New treatments for SLE: cell-depleting and anti-cytokine therapies

Model-based meta-analysis using latent variable modeling to set benchmarks for new treatments of systemic lupus erythematosus

Several investigational agents are under evaluation in systemic lupus erythematosus (SLE) clinical trials but quantitative frameworks to enable comparison of their efficacy to reference benchmark treatments are lacking. To benchmark SLE treatment effects and identify clinically important covariates, we developed a model-based meta-analysis (MBMA) within a latent variable model framework for efficacy end points and SLE composite end point scores (BILAG-based Composite Lupus Assessment and Systemic Lupus Erythematosus Responder Index) using aggregate-level data on approved and investigational therapeutics. SLE trials were searched using PubMed and www.clinicaltrials.gov for treatment name, SLE and clinical trial as search criteria that resulted in four data structures: (1) study and investigational agent, (2) dose and regimen, (3) baseline descriptors, and (4) outcomes. The final dataset consisted of 25 studies and 81 treatment arms evaluating 16 different agents. A previously developed (K Goteti et al. 2022) SLE latent variable model of data from placebo arms (placebo + standard of care treatments) was used to describe aggregate SLE end points over time for the various SLE placebo and treatment arms in a Bayesian MBMA framework. Continuous dose-effect relationships using a maximum effect model were included for anifrolumab, belimumab, CC-220 (iberdomide), epratuzumab, lulizumab pegol, and sifalimumab, whereas the remaining treatments were modeled as discrete dose effects. The final MBMA model was then used to benchmark these compounds with respect to the maximal efficacy on the latent variable compared to the placebo. This MBMA illustrates the application of latent variable models in understanding the trajectories of composite end points in chronic diseases and should enable model-informed development of new investigational agents in SLE.

The Role of IL-36 in the Pathophysiological Processes of Autoimmune Diseases

A member of the interleukin (IL)-1 superfamily was IL-36, which contained IL-36α, IL-36β, IL-36γ, and IL-36Ra. Heterotrimer complexes, consisting of heterodimeric receptor complexes and IL-36 agonist, gave signals through intracellular functional domains, so as to bind to downstream proteins and induce inflammatory response. IL-36 agonists upregulated mature-associated CD80, CD86, MHCII, and inductively produced several pro-inflammatory cytokines through the IL-36R-dependent manner in dendritic cells (DCs). Besides, DCs had the ability to initiate the differentiation of helper T (Th) cells. Up to date, the role of IL-36 in immunity, inflammation and other diseases is of great importance. Additionally, autoimmune diseases were characterized by excessive immune response, resulting in damage and dysfunction of specific or multiple organs and tissues. Most autoimmune diseases were related to inflammatory response. In this review, we will conclude the recent research advances of IL-36 in the occurrence and development of autoimmune diseases, which may provide new insight for the future research and the treatment of these diseases.

Association of microRNA-125a with the clinical features, disease activity and inflammatory cytokines of juvenile-onset lupus patients

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with marked variation in its clinical presentation. Juvenile-onset SLE (jSLE) exhibits an aggressive clinical phenotype and severe complications. Dysregulated expression of microRNAs (miRs) in immune cells from patients with SLE has been found. We aim to evaluate the association of miR-125a with the clinical and laboratory characteristics, disease activity and inflammatory cytokines of jSLE patients.

METHODS

60 jSLE patients and 25 normal controls were involved in the study. The expression pattern of miR-125a was determined in plasma of all subjects using qRT-PCR. In addition, plasma levels of IL-17 and IFN-γ were examined using ELISA. The correlation of miR-125a expression with the clinical manifestations and disease activity of jSLE patients was analyzed. Also, its association with the inflammatory cytokines was investigated in jSLE patients.

RESULTS

Our findings showed that miR-125a expression levels were significantly reduced in jSLE patients compared to normal controls (p < 0.01) and these expression levels differed based on the clinical variability of patients. In addition, plasma levels of IL-17 and IFN-γ in jSLE patients were significantly higher than healthy controls (p < 0.01). Finally, miR-125a expression had significant negative associations with each of SLEDAI-2K (p < 0.01), SLICC (p < 0.01), ESR (p < 0.05), proteinuria (p < 0.01) and IL-17 levels (p < 0.01) in jSLE patients.

CONCLUSION

Our findings postulate that miR-125a could act as a candidate therapeutic target for its possible regulation of inflammation in jSLE patients.

Shotgun Lipidomics Revealed Altered Profiles of Serum Lipids in Systemic Lupus Erythematosus Closely Associated with Disease Activity

The pathogenesis of systemic lupus erythematosus (SLE) remains elusive. It appears that serum lipid metabolism is aberrant in SLE patients. Determination of lipid profiles in the serum of SLE patients may provide insights into the underlying mechanism(s) leading to SLE and may discover potential biomarkers for early diagnosis of SLE. This study aimed to identify and quantify the profile of serum lipids in SLE patients (N = 30) with our powerful multi-dimensional mass spectrometry-based shotgun lipidomics platform. Multivariate analysis in the form of partial least squares-discriminate analysis was performed, and the associations between the changed lipids with cytokines and SLE disease activity index (SLEDAI) were analyzed using a multiple regression method. The results of this study indicated that the composition of lipid species including diacyl phosphatidylethanolamine (dPE) (16:0/18:2, 18:0/18:2, 16:0/22:6, 18:0/20:4, and 18:0/22:6), 18:2 lysoPC (LPC), and ceramide (N22:0 and N24:1) was significantly altered in SLE patients with p < 0.05 and variable importance of the projection (VIP) > 1 in partial least squares-discriminate analysis (PLS-DA). There existed significant associations between IL-10, and both 18:0/18:2 and 16:0/22:6 dPE species with p < 0.0001 and predicting 85.7 and 95.8% of the variability of IL-10 levels, respectively. All the altered lipid species could obviously predict IL-10 levels with F (8, 21) = 3.729, p = 0.007, and R² = 0.766. There was also a significant correlation between the SLEDAI score and 18:0/18:2 dPE (p = 0.031) with explaining 22.6% of the variability of SLEDAI score. Therefore, the panel of changed compositions of dPE and ceramide species may serve as additional biomarkers for early diagnosis and/or prognosis of SLE.

