Search

While apoptosis plays a role in B-cell self-tolerance, its significance in preventing autoimmunity remains unclear. Here, we report that dysregulated B cell apoptosis leads to delayed onset autoimmune phenotype in mice. Our longitudinal studies revealed that mice with B cell-specific deletion of pro-apoptotic Bim ( BBim fl/fl ) have an expanded B cell compartment with a notable increase in transitional, antibody secreting and recently described double negative (DN) B cells. They develop greater hypergammaglobulinemia than mice lacking Bim in all cells and accumulate several autoantibodies characteristic of Systemic Lupus Erythematosus (SLE) and related Sjögren's Syndrome (SS) including anti-nuclear, anti-Ro/SSA and anti-La/SSB at a level comparable to NODH2h4 autoimmune mouse model. Furthermore, lymphocytes infiltrated the tissues including submandibular glands and formed follicle-like structures populated with B cells, plasma cells and T follicular helper cells indicative of ongoing immune reaction. This autoimmunity was ameliorated upon deletion of Bruton's tyrosine kinase (Btk) gene, which encodes a key B cell signaling protein. These studies suggest that Bim-mediated apoptosis suppresses and B cell tyrosine kinase signaling promotes B cell-mediated autoimmunity., Competing Interests: Authors GC, LC, and TM are employed by AstraZeneca. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wright, Bazile, Clark, Carlesso, Boucher, Kleiman, Mahmoud, Cheng, López-Rodríguez, Satterthwaite, Altman, Greidinger and Khan.)

Gaucher disease (GD) is the most common lysosomal storage disorder, the aim of the current study was to investigate hyperimmunoglobulinemia and abnormalities of serum immunoglobulin G (IgG) subclasses in children with GD and the relation of those findings to the GD phenotype and genotype, duration of enzyme replacement therapy (ERT), and infection frequency. The study included 20 Egyptian children with GD receiving ERT and 20 age-matched and sex-matched healthy children as controls. Serum Ig and serum IgG subclass levels were measured in the children with GD. Serum IgG subclass levels were measured in the control subjects. Hyperimmunoglobulinemia was present in 15 of the 20 (75%) children with GD. In addition, it is found significantly lower IgG2 levels and significantly higher IgG3 levels in the GD group than in the control group (P<0.001 and <0.006, respectively). Patients with 12 infections per year had significantly higher IgG3 levels compared with patients with 6 infections per year (P=0.022). In conclusion, hyperimmunoglobulinemia and IgG subclass abnormalities occur in children with GD who are on ERT and may be related to recurrent infections.

The objectives of this study were to evaluate patients with aortic abdominal aneurysm (AAA) with regard to immunoglobulin (Ig)G4-related disease (IgG4-RD). IgG4-RD represents a recently defined condition comprised of a collection of disorders characterized by IgG4 hypergammaglobulinemia, the presence of IgG4-positive plasma cells in organs affected with fibrotic or sclerotizing changes and typical histopathological features. It was identified as a possible cause of vasculitis in large vessels. Studies have been published on a possible association between inflammatory aortic or cardiovascular disease and IgG4-RD. We examined 114 patients with AAA requiring surgery in order to identify findings which are characteristic of IgG4-RD. Aneurysm samples from seven patients showed histopathological features consistent with IgG4-RD and the presence of IgG4 + plasma cells. Only two of these seven patients showed elevated IgG4 serum levels higher 1·35 g/l. In five of the patients, the concentration of serum IgG4 was lower than 1·20 g/l, with the number of IgG4 + plasma cells being higher than 50/high-power field. These findings were consistent with AAA being a heterogeneous group of inflammatory diseases with different pathogenesis., (© 2019 The Authors. Clinical & Experimental Immunology published by John Wiley & Sons Ltd on behalf of British Society for Immunology.)

Visceral leishmaniasis, a chronic, potentially fatal disease, is characterized by high production of low-affinity antibodies. In humans, hypergammaglobulinemia is prediction of disease progression. Nevertheless, the contribution of hypermutated and/or class-switched immunoglobulins to disease pathogenesis has never been studied. Using Aicda -/- mice and the experimental model of Leishmania donovani infection, we demonstrate that the absence of hypermutated and/or class-switched antibodies was associated with increased resistance to disease, stronger protective Th1 responses, and a lower frequency of regulatory IFNγ + IL-10 + CD4 T cells. Interestingly, stronger Th1 responses and the absence of IFNγ + IL-10 + CD4 T cells during chronic infection in infected Aicda -/- mice were not caused by a T-cell intrinsic effect of AID, but by changes in the cytokine environment during chronic disease. Indeed TNF, IL-10 and IFN-ß expressions were only upregulated in the presence of hypermutated, class-switched antibodies and hypergammaglobulinemia at later stages of infection. Taken together, our results suggest that hypergammaglobulinemia sustains inhibitory responses during chronic visceral leishmaniasis., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Systemic rheumatic diseases are characterized by abnormal B cell activation with autoantibody production and hypergammaglobulinaemia. Ro52/SSA, also denoted tripartite motif (TRIM)21, is a major autoantigen in Sjögren's syndrome and systemic lupus erythematosus. Interestingly, TRIM21-deficient mice develop systemic autoimmunity with B cell-driven manifestations such as autoantibodies, hypergammaglobulinaemia and glomerulonephritis following tissue injury. The mechanisms by which TRIM21-deficiency leads to enhanced B cell activation and antibody production are, however, not well understood, and to further elucidate the role of TRIM21 in systemic autoimmunity, we investigated the B cell phenotype and antibody responses of Trim21 -/- mice following immunization with thymus-dependent (TD) and thymus-independent (TI) antigens. We found that TRIM21-deficient mice developed significantly higher specific antibody titres than their wild-type counterparts upon B cell receptor (BCR) engagement by TD and TI type II antigens, and this was accompanied by an altered B cell phenotype. Furthermore, BCR cross-linking, but not anti-CD40 stimulation, in vitro resulted in a significantly higher proliferation of Trim21 -/- cells. We also observed that splenic follicular B cells were expanded not only in immunized mice but also already in young, unmanipulated Trim21 -/- mice, and transcriptomic analysis of these cells revealed an up-regulation of genes associated with B cell differentiation, indicating a role for TRIM21 in their regulation. In conclusion, in this study we describe a link between the rheumatic autoantigen Ro52/TRIM21 and increased antibody production associated with follicular B cell expansion, implicating a potential role for Ro52/TRIM21 in the pathogenesis of systemic autoimmune diseases., (© 2018 British Society for Immunology.)

