The BAFF/APRIL system: emerging functions beyond B cell biology and autoimmunity

APRIL gene polymorphism and serum sAPRIL levels in children with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multi-factor autoimmune disorder with diverse clinical manifestations and unclear pathogenesis. Genetic components play important roles in the incidence and development of SLE. Among these, APRIL as a cytokine has roles in the stimulation and antibody production in B cells. APRIL was hypothesized to be associated with SLE. The aim of this study was to assess the involvement of the APRIL gene in SLE susceptibility in Iranian patients. A single-nucleotide polymorphism (SNP) for rs11552708 of APRIL gene was analyzed by real-time PCR in 60 SLE Iranian children and 64 healthy controls. DNA samples of patients and healthy controls were extracted from peripheral blood leukocytes by phenol-chloroform. Serum samples obtained from 45 children with SLE and 45 healthy controls were assayed by enzyme-linked immunosorbent assay (ELISA). The G/G genotype (odds ratio (OR) 0.67, 95% confidence interval (CI) 0.22-2.07; P = 0.68) and G allele (OR 0.81, 95% CI 0.25-2.56; P = 0.89) frequencies of polymorphism at codon 67 (67G) do not differ significantly in the SLE patients compared with those in the healthy controls. The serum APRIL levels in the SLE patients (mean ± SD = 29.27 ng/ml ± 20.77, range from 0 to 55.33 ng/ml) were significantly higher than those in the healthy controls (P = 0.02). Our results demonstrated that rs11552708 of the APRIL gene is not associated with SLE susceptibility in Iranian children. Likewise, these findings suggest that APRIL antagonist could be a potential therapeutic target to control SLE in children.

Thymic stromal lymphopoietin in tonsillar follicular dendritic cells correlates with elevated serum immunoglobulin A titer by promoting tonsillar immunoglobulin A class switching in immunoglobulin A nephropathy

Immunoglobulin A (IgA) nephropathy (IgAN) is characterized by high serum IgA levels and IgA deposition in the renal mesangium. Previous studies suggest that elevated serum IgA partly originates from the tonsils. Here, we investigated the mechanisms of IgA production in the tonsils of patients with IgAN. Immunohistochemistry revealed that the number and relative percentage of IgA-bearing cells were significantly increased in the tonsils of IgAN patients. Compared with non-IgAN patients, enhanced IgA class switching and overexpression of thymic stromal lymphopoietin (TSLP), TSLP receptor (TSLPR), activation-induced cytidine deaminase (AID), transforming growth factor-β1 (TGF-β1), B cell-activating factor of the tumor necrosis factor family (BAFF), and a proliferation-inducing ligand (APRIL) were detected in follicular dendritic cells (FDCs) of tonsillar germinal centers from IgAN patients. Importantly, TSLP correlated with IgA production in isolated FDC-associated clusters. Serum TSLP levels were increased and correlated with IgA overexpression in the tonsils and serum of IgAN patients. These data indicated that TSLP overexpression in tonsillar FDCs may promote IgA class switching in IgAN patients through the cooperative roles of AID, TGF-β1, BAFF, and APRIL. Therefore, interactions between TSLP in FDCs and IgA production in tonsils may be an important mechanism contributing to the pathogenesis of IgAN.

Exploring BAFF: its expression, receptors and contribution to the immunopathogenesis of Sjögren's syndrome

SS is an autoimmune condition characterized by exocrine gland destruction, autoantibody production, immune complex deposition and systemic complications associated with lymphocytic infiltration of many organs. Genetic, environmental and viral factors play a role in disease aetiology, however, the exact mechanisms driving the immunopathogenesis of SS remain uncertain. Here we discuss a role for B cell activating factor (BAFF), whereby B cell hyperactivity and increased BAFF secretion observed in patients and animal models of the disease can be explained by the altered expression of cell-specific BAFF/BAFF receptor (BAFF-R) variants in several immune cell types. Understanding the role of BAFF/BAFF-R heterogeneity in SS pathogenesis could help to facilitate new treatment strategies for patients.

Serum BAFF and APRIL Levels, T-Lymphocyte Subsets, and Immunoglobulins after B-Cell Depletion Using the Monoclonal Anti-CD20 Antibody Rituximab in Myalgic Encephalopathy/Chronic Fatigue Syndrome

Myalgic Encephalopathy/Chronic Fatigue Syndrome (ME/CFS) is a disease of unknown etiology. We have previously suggested clinical benefit from B-cell depletion using the monoclonal anti-CD20 antibody rituximab in a randomized and placebo-controlled study. Prolonged responses were then demonstrated in an open-label phase-II study with maintenance rituximab treatment. Using blood samples from patients in the previous two clinical trials, we investigated quantitative changes in T-lymphocyte subsets, in immunoglobulins, and in serum levels of two B-cell regulating cytokines during follow-up. B-lymphocyte activating factor of the tumor necrosis family (BAFF) in baseline serum samples was elevated in 70 ME/CFS patients as compared to 56 healthy controls (p = 0.011). There were no significant differences in baseline serum BAFF levels between patients with mild, moderate, or severe ME/CFS, or between responders and non-responders to rituximab. A proliferation-inducing ligand (APRIL) serum levels were not significantly different in ME/CFS patients compared to healthy controls at baseline, and no changes in serum levels were seen during follow-up. Immunophenotyping of peripheral blood T-lymphocyte subsets and T-cell activation markers at multiple time points during follow-up showed no significant differences over time, between rituximab and placebo groups, or between responders and non-responders to rituximab. Baseline serum IgG levels were significantly lower in patients with subsequent response after rituximab therapy compared to non-responders (p = 0.03). In the maintenance study, slight but significant reductions in mean serum immunoglobulin levels were observed at 24 months compared to baseline; IgG 10.6–9.5 g/L, IgA 1.8–1.5 g/L, and IgM 0.97–0.70 g/L. Although no functional assays were performed, the lack of significant associations of T- and NK-cell subset numbers with B-cell depletion, as well as the lack of associations to clinical responses, suggest that B-cell regulatory effects on T-cell or NK-cell subsets are not the main mechanisms for the observed improvements in ME/CFS symptoms observed in the two previous trials. The modest increase in serum BAFF levels at baseline may indicate an activated B-lymphocyte system in a subgroup of ME/CFS patients.