In vivo study: Th1-Th17 reduction in pristane-induced systemic lupus erythematosus mice after treatment with tolerogenic Lactobacillus probiotics

Uncontrolled inflammation in systemic lupus erythematosus (SLE) could cause dysfunction in multiple organs. T helper 17 (Th17) cells are a main branch of inflammatory responses in the pathogenesis of SLE, and by producing interleukin 17 (IL-17), represent a major functional tool in the progression of inflammation. Animal models provide a special field for better studies of the pathogenesis of diseases. Tolergenic probiotics could decrease inflammation in autoimmune diseases by modulating the immune system and maintaining homeostasis. The aim of this project was to evaluate the effects of Lactobacillus rhamnosus and Lactobacillus delbrueckii on Th17 cells and their related mediators in a pristane-induced BALB/c mice model of SLE. The mice were divided into pretreatment groups, which received probiotics or prednisolone at Day 0, and treatment groups, which received probiotics and prednisolone 2 months after injection. The presence of antinuclear antibody (ANA), anti-double-stranded DNA (anti-dsDNA), and anti-ribonucleoprotein (anti-RNP) and lipogranuloma was evaluated; also, the population of Th1-Th17 cells as well as interferon γ (IFN-γ), IL-17, and IL-10 levels, and the expression of RAR-related orphan related receptor gamma (RORγt) and IL-17 were determined. We observed that probiotics and prednisolone could delay SLE in pretreatment and treatment mice groups, with a reduction in ANA, anti-dsDNA, anti-RNP, and mass of lipogranuloma. Probiotics and prednisolone decreased the population of Th1-Th17 cells and reduced IFN-γ and IL-17 as inflammatory cytokines in the pretreatment and treatment groups in comparison with SLE-induced mice. Our results indicated that, due to their anti-inflammatory properties and reduction of Th17, Th1, and cytotoxic T lymphocyte (CTL) cells, the use of these probiotics could probably represent a new tool for the better management of SLE.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

A fully human monoclonal antibody with novel binding epitope and excellent neutralizing activity to multiple human IFN-α subtypes: A candidate therapy for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic, heterogeneous autoimmune disease short of effective therapeutic agents. A multitude of studies of SLE in the last decade have accentuated a central role of the interferon alpha (IFN-α) pathway in SLE pathogenesis. We report here a candidate therapeutic neutralizing antibody, AIA22, with a different binding epitope and discrepant neutralizing profile from the anti-multiple IFN-α subtype antibodies currently in clinical trials. AIA22 specifically interacts with multiple IFN-α subtypes, binds to the type I IFN receptor 2 (IFNAR2) recognition region of IFN-α (considered a novel antigen epitope), and effectively neutralizes the activity of almost all of the IFN-α subtypes (with the exception of IFN-α7) both in vitro and in vivo. Concurrently, structural modeling and computational design yielded a mutational antibody of AIA22, AIAmut, which exhibited substantially improved neutralizing activity to multiple IFN-α subtypes.

[Modulating the survival and maturation system of B lymphocytes: Current and future new therapeutic strategies in systemic lupus erythematosus]

Systemic lupus erythematosus is an autoimmune disease associated with an aberrant production of autoantibodies by self-reactive B lymphocytes. The study of the phenotypic characteristics of B lymphocytes and the identification of their surface receptors such as BAFF-R, TACI and BCMA, which are responsible of their survival and maturation, have contributed to the development of new therapeutic strategies in recent years.

B cell follicle sanctuary permits persistent productive simian immunodeficiency virus infection in elite controllers

Chronic-phase HIV and simian immunodeficiency virus (SIV) replication is reduced by as much as 10,000-fold in elite controllers (ECs) compared with typical progressors (TPs), but sufficient viral replication persists in EC tissues to allow viral sequence evolution and induce excess immune activation. Here we show that productive SIV infection in rhesus monkey ECs, but not TPs, is markedly restricted to CD4(+) follicular helper T (TFH) cells, suggesting that these EC monkeys' highly effective SIV-specific CD8(+) T cells can effectively clear productive SIV infection from extrafollicular sites, but their relative exclusion from B cell follicles prevents their elimination of productively infected TFH cells. CD8(+) lymphocyte depletion in EC monkeys resulted in a dramatic re-distribution of productive SIV infection to non-TFH cells, with restriction of productive infection to TFH cells resuming upon CD8(+) T cell recovery. Thus, B cell follicles constitute 'sanctuaries' for persistent SIV replication in the presence of potent anti-viral CD8(+) T cell responses, potentially complicating efforts to cure HIV infection with therapeutic vaccination or T cell immunotherapy.

Effect of proinflammatory cytokines (IL-6, TNF-α, and IL-1β) on clinical manifestations in Indian SLE patients

Systemic lupus erythematosus (SLE) is an inflammatory rheumatic disease characterized by production of autoantibodies and organ damage. Elevated levels of cytokines have been reported in SLE patients. In this study we have investigated the effect of proinflammatory cytokines (IL-6, TNF-α, and IL-1β) on clinical manifestations in 145 Indian SLE patients. One hundred and forty-five healthy controls of the same ethnicity served as a control group. Clinical disease activity was scored according to SLEDAI score. Accordingly, 110 patients had active disease and 35 patients had inactive disease. Mean levels of IL-6, TNF-α, and IL-1β were found to be significantly higher in SLE patients than healthy controls (P < 0.001). Mean level of IL-6 for patients with active disease (70.45±68.32 pg/mL) was significantly higher (P = 0.0430) than those of inactive disease patients (43.85±63.36 pg/mL). Mean level of TNF-α was 44.76±68.32 pg/mL for patients with active disease while it was 25.97±22.03 pg/mL for those with inactive disease and this difference was statistically significant (P = 0.0161). Similar results were obtained for IL-1β (P = 0.0002). Correlation between IL-6, TNF-α, and IL-1β serum levels and SLEDAI score was observed (r = 0.20, r = 0.27, and r = 0.38, resp.). This study supports the role of these proinflammatory cytokines as inflammatory mediators in active stage of disease.