Kaposi's sarcoma-associated herpesvirus (KSHV) induces B cell hyperplasia and neoplasia, such as multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL). To explore KSHV-induced B cell reprogramming in vivo , we expressed the KSHV latency locus, inclusive of all viral microRNAs (miRNAs), in B cells of transgenic mice in the absence of the inhibitory FcγRIIB receptor. The BALB/c strain was chosen as this is the preferred model to study B cell differentiation. The mice developed hyperglobulinemia, plasmacytosis, and B lymphoid hyperplasia. This phenotype was ameliorated by everolimus, which is a rapamycin derivative used for the treatment of mantle cell lymphoma. KSHV latency mice exhibited hyperresponsiveness to the T-dependent (TD) antigen mimic anti-CD40 and increased incidence of pristane-induced inflammation. Lastly, the adaptive immunity against a secondary infection with Zika virus (ZIKV) was markedly enhanced. These phenotypes are consistent with KSHV lowering the activation threshold of latently infected B cells, which may be beneficial in areas of endemicity, where KSHV is acquired in childhood and infections are common. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) establishes latency in B cells and is stringently linked to primary effusion lymphoma (PEL) and the premalignant B cell hyperplasia multicentric Castleman's disease (MCD). To investigate potential genetic background effects, we expressed the KSHV miRNAs in BALB/c transgenic mice. BALB/c mice are the preferred strain for B cell hybridoma development because of their propensity to develop predictable B cell responses to antigen. The BALB/c latency mice exhibited a higher incidence of B cell hyperplasia as well as sustained hyperglobulinemia. The development of neutralizing antibodies against ZIKV was augmented in BALB/c latency mice. Hyperglobulinemia was dampened by everolimus, a derivative of rapamycin, suggesting a role for mTOR inhibitors in managing immune activation, which is hallmark of KSHV infection as well as HIV infection., (Copyright © 2018 American Society for Microbiology.)

Aims: The aim of the present study was to investigate the presence of immunoglobulins (Ig) in whole saliva from patients affected by autoimmune hepatitis (AIH)., Design: Twelve individuals with AIH and 12 healthy individuals without (CON) autoimmune hepatitis, aged 8-18 years, participated in this study. Non-stimulated whole saliva was collected and centrifuged. Supernatants were separated and lyophilized. Salivary pH was measured and immunoglobulins were analyzed through ELISA technique., Results: Salivary pH (CON, 7.17 ± 0.45; AIH, 6.92 ± 0.43) did not differ between groups (p = 0.183). Measurable levels of IgG, IgA, IgM and IgE were detected on all patients. IgG levels were higher in AIH individuals (CON, 1.058 ± 0.386; AIH, 1.635 ± 0.373; p = 0.001), whereas IgA (CON, 0.915 ± 0.187; AIH, 0.995 ± 0.235; p = 0.362), IgM (CON, 0.683 ± 0.147, AIH, 0.646 ± 0.161; p = 0.561) and IgE levels (CON, 1.241 ± 0.378; AIH, 1.312 ± 0.412; p = 0.664) did not present differences between groups., Conclusions: The results of the present study suggest differences in salivary IgG levels between individuals with and without AIH. Thus, saliva has the potential of becoming an important diagnostic tool for the assessment of AIH., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Chronic infections with non-cytopathic viruses constitutively expose virus-specific adaptive immune cells to cognate antigen, requiring their numeric and functional adaptation. Virus-specific CD8 T cells are compromised by various means in their effector functions, collectively termed T cell exhaustion. Alike CD8 T cells, virus-specific CD4 Th1 cell responses are gradually downregulated but instead, follicular T helper (T FH ) cell differentiation and maintenance is strongly promoted during chronic infection. Thereby, the immune system promotes antibody responses, which bear less immune-pathological risk compared to cytotoxic and pro-inflammatory T cell responses. This emphasis on T FH cells contributes to tolerance of the chronic infection and is pivotal for the continued maturation and adaptation of the antibody response, leading eventually to the emergence of virus-neutralizing antibodies, which possess the potential to control the established chronic infection. However, sustained high levels of T FH cells can also result in a less stringent B cell selection process in active germinal center reactions, leading to the activation of virus-unspecific B cells, including self-reactive B cells, and to hypergammaglobulinemia. This dispersal of B cell help comes at the expense of a stringently selected virus-specific antibody response, thereby contributing to its delayed maturation. Here, we discuss these opposing facets of T FH cells in chronic viral infections.