Precursor B Cells Increase in the Lung during Airway Allergic Inflammation: A Role for B Cell-Activating Factor

Background

B cells, key cells in allergic inflammation, differentiate in the bone marrow and their precursors include pro-B, pre-B and immature B cells. Eosinophil progenitor cells increase in the lung after allergen exposure. However, the existence and possible role of B cell precursors in the lung during allergic inflammation remains elusive.

Methods

A BALB/c mouse model of allergic airway inflammation was utilized to perform phenotypic and quantification analyses of pro-B and pre-B cells in the lung by flow cytometry. B cell maturation factors IL-7 and B cell-activating factor (BAFF) and their receptors (CD127 and BAFFR, BCMA, TACI, respectively) were also evaluated in the lung and serum. The effect of anti-BAFF treatment was investigated both in vivo (i.p. administration of BAFF-R-Ig fusion protein) and in vitro (colony forming cell assay). Finally, BAFF levels were examined in the bronchoalveolar lavage (BAL) of asthmatic patients and healthy controls.

Results

Precursor pro and pre-B cells increase in the lung after allergen exposure, proliferate in the lung tissue in vivo, express markers of chemotaxis (CCR10 and CXCR4) and co-stimulation (CD40, CD86) and are resistant to apoptosis (Bax). Precursor B cells express receptors for BAFF at baseline, while after allergen challenge both their ligand BAFF and the BCMA receptor expression increases in B cell precursors. Blocking BAFFR in the lung in vivo decreases eosinophils and proliferating precursor B cells. Blocking BAFFR in bone marrow cultures in vitro reduces pre-B colony formation units. BAFF is increased in the BAL of severe asthmatics.

Conclusion

Our data support the concept of a BAFF-mediated role for B cell precursors in allergic airway inflammation.

Association of variants in BAFF (rs9514828 and rs1041569) and BAFF-R (rs61756766) genes with the risk of chronic lymphocytic leukemia

The B-cell activator factor (BAFF)/BAFF receptor (BAFF-R) axis seems to play an important role in the development and progression of chronic lymphocytic leukemia (CLL). Here, we investigated the association of eight single nucleotide polymorphisms (SNPs) in the BAFF (TNFSF13B) and BAFF-R (TNFRSF13C) genes with risk of sporadic CLL in a group of 439 CLL patients and 477 controls. We also examined the correlation between selected SNPs and CLL clinical parameters as well as BAFF plasma levels and intracellular BAFF expression. Our results point to a possible association between the rs9514828 (CT vs. CC + TT; OR = 0.74; CI 95 % = 0.57; 0.97; p = 0.022) and rs1041569 (AT vs. AA + TT; OR = 0.72; CI 95 % = 0.54; 0.95; p = 0.021) of BAFF gene and rs61756766 (CC vs. CT; OR = 2.03; CI 95 % = 1.03; 3.99; p = 0.03) of BAFF-R gene and CLL risk. Additionally, we observed that homozygotes rs1041569 AA and TT had a slightly higher risk (HR = 1.12) for the need of treatment in comparison to AT heterozygotes. In conclusion, our results indicate that SNPs in BAFF and BAFF-R genes may be considered as potential CLL risk factors.

A 3'UTR polymorphism marks differential KLRG1 mRNA levels through disruption of a miR-584-5p binding site and associates with pemphigus foliaceus susceptibility

Genetic variations mapping to 3' untranslated regions (3'UTRs) may overlap with microRNA (miRNA) binding sites, therefore potentially interfering with translation inhibition or messenger RNA (mRNA) degradation. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) located within the 3'UTRs of six candidate genes and predicted to interfere with miRNA ligation could account for disease-relevant differential mRNA levels. Focusing on pemphigus foliaceus (PF) - an autoimmune blistering skin condition with unique endemic patterns - we investigated whether nine 3'UTR SNPs from the CD1D, CTLA4, KLRD1, KLRG1, NKG7, and TNFSF13B genes differentially expressed in PF were disease-associated. The heterozygous genotype of the KLRG1 rs1805672 polymorphism was associated with increased predisposition to PF (A/G vs. A/A: P=0.038; OR=1.60), and a trend for augmented susceptibility was observed for carriers of the G allele (P=0.094; OR=1.44). In silico analyses suggested that rs1805672 G allele could disrupt binding of miR-584-5p, and indicated rs1805672 as an expression Quantitative Trait Locus (eQTL), with an effect on KLRG1 gene expression. Dual-luciferase assay showed that miR-584-5p mediated approximately 50% downregulation of the reporter gene's activity through the 3'UTR of KLRG1 harboring rs1805672 A allele (vs. miRNA-negative condition, P=0.006). This silencing relationship was lost after site-directed mutation to G allele (vs. miRNA-negative condition, P=0.391; vs. rs1805672 A allele, P=0.005). Collectively, these results suggest that a disease-associated SNP located within the 3'UTR of KLRG1 directly interferes with miR-584-5p binding, allowing for KLRG1 mRNA differential accumulation, which in turn may contribute to pathogenesis of autoimmune diseases, such as pemphigus.

BAFF and APRIL from Activin A-Treated Dendritic Cells Upregulate the Antitumor Efficacy of Dendritic Cells In Vivo

The members of the TGFβ superfamily play a key role in regulating developmental and homeostasis programs by controlling differentiation, proliferation, polarization, and survival of different cell types. Although the role of TGFβ1 in inflammation and immunity is well evident, the contribution of other TGFβ family cytokines in the modulation of the antitumor immune response remains less documented. Here we show that activin A triggers SMAD2 and ERK1/2 pathways in dendritic cells (DC) expressing type I and II activin receptors, and upregulates production of the TNFα family cytokines BAFF (TALL-1, TNFSF13B) and APRIL (TALL-2, TNFSF13A), which is blocked by SMAD2 and ERK1/2 inhibitors, respectively. BAFF and APRIL derived from activin A-treated DCs upregulate proliferation and survival of T cells expressing the corresponding receptors, BAFF-R and TACI. In vivo, activin A-stimulated DCs demonstrate a significantly increased ability to induce tumor-specific CTLs and inhibit the growth of melanoma and lung carcinoma, which relies on DC-derived BAFF and APRIL, as knockdown of the BAFF and APRIL gene expression in activin A-treated DCs blocks augmentation of their antitumor potential. Although systemic administration of activin A, BAFF, or APRIL for the therapeutic purposes is not likely due to the pluripotent effects on malignant and nonmalignant cells, our data open a novel opportunity for improving the efficacy of DC vaccines. In fact, a significant augmentation of the antitumor activity of DC pretreated with activin A and the proven role of DC-derived BAFF and APRIL in the induction of antitumor immunity in vivo support this direction. Cancer Res; 76(17); 4959-69. ©2016 AACR.

