SLE - Rituximab in lupus

Pathogenic and Epiphenomenal Anti-DNA Antibodies in SLE

The discoveries of natural and the development of manufactured highly efficient catalytic antibodies (abzymes) opens the door to many practical applications. One of the most fascinating is the use of such antibodies in human therapy and prevention (vaccination), of cancer, AIDS, autoimmune diseases. A special entity of naturally occurring DNA hydrolytic anti-DNA antibodies is emerging within past decades linked to autoimmune and lymphoproliferative disorders, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), Sjogren Syndrome (SS), B - Chronic lymphocytic leucosis (B-CLL), and Multiple Myeloma (MM). The origin of the antibodies is unknown. The underlying mechanisms of these activities are suggested to be penetration into the living cells and translocation in the nucleus, with recognition of the specific binding sites at particular (ss or ds) DNA. There are controversies in the literature whether hydrolysis is a sequence-specific event. The interplay between anti-DNA antibodies and DNA is not yet elucidated. This molecular “twist” also suggests that anti-DNA antibodies with DNA hydrolytic capacity could be the organism's immune response to a microbial attack, with microbial DNA, or specific genes within microbial DNA sequence, as a target for neutralization. The catalytic antibody-based approach can become a key tool in selective chemotherapeutic strategies.

Association of the BANK 1 R61H variant with systemic lupus erythematosus in Americans of European and African ancestry

Recently an association was demonstrated between the single nucleotide polymorphism (SNP), rs10516487, within the B-cell gene BANK1 and systemic lupus erythematosus (SLE) as a consequence of a genome wide association study of this disease in European and Argentinean populations. In a bid for replication, we examined the effects of the R61H non-synonymous variant with respect to SLE in our genotyped American cohorts of European and African ancestry. Utilizing data from our ongoing genome-wide association study in our cohort of 178 Caucasian SLE cases and 1808 Caucasian population-based controls plus 148 African American (AA) SLE cases and 1894 AA population-based controls we investigated the association of the previously described non-synonymous SNP at the BANK1 locus with the disease in the two ethnicities separately. Using a Fisher’s exact test, the minor allele frequency (MAF) of rs10516487 in the Caucasian cases was 22.6% while it was 31.2% in Caucasian controls, yielding a protective odds ratio (OR) of 0.64 (95% CI 0.49-0.85; one-sided p = 7.07 × 10⁻⁴). Furthermore, the MAF of rs10516487 in the AA cases was 18.7% while it was 23.3% in AA controls, yielding a protective OR of 0.75 (95% CI 0.55–1.034; one-sided p = 0.039). The OR of the BANK1 variant in our study cohorts is highly comparable with that reported previously in a South American/European SLE case-control cohort (OR = 0.72). As such, R61H in the BANK1 gene confers a similar magnitude of SLE protection, not only in European Americans, but also in African Americans.

Association of the shrinking lung syndrome in systemic lupus erythematosus with pleurisy: a systematic review

OBJECTIVES

To report 2 patients with systemic lupus erythematosus and typical shrinking lung syndrome (SLS) in which pleuritic chest pain was the predominant symptom. In addition, to record the prevalence of pleuritic chest pain in all reported cases of patients with SLS and diaphragmatic dysfunction.

METHODS

We conducted a comprehensive search of the English literature to record the association of pleurisy and SLS in all reported cases using the MEDLINE database from 1965 to present.

RESULTS

Of the 77 patients with SLS reported in the literature, 50 (65%) patients had pleuritic chest pain at the time of evaluation. Treatment with anti-inflammatory agents improved symptoms in the majority of cases.

CONCLUSIONS

Pleuritic inflammation and pain may have an important role in the pathogenesis of SLS. A possible mechanism linking pleural inflammation and diaphragm dysfunction may be via a reflex inhibition of diaphragmatic activation.