Objective: To explore changes in the phenotypic features of Sjögren's syndrome (SS), and in SS status among participants in the Sjögren's International Collaborative Clinical Alliance (SICCA) registry over a 2-3-year interval., Methods: All participants in the SICCA registry who were found to have any objective measures of salivary hypofunction, dry eye, focal lymphocytic sialadenitis in minor salivary gland biopsy, or anti-SSA/SSB antibodies were recalled over a window of 2 to 3 years after their baseline examinations to repeat all clinical examinations and specimen collections to determine whether there was any change in phenotypic features and in SS status., Results: As of September 15, 2013, a total of 3,514 participants had enrolled in SICCA, and among 3,310 eligible, 771 presented for a followup visit. Among participants found to have SS using the 2012 American College of Rheumatology (ACR) classification criteria, 93% again met the criteria after 2 to 3 years, and this proportion was 89% when using the 2016 ACR/European League Against Rheumatism (EULAR) criteria. Among those who did not meet ACR or ACR/EULAR criteria at baseline, 9% and 8%, respectively, had progressed and met them at followup. Those with hypergammaglobulinemia and hypocomplementemia at study entry were, respectively, 4 and 6 times more likely to progress to SS by ACR criteria than those without these characteristics (95% confidence interval 1.5-10.1 and 1.8-20.4, respectively)., Conclusion: While there was stability over a 2-3-year period of both individual phenotypic features of SS and of SS status, hypergammaglobulinemia and hypocomplementemia at study entry were predictive of progression to SS., (© 2017, American College of Rheumatology.)

IgG4-related disease (IgG4-RD) is a recently recognized disease entity characterized by high serum IgG4 concentrations and infiltration of IgG4+ plasma cells with hyperplastic ectopic germinal centres at affected sites. Although the underlying immune mechanism of this disease remains unclear, T cells are abundantly present at affected sites and key players in IgG4-RD pathogenesis. The role of T cell subsets has been investigated thoroughly in this disease. Recent advances in this field have clarified the importance of T follicular helper cells. In this review, we describe the role of T follicular helper cells in the disease process of IgG4-RD, in particular, for IgG4 class-switching, plasmablast and plasma cell differentiation, and germinal centre formation., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Summary: We describe the case of a 24-year-old male with hyper-IgE syndrome (HIES) which was diagnosed at 4 years of age and died from a very rare cardiac complication. He had typical clinical and laboratory manifestations of HIES, including total serum IgE as high as > 100,000 IU/mL. Stem cell transplantation was not available. During the 20-year follow-up, he suffered numerous various infections of the skin and deep organs, partial lung resection, as well as multiple bone fractures. At age 24, he developed acute decompensated heart failure associated with elevated serum troponin I and brain natriuretic protein. Two-dimensional echocardiogram revealed global hypokinesis of the left ventricle with estimated ejection fraction 20-25%, and catheterization revealed ectasia of multiple coronary arteries. Endomyocardial biopsy showed lymphocytic myocarditis, focal necrosis, mild fibrosis, and myxoid degeneration, but cultures were negative. The patient improved on corticosteroid therapy and was discharged on heart failure therapy and external defibrillator. Six weeks later, he developed supraventricular tachycardia and persistent global hypokinesis and was treated with amiodarone. A trial of intravenous immunoglobulin was initiated and was repeated as outpatient every four weeks for four times. However, his cardiac function did not improve and he developed severe hypotension and pulseless electrical activity arrest. Resuscitation was unsuccessful. To the best of our knowledge, this is the first reported case of HIES complicated with lymphocytic myocarditis. Both immunologists and cardiologists need to be aware of such a complication and practice caution in using immunosuppressants when the patient's immune status is markedly compromised.

A 78-year-old female with massive pericardial effusion fulfilled diagnostic criteria for immunoglobulin G4 (IgG4)-related disease. Although her adenosine deaminase (ADA) level in the pericardial effusion was high, all the tests for tuberculosis infection were negative. Immunostaining of the pericardium biopsy specimen revealed remarkably increased IgG4-positive cells. This is the first report describing IgG4-related pericarditis with elevated ADA level. We also demonstrate the elevated interleukin-10 (IL-10) level in pericardial fluid and IL-10-producing T-cells in the pericardium.