Phase 1 Study of Tabalumab, a Human Anti-B-Cell Activating Factor Antibody, and Bortezomib in Patients with Relapsed/Refractory Multiple Myeloma

PURPOSE

Tabalumab, a human mAb that neutralizes B-cell-activating factor (BAFF), demonstrated antitumor activity in xenograft models of multiple myeloma. Here we report on a phase I study of relapsed/refractory multiple myeloma patients in which the primary objective was to identify a tolerable and potentially efficacious dose of tabalumab when combined with bortezomib.

EXPERIMENTAL DESIGN

Forty-eight patients were enrolled; 20 to the dose-escalation cohort, and 28 to cohort expansion in which a dose of 100 mg of tabalumab was evaluated. All patients had received either prior bortezomib or an immunomodulatory drug; the median number of prior therapies was 3. Bortezomib was administered intravenously on days 1, 4, 8, and 11 of a 21-day schedule. Tabalumab was given every 21 days for 3 cycles, then every 42 days thereafter.

RESULTS

The most common grade 3/4 toxicities included thrombocytopenia, neutropenia, pneumonia, and peripheral sensory neuropathy. There were no dose-limiting toxicities, and the maximum tolerated dose was not reached. Pharmacokinetic data suggested serum exposure increased in a greater than dose-proportional manner up to a dose of 100 mg. Out of 46 evaluable patients, 20 had confirmed responses. The median time to progression (9 patients censored) was 4.8 months, and the median response duration (4 patients censored) was 7.2 months.

CONCLUSIONS

A dose of 100 mg tabalumab in combination with bortezomib was well tolerated and active and is currently under further investigation. Clin Cancer Res; 22(23); 5688-95. ©2016 AACR.

Glial cell activation, recruitment, and survival of B-lineage cells following MCMV brain infection

Background

Chemokines produced by reactive glia drive migration of immune cells and previous studies from our laboratory have demonstrated that CD19⁺ B cells infiltrate the brain. In this study, in vivo and in vitro experiments investigated the role of reactive glial cells in recruitment and survival of B-lineage cells in response to (murine cytomegalovirus) MCMV infection.

Methods

Flow cytometric analysis was used to assess chemokine receptor expression on brain-infiltrating B cells. Real-time RT-PCR and ELISA were used to measure chemokine levels. Dual-immunohistochemical staining was used to co-localize chemokine production by reactive glia. Primary glial cell cultures and migration assays were used to examine chemokine-mediated recruitment. Astrocyte: B cell co-cultures were used to investigate survival and proliferation.

Results

The chemokine receptors CXCR3, CXCR5, CCR5, and CCR7 were detected on CD19⁺ cells isolated from the brain during MCMV infection. In particular, CXCR3 was found to be elevated on an increasing number of cells over the time course of infection, and it was the primary chemokine receptor expressed at 60 days post infection Quite different expression kinetics were observed for CXCR5, CCR5, and CCR7, which were elevated on the highest number of cells early during infection and decreased by 14, 30, and 60 days post infection Correspondingly, elevated levels of CXCL9, CXCL10, and CXCL13, as well as CCL5, were found within the brains of infected animals, and only low levels of CCL3 and CCL19 were detected. Differential expression of CXCL9/CXCL10 and CXCL13 between microglia and astrocytes was apparent, and B cells moved towards supernatants from MCMV-infected microglia, but not astrocytes. Pretreatment with neutralizing Abs to CXCL9 and CXCL10 inhibited this migration. In contrast, neutralizing Abs to the ligand of CXCR5 (i.e., CXCL13) did not significantly block chemotaxis. Proliferation of brain-infiltrating B cells was detected at 7 days post infection and persisted through the latest time tested (60 days post infection). Finally, astrocytes produce BAFF (B cell activating factor of the TNF family) and promote proliferation of B cells via cell-to-cell contact.

Conclusions

CXCR3 is the primary chemokine receptor on CD19⁺ B cells persisting within the brain, and migration to microglial cell supernatants is mediated through this receptor. Correspondingly, microglial cells produce CXCL9 and CXCL10, but not CXCL13. Reactive astrocytes promote B cell proliferation.

Changes in inflammatory cytokine networks in myasthenia gravis

Myasthenia gravis (MG) is an autoimmunological inflammatory disorder of the neuromuscular junction. Inflammation could be a key player for understanding the pathogenesis of MG. We measured the serum levels of 24 inflammatory cytokines in 43 patients with anti-acetylcholine receptor antibody-positive MG and 25 healthy controls. In patients with MG, serum levels of a proliferation-inducing ligand (APRIL), IL-19, IL-20, IL-28A and IL-35 were significantly increased as compared with controls (p < 0.05). Among them, IL-20, IL-28A and IL-35 were significantly decreased after treatment (p < 0.05). In clinical subtype analyses, APRIL and IL-20 were increased in patients with late-onset MG and IL-28A levels were increased in patients with thymoma-associated MG compared with healthy controls (p < 0.01). The results of the present study demonstrate both anti-inflammatory and inflammatory cytokines are upregulated in MG, reflecting the importance of cytokine-mediated inflammation and its regulation in MG pathophysiology.

Immunologic profiles of multiple sclerosis treatments reveal shared early B cell alterations

Objective:

We undertook a systems immunology approach of the adaptive immune system in multiple sclerosis (MS), overcoming tradeoffs between scale and level of detail, in order to identify the immunologic signature of MS and the changes wrought by current immunomodulatory treatments.

Methods:

We developed a comprehensive flow cytometry platform measuring 38 immunologic cell types in the peripheral blood of 245 individuals in a routine clinical setting. These include patients with MS, untreated or receiving any of 4 current immunomodulatory treatments (interferon-β, glatiramer acetate, natalizumab, or fingolimod), patients with autoimmune thyroid disease, and healthy controls.

Results:

An increase in memory CD8⁺ T cells and B cells was observed in untreated patients with MS. Interferon-β and fingolimod induce significant changes upon multiple aspects of the peripheral immune system, with an unexpectedly prominent alteration of B cells. Overall, both treatments push the immune system in different directions, with only 2 significant effects shared across these treatments—an increase in transitional B cells and a decrease in class-switched B cells. We further identified heightened B cell-activating factor (BAFF) levels as regulating this shared B cell pathway.