Clinical trials in systemic lupus erythematosus: a status report on ongoing trials

To describe the characteristics of trials in systemic lupus erythematous (SLE) listed in ClinicalTrials.gov such as study design, funding sources and aspects of the disease and drugs under investigation. We conducted a survey of ongoing clinical trials that were registered in the ClinicalTrials.gov website. We used the advanced search option and applied the following inclusion criteria, "SLE," "open studies," "interventional," and "adults 18 years or older." Of 97 eligible studies, 34.0 % were phase 3 or 4, 49.5 % were phase 1, 2 or 2/3 and in 16.5 %, we could not determine the study phase. Most trials were randomized (69.0 %) and 48.4 % were double blinded; 34 % of the trials were placebo controlled, 19.6 % had an active agent comparator and 46.4 % had no comparator. Universities and pharmaceutical industries were the primary sponsors for 45.3 and 39.1 % of the trials, respectively, and government agencies for 10.3 %. Multi-center trials based in the USA (US) accounted for 40.2 % of the trials, 46.4 % were outside of the US and 13.4 % were in the US as well as other countries. The most frequently used endpoint was drug efficacy (30.9 %) followed by disease severity indices (25.7 %), drug safety (14.4 %), remission rates and times to remission (7.2 %), and inflammatory markers and antibody titers (7.2 %). The majority of ongoing clinical trials in SLE are university or industry-funded, randomized phase 1, 2, or 2/3 trials, focused on drug efficacy. Federal funding for trials in SLE within and outside the US remains low.

Pathology of systemic lupus erythematosus: the challenges ahead

Many studies have explored the pathology of systemic lupus erythematosus (SLE), an autoimmune rheumatic disorder with a striking female predominance. Numerous autoimmune phenomena are present in this disease, which ultimately result in organ damage. However, the specific cellular and humoral mechanisms underlying the immune dysfunction are not yet fully understood. It is postulated that autoimmunity is based on the interaction of genetic predisposition, hormonal and environmental triggers that result in reduced tolerance to self-tissues. These phenomena could occur because of altered antigen presentation, abnormalities in B cell responses, increases in the function of T-helper cells, abnormal cytokine production, exaggerated effector responses, or loss of regulatory T cells or B cells. Abnormalities in all of these components of the immune response have been implicated to varying degrees in the pathogenesis of SLE. This chapter will attempt to provide a "state-of-the-art" review of the evidence about the mechanisms underlying the pathology of SLE.

Immunopathogenic mechanisms of systemic autoimmune disease

Systemic lupus erythematosus, Sjögren's syndrome, and dermatomyositis are systemic autoimmune diseases that develop after environmental triggering of genetically susceptible individuals. The precise cellular and molecular mechanisms leading to autoimmune disease, and what factors determine which organs are involved, remain poorly understood. Recent insights into genetic susceptibility now make obvious that environmental triggers often act via cellular pathways containing disease-associated polymorphisms. In the breaking of tolerance, the initiating tissue--including dendritic cells--provides a decisive microenvironment that affects immune-cell differentiation, leading to activation of adaptive immunity. Type 1 interferon produced by innate immune cells has a central role in systemic autoimmunity and activates B cells and T cells. In turn, B-cell-derived autoantibodies stimulate dendritic cells to produce type 1 interferon; thus, a positive feedforward loop is formed that includes both the innate and adaptive systems. New treatments could simultaneously and specifically target several such vital pathways in autoimmunity.

Systemic lupus erythematosus: clinical manifestations, treatment and economics

Systemic lupus erythematosus (SLE) is a complex, multisystem disease that is characterized by variable and unpredictable manifestations that are often life-threatening. Although the prognosis has improved dramatically over the past 50 years, individuals with SLE still experience considerable morbidity and undue mortality. Furthermore, since SLE affects a predominantly young population at a critical time in their lives when they are establishing careers and starting families, the economic burden to society can be immense. Only three medications have ever received US FDA approval for use in the treatment of SLE and none have received FDA approval for over 25 years. Currently used therapies may have improved the prognosis but often have undesirable side effects, such as infertility, bone-marrow suppression and infection. Recent advances in our understanding of the disease pathogenesis, coupled with progress in drug development, have led to new therapeutic strategies that will potentially offer an improved side-effect profile and improved efficacy, but will almost certainly be much more expensive than current treatments.

Gene expression of cytokines (TNF-α, IFN-γ), serum profiles of IL-17 and IL-23 in paediatric systemic lupus erythematosus

OBJECTIVE

Paediatric systemic lupus erythematosus (pSLE) exhibits an aggressive clinical phenotype and severe complications commonly renal involvement. This could be reflective of the ongoing chronic pro-inflammatory cytokine milieu. We examined relative gene expression of tumour necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ) and serum levels of interleukin-17 (IL-17) and IL-23 and their association with SLEDAI (SLE disease activity index) score and organ manifestations in pSLE.

METHODS

We enrolled 40 pSLE patients (age 5-16 years, on treatment) and 20 age-matched healthy controls. Relative gene expression levels of IFN-γ and TNF-α in the peripheral blood were determined by quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR). β actin gene was used for normalization of gene expression. Serum levels of IL-17 and IL-23 were determined by solid phase sandwich ELISA. Statistical analysis were carried out for comparing (Mann-Whitney U test) and correlating data (Univariate, multivariate analysis and Pearson correlation test) with SLEDAI scores and clinical manifestations.

RESULTS

Over-expression of TNF-α and IFN-γ was found in 90% (36/40) and 80% (32/40) of pSLE patients, respectively. The relative gene expression of TNF-α and IFN-γ were significantly correlated with renal manifestations (p < 0.05). Further, relative expression of IFN-γ gene correlated significantly with skin manifestations and SLEDAI (p < 0.05). Serum levels of IL-17 (766.95 ± 357.83 pg/ml) and IL-23 (135.4 ± 54.23 pg/ml) in pSLE were significantly higher than in controls (IL-17, 172.7 ± 39.19 pg/ml and IL-23, 21.15 ± 10.99 pg/ml) (p < 0.05). Patients with cutaneous (p = 0.002) and haematological involvement (p = 0.003) had high serum IL-17 levels. Serum IL-17 levels correlated with SLEDAI (r = 0.447; p < 0.05).