MST1 deficiency causes T and B cell lymphopenia, resulting in combined immunodeficiency. However, MST1-deficient patients also exhibit autoimmune-like symptoms such as hypergammaglobulinemia and autoantibody production. Recent studies have shown that the autoimmune responses observed in MST1-deficient patients were most likely attributable to defective regulatory T (Treg) cells instead of intrinsic signals in MST1-lacking B cells. Nevertheless, it is not determined how MST1 deficiency in T cells breaks B cell tolerance and causes systemic autoimmune-like phenotypes. In this study, we confirmed that Mst1 -/- mice developed hypergammaglobulinemia associated with increased levels of IgG, IgA, and IgE. We also showed that uncontrolled B cell responses were resulted from the IL-4-rich environment created by CD4 + T cells. Defective MST1-FOXO1 signaling down-regulated Treg cells, resulting in the collapse of immune tolerance where the populations of Th2 and T follicular helper cells expanded. In conclusion, we suggest that MST1 acts as a molecular brake to maintain immune tolerance by regulating T cell-mediated B cell activation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Aim: To test the hypothesis that systemic auto-antibodies or hypergammaglobulinemia are related to the prevalence of extra-glandular tissue organ damage (EGOD) in primary Sjögren's syndrome (SS)., Methods: A real practice-based investigation of a relatively large (n = 110) Dutch cohort of primary SS patients systematically followed up in a large non-academic hospital., Results: After a follow up of mean 8.2 years a significant correlation was found between disease duration and the prevalence of EGOD. We did not observe a relationship between the total number or type of systemic auto-antibodies or hypergammaglobulinemia and the total number of EGOD. However, there was a correlation between the prevalence of polyneuropathy (PNP) and antinuclear antibodies (ANA) as well as anti-Ro/SS-A positivity and there was an inverse relationship between the presence of anti-Ro/SS-A antibodies and primary biliary cirrhosis (PBC). All PBC cases were anti-Ro/SS-A and anti-La/SS-B negative but ANA positive. There was a trend for a higher occurrence of pleuro-pulmonary disease in the ANA negative cases., Conclusions: Although we did not find a relationship between the total number or type of systemic auto-antibodies and the total number of EGOD, there were correlations between specific systemic auto-antibodies and specific types of EGOD. The presence of ANA and anti-Ro/SS-A was associated with the occurrence of PNP, as well as was the absence of anti-Ro/SS-A with PBC., (© 2017 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory condition characterized by tissue infiltration with IgG4 + plasma cells and an elevated serum IgG4 level. It usually occurs in middle-aged or older patients, with male predominance, and can involve multiple organs synchronously or metachronously. Patients with IgG4-RD generally respond to steroid therapy. IgG4-related skin lesions are typically erythematous and itchy plaques, subcutaneous nodules, or papules like prurigo nodularis located on the head and neck areas. Histologically, lymphoplasmacytic infiltrates with abundant IgG4+ plasma cells are seen in the dermis and/or subcutaneous tissue. The skin condition of IgG4-RD does not necessarily exhibit infiltration of IgG4 + plasma cells, which is a prerequisite for IgG4-related skin disease, but such skin lesions without infiltration by IgG4 + plasma cells can be included in the skin manifestations of IgG4-RD., (© 2017 Japanese Dermatological Association.)

Objective: The relevance of the Th17 pathway in primary SS (pSS) is unclear. Published studies have relied on restimulating circulating CD161 + T cells in vitro for quantitation of IL-17-producing cells. While CD161 marks all IL-17 + T cells, it is also expressed by other Th subsets. The aim of this study was to directly analyse retinoic acid receptor-related orphan nuclear receptor (ROR)-γ expressing and non-expressing subsets of CD161 + T cells to determine the relevance of the Th17 pathway in pSS., Methods: We quantitated the frequencies of both CD161 - and RORγ-expressing T cells by comparative flow cytometry in peripheral blood mononuclear cells from a well-stratified cohort of pSS patients and control subjects. We also analysed the expression of antigen D-related HLA (HLA-DR) and CD161 in labial salivary glands from nine subjects undergoing a diagnostic biopsy., Results: While the frequencies of both RORγ + and RORγ - subsets of CD161 + CD4 + T cells were increased in peripheral blood from pSS patients, the increase in the RORγ + subset positively correlated with humoral manifestations of the disease (anti-SSA/SSB autoantibodies and hypergammaglobulinaemia), but not with disease activity, and vice versa for the RORγ - subset. An increased frequency of HLA-DR + CD161 + CD4 + T cells was observed in labial salivary gland biopsies from pSS patients, suggesting chronic activation of CD161 + CD4 + T cells in the target tissue of the disease., Conclusion: In addition to pointing to CD161 as a marker of a pathogenic subset of CD4 + T cells in pSS patients, our data indicate that even though the RORγ + (Th17) CD161 + subset might contribute to humoral manifestations of the disease, the RORγ - (non-Th17) CD161 + subset is the one associated with disease activity in pSS patients., (© The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Simultaneous occurrence of T-cell and B-cell neoplasms is rare, and etiologic relationships between these 2 malignancies are poorly understood. We describe the case of a 66-year-old woman who was admitted to the hospital because of fever, hemoptysis, lymphadenopathy, and skin rash. Enlarged lymph nodes in axillary, pectoral, paratracheal, and periportal regions as well as slight hepatomegaly and splenomegaly were confirmed. A peripheral blood smear revealed rouleaux formation and numerous circulating plasma cells, with plasmacytoid lymphocytes. Immunofixation-electrophoresis detected a monoclonal band defined as immunoglobulin (IgG)-lambda light chains with broad-band polyclonal IgA. The patient died from abrupt splenic rupture before diagnostic work-up was finished. Postmortem examination revealed infiltration of atypical lymphoid cells exhibiting high proliferative activity admixed with typical and atypical plasma cells in several organs. Thus, plasma cell leukemia (IgG-lambda) as a rare and aggressive variant of plasma cell myeloma in the present case was associated with aggressive peripheral T-cell lymphoma and polyclonal (IgA) plasmacytosis.