Conclusions:

A systems immunology approach established different immunologic profiles induced by current immunomodulatory MS treatments, offering perspectives for personalized medicine. Pathways shared between the immunologic architecture of existing efficacious treatments identify targets for future treatment design.

The double-edge role of B cells in mediating antitumor T-cell immunity: Pharmacological strategies for cancer immunotherapy

Emerging evidence reveals the controversial role of B cells in antitumor immunity, but the underlying mechanisms have to be explored. Three latest articles published in the issue 521 of Nature in 2015 reconfirmed the puzzling topic and put forward some explanations of how B cells regulate antitumor T-cell responses both positively and negatively. This paper attempts to demonstrate that different B-cell subpopulations have distinct immunological properties and that they are involved in either antitumor responses or immunosuppression. Recent studies supporting the positive and negative roles of B cells in tumor development were summarized comprehensively. Several specific B-cell subpopulations, such as IgG(+), IgA(+), IL-10(+), and regulatory B cells, were described in detail. The mechanisms underlying the controversial B-cell effects were mainly attributed to different B-cell subpopulations, different B-cell-derived cytokines, direct B cell-T cell interaction, different cancer categories, and different malignant stages, and the immunological interaction between B cells and T cells is mediated by dendritic cells. Promising B-cell-based antitumor strategies were proposed and novel B-cell regulators were summarized to present interesting therapeutic targets. Future investigations are needed to make sure that B-cell-based pharmacological strategies benefit cancer immunotherapy substantially.

The Influence of Immunosuppressive Agents on the Risk of De Novo Donor-Specific HLA Antibody Production in Solid Organ Transplant Recipients

Production of de novo donor-specific antibodies (dnDSA) is a major risk factor for acute and chronic antibody-mediated rejection and graft loss after all solid organ transplantation. In this article, we review the data available on the risk of individual immunosuppressive agents and their ability to prevent dnDSA production. Induction therapy with rabbit antithymocyte globulin may achieve a short-term decrease in dnDSA production in moderately sensitized patients. Rituximab induction may be beneficial in sensitized patients, and in abrogating rebound antibody response in patients undergoing desensitization or treatment for antibody-mediated rejection. Use of bortezomib for induction therapy in at-risk patients is of interest, but the benefits are unproven. In maintenance regimens, nonadherent and previously sensitized patients are not suitable for aggressive weaning protocols, particularly early calcineurin inhibitor withdrawal without lymphocyte-depleting induction. Early conversion to mammalian target of rapamycin inhibitor monotherapy has been reported to increase the risk of dnDSA formation, but a combination of mammalian target of rapamycin inhibitor and reduced-exposure calcineurin inhibitor does not appear to alter the risk. Early steroid therapy withdrawal in standard-risk patients after induction has no known dnDSA penalty. The available data do not demonstrate a consistent effect of mycophenolic acid on dnDSA production. Risk minimization for dnDSA requires monitoring of adherence, appropriate risk stratification, risk-based immunosuppression intensity, and prospective DSA surveillance.

Biologics for the treatment of autoimmune renal diseases

Biological therapeutics (biologics) that target autoimmune responses and inflammatory injury pathways have a marked beneficial impact on the management of many chronic diseases, including rheumatoid arthritis, psoriasis, inflammatory bowel disease, and ankylosing spondylitis. Accumulating data suggest that a growing number of renal diseases result from autoimmune injury - including lupus nephritis, IgA nephropathy, anti-neutrophil cytoplasmic antibody-associated glomerulonephritis, autoimmune (formerly idiopathic) membranous nephropathy, anti-glomerular basement membrane glomerulonephritis, and C3 nephropathy - and one can speculate that biologics might also be applicable to these diseases. As many autoimmune renal diseases are relatively uncommon, with long natural histories and diverse outcomes, clinical trials that aim to validate potentially useful biologics are difficult to design and/or perform. Some excellent consortia are undertaking cohort studies and clinical trials, but more multicentre international collaborations are needed to advance the introduction of new biologics to patients with autoimmune renal disorders. This Review discusses the key molecules that direct injurious inflammation and the biologics that are available to modulate them. The opportunities and challenges for the introduction of relevant biologics into treatment protocols for autoimmune renal diseases are also discussed.

Interfering with baffled B cells at the lupus tollway: Promises, successes, and failed expectations

B cells play an important role in systemic lupus erythematosus by acting not only as precursors of autoantibody-producing cells but also as antigen-presenting, cytokine-secreting, and regulatory cells. Unopposed activation of B cells through their B-cell receptor for antigen, as seen in B cells lacking Lyn kinase, results in systemic autoimmunity. The B-cell activating factor of the TNF family (BAFF), nucleic acid-sensing Toll-like receptors (TLRs), and type I interferon can affect B-cell survival and decrease their threshold for activation. Herein we discuss both direct and indirect strategies aimed at targeting B cells in patients with lupus by blocking BAFF, type I interferon, or TLR7 to TLR9. Although BAFF-depleting therapy with belimumab achieved approval for lupus, other BAFF inhibitors were much less beneficial in clinical trials. Inhibitors of the B-cell receptor for antigen signaling and antibodies against type I interferon are in the pipeline. The TLR7 to TLR9 blocker hydroxychloroquine has been in use in patients with lupus for more than 50 years, but oligonucleotide-based inhibitors of TLR7 to TLR9, despite showing promise in animal models of lupus, have not reached the primary end point in a recent phase 1 trial. These data point toward possible redundancies in B-cell signaling/survival pathways, which must be better understood before future clinical trials are executed.

A pathogenic IFNα, BLyS and IL-17 axis in Systemic Lupus Erythematosus patients

This study aims to analyze in depth the role of IFNα in the upregulation of BLyS in different leukocyte populations and the possible relationship of these molecules with IL-17 and other pathogenic cytokines in SLE. Thus, IFNAR1 and membrane BLyS (mBLyS) expression was upregulated on various blood cell types from patients and closely correlated in all individuals. Moreover, BLyS serum levels associated positively with IFNα and IL-17A amounts, as well as with mBLyS on B cells and neutrophils. Interestingly, mBLyS on neutrophils was also correlated with IL-17A levels. Additionally, intracellular IL-17A expression was increased in both CD4⁺ lymphocytes and neutrophils from patients, and IL-17⁺CD4⁺ T cell frequency was associated with serum IFNα and IFNRA1 expression on B cells. Finally, in vitro assays support an IFNα role in the activation of Th17 cells in SLE. In conclusion, these data suggest that IFNα, BLyS and IL-17 could form a pathological axis in SLE, involving T and B lymphocytes, monocytes, DCs and neutrophils, which act in a vicious circle that encourage the preexisting inflammation and propagate the disease process.

