pathogenesis relating to neutrophil extracellular traps (NETs). We review studies implicating role of NETs in the pathogenesis of levamisole induced vasculitis. Further research to explore the use of NETs as therapeutic targets in drug induced vasculitis is needed.

Objectives Intravenous immunoglobulin G (IVIG) is used to treat antineutrophil cytoplasmic antibody (ANCA) patients with recurrent infections as a result of hypogammaglobulinemia (HG) induced by treatment regimens. We sought to characterize clinical features, treatment, and outcomes for patients treated with the novel subcutaneous IgG (SCIG) for the aforementioned purpose. Methods We conducted a retrospective study of 136 patients in our ANCA database to identify patients with recurrent infections and HG subsequently treated with SCIG. Patient demographics, serologies, treatment, and immunological parameters were assessed. Results Of 136 patients, four were treated with SCIG. All were Caucasian, proteinase-3 (PR3)-positive, and the majority (n = 3) were females. All patients had pulmonary involvement, and regimens of cyclophosphamide (CYC) and/or rituximab (RTX) were employed for induction and remission. Three patients each experienced recurrent bouts of respiratory tract infections and shingles. Ig levels (G, M, and A) were reduced in all patients, except for one patient who had normal IgA levels. CD19/20 cells were depleted and CD3/4/8/NK cells were preserved in all patients. Three patients had no discernible antibody response to the pneumococcal vaccine (specific pneumococcal serotypes measured pre- and post-vaccine). The mean duration elapsed between the first rituximab administration and commencement of SCIG was 7.2 years. The IgG level normalized and none of the patients had a recurrence of infection since the initiation of SCIG. Conclusion This data, albeit preliminary, is the first series that demonstrates SCIG can be a reliable alternative to IVIG in ANCA patients with recurrent infections secondary to HG. Early identification of this subset of patients is likely to mitigate infectious risks, associated morbidity, and hospitalization.

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) has the propensity to acquire a devastating disease course. Despite the advances in therapeutics, a significant proportion of patients progress to end-stage renal disease (ESRD). Renal transplantation is being increasingly employed in this population, with gradual improvement in outcomes over the years, however, recurrence of disease requires constant surveillance and is associated with graft failure. Areas covered: A structured literature search in PubMed and Medline and abstracts of international conferences was performed to identify cases and cohorts of AAV patients who had undergone renal transplantation for ESRD. The primary objective was to describe the long-term allograft and patient survival and to reflect on current trends in transplantation in AAV and provide recommendations for the phases of pre- and post-transplantation. Expert commentary: Renal transplantation is the treatment of choice for AAV patients with ESRD. The risk of relapse is low with modern immunosuppressive regimes employing mycophenolate mofetil and tacrolimus. It is recommended that the vasculitis be in clinical remission for 12 months prior to transplantation. Although ANCA positivity is not a contraindication for renal transplantation, these patients should be monitored closely for vasculitis relapse post-transplant.

ANCA-associated vasculitis (AAV) can present in an atypical manner and obscure the clinical picture. We sought to characterize clinical characteristics and outcomes in these uncommon presentations. We conducted a retrospective study of 171 AAV patients in our vasculitis database to identify patients with atypical presentation of AAV. Patient demographics, serologies, renal indices, and treatment regimens were assessed. Of the 171 patients, eight were identified to have uncommon presentations. These patients were usually extremes of age with three being less than 30 years and four being more than 70 years. Six patients were positive for PR3 antibodies. The mean delay in diagnosis from time of symptom development was 12 months. All patients developed acute kidney injury during their clinical course. Pancreatitis was the most frequent atypical presentation (n = 3), with pulmonary pathologies (cystic lung disease and usual interstitial pneumonia) and splenic infarcts being present in two patients each. The diagnosis of AAV was established by positive ANCA serology and renal or lung biopsy evidence of vasculitis. Six patients received induction therapy with steroids and rituximab, while two received steroids and cyclophosphamide. One patient died of respiratory failure in the first month following diagnosis while the remaining patients achieved disease remission. One patient developed end-stage renal disease. Uncommon presentations of AAV afflict extremes of age with a PR3 ANCA predominance and are associated with subsequent development of AKI. This case series demonstrates that a significant delay in diagnosis can be associated with these presentations. KEY POINTS: • Uncommon manifestations of AAV are seen more often with PR3 ANCA disease and respond to standard induction therapy of AAV. • High index of suspicion is required to avoid delays in diagnosis.