Rituximab anti-B-cell therapy in systemic lupus erythematosus: pointing to the future

Off-Label Uses of Rituximab in Dermatology

Purpose of Review

Rituximab has transformed the treatment of B-cell malignancies and rheumatoid arthritis in the past 2 decades. More recently, this anti-CD20 monoclonal antibody has seen increasing usage in the field of dermatology. This review highlights the evidence supporting its use in several important dermatologic conditions.

Recent Findings

Key recent findings include the 2018 FDA approval of rituximab for the treatment of moderate-to-severe pemphigus.

Summary

Data from randomized controlled trials have demonstrated the efficacy of rituximab in pemphigus, ANCA-associated vasculitis, and cryoglobulinemic vasculitis. More limited data suggests its use in recalcitrant cases of diseases such as pemphigoid, epidermolysis bullosa acquisita, and dermatomyositis. There is scarce evidence and mixed results for rituximab when studied in cutaneous polyarteritis nodosa and cutaneous lupus erythematosus.

Immunological Subsets Characterization in Newly Diagnosed Relapsing-Remitting Multiple Sclerosis

Objectives

Using flow cytometry, we characterized myeloid, B, and T cells in patients recently diagnosed with relapsing–remitting multiple sclerosis (RRMS) naive to disease-modifying therapies (DMTs).

Methods

This prospective case–control study was conducted in the tertiary MS center of Catania, Italy. Demographic/clinical data and peripheral bloods were collected from 52 naive patients recently diagnosed with RRMS and sex/age-matched healthy controls (HCs) in a 2:1 ratio. We performed flow cytometry on isolated peripheral blood mononuclear cells to assess immune cell subsets differences between RMMS patients and HCs. We explored the biomarker potential of cell subsets using receiver operating characteristic (ROC) curves and relative area under the curve (AUC) analyses.

Results

Monocytic myeloid-derived suppressor cells (Mo-MDSCs CD14+/HLADR^−/low) and inflammatory monocytes (CD14+CD16+) displayed higher frequencies in RRMS patients when compared with HCs (p <.05). A lower percentage of B-unswitched memory cells was observed in RRMS patients when compared with HCs (p = .026). T cells had a higher frequency of T-helper CD4+ cells and their subset, CD4+CD161+, in RRMS patients when compared with HCs (p <.001). ROC analyses revealed an AUC >70% for Mo-MDSCs CD14+/HLADR^−/low and inflammatory CD14+CD16+, T-helper CD3+CD4+, and T-helper CD4+CD161+.

Conclusions

Patients with a recent RRMS diagnosis and naive to DMTs, showed peculiar myeloid, B-, and T-cell immunophenotypes.

B-cell oligoclonal expansions in renal tissue of patients with immune-mediated glomerular disease

B-cell clonal expansion has been sporadically described in the blood and/or renal tissue of patients with glomerulonephritides, albeit with unclear pathogenetic role. Herein, using spectratyping analysis, we observed oligoclonal intrarenal B-cell populations in 59% of glomerulonephritis patients with podocyte injury (6/7 with focal segmental glomerulosclerosis, 1/3 minimal change disease, 1/3 idiopathic membranous nephropathy, 3/4 IgA nephropathy, 2/5 membranous lupus nephritis), 20% of glomerulonephritis patients without podocyte involvement (4/13 with mesangial or proliferative lupus nephritis, 0/3 idiopathic membranoproliferative glomerulonephritis, 0/4 pauci-immune vasculitis) and 17% of control patients with renal cancer. In multivariate analysis, oligoclonal B-cells were associated with podocyte injury and the grade of glomerulosclerosis (both p = .009). B-cell oligoclonal expansions were not found in the paired peripheral blood samples. We postulate that B-cell expansion in the kidney results from local stimuli, including antigens expressed on podocytes. Further studies to unravel the role of oligoclonal B-cells in (auto)immune-mediated kidney disease are warranted.

Effectiveness and Safety of Rituximab in Systemic Lupus Erythematosus: A Case Series Describing the Experience of 2 Centers

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple organs and systems. B cells have a critical role in the pathogenesis of SLE. Rituximab (RTX) is a drug composed of chimeric monoclonal antibodies against the CD20 protein, producing a depletion of B lymphocytes.

OBJECTIVE

To analyze the effectiveness and safety of RTX in patients with SLE in clinical practice.

METHODS

Collection of retrospective variables of the medical records of 20 patients with SLE treated with RTX in 2hospitals (Hospital de la Santa Creu i Sant Pau, and Hospital del Mar, in Barcelona, Spain). We evaluated demographic, clinical, serological and treatment variables.

RESULTS

There was a statistically significant association in the following variables collected in the study before and after treatment: there was a decrease in the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) (P<.001), erythrocyte sedimentation rate (P=.017), use of glucocorticoids (P=.025) and IgM values (P=.031), as well as an increase in the C4 values (P=.014) after treatment with RTX. A patient with SLE, antiphospholipid syndrome, complex comorbidity and multiorgan lupus involvement died after developing a septic process, months after receiving a single treatment cycle with RTX.

CONCLUSIONS

Although RTX currently has no official indication approved for SLE, our data suggest that it may be effective in reducing the activity of the disease and as a steroid-sparing agent, with an acceptable safety profile. However, larger follow-up periods with a greater number of patients are needed to solve the remaining doubts about the use of RTX in SLE.

The Function of MicroRNAs in B-Cell Development, Lymphoma, and Their Potential in Clinical Practice

B-cell formation, development, and differentiation are complex processes regulated by several mechanisms. Recently, there has been growing evidence indicating that microRNAs (miRNAs) are important for normal B-cell lineage development. miRNAs are small non-coding RNA molecules, about 20–22 nucleotide in length, that play an important role in regulating gene expression. They pair with specific messenger RNAs (mRNAs), resulting in mRNAs translational repression or degradation. Here, we review current research about the function of miRNAs in the aspects of B-cell physiology and pathology. We start by introducing the process of miRNA biogenesis. We will then focus on the role of miRNAs during B-cell lineage commitment and development in the bone marrow, followed by a discussion of miRNAs’ role in subsequent peripheral B-cell activation, proliferation, and final differentiation (including B-cell central tolerance and autoimmunity). We list and describe several examples to illustrate miRNAs’ role in the development of B-cell lymphoma, both as oncogenes and tumor suppressor genes. Finally, we delineate the potential value of miRNAs in diagnosing B-cell lymphoma, predicting clinical outcomes, and modulating the efficiency of anticancer treatments. Despite the vast amount of research conducted on miRNAs in recent years, it is still necessary to increase and further strengthen studies on miRNAs and their targets to promote a better understanding on B-cell development and as a result, construct more effective treatments against B-cell disease.