CONCLUSIONS

In this preliminary study, we observed a persistent, strong pro-inflammatory cytokine milieu in pSLE patients which reflects ongoing inflammatory damage in different organs. The gene expression profile of these cytokines may be used for assessing organ involvement in pSLE. IL-17 may also serve as a prognostic marker in pSLE. However, longitudinal studies on treatment of naïve patients are required to corroborate these findings.

Role of microRNA-15a in autoantibody production in interferon-augmented murine model of lupus

MicroRNAs (miRNAs) are involved in the regulation of immunity via targeting of mRNA encoding immune response elements. In this report, alterations in the expression of microRNAs as autoantibody levels increase was investigated. The (NZB×NZW)F1 or B/W mouse model of systemic lupus erythematosus (SLE) naturally has increased autoantibodies with aging. IFNα (type I IFN) accelerates B/W disease, however, the effects of a related IFN, IFNλ, which is a type III IFN, is largely unknown. The purpose of the study was to investigate the relationship between IFN-accelerated disease, microRNAs, immunoregulatory B cell subsets and autoantibody production in the autoimmune-prone environment in vivo. B/W mice received osmotic pumps to chronically deliver IFNα and IFNλ for up to 16 weeks. Urine protein level was monitored weekly by urine strips and proteinuria was used as the disease marker. Splenic cells were taken for flow analysis of B cell subsets and levels of microRNAs determined. Plasma were analyzed for autoantibodies and microRNA levels. As a result of treatment, IFNα accelerated proteinuria in a dose dependent manner, while IFNλ single treatment did not show a significant effect, but greatly enhanced low dose IFNα effects in the combination treatment. Both the splenic cellular and plasma miR-15a were elevated in diseased compared to pre-diseased mice as well as autoantibody levels. Autoantibodies and miR-15a levels were significantly correlated. The immunosuppressive B subpopulation, B-10, was reduced following IFNα treatment. In addition in diseased mice, B-10 versus B-2 ratios were reduced in IFN-treated B/W compared to the control PBS treated group. In all B/W the miR-15a was highly expressed in the B-10 subset and this increased with disease development, suggesting that miR-15a has a specific negative effect on the B-10 subpopulation. In conclusion, our data support the involvement of elevated miR-15a in autoimmune disease development in B/W mice and suggest that decreasing this microRNA might be beneficial in B/W mice.

Biological therapy in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic inflammatory autoimmune disorder characterized by multisystem involvement and fluctuating disease activity. Symptoms range from rather mild manifestations such as rash or arthritis to life-threatening end-organ manifestations. Despite new and improved therapy having positively impacted the prognosis of SLE, a subgroup of patients do not respond to conventional therapy. Moreover, the risk of fatal outcomes and the damaging side effects of immunosuppressive therapies in SLE call for an improvement in the current therapeutic management. New therapeutic approaches are focused on B-cell targets, T-cell downregulation and costimulatory blockade, cytokine inhibition, and the modulation of complement. Several biological agents have been developed, but this encouraging news is associated with several disappointments in trials and provide a timely moment to reflect on biologic therapy in SLE.

Kinetic analysis of unpurified native antigens available in very low quantities and concentrations

Affinity measurements of antigen-antibody interactions are generally performed using known concentrations of purified or recombinant materials. In addition, many technologies that measure affinity require the interacting components to be present in at least microgram quantities. Specifically, if the antigen is either available only in low quantities or unable to be purified, or if the quantity is unknown, then the measurement of affinity can be very difficult. Using the Kinetic Exclusion Assay (KinExA) technology, here we describe a method that overcomes the requirement for large amounts of purified and known quantities of antigen. We used this method to precisely measure the affinity of fully human anti-human interleukin 13 (IL13) monoclonal antibodies to IL13 produced in native form from primary T cells derived from a variety of species, including human. These antigens were available only in the limited quantities present in the conditioned cell culture medium, and the affinity was measured directly without further purification.

Monocyte response to LPS after exposure to corticosteroids and chloroquine with implications for systemic lupus erythematosus

Essential part of a response to infection is early pathogen recognition and adequate initiation of innate immunity. One of the hallmarks of systemic lupus erythematosus (SLE) is reduced resistance to infection despite overall hyperactivity of the immune system. Immunosuppressive drugs (high-dose corticosteroids and cytotoxic agents) are independent risk factors for infection in SLE, with bacteria as predominant cause. To investigate whether less aggressive immunomodulatory treatment may still affect recognition and response to Gram-negative bacteria, we measured TLR4 expression in monocytes of untreated SLE patients and patients on chloroquine and low-dose steroid therapy and examined the drugs' influence on monocyte TLR4 expression in peripheral blood mononuclear cell (PBMC) culture. Additionally, we determined whether induction of monocyte NF-κB signalling, TNF-α and IL-6 production with lipopolysaccharide (LPS), a TLR4 ligand, can be altered with dexamethasone, chloroquine or both. There was no statistically significant difference in TLR4 expression between patients with SLE and controls, even though treated SLE patients tended to have lower frequency of TLR4(+) monocytes and TLR4 mean fluorescence intensity than healthy controls. However, neither dexamethasone nor chloroquine had major influence on TLR4 expression in vitro or suppressed LPS-induced NF-κB activation in monocytes, although dexamethasone decreased TNF-α and IL-6 production. Therefore, even if low-dose steroids or chloroquine do not seem to affect TLR4 expression and signalling, steroids might decrease cytokine production in response to LPS.