Autoimmune hepatitis (AIH) is a chronic liver disease characterized by progressive inflammation, female preponderance and seropositivity for autoantibodies such as anti-smooth muscle actin and/or anti-nuclear, anti-liver kidney microsomal type 1 (anti-LKM1) and anti-liver cytosol type 1 (anti-LC1) in more than 80% of cases. AIH is linked strongly to several major histocompatibility complex (MHC) alleles, including human leucocyte antigen (HLA)-DR3, -DR7 and -DR13. HLA-DR4 has the second strongest association with adult AIH, after HLA-DR3. We investigated the role of HLA-DR4 in the development of AIH by immunization of HLA-DR4 (DR4) transgenic non-obese diabetic (NOD) mice with DNA coding for human CYP2D6/FTCD fusion autoantigen. Immunization of DR4 mice leads to sustained mild liver injury, as assessed biochemically by elevated alanine aminotransferase, histologically by interface hepatitis, plasma cell infiltration and mild fibrosis and immunologically by the development of anti-LKM1/anti-LC1 antibodies. In addition, livers from DR4 mice had fewer regulatory T cells (T regs ), which had decreased programmed death (PD)-1 expression. Splenic T regs from these mice also showed impaired inhibitory capacity. Furthermore, DR4 expression enhanced the activation status of CD8 + T cells, macrophages and dendritic cells in naive DR4 mice compared to naive wild-type (WT) NOD mice. Our results demonstrate that HLA-DR4 is a susceptibility factor for the development of AIH. Impaired suppressive function of T regs and reduced PD-1 expression may result in spontaneous activation of key immune cell subsets, such as antigen-presenting cells and CD8 + T effectors, facilitating the induction of AIH and persistent liver damage., (© 2016 British Society for Immunology.)

Objective: Anticentromere antibodies (ACAs) define a subset of primary Sjögren's syndrome (SS) with a unique phenotype, including features of limited cutaneous systemic sclerosis and a lower frequency of anti-SSA/SSB antibodies. We sought to determine whether ACAs are associated with more severe exocrine glandular dysfunction in a large cohort of primary SS subjects., Methods: We performed a cross-sectional analysis of 1,361 subjects with primary SS from the Sjögren's International Collaborative Clinical Alliance Registry, stratified by the presence or absence of ACAs. ACAs were assayed by immunofluorescence staining on HEp-2 cells., Results: ACAs were present in 82 of the 1,361 SS subjects (6%) and were associated with older age, female sex, and lower frequencies of anti-SSA/SSB, rheumatoid factor, and hyperglobulinemia. Among ACA-positive versus ACA-negative subjects, there was a higher frequency of a focus score ≥2 (71% versus 53%; P = 0.002), a higher median focus score (2.8 versus 2.5; P = 0.0440), and greater exocrine gland dysfunction: Schirmer's test value: median 4 versus 5 mm/5 minutes; P = 0.0003, and unstimulated whole saliva (UWS) flow rate: median 0.08 versus 0.37 ml/5 minutes; P < 0.0001. ACA-positive subjects had an increased risk of UWS <0.1 ml/minute (odds ratio [OR] 12.24 [95% confidence interval (95% CI) 4.91-41.02]) and Schirmer's test value <5 mm/5 minutes (OR 2.52 [95% CI 1.50-4.36]) after correcting for age, sex, anti-SSA/SSB, and focus score. Labial gland fibrosis was not different between the 2 groups., Conclusion: In a large international registry of SS, ACA had an independent association with more severe exocrine glandular dysfunction. This dysfunction was associated with more pronounced labial salivary glandular inflammation but not fibrosis., (© 2016, American College of Rheumatology.)

Matrix metalloproteases (MMPs) regulate innate immunity acting over proinflammatory cytokines, chemokines, and other immune-related proteins. MMP-25 (membrane-type 6-MMP) is a membrane-bound enzyme predominantly expressed in leukocytes whose biological function has remained largely unknown. We have generated Mmp25-deficient mice to elucidate the in vivo function of this protease. These mutant mice are viable and fertile and do not show any spontaneous phenotype. However, Mmp25-null mice exhibit a defective innate immune response characterized by low sensitivity to bacterial LPS, hypergammaglobulinemia, and reduced secretion of proinflammatory molecules. Moreover, these immune defects can be tracked to a defective NF-κB activation observed in Mmp25-deficient leukocytes. Globally, our findings provide new mechanistic insights into innate immunity through the activity of MMP-25, suggesting that this proteinase could be a potential therapeutic target for immune-related diseases., (Copyright © 2016 by The American Association of Immunologists, Inc.)

Participation of B cells in the immune response by various antibody-independent mechanisms has recently been uncovered. B cells producing cytokines have been described for several infections and appear to regulate the adaptive immune response. B cell activation by Leishmania donovani results in disease exacerbation. How Leishmania activates B cells is still unknown. We show that L. donovani amastigotes activate B cells by triggering endosomal TLRs; this activation leads to the induction of various cytokines. Cytokine expression is completely abrogated in B cells from Ifnar(-/-) mice upon exposure to L. donovani, suggesting an involvement of IFN-I in a positive feedback loop. IFN-I also appears to enhance the expression of endosomal TLRs following exposure to L. donovani. Cell-specific ablation of endosomal TLR signaling in B cells revealed that innate B cell activation by L. donovani is responsible for disease exacerbation through IL-10 and IFN-I production and for the promotion of hypergammaglobulinemia., (Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.)