Efficacy and Safety of Rituximab in the Management of Pediatric Systemic Lupus Erythematosus: A Systematic Review

OBJECTIVES

To evaluate the efficacy and safety of rituximab for treating pediatric systemic lupus erythematosus (pSLE).

STUDY DESIGN

We performed a systematic review to evaluate the efficacy and safety of rituximab in children with pSLE. Data from studies performed before July 2016 were collected from MEDLINE, the Cochrane Library, Scopus, and the International Rheumatic Disease Abstracts, with no language restrictions. Study eligibility criteria included clinical trials and observational studies with a minimal sample size of 5 patients, regarding treatment with rituximab in patients with refractory pSLE (aged <18 years at the time of diagnosis). Independent extraction of articles was performed by 2 investigators using predefined data fields.

RESULTS

Twelve case series met the criteria for data extraction for the systematic review with a good quality assessment according to an 18-criteria checklist using a modified Delphi method. Among them, 3 studies were multicenter and 3 were prospective. The total number of patients was 272. Studies collected patients with active disease refractory to steroids and immunosuppressant drugs. Refractory lupus nephritis was the most common indication (33%). Acceptable evidence suggested improvements in renal, neuropsychiatric and haematological manifestations, disease activity, complement and anti-double stranded Desoxy-Nucleo-Adenosine, with a steroid-sparing effect. However, there was poor evidence suggesting efficacy on arthralgia, photosensitivity, and mucocutaneous manifestations of SLE in children. An overall acceptable safety profile with few major adverse events was shown.

CONCLUSION

Rituximab exhibited a satisfactory profile regarding efficacy and safety indicating that this agent is a promising therapy for pSLE and should be further investigated.

Glomerular Diseases and Renal Transplantation: Pathogenic Pathways and Evolution of Therapeutic Interventions

Glomerular diseases and renal transplantation are the main fields of nephrology in which the immune system plays a prevalent role. Glomerular diseases have traditionally been attributed to auto-immune conditions, whereas allograft rejection has been considered an allo-immune response. However, common immunopathologic mechanisms that include Toll-like receptors, complement and B-cell activation, as well as genetic and infectious factors appear to be involved in the pathogenesis of both entities. Novel therapeutic regimens directed against specific targets of the immune system show promising results in glomerulopathies as well as in renal transplantation.

Immune Renal Injury: Similarities and Differences Between Glomerular Diseases and Transplantation

Glomerular diseases and renal transplantation are the main fields in nephrology in which the immune system plays a prevalent role. They have for long been considered as independent conditions due to the prominent role of autoimmunity in glomerular diseases and of alloimmunity in renal transplantation.

Moreover, histologic features differ between glomerular diseases and transplantation: in glomerular diseases, histologic damage involves primarily the glomeruli and secondarily the tubulointerstitium and small vessels, whereas in transplantation, allograft injury comprises primarily the tubulointerstitium and vessels and to a lesser degree the glomeruli.

However, recent research has shown that the pathogenetic mechanisms in both conditions share common pathways and that there is cross-reaction between innate and adaptive immunity as well as between auto- and alloimmunity [1].

Hypertension and Afro-descendant ethnicity: a bad interaction for lupus nephritis treated with cyclophosphamide?

Hypertension and ethnicity are important prognostic factors in evolution of lupus nephritis. A cohort of 75 patients with lupus nephritis treated with cyclophosphamide was conducted to investigate the evolution of creatinine levels between Caucasians and Afro-descendants. A multiple linear model was used to evaluate the combined effects of ethnicity and hypertension over delta creatinine controlling confounders. Sample characteristics were: 85% females; mean (±SD) age of 33.6 ± 12.0 years; 77% Caucasians; 40% hypertensive at renal biopsy; 91% WHO class IV; mean basal creatinine: 1.5 ± 1.3 mg/dL; mean final creatinine: 2.1 ± 2.5 mg/dL; 40% anaemia; proteinuria: 5.4 ± 4.8 g/day. Comparing Caucasians and Afro-descendants, it was found: 28.1% versus 72.2% for hypertension ( P = 0.002); 31.6% versus 66.7% for anaemia ( P = 0.018); 5.9 ± 5.0 versus 3.8 ± 4.0. g/day ( P = 0.02) for proteinuria. Other comparisons including basal creatinine did not reach statistical significance. Comparing outcomes between Caucasians and Afro-descendants, it was found: 10.5% versus 22.2% for doubling of creatinine ( P = 0.24); 0.41 ± 2.03 versus 1.05 ± 2.41 for delta creatinine ( P = 0.29); 8.8% versus 22.2% for haemodialysis ( P = 0.21) and 3.5% versus 5.6% for death ( P = 0.99). Analysing delta creatinine with multiple linear regression showed that hypertension had a significant overall effect ( b = 0.80; SE = 0.32; P = 0.015), ethnicity alone was not significant ( b = 0.35; SE = 0.29; P = 0.228); however, the effect of hypertension on delta creatinine was more intense among Afro-descendants than among Caucasians (interaction term b = — 0.83; SE = 0.37; P = 0.027). Afro-descendants lupus patients experience worst prognosis of renal function probably due to the effect of hypertension and not ethnicity per se. Lupus (2007) 16, 724—730.

Exploring new territory: considering the future

The European League Against Rheumatism (EULAR)'s guidelines for lupus state that mycophenolate mofetil has at least equivalent efficacy to and less toxicity than cyclophosphamide for the short-and medium-term treatment of lupus nephritis but that long-term data are available only for cyclophosphamide. New therapies are needed to reduce toxicity and the need for steroids and to offer the possibility of cure. Therapies under investigation include other immunosuppressive agents, anticellular therapies, drugs that modify cell-cell interactions, (anti-)cytokine therapy, hormone therapy and lupus-specific immunomodulation.