Successful rituximab-CHOP treatment of systemic lupus erythematosus associated with diffuse large B-cell non-Hodgkin lymphoma

The authors discuss the case of a 76-year-old female patient who has been suffering from subacute cutaneous lupus erythematosus since 1983. In 1999 she was diagnosed with systemic lupus erythematosus (SLE) based on her symptoms of malar rash, polyarthritis, leukopenia, autoimmune hemolytic anemia and positive anti-DNA antibody test. For this she received methylprednisolone and cyclophosphamide. After 3 years of remission, symptoms of cutaneous vasculitis appeared in 2004, which transitionally responded to treatment with azathioprin and methylprednisolone. Her cutaneous symptoms, however, progressed quickly along with generalized lymphadenopathy, splenomegaly and thrombocytopenia. Immunohistological evaluation of the lymph node biopsy showed diffuse large B-cell lymphoma. She developed complete remission after treatment with six-cycle R-CHOP (rituximab, and reduced doses of cyclophosphamide, vincristin, adriablastin, methylprednisolone). SLE became inactive and her symptoms of vasculitis resolved. The authors are bringing attention to one of the possible late complications of systemic lupus, and also underscoring that treatment with rituximab (+CHOP) was beneficial not only for the lymphoma but the SLE as well.

Targeting BAFF: Immunomodulation for autoimmune diseases and lymphomas

In an effort to develop more effective treatments for inflammatory diseases, immunologists have targeted numerous molecular pathways, but with limited success. Notable exceptions are anti-TNF agents, which have proved efficacious in a proportion of rheumatoid arthritis (RA) patients. Another TNF family member, termed BAFF ("B cell-activating factor belonging to the TNF family"), plays a central role in autoimmune diseases, as well as in B cell maturation, survival, and T cell activation. Agents that block BAFF have proven to be highly effective in the treatment of certain autoimmune conditions in mice. In addition, phase II data in human clinical trials for RA appear very promising. BAFF is also a survival factor for certain B cell lymphomas. Despite the relatively recent identification of BAFF, this molecule has provided considerable new insight into B cell homeostasis and immune function, and represents an important new molecular target for treatment of autoimmune diseases and lymphomas.

Increased prevalence of activated CD70+CD4+ T cells in the periphery of patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by loss of immune tolerance. A hallmark of SLE is the presence of autoantibodies resulting from B cell hyperactivity. Previous studies have shown that the presence of abnormal B cell subsets in the periphery, such as CD27highCD20- B cells, correlate with disease activity. We examined the relationship between the expression of CD70, the ligand for CD27 expressed by activated T cells, and indicators of disease activity. A significant increase in median CD70+CD4+ T cell frequencies and memory CD45RA-CD4+ T cell frequencies was observed in SLE samples as compared to healthy controls. The frequencies of CD70+CD4+ T cells correlated with disease duration but not age, treatment, or disease activity. Although a majority of CD70+CD4+ T cells appeared to be effector memory cells, mitogen-stimulated CD70+CD4+ T cells were capable of secreting a full repertoire of effector cytokines. Despite the presence of activated CD4+ T cells, no increase in immunosenescent CD4+ T cells, as defined by the loss of CD28 and/or the acquisition of CD57 was observed in samples from SLE patients. These studies indicate that increased CD70 expression might serve as a useful marker of abnormal T cell activity in SLE.

B-cell depletion inhibits arthritis in a collagen-induced arthritis (CIA) model, but does not adversely affect humoral responses in a respiratory syncytial virus (RSV) vaccination model

We report the development of a mouse B cell-depleting immunoconjugate (anti-CD22 monoclonal antibody [mAb] conjugated to calicheamicin) and its in vivo use to characterize the kinetics of CD22+ B-cell depletion and reconstitution in murine primary and secondary lymphoid tissues. The effect of B-cell depletion was further studied in a murine collagen-induced arthritis (CIA) model and a respiratory syncytial virus (RSV) vaccination model. Our results show that (1) the immunoconjugate has B-cell-specific in vitro and in vivo cytotoxicity; (2) B-cell reconstitution starts in the bone marrow and spleen around day 30 after depletion and is completed in all tissues tested by day 50; (3) B-cell depletion inhibits the development of clinical and histologic arthritis in the CIA model; (4) depletion of type II collagen antibody levels is not necessary for clinical and histologic prevention of CIA; and (5) B-cell depletion does not adversely affect memory antibody responses after challenge nor clearance of infectious virus from lungs in the RSV vaccination model. These results demonstrate for the first time that only B-cell reduction but not type II collagen antibody levels correlate with the prevention of arthritis and represent key insights into the role of CD22-targeted B-cell depletion in mouse autoimmunity and vaccination models.

The therapeutic potential of anti-CD20 "what do B-cells do?"