Visceral leishmaniasis (VL) is a disease caused by Leishmania infantum, which is transmitted by phlebotomine sandflies. Dogs are the main urban reservoir of this parasite and the disease presents similar characteristics in both humans and dogs. In this paper, we investigated the potential pathways involved in plasma cell replacement of normal cell populations in the spleen, with respect to disease severity in dogs from an endemic area for visceral leishmaniasis. To this end, canine spleen samples were grouped into three categories: TYPE1SC- (non-infected dogs or without active infection with organized white pulp), TYPE1SC+ (infected dogs with organized white pulp) or TYPE3SC+ (infected animals with disorganized white pulp). We analyzed the distribution of different plasma cell isotypes (IgA, IgG and IgM) in the spleen. The expression of cytokines and chemokines involved in plasma cell homing and survival were assessed by real time RT-PCR. Polyclonal B cell activation and hypergammaglobulinemia were also evaluated. The proportion of animals with moderate or intense plasmacytosis was higher in the TYPE3SC+ group than in the other groups (Fisher test, P<0.05). This was mainly due to a higher density of IgG+ plasma cells in the red pulp of this group. The albumin/globulin ratio was lower in the TYPE3SC+ animals than in the TYPE1SC- or TYPE1SC+ animals, which evidences VL-associated dysproteinemia. Interestingly, TYPE3SC+ animals showed increased expression of the BAFF and APRIL cytokines, as well as chemokine CXCL12. Aberrant expression of BAFF, APRIL and CXCL12, together with amplified extrafollicular B cell activation, lead to plasma cell homing and the extended survival of these cells in the splenic red pulp compartment. These changes in the distribution of immunocompetent cells in the spleen may contribute to the progression of VL, and impair the spleen's ability to protect against blood borne pathogens.

Objective: Autoantibodies reactive with Ro52 (tripartite motif-containing protein 21 [TRIM21]) are detected in 70% of patients with primary Sjögren's syndrome (SS). TRIM21 belongs to a 34-member C-IV family of TRIM proteins. Although autoantibodies against other TRIM proteins within the C-IV family have been detected in the sera of patients with primary SS, their clinical relevance remains unclear. This study was undertaken to investigate the frequency of anti-TRIM38 in patients with primary SS and evaluate its association with various clinical measures of the disease., Methods: Serum samples from patients with primary SS (n = 235) and controls (n = 50) were analyzed for reactivity with in vitro-transcribed and -translated (35) S-methionine-labeled TRIM38 protein. The associations of anti-TRIM38 with various laboratory and clinical measures of primary SS were evaluated. Reactivity of anti-TRIM38 with different structural domains of TRIM38 was analyzed. Affinity-purified anti-TRIM38 antibodies were used to immunoprecipitate TRIM21., Results: TRIM38-reactive autoantibodies were detected in the sera of 24 of the 235 patients with primary SS and 2 of the 50 controls. Anti-TRIM38 positivity was significantly associated with the presence of anti-Ro60, anti-Ro52, anti-La, rheumatoid factor, and hypergammaglobulinemia. Clinically, anti-TRIM38 was associated with significantly higher ocular surface staining scores, lower Schirmer's test scores, and minor labial salivary gland biopsy focus scores of ≥3.0. Anti-TRIM38 antibodies mainly recognized the cortactin-binding protein 2 (CortBP-2; amino acids 128-238) and the B30.2/SPRY (amino acids 268-465) domains on TRIM38. Affinity-purified antibodies to TRIM38-CortBP-2 and TRIM38-B30.2/SPRY domains reacted with TRIM21., Conclusion: Our data demonstrate that anti-TRIM38 specificity arising in a subset of patients with primary SS is associated with increased severity of the disease., (© 2016, American College of Rheumatology.)

A subpopulation (60-70%) of Foxp3(+) regulatory T cells (Tregs) in both mouse and man expresses the transcription factor Helios, but its role in Treg function is still unknown. We generated Treg-specific Helios-deficient mice to examine the function of Helios in Tregs. We show that the selective deletion of Helios in Tregs leads to slow, progressive systemic immune activation, hypergammaglobulinemia, and enhanced germinal center formation in the absence of organ-specific autoimmunity. Helios-deficient Treg suppressor function was normal in vitro, as well as in an in vivo inflammatory bowel disease model. However, Helios-deficient Tregs failed to control the expansion of pathogenic T cells derived from scurfy mice, failed to mediate T follicular regulatory cell function, and failed to control both T follicular helper cell and Th1 effector cell responses. In competitive settings, Helios-deficient Tregs, particularly effector Tregs, were at a disadvantage, indicating that Helios regulates effector Treg fitness. Thus, we demonstrate that Helios controls certain aspects of Treg-suppressive function, differentiation, and survival.