Rituximab has shown promise in patients refractory to conventional immunosuppression, which suggests that targeting B cells may be successful. Other anti-cell therapies include epratuzumab, belimumab and alemtuzumab. Anti-cytokine approaches include tumour necrosis factor alpha blockade with infliximab, anti-interleukin 6-receptor therapy with tocilizumab and interferon-α blockade. As anti-double-stranded DNA antibodies correlate with flares of lupus nephritis, they may represent another therapeutic target – as do monocyte chemoattractant protein-1 and protein kinase CK2. Therapeutic options to prevent damage in lupus nephritis include non-immunosuppressive treatments aimed at reducing cardiovascular risk (such as statins, angiotensin-converting enzyme inhibitors and aspirin).

As was the case with rheumatoid arthritis, a change in therapeutic aims – from survival through prevention of renal failure to induction of remission – may modify outcomes. EULAR's guidelines state that renal biopsy is the best monitor of clinical outcome in lupus nephritis, as immunological tests have limited predictive value. Measurement of urinary mRNA for cytokine and growth factor genes may provide a more sensitive, non-invasive method of monitoring therapeutic response.

Review: Systemic lupus erythematosus in children: current and emerging therapies

Treatment of children with systemic lupus erythematosus (SLE) is challenging. The therapeutic issues and risks and balances faced by adult patients are further complicated by an unpredictable disease course and long requirement for therapy in children with SLE. Further, non-compliance is a major obstacle to satisfactory outcome which must be recognized and dealt with in every adolescent in our efforts to attain optimal outcome. Treatment with combinations of cytotoxic agents and biologics which result in significant B-cell depletion often provide improved disease control. As our knowledge of the pathogenesis of SLE delineates more specific targets for immunotherapy the incidence of long-term remission rises. Our current emphasis is on therapeutic regimens which will induce remission followed by maintenance therapy in the oncologic model. SLE like neoplastic disease is no longer simply `treatable'. With appropriate therapy many children with SLE attain sustained remissions. In the foreseeable future childhood SLE may be curable. Lupus (2007) 16, 677—683.

Safety and tolerability of an anti-CD19 monoclonal antibody, MEDI-551, in subjects with systemic sclerosis: a phase I, randomized, placebo-controlled, escalating single-dose study

Background

Systemic sclerosis (SSc) is a clinically heterogeneous, life-threatening disease characterized by fibrosis, microvasculopathy, and autoimmunity. Extensive nonclinical and clinical data implicate B cells in the pathogenesis of SSc. MEDI-551 is an investigational humanized monoclonal antibody that targets the B cell surface antigen CD19 and mediates antibody-dependent, cell-mediated cytotoxicity of B cells. This clinical study evaluated the safety and tolerability, pharmacokinetics, and pharmacodynamics of MEDI-551 in subjects with SSc.

Methods

This phase I multicenter, randomized, double-blind, placebo-controlled, single escalating dose study enrolled adult subjects with either limited or diffuse cutaneous SSc. A single intravenous dose of MEDI-551 was administered, and safety and tolerability were evaluated. MEDI-551 pharmacokinetics (PK), pharmacodynamics, and immunogenicity were also assessed. Safety assessments included the incidence of adverse events and changes in clinical and laboratory results. MEDI-551 serum concentrations, effects on circulating and tissue B cells and plasma cells (PCs), and antidrug antibodies were analyzed. Modified Rodnan skin score (MRSS) and pulmonary function tests were used to explore the clinical effect of MEDI-551.

Results

The study enrolled 28 subjects with SSc (mean age, 47.3 years; 67.9 % female). Twenty-four received a single dose of MEDI-551 (0.1–10.0 mg/kg) and four received placebo. Treatment-emergent adverse events (TEAEs) occurred in 95.8 % of subjects in the MEDI-551 group and in 75.0 % of subjects in the placebo group; the majority of TEAEs were mild or moderate in severity. Two serious adverse events were considered possibly related to the study drug. One death, deemed not related to the study drug, occurred in a MEDI-551-treated subject. MEDI-551 exhibited linear PK in the dose range of 1.0 to 10.0 mg/kg, and more rapid clearance at lower doses. Dose-dependent depletion of circulating B cells and plasma cells was observed. MRSS assessments suggest a possible clinical effect of MEDI-551 on affected skin.

Conclusions

A single escalating dose of MEDI-551 was tolerable and safe in this subject population. B cell depletion was achieved and was dose dependent. A signal of clinical effect was observed. Based on these results, further investigation of MEDI-551 as a disease-modifying treatment for SSc is warranted.

Trial registration

www.clinicaltrials.gov identifier, NCT00946699; registered 23 July 2009.

The Autoimmune Ecology

Autoimmune diseases (ADs) represent a heterogeneous group of disorders that affect specific target organs or multiple organ systems. These conditions share common immunopathogenic mechanisms (i.e., the autoimmune tautology), which explain the clinical similarities they have among them as well as their familial clustering (i.e., coaggregation). As part of the autoimmune tautology, the influence of environmental exposure on the risk of developing ADs is paramount (i.e., the autoimmune ecology). In fact, environment, more than genetics, shapes immune system. Autoimmune ecology is akin to exposome, that is all the exposures - internal and external - across the lifespan, interacting with hereditary factors (both genetics and epigenetics) to favor or protect against autoimmunity and its outcomes. Herein, we provide an overview of the autoimmune ecology, focusing on the immune response to environmental agents in general, and microbiota, cigarette smoking, alcohol and coffee consumption, socioeconomic status (SES), gender and sex hormones, vitamin D, organic solvents, and vaccines in particular. Inclusion of the autoimmune ecology in disease etiology and health will improve the way personalized medicine is currently conceived and applied.