Anticytokine therapy in systemic lupus erythematosus

Systemic lupus erythematosus is a prototype of heterogeneous autoimmune disease. There have been few newly approved therapeutic agents in lupus treatment for many reasons. Several animal studies and human data have shown that many potential cytokines are related to the pathogenesis and disease activity of systemic lupus erythematosus. Cytokines are produced by many immune cell types and have variable functions in the immune system. Following the success of biological agents in the treatment of inflammatory arthritis, inflammatory bowel disease, and psoriasis, biological targeting to specific cytokines or receptor molecules is now promising in the treatment of systemic lupus erythematosus. In addition to B-cell deleting modalities, clinical trials targeting potential cytokines associated with disease pathogenesis are underway at various clinical stages. Among potential cytokines, targeting agents against B-cell activating factor and interferon-alpha are in the most advanced stage, and belimumab (anti-B-cell activating factor antibody) could be the first biological agent approved in the treatment of systemic lupus erythematosus. Anti-tumor necrosis factor was tried with some success, but with a potential risk of infection in a small number of patients. In this review, we discuss the rationale for anticytokine therapies and review agents currently in clinical trials, and those that could be developed in the near future for systemic lupus erythematosus. We present the results mostly from published trials and data from http://clinicaltrials.gov/ct2/

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Rituximab in autoimmune hematologic diseases: not just a matter of B cells

Rituximab, a chimeric monoclonal antibody that depletes B cells by binding to the CD20 cell-surface antigen, has been investigated extensively in autoimmune disorders. Following the encouraging results in immune thrombocytopenia (ITP), the use of this agent was explored in other autoimmune hematologic diseases, most notably autoimmune hemolytic anemia (AIHA) and thrombotic thrombocytopenic purpura (TTP), characterized by the presence of pathogenetic autoantibodies. Although randomized clinical trials are lacking, the cumulative data would suggest that rituximab has a beneficial role in their treatment. Response to B-cell-depleting therapy is actually associated with a significant decrease of circulating autoantibodies. However, several lines of evidence indicate that the T-cell compartment may also be modulated by these interventions. The doses and the duration of rituximab treatment in patients with autoimmune diseases are still unclear. The incidence of severe side effects is low but not insignificant. In particular, the risk of systemic infections and viral reactivation is a major concern.

Gene expression profiles of systemic lupus erythematosus and rheumatoid arthritis

Gene expression profiling using microarray technology is being employed to define specific molecular mediators and pathways involved in immunobiology, to understand the intricate interplay of genes participating in the pathogenesis, and to develop biomarkers of disease activity in both systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This review summarizes the latest information on the pathogenesis of SLE and RA and describes the utilization of microarray technology in these systemic autoimmune diseases.

Management of systemic lupus erythematosus in Chinese patients

Systemic lupus erythematosus (SLE) is a worldwide disease with prevalence figures ranging from nine to 130 per 100,000 individuals. SLE appears to be more prevalent in certain ethnic groups, such as the African-Americans, African-Caribbeans and Asians. The prevalence of SLE in Hong Kong Chinese was estimated to be 59 out of 100,000 (104/100,000 among women), which is mid-way between that of the Caucasians and African-Americans. Certain organ manifestations, such as lupus nephritis, are more common in Chinese than Caucasians. A recent prospective study reported that the cumulative incidence of renal disease within 5 years of diagnosis of SLE in Chinese patients was 60%. Despite the improvement in survival of SLE in the past few decades, manifestations that are refractory to conventional therapies and treatment related complications are still major challenges in the management of SLE. Novel-therapeutic modalities for SLE should aim at targeting more specifically the immunopathogenetic pathways to achieve higher efficacy and reduce short- and long-term therapy-related toxicities. This review summarizes the management strategies and novel therapeutic modalities in SLE.

Pharmacotherapy of systemic lupus erythematosus

The pharmacological management of systemic lupus erythematosus (SLE) is challenging owing to its unpredictable clinical course, the variable organ system involvement and the lack of clear understanding of disease pathogenesis. The widely used corticosteroids and immunosuppressive drugs, which can control disease activity, have serious, potentially fatal, side effects. In the last decade, a better understanding of lupus pathogenesis has led to the development of biological agents that are directed at biomarkers. However, these biologicals also exert side effects due to infections resulting from completely eliminating immune cells (e.g., B cells) or cytokine signals (e.g., interferon-alpha) or affecting molecular targets outside the immune system (CD40L on platelets). New biomarker-driven clinical trials are ongoing to evaluate the safety and efficacy of B-cell depletion, blocking of interferon signaling, inhibition of the mTOR pathway, and restoration of glutathione deficiency in lupus T cells.

B cells as a target of immune modulation

B cells have recently been identified as an integral component of the immune system; they play a part in autoimmunity through antigen presentation, antibody secretion, and complement activation. Animal models of multiple sclerosis (MS) suggest that myelin destruction is partly mediated through B cell activation (and plasmablasts). MS patients with evidence of B cell involvement, as compared to those without, tend to have a worse prognosis. Finally, the significant decrease in new gadolinium-enhancing lesions, new T2 lesions, and relapses in MS patients treated with rituximab (a monoclonal antibody against CD20 on B cells) leads us to the conclusion that B cells play an important role in MS and that immune modulation of these cells may ameliorate the disease. This article will explore the role of B cells in MS and the rationale for the development of B cell-targeted therapeutics. MS is an immune-mediated disease that affects over 2 million people worldwide and is the number one cause of disability in young patients. Most therapeutic targets have focused on T cells; however, recently, the focus has shifted to the role of B cells in the pathogenesis of MS and the potential of B cells as a therapeutic target.

Mechanism and regulatory function of CpG signaling via scavenger receptor B1 in primary B cells

It is well established that CpG promotes pro-inflammatory cytokine and antibody production by B cells via the Toll-like receptor 9 (TLR9)-dependent pathway. However, scavenger receptors (SRs) are also capable of binding such pathogen-derived molecules, yet their contribution to CpG-induced signaling events has not yet been evaluated. Here we identified a novel TLR9-independent mechanism of CpG-induced signaling and immune function that is mediated by the scavenger B1 receptor (SR-B1). Specifically, we show that CpG/SR-B1 triggers calcium entry into primary B lymphocytes via phospholipase C gamma-1-mediated activation of TRPC3 channels and also B cell adhesion to vascular cell adhesion molecule-1. CpG-induced calcium signals and vascular cell adhesion molecule-1 adhesion are TLR9-independent and are mediated exclusively by SR-B1. Although pro-inflammatory cytokine and Ig production induced by CpG require TLR9 expression, we also found that SR-B1 negatively regulates TLR9-dependent production of interleukin-6, interleukin-10, and IgM. Thus, our results provide a novel perspective on the complexity of CpG signaling within B cells by demonstrating that SR-B1 is an alternative pathway for nucleic acid-induced signaling that provides feedback inhibition on specific TLR9-dependent responses of B cells. Consequently, these results have wide implications for understanding the mechanisms regulating immune tolerance to nucleic acids and pathogen-associated molecules.