B-cells play a major role in the immunopathogenesis of autoimmune diseases. Not only do they produce autoantibodies, but they regulate other cell types, secrete cytokines, and present antigens. They are thus potential targets for therapeutic intervention. CD20 is a B-cell specific cell surface molecule of uncertain function. An anti-CD20 chimeric mAb (rituximab) has been FDA approved for treatment of B-cell lymphomas since 1997. Rituximab also depletes normal B-cells by several mechanisms, including ADCC. Over the past seven years, it has shown promise in a number of autoimmune diseases in phase I trials and anecdotal reports. Efficacy in rheumatoid arthritis has already been demonstrated in randomized control trials (RCTs), and RCTs in SLE, inflammatory myositis, and ANCA associated vasculitis are under way. Safety does not appear to be a major problem, but continued vigilance is warranted. The increased use of rituximab, other anti-CD20 agents, and other B-cell targeting therapies holds great promise for substantial clinical benefits, as well as providing special opportunities to understand better disease pathogenesis.

Rituximab in childhood systemic lupus erythematosus refractory to conventional immunosuppression: case report

Rituximab, a chimeric monoclonal antibody specific for human CD20, has recently been used for the treatment of autoimmune diseases. A 14-year-old patient with severe systemic lupus erythematosus (SLE) and class IV glomerulonephritis presented with immunologic and clinical resistance to conventional immunosuppressive therapy for 10 months after diagnosis. To induce remission of active SLE, treatment with 6 monthly rituximab at 375 mg/m(2), oral mycophenolate and prednisone was initiated followed by maintenance rituximab every 3 months. The SLEDAI decreased significantly from 31 at diagnosis to 14 after nine applications of rituximab. Extrarenal symptoms of SLE improved significantly. However, after induction therapy with rituximab the patient presented a reversible intrinsic acute renal insufficiency for a period of 3 weeks. The discontinuation of the daily medication (oral prednisone and mycophenolate) by the patient herself may explain the progression of active SLE associated with the reversible acute renal failure. Under intensive immunosuppressive therapy improvement of active disease manifestations and stabilization of plasma creatinine concentrations to normal values was observed. However, proteinuria remained elevated and improved only after a protracted period (median protein-to-creatinine ratio 5.2 g/g, range 0.8-11.2 g/g). Hematuria and urinary cell casts persisted. In conclusion, the extrarenal symptoms of the patient responded particularly well to rituximab. However, despite complete B-cell elimination, renal remission of SLE was not achieved. Thus, it may be possible that humoral and cellular immune mechanisms have a fundamental involvement in the pathogenesis of SLE nephritis.

Depletion of B Cells by a Humanized Anti-CD20 Antibody PRO70769 in Macaca Fascicularis

PRO70769 is a humanized IgG1 monoclonal antibody against the CD20 molecule that is present on normal and malignant B cells. PRO70769 is being evaluated for treatment of B-cell-mediated diseases and is in a phase 1 trial for rheumatoid arthritis. As part of the preclinical toxicology evaluation, B-cell depletion profiles and safety of PRO70769 were assessed in cynomolgus monkeys. Animals were administered drug (IV) on days 1 and 15 with 10, 50, or 100 mg/kg PRO70769 and killed 2 weeks after the second dose and after a 3-month recovery period. In a parallel study, animals were not necropsied but instead were retreated with a second cycle of PRO70769 administered under an identical regimen. PRO70769 suppressed B cells in the blood to undetectable levels and significantly reduced B cells in lymphoid tissues. Splenic B cells were depleted to a greater extent compared with lymph node B cells. A second cycle of treatment resulted in a greater extent of depletion in lymphoid tissues compared with the depletion observed after one cycle of treatment; however, residual B cells in lymphoid tissues were still detectable, even at the highest dose. The rate of B-cell recovery in peripheral blood appeared similar between one and two cycles of treatment. Upon depletion there was a change in the profile of lymph node B-cell subsets. After recovery, B-cell subsets were reconstituted to normal levels. Depletion of CD20-expressing cells and lymphoid follicular atrophy were the only treatment-related effects.

[Rituximab: a original biotherapy in auto-immune disorders]

SUBJECT

After several decades of hegemony of the T lymphocyte, recent work has suggested the importance of the B lymphocyte in auto-immune diseases. As a consequence, there has emerged over the last few years the idea of using anti-B lymphocyte therapy, in particular rituximab (a chimeric anti-CD20 monoclonal antibody).