Insights into the naturally acquired immune response toPlasmodium vivaxmalaria

Plasmodium vivaxis the most geographically widespread of the malaria parasites causing human disease, yet it is comparatively understudied compared withPlasmodium falciparum.In this article we review what is known about naturally acquired immunity toP. vivax, and importantly, how this differs to that acquired againstP. falciparum.Immunity to clinicalP. vivaxinfection is acquired more quickly than toP. falciparum, and evidence suggests humans in endemic areas also have a greater capacity to mount a successful immunological memory response to this pathogen. Both of these factors give promise to the idea of a successfulP. vivaxvaccine. We review what is known about both the cellular and humoral immune response, including the role of cytokines, antibodies, immunoregulation, immune memory and immune dysfunction. Furthermore, we discuss where the future lies in terms of advancing our understanding of naturally acquired immunity toP. vivax, through the use of well-designed longitudinal epidemiological studies and modern tools available to immunologists.

B cells expressing IFN-γ suppress Treg-cell differentiation and promote autoimmune experimental arthritis

Clinical efficacy in the treatment of rheumatoid arthritis with anti-CD20 (Rituximab)-mediated B-cell depletion has garnered interest in the mechanisms by which B cells contribute to autoimmunity. We have reported that B-cell depletion in a murine model of proteoglycan-induced arthritis (PGIA) leads to an increase in Treg cells that correlate with decreased autoreactivity. Here, we demonstrate that the increase in Treg cells after B-cell depletion is due to an increase in the differentiation of naïve CD4(+) T cells into Treg cells. Since the development of PGIA is dependent on IFN-γ and B cells are reported to produce IFN-γ, we hypothesized that B-cell-specific IFN-γ plays a role in the development of PGIA. Accordingly, mice with B-cell-specific IFN-γ deficiency were as resistant to the induction of PGIA as mice that were completely IFN-γ deficient. Importantly, despite a normal frequency of IFN-γ-producing CD4(+) T cells, B-cell-specific IFN-γ-deficient mice exhibited a higher percentage of Treg cells compared with that in WT mice. These data indicate that B-cell IFN-γ production inhibits Treg-cell differentiation and exacerbates arthritis. Thus, we have established that IFN-γ, specifically derived from B cells, uniquely contributes to the pathogenesis of autoimmunity through prevention of immunoregulatory mechanisms.

Cell-based therapies for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a female predominant autoimmune disease characterized by multi-organ disorders. The pathogenesis of SLE is complex. Corticosteroids and immunosuppressive drugs are widely used to treat patients with SLE. However, these indiscriminate suppressors of the immune-mediated inflammatory aberration treat SLE at the cost of considerable adverse effects. Undoubtedly, there is a need for safer and more effective treatments for SLE. Cell-based therapies, although very much in their infancy, are of increasing interest in the treatment of SLE due to their potential for long-term suppression or a possible cure of the disease. Several immunoregulatory cell types, including regulatory T cells, mesenchymal stem cells, B-cells and natural killer cells, have recently been developed as novel products for tolerance-promoting therapies. Here, we provide a brief overview of current research of new cell-based therapeutic approaches that have undergone pre-clinical or clinical trials in the treatment of SLE.

A systematic review of biologics for the treatment of noninfectious uveitis

Noninfectious uveitis is a potentially sight-threatening ocular disorder and variable therapeutic strategies have been proposed. Biologic therapies were introduced as a new option for patients with uveitis refractory to the conventional therapy using corticosteroids and immunosuppressive agents, and 10 years have passed since the initiation. In this review, the author summarizes current articles on the assessment of therapeutic application of biologics for refractory uveitis including other autoimmune diseases. Although some results are based on investigation with insufficient clinical trials, especially in biologics, the majority of biologics indicate preferable outcomes on refractory uveitis, with remarkable promise to increase the possibility of long-term remissions.

Rituximab in dermatology

Rituximab was introduced into clinical practice as a medication with considerable potential. Its use in patients with B-cell lymphoma and rheumatoid arthritis revealed numerous indications in autoimmune diseases, many of which involve the skin, thus requiring dermatologists to become familiar with both the characteristics of anti-CD20 antibodies and the role of B cells in multiple skin diseases. Thanks to these developments, we will be able to use rituximab more frequently and appropriately in our patients and draw up consensus guidelines based on large case series. In other words, establishing the indications for rituximab will make it possible to shorten disease course and reduce morbidity due to more specific drugs.

Rituximab in the treatment of resistant lupus nephritis: therapy failure in rapidly progressive crescentic lupus nephritis

OBJECTIVE

The objective of this paper is to report the clinical outcome of B cell depletion therapy in 18 patients with refractory lupus nephritis (LN).

METHODS

Eighteen patients received rituximab on an open-label basis with prospective evaluations. All patients had renal disease refractory to conventional immunosuppressive therapy, including intravenous cyclophosphamide (CyC). All patients fulfilled the revised ACR classification criteria for SLE. Rituximab was given as 2 × 1 g infusions with 500 mg iv CyC and 500 mg iv methylprednisolone, two weeks apart. Complete remission (CR) of nephritis at six months was defined as normal serum creatinine and serum albumin levels, inactive urine sediment, and proteinuria < 0.5 g/day; partial remission (PR) was defined as a ≥50% improvement in all renal parameters that were abnormal at baseline. Clinical response was assessed by the British Isles Lupus Assessment Group (BILAG) score pre- and post-rituximab treatment, and efficacy was recorded by extent and duration of B lymphocyte depletion (normal range 0.100-0.500 × 10(9)/l). Follow-up data were collected at six months, one year post-treatment and at the most recent clinic visit.

RESULTS

At six months, 11/18 patients reached renal CR and two of 18 PR. The mean global BILAG scores for responders decreased from 15 (SD 10) to 5 (SD 3), and a total of ten A scores disappeared. Five patients failed to show complete or partial renal response despite peripheral B lymphocyte count depletion, and progressed to end-stage renal failure (ESRF) and dialysis. Four of these patients had severe proliferative, crescentic nephritis, of whom three had Class IV-G, one Class III and one late membranous glomerulonephritis. One patient died six years after rituximab therapy from overwhelming sepsis while on long-term haemodialysis.