Targeted approaches to induce immune tolerance for Pompe disease therapy

Enzyme and gene replacement strategies have developed into viable therapeutic approaches for the treatment of Pompe disease (acid α-glucosidase (GAA) deficiency). Unfortunately, the introduction of GAA and viral vectors encoding the enzyme can lead to detrimental immune responses that attenuate treatment benefits and can impact patient safety. Preclinical and clinical experience in addressing humoral responses toward enzyme and gene therapy for Pompe disease have provided greater understanding of the immunological consequences of the provided therapy. B- and T-cell modulation has been shown to be effective in preventing infusion-associated reactions during enzyme replacement therapy in patients and has shown similar success in the context of gene therapy. Additional techniques to induce humoral tolerance for Pompe disease have been the targeted expression or delivery of GAA to discrete cell types or tissues such as the gut-associated lymphoid tissues, red blood cells, hematopoietic stem cells, and the liver. Research into overcoming preexisting immunity through immunomodulation and gene transfer are becoming increasingly important to achieve long-term efficacy. This review highlights the advances in therapies as well as the improved understanding of the molecular mechanisms involved in the humoral immune response with emphasis on methods employed to overcome responses associated with enzyme and gene therapies for Pompe disease.

Recent Advances in the Treatment of Immune-Mediated Inflammatory Diseases

The treatment of immune-mediated inflammatory diseases (IMIDs) has dramatically improved over the last two decades by the development of a series of targeted biological therapies. This paper focuses on new developments in the treatment of IMIDs. In particular, we discuss how different ways of targeting the same mediators can lead to different efficacy and safety profiles, using B cell targeting as example. In addition, we discuss the emerging field of 'small molecules' that target specifically intracellular processes related to cytokine signaling, cell activation, cell migration, and other processes relevant to tissue inflammation.

B Cells, Antibodies, and More

B cells play a central role in the immunopathogenesis of glomerulonephritides and transplant rejection. B cells secrete antibodies that contribute to tissue injury via multiple mechanisms. In addition, B cells contribute to disease pathogenesis in autoimmunity and alloimmunity by presenting antigens as well as providing costimulation and cytokines to T cells. B cells also play an immunomodulatory role in regulating the immune response by secreting cytokines that inhibit disease onset and/or progression. B cell-targeted approaches for treating immune diseases of the kidney and other organs have gained significant momentum. However, much remains to be understood about B-cell biology in order to determine the timing, duration, and context of optimal therapeutic response to B cell-targeted approaches. In this review, we discuss the multifaceted roles of B cells as enhancers and regulators of immunity with relevance to kidney disease and transplantation.

Role of B Cell-Activating Factor in Chronic Obstructive Pulmonary Disease

RATIONALE

B cell-activating factor (BAFF) plays a major role in activation of B cells and in adaptive humoral immune responses. In chronic obstructive pulmonary disease (COPD), lymphoid follicles have been associated with disease severity, and overexpression of BAFF has been demonstrated within lymphoid follicles of patients with severe COPD.

OBJECTIVES

To investigate expression and localization of BAFF in the lungs of patients with COPD and to study the role of BAFF in COPD by antagonizing BAFF in a mouse model of chronic cigarette smoke (CS) exposure.

METHODS

We quantified and localized BAFF expression in lungs of never-smokers, smokers without COPD, and patients with COPD and in lungs of air- or CS-exposed mice by reverse-transcriptase polymerase chain reaction, ELISA, immunohistochemistry, and confocal imaging. Next, to investigate the role of BAFF in COPD, we antagonized BAFF by prophylactic or therapeutic administration of a soluble fusion protein of the BAFF-receptor, BAFFR-Fc, in mice exposed to air or CS for 24 weeks and evaluated several hallmarks of COPD and polarization of lung macrophages.

MEASUREMENTS AND MAIN RESULTS

BAFF expression was significantly increased in lungs of patients with COPD and CS-exposed mice. BAFF staining in lymphoid follicles was observed around B cells, CD4(+) cells, dendritic cells, follicular dendritic cells, and fibroblastic reticular cells. Prophylactic and therapeutic administration of BAFFR-Fc in mice reduced pulmonary B-cell numbers and prevented CS-induced formation of lymphoid follicles and increases in immunoglobulin levels. Interestingly, prophylactic BAFFR-Fc administration significantly attenuated pulmonary inflammation and destruction of alveolar walls. Moreover, antagonizing BAFF altered the phenotype of alveolar and interstitial macrophages.

CONCLUSIONS

BAFF is significantly increased in lungs of patients with COPD and is present around both immune and stromal cells within lymphoid follicles. Antagonizing BAFF in CS-exposed mice attenuates pulmonary inflammation and alveolar destruction.

Toll-like receptor signaling in primary immune deficiencies

Toll-like receptors (TLRs) recognize common microbial or host-derived macromolecules and have important roles in early activation of the immune system. Patients with primary immune deficiencies (PIDs) affecting TLR signaling can elucidate the importance of these proteins to the human immune system. Defects in interleukin-1 receptor-associated kinase-4 and myeloid differentiation factor 88 (MyD88) lead to susceptibility to infections with bacteria, while mutations in nuclear factor-κB essential modulator (NEMO) and other downstream mediators generally induce broader susceptibility to bacteria, viruses, and fungi. In contrast, TLR3 signaling defects are specific for susceptibility to herpes simplex virus type 1 encephalitis. Other PIDs induce functional alterations of TLR signaling pathways, such as common variable immunodeficiency in which plasmacytoid dendritic cell defects enhance defective responses of B cells to shared TLR agonists. Dampening of TLR responses is seen for TLRs 2 and 4 in chronic granulomatous disease (CGD) and X-linked agammaglobulinemia (XLA). Enhanced TLR responses, meanwhile, are seen for TLRs 5 and 9 in CGD, TLRs 4, 7/8, and 9 in XLA, TLRs 2 and 4 in hyper IgE syndrome, and for most TLRs in adenosine deaminase deficiency.