CURRENT TOPICS AND IMPORTANT RESULTS

This review addresses various current topics: a) the role of B lymphocytes in auto-immune diseases, notably their capacity to be antigen presenting cells and to be activated by original systems like Blys/Baff; b) the mechanism of action of rituximab (apoptosis, complement-dependent cytotoxicity and antibody-dependent cell cytotoxicity) and the phenomena explaining failures and cases escaping treatment, in particular among lymphoproliferations; c) The results include efficacy and tolerance data for the principal auto-immune affections. Among these, the most promising indications would seem to be for rheumatoid polyarthritis and systemic lupus erythematosis, although some preliminary open studies point to an effect in Goujerot-Sjögren's syndrome, neuropathies, auto-immune cytopenia, idiopathic thrombocytopenic purpura, cryoagglutinins, blistering cutaneous affections...

PERSPECTIVES AND PROJECTS

Controlled studies will be required to determine the true efficacy and tolerance of this molecule, as it is imperative to validate these new immunotherapeutic strategies, above all when they concern innovative and expensive therapy. Nevertheless, these different observations arouse great hopes and at the same time exciting questions, notably as to the role of B lymphocytes in auto-immune diseases.

Challenges in bringing the bench to bedside in drug development for sle

It is now widely accepted that the current standard of care for systemic lupus erythematosus (SLE) patients is inadequate. There has not been a new medication approved for this disease in thirty years. Attempts to develop and test new drugs have been ongoing since the mid-1990s, but have encountered formidable obstacles. Current models for lupus pathogenesis have provided a theoretical framework for understanding how heterogeneous genetic defects might combine in various ways to increase susceptibility to SLE in different individuals, and could have important implications for new drug development. With the current burst of drug discovery and increased public awareness of SLE, the impetus to overcome these obstacles has never been greater.

Systemic lupus erythematosus trials: successes and issues

PURPOSE OF REVIEW

The purpose of this review is to discuss the most recent published clinical trials for systemic lupus erythematosus and to identify important issues that have arisen in association with the search for new therapies for systemic lupus erythematosus, as well as new regimens or indications for the use of "standard-of-care" agents such as corticosteroids and cyclophosphamide.

RECENT FINDINGS

Important developments have occurred during the past 2 years as interest in this area has increased, largely because of the participation of pharmaceutical and biotechnical companies in the development and testing of novel agents for systemic lupus erythematosus. Several important large-scale, multicenter, randomized controlled trials have been completed, but none has yet resulted in a new, approved indication for systemic lupus erythematosus. Many issues in the identification of new therapeutic modalities remain. These include the fact that a majority of published reports include either small numbers of patients in controlled trials that lack statistical power to draw conclusions, or are uncontrolled anecdotal series or individual case reports. Among the larger controlled trials, a pervasive issue in the failure to reach statistical significance may be the initial study design. Inclusion of patients with mild and/or stable disease activity does not allow for an effect size sufficient to show differences in treatment arms without recruitment of very large numbers of subjects. Finally, several potentially important trials have been reported only in abstract form to date. Further assessment of the results must await formal publication of these studies.

Rituximab-mediated depletion of cynomolgus monkey B cells in vitro in different matrices: possible inhibitory effect of IgG

The mechanism of rituximab-mediated depletion of nonmalignant CD20+B cells remains to be clarified. In this report, we examine contributions of complement- and cell-dependent killing to the rituximab-mediated depletion of cynomolgus monkey B cells in the in vitro assay. B cell depletion was assessed in whole blood, buffer, autologus plasma (plasma), heat-inactivated plasma (H/I plasma), and cobra venom factor (CVF)-treated plasma matrices in cynomolgus monkey and human samples. Rituximab-mediated B cell depletion in buffer appeared to be greater than that in whole blood or in autologus plasma. Heat inactivation of plasma resulted in the degree of B cell depletion closer to that seen in buffer, whereas CVF treatment of plasma had no effect on B cell depletion. Addition of IgG to the buffer decreased the degree of B cell depletion. The results of these studies imply that (i) plasma components (including complement) are not the mediators of the rituximab-triggered B cell depletion in the in vitro assay, suggesting that cell-mediated mechanisms are likely to be responsible for in vitro killing of normal B cells, and that (ii) some plasma components appear to inhibit rituximab-mediated B cell depletion in the in vitro assay, with IgG identified as a possible inhibitor component.