Background/aims: Cutaneous plasmacytosis is rare and still not well understood. A retrospective study was made of 9 Chinese patients with 1- to 15-year histories of biopsy-proven cutaneous plasmacytosis diagnosed between 2003 and 2015., Methods: Patient records and archival photographs helped establish the pattern and duration of skin lesions, and skin biopsy specimens provided additional data., Results: The mean age at diagnosis was 46.4 years. Two patients had lesions within 1 year of developing the disease, and 4 had lesions lasting longer than 5 years. One patient had lymphadenopathy of the neck that was later determined to be Castleman disease. Three patients had elevated IgG4 levels; only 2 had increased IgG4+ cells in skin tissues. Flexural accentuation was prominent. Four patients had elevated IgG levels, and 1, with an IgG level >5,000 mg/dL, developed systemic plasmacytosis (later confirmed as Castleman disease). The level of IgG4 subclass was related to disease duration, whereas IgG4+ plasma cells in tissues seemed irrelevant., Conclusion: Routine laboratory tests, especially measurement of IgG4 levels, may be useful for following patients with cutaneous plasmacytosis. Because of the retrospective nature of our study, we could only evaluate the results of a single IgG4 test for each patient, but the results pointed to cutaneous plasmacytosis in all 9 patients, who had different stages of the disease. Serial skin biopsies may also be helpful for gauging disease progress. Although IgG4-related disease was not established in any of these patients, long-term follow-up is warranted for all patients., (© 2017 S. Karger AG, Basel.)

Purpose: Patients with DiGeorge syndrome suffer from T-lymphopenia. T-cells are important for the maturation and regulation of B-cell function. Our aim was to characterize the B-cell compartment in DiGeorge syndrome patients., Methods: B-cell subset phenotypization using flow cytometry. Serum BAFF (B-cell activating factor) and serum anti-alpha-galactosyl IgM measurement using ELISA. Serum IgG measurement using nephelometry., Results: We observed a significantly increased number of naïve B-cells and decreased number of switched memory B-cells in DiGeorge patients. Furthermore, we observed increased BAFF levels and a trend toward hypergammaglobulinemia later in life. Surprisingly, we detected a decrease in marginal zone-like (MZ-like) B-cells and natural antibodies in DiGeorge patients., Conclusion: The maturation of B-cells is impaired in DiGeorge patients, with high naïve and low switched memory B-cell numbers being observed. There is a clear trend toward hypergammaglobulinemia later in life, coupled with increased serum BAFF levels. Surprisingly, the T-independent humoral response is also impaired, with low numbers of MZ-like B-cell and low levels of anti-alpha-galactosyl IgM natural antibodies being detected., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Hyperimmunoglobulinemia is frequently observed in patients with chronic liver diseases. However, the exact mechanism underlying the high level of antibody formation is not fully understood. In our study, we provide evidence for the functional role of the liver and the stimulation of plasma cell proliferation in hyperimmunoglobulinemia. We collected sera from patients with chronic liver diseases, and the level of serum immunoglobulins in patients was examined; this was also investigated in animal models of liver cirrhosis and hepatocellular carcinoma. An end-to-side microsurgical portacaval shunt was used to mimic liver dysfunction in rats. We used portal vein serum and inferior vena cava serum to immunize healthy rats and mice in order to confirm the function of the healthy liver in disposing of antigens and endotoxins from the gut. For the analysis of the state of plasma cell activation, plasma cells from mice were stained with PE-conjugated anti-CD138 and FITC-conjugated anti-BrdU for flow cytometry analysis. Hyperimmunoglobulinemia was observed both in patients with chronic liver diseases and in related animal models, and high plasma LPS levels were also observed. There was a significant increase in the activation and proliferation of plasma cell in mice immunized with antigens or LPS-positive serum compared with controls that were immunized with antigens and LPS-negative serum. We confirmed that the healthy liver plays an important role in disposing of antigens and endotoxins derived from the gut. Hyperimmunoglobulinemia in chronic liver diseases mainly arises due to the collateral circulation secondary to portal hypertension, gut antigens and endotoxins that bypass the liver and reach the antibody-producing cells.

Autoantibody production and immune complex (IC) formation are frequently observed in autoimmune diseases associated with bone loss. However, it has been poorly understood whether ICs regulate bone metabolism directly. Here we show that the level of osteoclastogenesis is determined by the strength of FcRγ signalling, which is dependent on the relative expression of positive and negative FcγRs (FcγRI/III/IV and IIB, respectively) as well as the availability of their ligands, ICs. Under physiological conditions, unexpectedly, FcγRIII inhibits osteoclastogenesis by depriving other osteoclastogenic Ig-like receptors of FcRγ. Fcgr2b(-/-) mice lose bone upon the onset of a hypergammaglobulinemia or the administration of IgG1 ICs, which act mainly through FcγRIII. The IgG2 IC activates osteoclastogenesis by binding to FcγRI and FcγRIV, which is induced under inflammatory conditions. These results demonstrate a link between the adaptive immunity and bone, suggesting a regulatory role for ICs in bone resorption in general, and not only in inflammatory diseases.

IgG4-related disease (IgG4-RD) is a systemic entity characterised by multiorgan inflammatory lesions with abundant IgG4+ plasma cells, obliterative phlebitis, and storiform fibrosis. Involvement of several organs such as the pancreas, gastrointestinal tract, salivary glands, periorbital tissue and lymph nodes has been described. Up to now, vascular involvement by IgG4-RD has been thought to be essentially confined to large vessels. We present a patient with small-vessel systemic vasculitis involving muscle, peripheral nerve and kidney (glomerulonephritis) in the context of IgG4-RD diagnosed on the basis of elevated serum IgG4+ concentrations and histologically consistent signs in all biopsied tissues. Thoracic and abdominal aortic aneurysms in addition to aortitis, suggestive of large-vessel involvement, were also present. This observation expands the spectrum of vascular involvement in the context of IgG4-RD and supports the inclusion of IgG4-RD in the category of vasculitis associated with systemic disorder.