Increase of Intracellular BAFF in B Cells of Sjögren's Patients Is Not Affected by Decrease of BAFFR

The presence of a broad spectrum of autoantibodies in Sjögren's syndrome (SjS) patients is the result of abnormal B-cell regulation that can be at least partially explained by abnormal BAFF/BAFFR regulation. The objective of this study was to determine both membrane and intracellular expression of BAFF/BAFFR in monocytes and B-cells in peripheral blood of 19 primary Sjögren's syndrome patients and 20 healthy controls using flow cytometry. We also measured sBAFF in serum. Compared to healthy controls, both surface and intracellular expression of BAFF was significantly increased in monocytes and B-cells of SjS patients. Also serum sBAFF level was elevated. Expression of BAFFR on B-cells of SjS patients was surprisingly decreased, but there was no clear increase or decrease within monocytes. Our results indicate that activated monocytes communicate with B-cells via BAFF and BAFFR, so that B-cells are stimulated, but BAFF is also produced to stimulate cells in autocrine way. The decrease of BAFFR expression in SjS patients suggests that there is the mechanism that attempts to take over in order to balance the high level of BAFF.

Hypersensitivity Responses in the Central Nervous System

Immune-mediated tissue damage or hypersensitivity can be mediated by autospecific IgG antibodies. Pathology results from activation of complement, and antibody-dependent cellular cytotoxicity, mediated by inflammatory effector leukocytes include macrophages, natural killer cells, and granulocytes. Antibodies and complement have been associated to demyelinating pathology in multiple sclerosis (MS) lesions, where macrophages predominate among infiltrating myeloid cells. Serum-derived autoantibodies with predominant specificity for the astrocyte water channel aquaporin-4 (AQP4) are implicated as inducers of pathology in neuromyelitis optica (NMO), a central nervous system (CNS) demyelinating disease where activated neutrophils infiltrate, unlike in MS. The most widely used model for MS, experimental autoimmune encephalomyelitis, is an autoantigen-immunized disease that can be transferred to naive animals with CD4⁺ T cells, but not with antibodies. By contrast, NMO-like astrocyte and myelin pathology can be transferred to mice with AQP4–IgG from NMO patients. This is dependent on complement, and does not require T cells. Consistent with clinical observations that interferon-beta is ineffective as a therapy for NMO, NMO-like pathology is significantly reduced in mice lacking the Type I IFN receptor. In MS, there is evidence for intrathecal synthesis of antibodies as well as blood–brain barrier (BBB) breakdown, whereas in NMO, IgG accesses the CNS from blood. Transfer models involve either direct injection of antibody and complement to the CNS, or experimental manipulations to induce BBB breakdown. We here review studies in MS and NMO that elucidate roles for IgG and complement in the induction of BBB breakdown, astrocytopathy, and demyelinating pathology. These studies point to significance of T-independent effector mechanisms in neuroinflammation.

Association of BAFF, APRIL serum levels, BAFF-R, TACI and BCMA expression on peripheral B-cell subsets with clinical manifestations in systemic lupus erythematosus

Objective

B-cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) signaling pathways regulate B-cell survival through interactions with their receptors BAFF-R, TACI and BCMA. We evaluated the association of these ligands/receptors on B-cell subsets according to clinical manifestations of systemic lupus erythematosus (SLE).

Methods

BAFF and APRIL serum concentrations were measured in 30 SLE patients by enzyme-linked immunosorbent assay. The BAFF-R, TACI and BCMA expression was analyzed on each B cell subset (CD19 + CD27-CD38–/ + naïve; CD19 + CD27 + CD38–/ + memory; CD19 + CD27-CD38 + + immature and CD19 + CD27 + CD38 + + plasma cells) by flow cytometry, and compared among patients with different clinical manifestations as well as healthy controls (HCs).

Results

Serum BAFF and APRIL levels were high in SLE patients and correlated with the Mex-SLEDAI disease activity index ( r = 0.584; p = 0.001 and r = 0.456; p = 0.011, respectively). The SLE patients showed an increased proportion of memory and plasma B cells ( p < 0.05). BAFF-R, TACI and BCMA expression in SLE patients was decreased in almost all B cell subsets compared to HCs ( p < 0.05). A lower BCMA expression was associated with severe disease activity, glomerulonephritis, serositis and hemolytic anemia ( p < 0.01). BCMA expression showed a negative correlation with Mex-SLEDAI score ( r = –0.494, p = 0.006).

Conclusions

Decreased BCMA expression on peripheral B cells according to severe disease activity suggests that BCMA plays an important regulating role in B-cell hyperactivity and immune tolerance homeostasis in SLE patients.

The regulatory role of B cells in autoimmunity, infections and cancer: Perspectives beyond IL10 production

The term regulatory B cells (B regs) is ascribed to a heterogeneous population of B cells with the function of suppressing inflammatory responses. They have been described mainly during the last decade in the context of different immune-mediated diseases. Most of the work on B regs has been focused on IL-10-producing B cells. However, B cells can exert regulatory functions independently of IL-10 production. Here we discuss the phenotypes, development and effector mechanisms of B regs and advances in their role in autoimmunity, infections and cancer.

The Clinical Relevance of IL-17-Producing CD4+CD161+ Cell and Its Subpopulations in Primary Sjögren's Syndrome

Objective. Th17 cells have been demonstrated to play an important role in the onset and development of primary Sjögren's syndrome (pSS). In this study, we evaluated the expansion and clinical significance of circulating CD4+CD161+ T cell and its “effector” (CD4+CD25−CD161+ T cell) and “regulatory” (CD4+CD25+CD161+ T cell) subpopulations. Methods. Fifty-eight pSS patients and 16 healthy controls (HCs) were recruited in our study. The cell populations and intracellular IL-17 expression were analyzed by flow cytometry. The disease activity was evaluated by the EULAR-SS Disease Activity Index (ESSDAI). Autoantibodies were measured by ELISA or indirect immunofluorescence assay. Results. The CD161+ T cell fractions showed higher proportions of IL-17-producing cells. The frequencies of the overall CD4+CD161+ T cell population and its effector subset were positively correlated with disease activity parameters and more severe disease manifestations. A significant elevation of the CD4+CD25+CD161+ T cell subpopulation was observed in the peripheral blood of pSS patients compared to HCs and this subset showed decreased regulatory functions compared with the CD4+CD25+CD161− population. Conclusion. Circulating CD4+CD161+ T cell populations associated with pSS disease activity and severity. These cells might be involved in the development of pSS and could be potential therapeutic targets in the treatment of pSS.