T cell CD40LG gene expression and the production of IgG by autologous B cells in systemic lupus erythematosus

CD40 ligand (CD40LG), encoded on the X chromosome, has been reported to be overexpressed on lupus T cells. Herein, we investigated the effect of DNA demethylation on T cell CD40LG expression and the production of IgG by autologous B cells in lupus. We found normal human T cells transfected with CD40LG induced autologous B cell activation and plasma cell differentiation. Both female lupus CD4+ T cells and demethylating agents treated CD4+ T cells overexpressed CD40LG mRNA. Further, lupus T cells from both genders or demethylated CD4+ T cells from healthy women overstimulated autologous B cells, and this could be reversed with anti-CD40LG Ab in only females. We demonstrated that female lupus CD4+ T cells and demethylated CD4+ T cells express high level of CD40LG and overstimulate B cells to produce IgG. This is due to DNA demethylation and thereby reactivation of the inactive X chromosome in female.

New directions in the treatment of systemic lupus erythematosus

OBJECTIVE

The aim of this review is to provide an up-to-date overview of treatment approaches for systemic lupus erythematosus (SLE), highlighting the multiplicity and heterogeneity of clinical symptoms that underlie therapeutic decisions. Discussion will focus on the spectrum of currently available therapies, their mechanisms and associated side-effects. Finally, recent developments with biologic treatments including rituximab, epratuzumab, tumor necrosis factor (TNF) inhibitors, and belimumab, will be discussed.

RESEARCH DESIGN AND METHODS

A MEDLINE literature search for 'systemic lupus erythematosus' and 'damage' and 'treatment' was undertaken for 1996-2008. Secondary citations were obtained from selected manuscripts. Individual case studies were excluded.

FINDINGS

SLE is an autoimmune disease involving multiple organ systems, a clinical pattern of flares and remissions, and the presence of anti-nuclear autoantibodies. Whereas early symptoms most frequently involve the skin and joints, disease morbidity and mortality are usually associated with cardiovascular events and damage to major organs, particularly the kidneys. Many of the current therapeutic options are considered to be inadequate because of toxicities, accrual of organ damage, and insufficient control of the underlying disease pathology. Improved understanding of SLE pathogenesis and immunology has led to the identification of new treatment targets. Current interest is mainly focused on the targeted immunosuppressive actions provided by biologic therapy. Although the potential long-term beneficial or harmful effects of the new molecular treatments are unclear, their precise molecular targeting may reveal key relationships within the immune system and advance the cause of individualized molecular medicine.

CONCLUSIONS

Biologic compounds that target specific immunologic mechanisms offer a new paradigm in the treatment of SLE, one that may, at best, reverse the course of the disease and, at the very least, might provide some new alternatives to reduce symptoms and limit tissue damage without undue contribution to overall morbidity and mortality.

Why can't we find a new treatment for SLE?

No new therapy for systemic lupus erythematosus has been approved. In the last decade, the development of several novel compounds has been pursued for lupus, but so far nothing has been proven to be effective. This review discusses some of the reasons why it may be so difficult to demonstrate that a novel therapy is effective for this disease. These include the complexity of the disease itself; the lack of reliable outcome measures; our limited understanding of the pathogenesis of the disease; the propensity of lupus patients to have bad outcomes and to react to medicines in unusual ways; the heterogeneity of the patient population; the unpredictable course of disease in individual patients; and the lack of reliable biomarkers. Although some of the tested targeted compounds that are apparently based on strong preclinical and mechanistic data may indeed not be effective therapies for SLE, it is hard not to believe that among the various specific agents now being tested that at least some of them should downregulate the abnormal immunoregulation characteristic of SLE, and thus be clinically effective. We need to be persistent and imaginative in identifying these effective agents and proving their efficacy so that they may be widely used in our lupus populations.

Severe tissue trauma triggers the autoimmune state systemic lupus erythematosus in the MRL/++ lupus-prone mouse

Tissue damage associated with a severe injury can result in profound inflammatory responses that may trigger autoimmune development in lupus-prone individuals. In this study, we investigated the role of a large full-thickness cutaneous burn injury on the early onset of autoimmune disease in lupus-prone MRL/++ mice. MRL/++ mice (chronic model) exhibit autoimmune symptoms at >70 weeks of age, whereas MRL/-Faslpr mice (acute model) develop autoimmune disease in 17–22 weeks due to a lymphoproliferative mutation. Autoimmune disease developed in MRL/++ mice (4–15 weeks post injury) is manifested by skin lesions, vasculitis, epidermal ulcers, cellular infiltration, splenomegaly, lymphadenopathy, hypergammaglobulinemia, elevated autoantibodies and renal pathologies including proteinuria, glomerulonephritis and immune complex deposition; complications that contribute to reduced survival. Transcription studies of wound margin tissue show a correlation between the pathogenic effects of dysregulated IL-1β, IL-6, TNF-α and PGE2 synthesis during early wound healing and early onset of autoimmune disease. Interestingly, MRL/++ mice with healed wounds (30–40 days post burn) strongly rejected skin isografts. Conversely, skin isografts transplanted onto naive age-matched MRL/++ littermates achieved long-term survival. Collectively, these findings suggest that traumatic injury exacerbates inflammatory skin disease and severe multi-organ pathogenesis in lupus-prone mice.