T cell dysfunction is well documented during chronic viral infections but little is known about functional abnormalities in humoral immunity. Here we report that mice persistently infected with lymphocytic choriomeningitis virus (LCMV) exhibit a severe defect in Fcγ-receptor (FcγR)-mediated antibody effector functions. Using transgenic mice expressing human CD20, we found that chronic LCMV infection impaired the depletion of B cells with rituximab, an anti-CD20 antibody widely used for the treatment of B cell lymphomas. In addition, FcγR-dependent activation of dendritic cells by agonistic anti-CD40 antibody was compromised in chronically infected mice. These defects were due to viral antigen-antibody complexes and not the chronic infection per se, because FcγR-mediated effector functions were normal in persistently infected mice that lacked LCMV-specific antibodies. Our findings have implications for the therapeutic use of antibodies and suggest that high levels of pre-existing immune complexes could limit the effectiveness of antibody therapy in humans., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Mice infected with mouse hepatitis virus A59 (MHV-A59) develop autoantibodies (autoAb) to liver and kidney fumarylacetoacetate hydrolase (FAH) with a concomitant enhancement of transaminases and release of alarmins such as uric acid and high-mobility group box protein 1 (HMGB1). Tryptophan catabolism is an endogenous mechanism that restricts excessive immune responses, thereby preventing immunopathology. Since indoleamine-2,3-dioxygenase (IDO) is the key and rate-limiting enzyme of tryptophan catabolism, the aim of this work was to explore whether specific inhibition of IDO by Levo-1-methyl tryptophan (MT) could affect MHV actions. Results showed that MT strongly enhanced the hypergammaglobulinemia induced by the virus, as well as anti-MHV Ab and uric acid release. Moreover, infected mice treated with MT did express anti-FAH autoAb and high levels of serum HMGB1. Survival of MHV-infected animals treated with MT was severely reduced compared with that of MHV-infected mice or controls only treated with MT. Furthermore, histological liver examination indicated that MT induced fibrosis in MHV-infected animals, whereas MT itself increased uric acid levels without shortening the animal life Thus, under our experimental conditions, results indicated an exacerbated response to MHV infection when IDO was blocked by MT., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Immunoglobulin G4-related disease is a recently described systemic clinicopathological entity characterized by immunoglobulin G4-producing plasmacytic infiltration of tissue and frequently by elevated serum immunoglobulin G4 concentration. Manifestations of this disease have been documented in nearly all organs and locations, but coronary artery involvement is not widely recognized. We report the coronary findings of a patient with multi-organ immunoglobulin G4-related disease. Non-electrocardiogram-gated computed tomography of the chest demonstrated nodular and rind-like periarterial soft tissue thickening along the proximal coronary artery segments with improvement following steroid therapy.

Hyperimmunoglobulin M (HIGM) type 3 due to CD40 deficiency is a very rare syndrome. Only 16 cases have been reported thus far. The clinical presentation is very variable. We present the first case of this rare disorder from India. The case is of a two-and-a-half-year-old female, with a history of repeated episodes of skin infections and diarrhea since birth. Laboratory evaluation revealed elevated absolute lymphocyte count and an absolute neutrophil count (ANC) of 1026/mm3. The lymphocyte subset analysis showed normal absolute counts of Natural Killer (NK) cells and elevated absolute counts of T-cells (CD4 and CD8) and B-cells. The serum immunoglobulin estimation showed low levels of IgG, IgA, IgE and an elevated level of IgM. The CD154 analysis was normal and expression of CD40 was absent on the B-cells. Molecular analysis showed a novel mutation, with deletion of 3bp (AAG) [p.Glu107GlyfsX84] in the homozygous state, in the CD40 gene. Thus the patient was diagnosed as HIGM type 3. The parents were screened and counseled regarding prenatal diagnosis at the time of next pregnancy.

Background: Schnitzler syndrome (SS) is a rare clinical entity characterized by chronic recurrent urticarial rash, monoclonal IgM gammopathy, intermittent fever and other symptoms. In this report, we present the cases of two patients with SS: a male and a female aged 50 and 49 years, respectively. Both patients had hyperimmunoglobulinemia E and showed good response to elimination diet., Methods: The patients had chronic urticaria, IgM gammopathy and an elevation of the serum levels of inflammation markers. Total IgE levels were found to be high (2000 U/ml and 540 U/ml, respectively). No underlying causes for hyperimmunoglobulinemia E (allergy, parasites, etc.) were revealed. The first patient did not respond to the treatment with antihistamines, while the second one responded only to high doses. The response to prednisolone in the second patient was incomplete., Results: Following a strict elimination diet resulted in marked improvement in skin lesions in both patients. In one of our patients we observed a decrease in IgE and IgM levels after a 3 week diet. The systemic symptoms persisted and improved only after adding pefloxacin, followed by a 3-day empirical course of intravenous prednisone in the first patient and a course of plasmapheresis in the second one., Conclusion: The high serum levels of total IgE may be associated with chronic urticaria activity, severe disease course and a poor response to treatment with antihistamines, and may be considered a possible marker of a subset of patients with SS showing a good response to the restriction diet. In general, we can assume that elimination diet can have an influence on the skin lesions and other symptoms of SS as well as on total IgE and IgM levels, but such association, the underlying mechanisms and the reasons for excessive IgE synthesis should be investigated in further studies.