TSP-1 Deficiency Alters Ocular Microbiota: Implications for Sjögren's Syndrome Pathogenesis

PURPOSE

The potential role of commensals as triggering factors that promote inflammation in dry eye disease has not been explored. The objective of this study was to evaluate whether ocular microbiota changes with the onset of dry eye disease in thrombospondin-1-deficient (TSP-1(-/-)) mice, a strain that develops Sjögren's syndrome-like disease.

METHODS

Conjunctival swabs were collected from TSP-1(-/-) and C57BL/6 mice and analyzed for bacterial presence. Opsonophagocytosis of the bacterial conjunctival isolates derived from the aged TSP-1(-/-) mice by neutrophils derived from either TSP-1(-/-) or C57BL/6 bone marrow was evaluated. The bactericidal activities of TSP-1-derived peptide were examined.

RESULTS

We found that in TSP-1(-/-) mice, the conjunctival colonization with Staphylococcus aureus and coagulase negative staphylococci sp (CNS) species was significantly increased with aging and preceded that of the wild-type C57BL/6 control mice. This correlated with increased neutrophil infiltration into the conjunctiva of the TSP-1(-/-) mice, suggesting that TSP-1 plays a significant role in regulating immunity to commensals. Accordingly, the TSP-1(-/-) PMNs opsonophagocytozed the ocular commensals less efficiently than the TSP-1-sufficient neutrophils. Furthermore, a TSP-1-derived peptide, 4N1K, exhibited significant antimicrobial activity when compared to a control peptide against commensal sp.

CONCLUSION

These studies illustrate that alterations in the commensal frequency occur in the early stages of development of Sjögren's-like pathology and suggest that interventions that limit commensal outgrowth such as the use of TSP-1-derived peptides could be used for treatment during the early stages of the disease to reduce the commensal burden and ensuing inflammation.

B-cell survival factors in autoimmune rheumatic disorders

Autoimmune rheumatic disorders have complex etiopathogenetic mechanisms in which B cells play a central role. The importance of factors stimulating B cells, notably the B-cell activating factor (BAFF) and A proliferation inducing ligand (APRIL) axis is now recognized. BAFF and APRIL are cytokines essential for B-cell proliferation and survival from the immature stages to the development of plasma cells. Their levels are increased in some subsets of patients with autoimmune disorders. Several recent biologic drugs have been developed to block this axis, namely belimumab [already licensed for systemic lupus erythematosus (SLE) treatment], tabalumab, atacicept and blisibimod. Many clinical trials to evaluate the safety and efficacy of these drugs in several autoimmune disorders are ongoing, or have been completed recently. This review updates the information on the use of biologic agents blocking BAFF/APRIL for patients with SLE, rheumatoid arthritis, Sjögren's syndrome and myositis.

The role of chemokine C-C motif ligand 2 genotype and cerebrospinal fluid chemokine C-C motif ligand 2 in neurocognition among HIV-infected patients

OBJECTIVES

We examined interrelationships between chemokine C-C motif ligand 2 (CCL2) genotype and expression of inflammatory markers in the cerebrospinal fluid (CSF), plasma viral load, CD4 cell count and neurocognitive functioning among HIV-infected adults. We hypothesized that HIV-positive carriers of the 'risk' CCL2 -2578G allele, caused by a single nucleotide polymorphism (SNP) at rs1024611, would have a higher concentration of CCL2 in CSF, and that CSF CCL2 would be associated with both higher concentrations of other proinflammatory markers in CSF and worse neurocognitive functioning.

DESIGN

A cross-sectional study of 145 HIV-infected individuals enrolled in the National NeuroAIDS Tissue Consortium cohort for whom genotyping, CSF and neurocognitive data were available.

METHODS

Genomic DNA was extracted from peripheral blood mononuclear cells and/or frozen tissue specimens. CSF levels of CCL2, interleukin (IL)-2, IL-6, tumour necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), soluble tumor necrosis factor receptor 2, sIL-6Rα, sIL-2, sCD14 and B-cell activating factor were quantified. Neurocognitive functioning was measured using a comprehensive battery of neuropsychological tests.

RESULTS

Carriers of the CCL2 -2578G allele had a significantly higher concentration of CCL2 in CSF. CSF CCL2 level was positively and significantly associated with other CSF neuroinflammatory markers and worse cognitive functioning. There was a significant association between genotype and plasma viral load, such that carriers of the CCL2 -2578G allele with high viral load expressed greater levels of CCL2 and had higher neurocognitive deficit scores than other genotype/viral load groups.

CONCLUSION

Individuals with the CCL2 -2578G allele had higher levels of CCL2 in CSF, which was associated with increased pro-inflammatory markers in CSF and worse neurocognitive functioning. The results highlight the potential role of intermediate phenotypes in studies of genotype and cognition.

TACI deficiency leads to alternatively activated macrophage phenotype and susceptibility to Leishmania infection

The TNF family member, transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI), is a key molecule for plasma cell maintenance and is required in infections where protection depends on antibody response. Here, we report that compared with WT mouse, TACI KO Μϕs expressed lower levels of Toll-like receptors (TLRs), CD14, myeloid differentiation primary response protein 88, and adaptor protein Toll/IL-1 receptor domain-containing adapter-inducing IFN-β and responded poorly to TLR agonists. Analysis of Μϕ phenotype revealed that, in the absence of TACI, Μϕs adapt the alternatively activated (M2) phenotype. Steady-state expression levels for M2 markers IL-4Rα, CD206, CCL22, IL-10, Arg1, IL1RN, and FIZZ1 were significantly higher in TACI KO Μϕ than in WT cells. Confirming their M2 phenotype, TACI-KO Mϕs were unable to control Leishmania major infection in vitro, and intradermal inoculation of Leishmania resulted in a more severe manifestation of disease than in the resistant C57BL/6 strain. Transfer of WT Μϕs to TACI KO mice was sufficient to significantly reduce disease severity. TACI is likely to influence Mϕ phenotype by mediating B cell-activating factor belonging to the TNF family (BAFF) and a proliferation inducing ligand (APRIL) signals because both these ligands down-regulated M2 markers in WT but not in TACI-deficient Μϕs. Moreover, treatment of Μϕs with BAFF or APRIL enhanced the clearance of Leishmania from cells only when TACI is expressed. These findings may have implications for understanding the shortcomings of host response in newborns where TACI expression is reduced and in combined variable immunodeficiency patients where TACI signaling is ablated.