CONCLUSION

Rituximab therapy achieved a response in 13/18 patients with refractory LN. However, in patients with rapidly progressive crescentic LN, when there is already evidence of significant renal impairment, rituximab therapy may not prevent progression to ESRF and dialysis. Our data also suggest that severe Class IV-G LN may be associated with a poor response to therapy.

Pediatric lupus nephritis: more options, more chances?

Lupus nephritis (LN) is more common and severe in childhood-onset systemic lupus erythematosus (SLE) than in adults. It is one of the major causes of acute kidney injury (AKI) and chronic kidney disease (CKD) in children. Steroid therapy has been used as the first-line treatment for SLE since 1970, and has improved the survival of SLE patients from ∼ 50% to >80%. Over the years many immunosuppressive drugs, including pulse methylprednisolone, oral cyclophosphamide, pulse intravenous cyclophosphamide, mycophenolate mofitil, rituximab, and tacrolimus, have been combined with prednisolone, further improving survival rates to 90%-95%. However, the effectiveness of these drugs is still uncertain, as most seem very good in the beginning, but in studies examining longer-term follow-up the remission of disease does not remain. Fatal infection is still a major complication of aggressive chemotherapy, and the potential benefits as well as adverse events from each drug need to be considered. Induction of remission is the major aim of therapy, with safe and effective maintenance therapy for long-term remission. The survival rates of many published studies vary widely because of differences in patients and treatment modalities, severity of disease, renal histopathology, racial factors, and duration of follow-up. Finding the optimal treatment for SLE and related co-morbidities is highly challenging, and will likely involve a complex combination of different drugs for different patients in the search for giving them an opportunity to be free from this debilitating disease.

Rituximab and multiple sclerosis

B lymphocytes seem to have a fundamental role in multiple sclerosis, acting as sensors, coordinators, and regulators of the immune response. Furthermore, they are important in activating T cells and they can mediate tissue injury through diverse mechanisms. Such findings have important therapeutic implications in autoimmune central nervous system diseases in a fashion similar to other autoimmune processes. The best known monoclonal antibody targeting B cells that has been used as a novel therapy for various autoimmune conditions, as well as multiple sclerosis, is rituximab. This review summarizes the available data on the role of B cell in multiple sclerosis and further reports on current knowledge on the B-cell-depleting monoclonal antibody rituximab, its mechanism of action, and its efficacy on multiple sclerosis. Data presented were categorized in 3 groups based on the nature of data presented (radiological, clinical, and immunological data). Both case-control studies and case reports were included, while table classification was in chronological order.

The effect of targeted delivery of anti-TNF-α oligonucleotide into CD169+ macrophages on disease progression in lupus-prone MRL/lpr mice

Systemic blockade of TNF-α via monoclonal antibodies and soluble receptors has shown considerable effects against several typical autoimmune disorders, but remains unconvincing for the treatment of lupus. Based on our previous study, a CD169(+) macrophage-specific therapy using TNF-α antisense oligonucleotides (ASO) was tested for its efficacy in MRL/lpr lupus-prone mice. ASO-containing cationic agarose hydrogel were injected into mice subcutaneously. Tissue distribution and cellular localization of ASO were determined. The therapeutic effects and possible mechanism were further studied in MRL/lpr lupus-prone mice. The results showed that specifically accumulation of the anti-TNF-α ASO in CD169(+) macrophages could significantly reduce TNF-α expression in CD169(+) macrophages and inhibit lymphocytes over-proliferation, finally resulted in the relief of the lupus-like symptoms of the animals. The nucleic acid drug based on CD169(+) macrophage-specific TNF-α regulation represents a potential therapeutic approach that may be valuable for lupus therapy.

Multicenter longitudinal study of B-lymphocyte depletion in refractory systemic lupus erythematosus: the LESIMAB study

OBJECTIVE

This study aimed to investigate the effectiveness and safety of single and repeated courses of rituximab in patients with refractory lupus.

METHODS

LESIMAB is a multicenter, retrospective, longitudinal study of lupus patients who have not responded to standard therapy and have been treated with rituximab. Response rates at six months and at follow-up were defined as efficacy outcomes. Complete response was defined as a SELENA-SLEDAI score ≤ two and a SELENA-SLEDAI Flare Index of zero. Partial response was defined as a reduction in the SELENA-SLEDAI score of ≥four points with no new or worsening of symptoms. Adverse events were collected.

RESULTS

Seventy-three (62.9%) of 116 patients achieved a response at six months (complete in 22 and partial in 51). Ninety-seven (77.6%) of 128 patients achieved a response after a mean follow-up of 20.0 ± 15.2 months (complete in 50 and partial in 47). High baseline SLEDAI score, previous treatment with ≥100 mg/day prednisone, and no history of severe hematologic flare were associated with response after the first treatment course. The median time to response was 6.5 months (95% CI, 5.0-8.0). Thirty-seven patients (38.1%) relapsed after the first infusion. The flare was severe in seven cases and mild to moderate in 29 cases. Serious infection rate was 12.6/100 patient-years. A schedule of four weekly doses was associated with more serious infections. Six patients died: two of infection and four of lupus complications.

CONCLUSION

Rituximab can be an effective treatment option for patients who have refractory lupus with severe or life-threatening disease with an acceptable tolerance profile.

B cell depletion enhances T regulatory cell activity essential in the suppression of arthritis

The efficacy of B cell-depletion therapy in rheumatoid arthritis has driven interest in understanding the mechanism. Because the decrease in autoantibodies in rheumatoid arthritis does not necessarily correlate with clinical outcome, other mechanisms may be operative. We previously reported that in proteoglycan-induced arthritis (PGIA), B cell-depletion inhibits autoreactive T cell responses. Recent studies in B cell-depletion therapy also indicate a role for B cells in suppressing regulatory mechanisms. In this study, we demonstrate that B cells inhibited both the expansion and function of T regulatory (Treg) cells in PGIA. Using an anti-CD20 mAb, we depleted B cells from mice with PGIA and assessed the Treg cell population. Compared to control Ab-treated mice, Treg cell percentages were elevated in B cell-depleted mice, with a higher proportion of CD4(+) T cells expressing Foxp3 and CD25. On a per-cell basis, CD4(+)CD25(+) cells from B cell-depleted mice expressed increased amounts of Foxp3 and were significantly more suppressive than those from control Ab-treated mice. The depletion of Treg cells with an anti-CD25 mAb concurrent with B cell-depletion therapy restored the severity of PGIA to levels equal to untreated mice. Although titers of autoantibodies did not recover to untreated levels, CD4(+) T cell recall responses to the immunizing Ag returned as measured by T cell proliferation and cytokine production. Thus, B cells have the capacity to regulate inflammatory responses by enhancing effector T cells along with suppressing Treg cells.