[Pancytopenia and lymph node swelling. Cardinal symptoms of an unusual differential diagnosis]

A 47-year-old woman was admitted to our emergency room because of anemia and acute tonsillitis. She reported recurrent fever and a sore throat. Clinical examination and CT scans showed general lymph node swelling and liver enlargement. In the course of the disease she developed pancytopenia with neutropenic fever, pleuropneumonia, and deep vein thrombosis. The histological examination of a lymph node showed a reactive, EBV-associated lymphadenitis. The examination of the bone marrow showed an activated marrow. The diagnosis of an active EBV infection was established with 2 x 10(6)/ml EBV gene copies in the blood. In addition, systemic lupus erythematosus was diagnosed because of the typical autoantibody constellation and clinical findings. The immunohematological examination showed autoantibodies against the three blood cell compartments. Because of the severe pancytopenia as a result of the EBV- and SLE-associated autoantibodies and despite recurrent infections, we initiated immunosuppressive therapy with low-dose corticosteroids. This therapy resulted in normalization of the blood counts. Anitibody levels and the EBV genome levels became negative.

The BLyS family: toward a molecular understanding of B cell homeostasis

The B Lymphocyte Stimulator (BLyS) family of ligands and receptors regulates humoral immunity by controlling B lymphocyte survival and differentiation. Herein, we review the ligands and receptors of this family, their biological functions, and the biochemical processes through which they operate. Pre-immune B lymphocytes rely on BLyS signaling for their survival, whereas antigen experienced B lymphocytes generally interact more avidly with a homologous cytokine, A Proliferation Inducing Ligand (APRIL). The molecular basis for signaling via the three BLyS family receptors reveals complex interplay with other B lymphocyte signaling systems, affording the integration of selective and homeostatic processes. As our understanding of this system advances, molecular targets for manipulating humoral immunity in both health and disease should be revealed.

Pharmacokinetic and pharmacodynamic modeling of a humanized anti-IL-13 antibody in naive and Ascaris-challenged cynomolgus monkeys

PURPOSE

Neutralization of IL-13 is an attractive approach for treatment of asthma. In this report, we developed a novel PK-PD model that described the relationship between the circulating concentrations of total IL-13 and a neutralizing anti-IL-13 antibody (Ab-02) in the model of acute airway inflammation induced by Ascaris challenge to cynomolgus monkeys, as well as in naive monkeys.

METHODS

Cynomolgus monkeys were administered a single intravenous or subcutaneous dose of Ab-02. Total IL-13 and Ab-02 concentrations were measured by immunoassays.

RESULTS

Modeling and simulations indicated that: (1) Ascaris challenge induced approximately three-fold increase in circulating IL-13 concentrations, when compared to naive animals, consistent with the notion that Ascaris-induced airway inflammation was IL-13-mediated; (2) the transient increase in total IL-13 concentrations observed in both naive and Ascaris-challenged monkeys following Ab-02 administration was due to the increase in Ab-02-bound IL-13, while free IL-13 was decreased; and (3) the extent and duration of neutralization of circulating IL-13 were different in naive and Ascaris-challenged monkeys for the same Ab-02 dose regimen.

CONCLUSIONS

The PK-PD model presented in this report may be applied to study drug-ligand interactions when a free ligand cannot be directly assayed but total ligand concentrations are modulated by the drug administration.

Efficacy and safety of TNF-blocker therapy in systemic lupus erythematosus

BACKGROUND

There is still unmet medical need in the therapy of severe organ manifestations of patients with systemic lupus erythematosus (SLE). Therapeutic agents targeting pro-inflammatory cytokines may be an interesting option.

OBJECTIVE

To review available data on the efficacy and safety of tumour necrosis factor (TNF) blockade in SLE.

METHODS

A review of the literature was conducted.

RESULTS/CONCLUSIONS

Open-label experience suggests that TNF blockade is effective in SLE patients with arthritis, nephritis and skin disease. In particular, nephritis may remain in long-term remission after just four infusions of infliximab administered. Despite the induction of lupus-specific autoantibodies, short-term therapy with infliximab in combination with azathioprine appears feasible and relatively safe. The data call for controlled clinical trials, at least one of which has been initiated.

Novel therapeutics for systemic lupus erythematosus

PURPOSE OF REVIEW

This review provides an update on recently explored therapies in systemic lupus erythematosus and introduces novel therapeutic approaches under consideration. Recent advances in our understanding of systemic lupus are highlighted as well, as these must now inform consideration of therapeutics.

RECENT FINDINGS

Many therapeutic strategies have been shown to be beneficial in murine models of lupus. Compounds that inhibit cellular signaling in response to autoantigens or other triggers and protocols that reconstitute the immune repertoire to diminish autoreactivity are now entering clinical trials.

SUMMARY

Requirements for novel approaches in lupus include improved efficacy and lower toxicity than current therapies, with the goal to reduce tissue damage while preserving immunocompetence.

B-cell-targeted treatment for multiple sclerosis: mechanism of action and clinical data

Strategies for treating autoimmune disorders are increasingly employing targeted therapies rather than non-specific, multitargeted treatments. Accumulating evidence on the involvement of B lymphocytes in the pathophysiology of autoimmune demyelinating disease has led to a renewed interest in B cells as potential therapeutic targets. In particular, antigen presentation between B cells and T cells, increased trafficking of B cells across the blood-brain barrier, and autoantibodies produced by plasma cells may contribute to the pathophysiology of autoimmune disorders such as multiple sclerosis. Several B-cell-targeted, depletion therapies are currently in development, including rituximab, epratuzumab, diphtheria toxin-single chain Fv (DC2219), belimumab, atacicept, abatacept, and abetimus sodium. Of these agents, only rituximab and abatacept have been evaluated in multiple sclerosis patients. Preliminary results of a phase II trial of rituximab in multiple sclerosis suggest that rituximab is well tolerated and significantly reduces the number of gadolinium enhancing lesions over 24 weeks of treatment. Results of an exploratory analysis suggest the potential promise of abatacept 10 mg/kg for multiple sclerosis. It is expected that future clinical trials will establish a role for B-cell-targeted therapies in the treatment of multiple sclerosis and other autoimmune neurological diseases. This article describes the mechanism of action behind B-cell-targeted depletion therapies in development and reviews available clinical data.