The BAFF receptor TACI controls IL-10 production by regulatory B cells and CLL B cells

Interleukin (IL)-10-producing B cells (B10 cells) have emerged as important regulatory players with immunosuppressive roles. Chronic lymphocytic leukemia (CLL) B cells also secrete IL-10 and share features of B10 cells, suggesting a possible contribution of CLL B cells to immunosuppression in CLL patients. Factors controlling the emergence of B10 cells are not known. B cell-activating factor of the tumour necrosis factor (TNF) family (BAFF) is critical for B cell maturation and survival, and is implicated in the development and progression of CLL. We sought to investigate the role of BAFF in the emergence of IL-10-producing B regulatory cells in healthy donors and CLL patients. Here, we report that BAFF signaling promotes IL-10 production by CLL B cells in a mouse model of CLL and in CLL patients. Moreover, BAFF-mediated IL-10 production by normal and CLL B cells is mediated via its receptor TACI. Our work uncovered a major targetable pathway important for the generation of regulatory B cells that is detrimental to immunity in CLL.

High expression levels of BLyS/BAFF by blood dendritic cells and granulocytes are associated with B-cell dysregulation in SIV-infected rhesus macaques

Dendritic cells (DCs) modulate B-cell survival and differentiation, mainly through production of growth factors such as B lymphocyte stimulator (BLyS/BAFF). In recent longitudinal studies involving HIV-1-infected individuals with different rates of disease progression, we have shown that DCs were altered in number and phenotype in the context of HIV-1 disease progression and B-cell dysregulations were associated with increased BLyS/BAFF expression in plasma and by blood myeloid DCs (mDCs) in rapid and classic progressors but not in HIV-1-elite controllers (EC). Suggesting that the extent to which HIV-1 disease progression is controlled may be linked to BLyS/BAFF expression status and the capacity to orchestrate B-cell responses. Herein, longitudinal analyses of simian immunodeficiency virus (SIV)-infected rhesus macaques also revealed increased expression of BLyS/BAFF by blood mDCs as soon as day 8 and throughout infection. Strikingly, granulocytes presented the highest BLyS/BAFF expression profile in the blood of SIV-infected macaques. BLyS/BAFF levels were also increased in plasma and correlated with viral loads. Consequently, these SIV-infected animals had plasma hyperglobulinemia and reduced blood B-cell numbers with altered population frequencies. These data underscore that BLyS/BAFF is associated with immune dysregulation in SIV-infected rhesus macaques and suggest that BLyS/BAFF is a key regulator of immune activation that is highly conserved among primates. These findings emphasize the potential importance of this SIV-infected primate model to test whether blocking excess BLyS/BAFF has an effect on the overall inflammatory burden and immune restoration.

γ-Secretase directly sheds the survival receptor BCMA from plasma cells

Survival of plasma cells is regulated by B-cell maturation antigen (BCMA), a membrane-bound receptor activated by its agonist ligands BAFF and APRIL. Here we report that γ-secretase directly cleaves BCMA, without prior truncation by another protease. This direct shedding is facilitated by the short length of BCMA's extracellular domain. In vitro, γ-secretase reduces BCMA-mediated NF-κB activation. In addition, γ-secretase releases soluble BCMA (sBCMA) that acts as a decoy neutralizing APRIL. In vivo, inhibition of γ-secretase enhances BCMA surface expression in plasma cells and increases their number in the bone marrow. Furthermore, in multiple sclerosis, sBCMA levels in spinal fluid are elevated and associated with intracerebral IgG production; in systemic lupus erythematosus, sBCMA levels in serum are elevated and correlate with disease activity. Together, shedding of BCMA by γ-secretase controls plasma cells in the bone marrow and yields a potential biomarker for B-cell involvement in human autoimmune diseases.

B-cell maturation antigen (BCMA) regulates the survival of B cells and is essential for the maintenance of long-lived plasma cells. Here, the authors show that γ-secretase directly sheds BCMA from the cell surface and therefore regulates the number of plasma cells.

High fidelity between saliva proteomics and the biologic state of salivary glands defines biomarker signatures for primary Sjögren's syndrome

OBJECTIVE

Dependence on invasive procedures for classification of patients with Sjögren's syndrome (SS) hampers timely diagnosis and suitable patient followup. The aim of this study was to recapitulate the diagnosis of SS through noninvasive means and to define the biologic state of SS patients' salivary glands.

METHODS

Using a 187-plex capture antibody-based assay, salivary proteomic biomarker profiles were generated from patients with primary SS, patients with rheumatoid arthritis, and asymptomatic controls. Discriminant function analyses and Gene Ontology-based network analyses allowed data analyses with a reductionist approach and with a focus on systems biology.

RESULTS

Characterized by significant changes in 61 and 55 proteins, respectively, the salivary proteome of SS patients appeared profoundly altered compared to that of individuals without SS. On this basis, 4-plex and 6-plex biomarker signatures, both including interleukin-4 (IL-4), IL-5, and clusterin, achieved accurate prediction of an individual's group membership for at least 94% of cases. Of note, all misclassified SS patients presented with ectopic germinal center-like structures. Systematic inference of biologic meaning identified SS-related protein patterns delineating B cell-dominated immune responses, macrophage differentiation, and signs of T cell chemotaxis. In addition, proteomic Multi-Analyte Profiles provided insight about proteins related to collagen, cytokine, and growth factor synthesis as well as lipid transport.

CONCLUSION

The SS-related molecular landscape conveyed by saliva showed great congruence with histopathologic features found in SS and advances understanding of this disease at a molecular level. Such salivary biomarker signatures harbor great potential for improving timeliness of SS diagnosis and enabling suitable patient followup.

Treatment of Bullous Systemic Lupus Erythematosus

Bullous systemic lupus erythematosus (BSLE) is an autoantibody-mediated vesiculobullous disease in patients with SLE. Autoimmunity in BSLE is characterized by the presence of circulating anti-type VII collagen antibodies. BSLE patients often present with multiple, tense, clear fluid-filled vesicles and bullae overlying erythematous edematous plaques. Skin biopsy from BSLE patients shows subepidermal bullae with numerous neutrophils and only occasional eosinophils. Furthermore, immunofluorescence examination showed linear deposition of lgG, lgA, C3, and C1q along the basement membrane zone. BSLE patients with corticosteroids treatment constantly do not receive a marked improvement, while dapsone generally dramatically improved the skin condition. Recently, it has been reported that quite a few cases of BSLE were successfully treated with other immune suppressive drugs. Therefore, a comprehensive review of the treatment of BSLE would be beneficial to cure the disease.