An acquired defect in IgG-dependent phagocytosis explains the impairment in antibody-mediated cellular depletion in Lupus

B cells play important roles in autoimmune diseases ranging from multiple sclerosis to rheumatoid arthritis. B cells have also long been considered central players in systemic lupus erythematosus. However, anti-CD20-mediated B cell depletion was not effective in two clinical lupus studies, whereas anti-B lymphocyte stimulator, which inhibits B cell survival, was effective. Others and we previously found that anti-CD20-based depletion was surprisingly ineffective in tissues of lupus-prone mice, but that persistent high doses eventually led to depletion and ameliorated lupus. Lupus patients might also have incomplete depletion, as suggested in several studies, and which could have led to therapeutic failure. In this study, we investigated the mechanism of resistance to Ab-mediated cellular depletion in murine lupus. B cells from lupus-prone mice were easily depleted when transferred into normal environments or in lupus-prone mice that lacked serum Ig. Serum from lupus-prone mice transferred depletion resistance, with the active component being IgG. Because depletion is FcγR-dependent, we assayed macrophages and neutrophils exposed to lupus mouse serum, showing that they are impaired in IgG-mediated phagocytosis. We conclude that depletion resistance is an acquired, reversible phagocytic defect depending on exposure to lupus serum IgG. These results have implications for optimizing and monitoring cellular depletion therapy.

[Resistant orbital pseudotumor treated with rituximab in a patient with systemic lupus erythematosus. A case presentation]

Ocular manifestations in Systemic Lupus Erythematosus (SLE) are relatively frequent, with a major prevalence of the Keratoconjunctivitis sicca. Nevertheless, the appearance of unilateral exophthalmos secondary to orbital pseudotumor in patients with SLE is extremely rare(1-7), and on occasion it can be refractory to conventional pharmacological treatment (glucocorticoids and immunosuppressants). We present the case of a patient with SLE and orbital pseudotumor refractory to treatment with Cyclophosphamide (CF) and an excellent clinical response, with disappearance of the ophthalmological condition after the beginning of therapy with Rituximab (1g×2), continuing after the infusion of two complete cycles without incidents.

Treatment of severe uveitis associated with juvenile idiopathic arthritis with anti-CD20 monoclonal antibody (rituximab)

OBJECTIVE

Rituximab (RTX), a chimeric mAb directed against the B-cell marker CD20, was investigated for its anti-inflammatory effect in treating refractory uveitis associated with JIA.

METHODS

Case series, retrospective multicentre. JIA patients with severe uveitis with vision-threatening complications (n = 10) and with insidious onset. All patients were treated with RTX for active uveitis refractory to topical and systemic CSs, immunosuppressives and at least one of the TNF-α inhibitors. All had active arthritis. Uveitis and arthritis course were assessed before and after RTX treatment.

RESULTS

After one RTX cycle (mean follow-up 11 months, range 7-18 months), uveitis inactivity was achieved in seven oligoarthritis patients (ANA⁺, HLA-B27⁻) for a prolonged period of time (mean 7.5 months, range 6-9 months). Therefore, CSs and immunosuppression could be spared. In three of four patients responding to RTX, uveitis recurred thereafter, and RTX re-treatment led to inactivity again. In another three patients (ANA⁺ polyarthritis, n = 1; ANA⁺ HLA-B27⁺ oligo- or polyarthritis, n = 2) uveitis activity persisted after RTX therapy. In seven patients, arthritis improved or was inactive after RTX treatment (PedACR30/50/70).

CONCLUSION

RTX may represent a rescue therapy option for severe JIA-associated uveitis refractory to CSs, immunosuppression and TNF-α inhibitors.

Rituximab treatment in patients with active Graves' orbitopathy: effects on proinflammatory and humoral immune reactions

In active Graves' orbitopathy (GO), proinflammatory cytokines predominate. Circulating thyroid stimulating hormone (TSH)-receptor antibodies (TRAb) have been correlated with GO clinical activity and severity. In preliminary studies rituximab (RTX), an anti-CD 20 monoclonal antibody, has induced clinical improvement of active GO without a change in serum anti-thyroid antibodies. We have studied whether RTX in GO acts by affecting proinflammatory cytokines and thyroid and orbital-directed antibodies. Ten patients with GO were treated with RTX, administered twice intravenously (i.v.) (1000 mg) at days 1 and 15, and 20 with methylprednisolone, administered weekly i.v. (500 mg), for 16 weeks. Patients were studied before treatment, at B cell depletion and at 4, 8, 16, 20, 30 and 50 weeks. Peripheral lymphocytes, serum interleukin (sIL)-6, sIL-6r, chemokine (C-X-C motif) ligand 10 (CXCL10), TRAb and stimulating antibodies (TSAb) and autoantibodies against orbital calsequestrin, collagen XIII and flavoprotein subunit of succinate dehydrogenase (FP-SDH) were measured at baseline and after treatment. Serum IL-6 and sIL-6R concentrations did not change after RTX [P = not significant (n.s.)]. Serum CXCL10 increased after RTX at B cell depletion and at 30 weeks (P < 0·003). Serum TSAb did not change in relation to TRAb, nor did antibodies against orbital antigens (P = n.s.). In conclusion, this study shows that RTX in GO does not affect humoral reactions. The observed increase of serum CXCL10 concentrations at B cell depletion may result from cell lysis. We suggest that RTX may exert its effect in GO by inhibiting B cell antigen presentation.