TLR7 and CD40 cooperate in IL-6 production via enhanced JNK and AP-1 activation

During vaccination or infection, adaptive and innate immune receptors of B cells are engaged by microbial antigens/ligands. A better understanding of how innate and adaptive signaling pathways interact could enlighten B lymphocyte biology as well as aid immunotherapy strategies and vaccine design. To address this goal, we examined the effects of TLR stimulation on BCR and CD40-induced B cell activation. Synergistic production of IL-6 was observed in both human and mouse primary B cells stimulated through B cell antigen receptors, CD40 and TLR7, and these two receptors also cooperated independently of BCR signals. The enhanced IL-6 production was dependent upon the activity of c-Jun kinase (JNK) and cFos. Dual stimulation through CD40 and TLR7 markedly enhanced JNK activity. The increased level of active JNK in dual-stimulated cells was accompanied by an increase in the level of active AP-1 monomers cJun and cFos. The stimulation of B cells through both CD40 and TLR7 therefore enhanced the production of cytokines through increased JNK signaling and AP-1 activity. In addition, the dual stimulation increased cFos/AP-1 species in stimulated cells, effectively expanding the repertoire of AP-1 dimers as compared to singly stimulated B cells.

Mycophenolate mofetil as induction and maintenance therapy for lupus nephritis: rationale and protocol for the randomized, controlled Aspreva Lupus Management Study (ALMS)

The Phase III Aspreva Lupus Management Study (ALMS) will investigate mycophenolate mofetil (MMF) therapy for lupus nephritis (LN). Eligibility criteria include: 12-75 years of age; diagnosis of systemic lupus erythematosus according to revised American College of Rheumatology criteria; and biopsy-demonstrated LN (Class III-V). Randomized patients will receive open-label induction therapy with MMF or cyclophosphamide in combination with corticosteroids for 24 weeks. The primary efficacy endpoint is treatment response [decreased proteinuria and stabilized (within 25% of baseline) or improved serum creatinine level]. Patients achieving response or complete remission (normalization of all parameters) will be rerandomized to double-blind, placebo-controlled maintenance treatment with MMF or azathioprine, both plus corticosteroids. The maintenance phase primary endpoint is time to treatment failure. To detect a 15% rate improvement in the MMF group compared with cyclophosphamide, and to provide 90% power, a total of 358 patients will be required for the induction phase. On the basis of a projected 278 rerandomized patients, the maintenance phase will have 90% power to detect a difference between treatment groups assuming azathioprine and MMF three-year failure rates of 59.5% and 40.7%, respectively. Aspreva Lupus Management Study may provide invaluable comparative data on the efficacy and safety of MMF as LN induction and maintenance therapy.

[Aquired inhibitors of coagulation in a patient with systemic lupus erythematosus and antiphospholipid antibodies: response to rituximab]

Hematologic signs of systemic lupus erythematosus are diverse (SLE). Although a delayed coagulation time is anti-phospholipid antibody related, thrombotic events are the usual clinical manifestation. Spontaneous appearance of circulating anticoagulant in the absence of a previous coagulation disorder is secondary to the development of antibodies to factors II, V, VIII, IX, XI, XII,vonWillebrand, and other membrane glucoproteins, all of them uncommon causes (1 case per million persons per year) of life threatening coagulopathies. We report a case of SLE and antiphospholipid antibodies in a woman with a hemorrhagic syndrome, probably caused by multiple antibodies to coagulation factors, unresponsive to steroids and high-dose immunosupressive therapy and a favorable response to rituximab.

Bone status in juvenile systemic lupus erythematosus

Osteoporosis is a well-recognized major health problem in adult patients with systemic lupus erythematosus (SLE). Children and adolescents with SLE, however are at even higher risk of developing osteoporosis later in life, since they develop the disease before achieving peak bone mass, which serves as a 'bone bank' for the rest of life. There is still a paucity of studies on bone mass in pediatric SLE, but those studies available provide evidence of reduced bone mass in this age group. A frequency of osteopenia of 40% measured by dual energy X-ray absorptiometry at one or more skeletal sites has been reported, and the lumbar spine is most seriously affected. Peak bone mass seems to be lower in childhood-onset SLE patients compared to healthy controls, and there are no signs of catch-up of bone mass in young adult patients with a history of pediatric SLE. Glucocorticoid therapy has been found to have a major negative effect on bone mass in these patients, thus the importance of keeping corticosteroid doses down to the lowest possible dose whenever possible. Interestingly, studies of oral alendronate therapy in children with rheumatic childhood diseases have shown promising results with increases of 15-33% during one year of treatment with no major side effects reported. Finally, there is a hope that new biologic therapies, which are more specific and steroid-sparing, will also have a beneficial effect on bone health in SLE in the future.

Modulatory effects of 1,25-dihydroxyvitamin D3 on human B cell differentiation

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) can modulate immune responses, but whether it directly affects B cell function is unknown. Patients with systemic lupus erythematosus, especially those with antinuclear Abs and increased disease activity, had decreased 1,25(OH)(2)D(3) levels, suggesting that vitamin D might play a role in regulating autoantibody production. To address this, we examined the effects of 1,25(OH)(2)D(3) on B cell responses and found that it inhibited the ongoing proliferation of activated B cells and induced their apoptosis, whereas initial cell division was unimpeded. The generation of plasma cells and postswitch memory B cells was significantly inhibited by 1,25(OH)(2)D(3), although the up-regulation of genetic programs involved in B cell differentiation was only modestly affected. B cells expressed mRNAs for proteins involved in vitamin D activity, including 1 alpha-hydroxylase, 24-hydroxylase, and the vitamin D receptor, each of which was regulated by 1,25(OH)(2)D(3) and/or activation. Importantly, 1,25(OH)(2)D(3) up-regulated the expression of p27, but not of p18 and p21, which may be important in regulating the proliferation of activated B cells and their subsequent differentiation. These results indicate that 1,25(OH)(2)D(3) may play an important role in the maintenance of B cell homeostasis and that the correction of vitamin D deficiency may be useful in the treatment of B cell-mediated autoimmune disorders.