Targeting B cells with biologics in systemic lupus erythematosus

IMPORTANCE OF THE FIELD

The use of biologics as immune modulators in several autoimmune diseases has provided new tools to the physician's therapeutic armamentiarium and has led to improved patients' outcomes and quality of life. By producing autoantibodies, B cells in systemic lupus erythematosus (SLE) are key players in the pathogenesis of the disease and in its clinical manifestations. Therefore, biologics that target B cells in SLE aim at reducing the activity of these cells for the induction of remissions and/or amelioration of disease activity, reduction of organ involvement, and limitation of the complications and side effects caused by immunosuppressive therapies.

AREAS COVERED IN THIS REVIEW

This review describes the past and current clinical trials with B-cell-targeted biologics in SLE, to provide a historical perspective and the state-of-the-art on the topic.

WHAT THE READER WILL GAIN

We review how the disappointment in the field from promising agents has been instrumental in providing valuable lessons leading to an improved design of new trials that are now giving encouraging results.

TAKE HOME MESSAGE

In systemic lupus erythematosus (SLE), the use of B-cell-based biologics in clinical trials has shown both disappointment and promise.

Rituximab therapy in idiopathic membranous nephropathy: a 2-year study

BACKGROUND AND OBJECTIVES

It was postulated that in patients with membranous nephropathy (MN), four weekly doses of Rituximab (RTX) would result in more effective B cell depletion, a higher remission rate, and maintaining the same safety profile compared with patients treated with RTX dosed at 1 g every 2 weeks. This hypothesis was supported by previous pharmacokinetic (PK) analysis showing that RTX levels in the two-dose regimen were 50% lower compared with nonproteinuric patients, which could potentially result in undertreatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty patients with MN and proteinuria >5 g/24 h received RTX (375 mg/m(2) × 4), with re-treatment at 6 months regardless of proteinuria response. PK analysis was conducted simultaneously with immunological analyses of T and B cells to ascertain the effect of RTX on lymphocyte subpopulations.

RESULTS

Baseline proteinuria of 11.9 g/24 h decreased to 4.2 and 2.0 g/24 h at 12 and 24 months, respectively, whereas creatinine clearance increased from 72.4 ml/min per 1.73 m(2) at baseline to 88.4 ml/min per 1.73 m(2) at 24 months. Of 18 patients who completed 24-month follow-up, 4 are in complete remission, 12 are in partial remission, 1 has a limited response, and 1 patient relapsed. Serum RTX levels were similar to those obtained with two doses of RTX.

CONCLUSIONS

Four doses of RTX resulted in more effective B cell depletion, but proteinuria reduction was similar to RTX at 1 g every 2 weeks. Baseline quantification of lymphocyte subpopulations did not predict response to RTX therapy.

[Efficacy of rituximab versus cyclophosphamide in lupus patients with severe manifestations. A randomized and multicenter study]

There are no controlled studies that compare the efficacy of RTX with standard treatment, such as cyclophosphamide, in patients with systemic lupus erythematosus (SLE).

OBJECTIVE

The objective of this study was to compare the efficacy of rituximab to that of cyclophosphamide in patients with severe manifestations of SLE.

MATERIALS AND METHOD

This is a multicenter, randomized open and controlled trial in adults with a diagnosis of active SLE. Patients were randomized into two groups; group 1: treated with RTX and group 2: cyclophosphamide pulses with the same steroid scheme. We registered MEX-SLEDAI, steroid requirements and adverse events for 12 months. Descriptive and comparative statistic analysis was performed.

RESULTS

19 patients were included, 17 females, mean age 35.7±12.1 years and duration of disease 5.6 years (range 0.35 to 30.8 years). There were no differences at baseline regarding gender, age, duration of disease, previous treatments or disease activity between both groups. MEX-SLEDAI was reduced from 12 to 3 in group 1 and from 9 to 2 in group 2 (p=0.80). Nevertheless, patients treated with RTX had a faster improvement. There was no difference in the cumulative steroid dose. Both groups had significant reduction in antinuclear antibody levels and similar increase in C3 levels. Adverse events were similar in both groups.

CONCLUSION

This comparative clinical study in patients with SLE shows that rituximab can be as useful as cyclophosphamide for severe manifestations, maybe showing a faster response. Adverse events were no different. Rituximab should be considered as an adequate alternative for this group of patients.

A new site-directed transgenic rheumatoid factor mouse model demonstrates extrafollicular class switch and plasmablast formation

The AM14 rheumatoid factor (RF) transgenic (Tg) mouse has been valuable for studying how self-reactive B cells are regulated beyond central tolerance, because they remain ignorant in normal mice. AM14 B-cell activation can be studied on autoimmune-prone strains or by inducing activation with IgG2a anti-chromatin antibodies (Abs). Despite the utility of conventional Ig-Tg mice, site-directed Ig-Tg (sd-Tg) mice provide a more physiological model for B-cell responses, allowing class switch and somatic hypermutation. We report here the creation of an AM14 sd-Tg mouse and describe its phenotype on both normal and autoimmune-prone backgrounds. AM14 sd-Tg B cells develop normally but remain unactivated in the BALB/c background, even after significant aging. In contrast, in the autoimmune-prone strain MRL/lpr, AM14 sd-Tg B cells become activated and secrete large amounts of IgG RF Ab into the serum. Class-switched Ab-forming cells were found in the spleen and bone marrow. IgG RF plasmablasts were also observed in extrafollicular clusters in the spleens of aged AM14 sd-Tg MRL/lpr mice. Class switch and Ab secretion were observed additionally in AM14 sd-Tg BALB/c B cells activated in vivo using IgG2a anti-chromatin Abs. Development of IgG auto-Abs is a hallmark of severe autoimmunity and is related to pathogenesis. Using the AM14 sd-Tg, we now show that switched auto-Ab-forming cells develop robustly outside germinal centers, further confirming the extrafollicular expression of activation induced cytidine deaminase (AID). This model will allow more physiological studies of B-cell biology in the future, including memory responses marked by class switch.

Pathogenesis of human systemic lupus erythematosus: recent advances

Systemic lupus erythematosus (SLE) is an autoimmune disease with manifestations derived from the involvement of multiple organs including the kidneys, joints, nervous system and hematopoietic organs. Immune system aberrations, as well as heritable, hormonal and environmental factors interplay in the expression of organ damage. Recent contributions from different fields have developed our understanding of SLE and reshaped current pathogenic models. Here, we review recent findings that deal with (i) genes associated with disease expression; (ii) immune cell molecular abnormalities that lead to autoimmune pathology; (iii) the role of hormones and sex chromosomes in the development of disease; and (iv) environmental and epigenetic factors thought to contribute to the expression of SLE. Finally, we highlight molecular defects intimately associated with the disease process of SLE that might represent ideal therapeutic targets and disease biomarkers.

B-cell biology and related therapies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex disease characterized by numerous autoantibodies and clinical involvement in multiple organ systems. The immunologic events triggering the onset and progression of clinical manifestations have not yet been fully defined, but a central role for B cells in the pathogenesis has been brought to the fore in the last several years. The breakdown of B-cell tolerance is likely a defining and early event in the disease process and may occur by multiple pathways, including alterations in factors that affect B-cell activation thresholds, B-cell longevity, and apoptotic cell processing. Antibody-dependent and -independent mechanisms of B cells are important in SLE. Thus, autoantibodies contribute to autoimmunity by multiple mechanisms including immune complex mediated type III hypersensitivity reactions, type II antibody-dependent cytotoxicity, and by instructing innate immune cells to produce pathogenic cytokines including interferon alpha, tumor necrosis factor, and interleukin 1. Recent data have highlighted the critical role of toll-like receptors as a link between the innate and adaptive immune system in SLE immunopathogenesis. Given the large body of evidence implicating abnormalities in the B-cell compartment in SLE, there has been a therapeutic focus on developing interventions that target the B-cell compartment. Several different approaches to targeting B cells have been used, including B-cell depletion with monoclonal antibodies against B-cell-specific molecules, induction of negative signaling in B cells, and blocking B-cell survival and activation factors. Overall, therapies targeting B cells are beginning to show promise in the treatment of SLE and continue to elucidate the diverse roles of B cells in this complex disease.

Differential cytokine production and bystander activation of autoreactive B cells in response to CpG-A and CpG-B oligonucleotides

Synthetic oligonucleotides containing CpG motifs have been shown to induce proliferation, differentiation, and cytokine production in B cells, macrophages, and dendritic cells through a TLR9-dependent mechanism. A class (CpG-A) and B class (CpG-B) oligonucleotides display distinct physical properties. CpG-A, but not CpG-B, can multimerize to form exceedingly large lattices. CpG-A cannot effectively activate B cells but does induce plasmacytoid dendritic cells to produce high levels of IFNalpha, while CpG-B is a potent B cell mitogen. In this study, we report that CpG-A is internalized by B cells, and CpG-A and CpG-B accumulate in distinct intracellular compartments. When present in the form of an immune complex (CpG-A IC), CpG-A is taken up more efficiently by AM14 IgG2a-specific B cells, and elicits a robust TLR9-dependent B cell proliferative response. B cells proliferating comparably and in a TLR9-dependent fashion in response to CpG-A IC and CpG-B exhibited distinct cytokine profiles. CpG-A IC induced enhanced production of RANTES and markedly reduced levels of IL-6 when compared with CpG-B. We also found that engagement of the AM14 BCR by a protein IC, which cannot by itself induce proliferation, promoted TLR9-dependent but BCR-independent proliferation by bystander CpG-A or fragments of mammalian dsDNA. These data identify direct and indirect mechanisms by which BCR engagement facilitates access of exogenous ligands to TLR9-associated compartments and subsequent B cell activation.

Rituximab: beyond simple B cell depletion

Rituximab, a chimeric anti-CD20 monoclonal antibody, has a proven track record for over a decade in the treatment of lymphomas, where it has been used to eradicate malignant lymphocytes. In appreciation of the putative role of B cells, especially with respect to autoantibody production, in the pathogenesis of autoimmune diseases, successful trials of B-cell depletion therapy in RA, SLE, and other autoimmune diseases have been carried out. In these trials, clinical benefit has generally correlated with the extent and duration of B-cell depletion, but at times imperfectly, and autoantibody reduction only selectively. Additional mechanisms whereby rituximab may assert its clinical benefit in autoimmune diseases have been examined including a look at B-cell functions as T-cell modulator and antigen-presenting cell, T-regulatory cell behavior, NK cell activity, and macrophage activities in immune inflammation. The available data on rituximab's action in autoimmune diseases is reviewed.

A retrospective seven-year analysis of the use of B cell depletion therapy in systemic lupus erythematosus at University College London Hospital: the first fifty patients

OBJECTIVE

To describe the 6-month clinical outcome and the long-term safety profile of B cell depletion therapy (BCDT) in 50 patients with active systemic lupus erythematosus (SLE), who were nonresponsive or poorly responsive to conventional immunosuppression.

METHODS

All except 4 of 50 patients with active SLE received 1 gm of rituximab, 750 mg of cyclophosphamide, and 100-250 mg of methylprednisolone, administered on 2 occasions 2 weeks apart, to achieve B cell depletion. Clinical outcome was assessed using the British Isles Lupus Assessment Group (BILAG) activity index and serial serologic measurements of disease activity. Remission was defined as a change from a BILAG A or B score to a C or D score in every organ system. Partial remission was a change from a BILAG A or B score to a C or D score in at least 1 system, but with the persistence of 1 score of A or B in another system. No improvement was defined as a BILAG A or B score that remained unchanged after treatment.

RESULTS

Of the 45 patients available for followup at 6 months, 19 patients (42%) achieved remission, and 21 patients (47%) reached partial remission after 1 cycle of BCDT (mean followup 39.6 months). BCDT resulted in a decrease in median global BILAG scores from 12 to 5 (P < 0.0001) and median anti-double-stranded DNA antibody titers from 106 to 42 IU/ml (P < 0.0001), and an increase in the median C3 level from 0.81 to 0.95 mg/liter (P < 0.02) at 6 months. Five serious adverse events were observed.

CONCLUSION

BCDT is an effective treatment for patients with active SLE whose disease has failed to respond to standard immunosuppressive therapy. Although the safety profile of BCDT is favorable, ongoing monitoring is required.