Novel approaches to therapy for systemic lupus erythematosus

Peptides from antibodies to DNA elicit cytokine release from peripheral blood mononuclear cells of patients with systemic lupus erythematosus: relation of cytokine pattern to disease duration

Peptides from VH regions of antibodies to DNA drive immune responses in systemic lupus erythematosus (SLE). We studied peptide-induced cytokine release by peripheral blood mononuclear cells (PBMC) of patients, the influence of peptide concentration, disease characteristics and HLA-D haplotypes. Cells secreting cytokines (IFNg, IL-2, IL-4 and IL-10) were measured by ELISPOT in PBMC from 31 patients with SLE and 20 matched healthy controls in response to seven peptides (A-G) from the CDR1/FR2 to CDR2/FR3 VH regions of human anti-DNA MAbs. Disease activity was assessed by SELENA-SLEDAI. HLA-DR and -DQ alleles were determined by molecular typing techniques. PBMC from significantly higher proportions of SLE patients than controls responded to VH peptides by generating IFNg and IL-10. Type of cytokines released in response to at least one peptide (D) depended on antigen concentration. Cytokine release was not associated with clinical features of SLE except for disease duration. A shift occurred from IFNg, IL-4 and IL-10 production in early disease to IL-4 and IL-10 in late disease (suggesting increasing TH2-like responses over time). Three peptides (B, D, G) were more stimulatory in the SLE patients than controls. Although none of the peptides was restricted by any particular MHC class II allele, among responders there was increased prevalence of HLA-DQB1 0201 and/or DRB1 0301, alleles known to predispose to SLE. Thus, responses to some VH peptides are more frequent in SLE and vary with disease duration. Increased responses in individuals with HLA class II genotypes that predispose to SLE suggest that peptide presentation by those molecules permits brisker peripheral blood cell responses to autoantibody peptides, thus increasing risk for disease.

Etoposide selectively ablates activated T cells to control the immunoregulatory disorder hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is an inborn disorder of immune regulation caused by mutations affecting perforin-dependent cytotoxicity. Defects in this pathway impair negative feedback between cytotoxic lymphocytes and APCs, leading to prolonged and pathologic activation of T cells. Etoposide, a widely used chemotherapeutic drug that inhibits topoisomerase II, is the mainstay of treatment for HLH, although its therapeutic mechanism remains unknown. We used a murine model of HLH, involving lymphocytic choriomeningitis virus infection of perforin-deficient mice, to study the activity and mechanism of etoposide for treating HLH and found that it substantially alleviated all symptoms of murine HLH and allowed prolonged survival. This therapeutic effect was relatively unique among chemotherapeutic agents tested, suggesting distinctive effects on the immune response. We found that the therapeutic mechanism of etoposide in this model system involved potent deletion of activated T cells and efficient suppression of inflammatory cytokine production. This effect was remarkably selective; etoposide did not exert a direct anti-inflammatory effect on macrophages or dendritic cells, and it did not cause deletion of quiescent naive or memory T cells. Finally, etoposide's immunomodulatory effects were similar in wild-type and perforin-deficient animals. Thus, etoposide treats HLH by selectively eliminating pathologic, activated T cells and may have usefulness as a novel immune modulator in a broad array of immunopathologic disorders.

Intravenous immunoglobulin-based immunotherapy: an arsenal of possibilities for patients and science

The use of intravenous immunoglobulin (IVIG) concentrated from pooled healthy donors' plasma has gained increasing popularity. IVIG therapy has become important as a replacement therapy in primary and acquired humoral immunodeficiencies, and it has been extended to autoimmune, neurodegenerative and inflammatory conditions and transplantation therapy. Recurrent pregnancy failure and cancer are rather new platforms, where IVIG has shown its beneficial effects. This manuscript is focused on these two off-labelled usages. The immunomodulatory mechanisms of IVIG therapy appear as a coordinated orchestration of different functions, resulting in a synergistic effect. Treatment monitoring and detailed molecular analyses reveal how such treatments may interfere with disease pathogenesis. These finding may foster the development of novel therapeutic and/or preventive strategies. Studying this field with bidirectional bench-to-bedside and bedside-to-bench approaches fit well into 'the two-way road' paradigm of translational medicine.

Insertion of a targeting peptide on capsid surface loops of human papillomavirus type-16 virus-like particles mediate elimination of anti-dsDNA Abs-producing B cells with high efficiency

The purpose of this study was to design chimeric human papillomavirus type-16 L1 virus-like particles (VLPs) and to explore the potential capacity of elimination to anti-dsDNA antibody-producing B cells. To test it, VLPs were achieved by combination of human papillomavirus type-16 L1 proteins inserted into a targeting peptide (DWEYSVWLSN) and plasmids encoding diphtheria toxin A ligand. Additionally, VLPs were cocultured with target cells to assess the killing efficiency by lactate dehydrogenase assay in vitro. Lastly, lupus-prone (BWF1) mice vaccinated with VLPs were used as a model to assess the killing efficiency in vivo. The results showed that the VLPs were constructed successfully, and possessed the potential of killing anti-dsDNA antibody-producing B cells with high efficiency. The findings indicate the possibility that the VLPs ablate autoreactive B cells represents a novel strategy in the immunotherapy of autoantibody-mediated diseases.

Nuclear factor of activated T cells (NFAT) mediates CD154 expression in megakaryocytes

Platelets are an abundant source of CD40 ligand (CD154), an immunomodulatory and proinflammatory molecule implicated in the onset and progression of several inflammatory diseases, including systemic lupus erythematosus (SLE), diabetes, and cardiovascular disease. Heretofore considered largely restricted to activated T cells, we initiated studies to investigate the source and regulation of platelet-associated CD154. We found that CD154 is abundantly expressed in platelet precursor cells, megakaryocytes. We show that CD154 is expressed in primary human CD34+ and murine hematopoietic precursor cells only after cytokine-driven megakaryocyte differentiation. Furthermore, using several established megakaryocyte-like cells lines, we performed promoter analysis of the CD154 gene and found that NFAT, a calcium-dependent transcriptional regulator associated with activated T cells, mediated both differentiation-dependent and inducible megakaryocyte-specific CD154 expression. Overall, these data represent the first investigation of the regulation of a novel source of CD154 and suggests that platelet-associated CD154 can be biochemically modulated.

Induction of dominant tolerance using monoclonal antibodies

Monoclonal antibodies (MAb) have been shown to be effective in inducing immune tolerance in transplantation and autoimmunity. Several different MAb have tolerogenic properties and their effect has been studied in a range of experimental animal models and, in some cases, in clinical trials. The tolerant state seems to be maintained by CD4+ regulatory T cells (Treg), induced in the periphery, capable of suppressing other T cells specific for the same antigens or antigens presented by the same antigen presenting cells. Furthermore, following the initial induction of Treg cells under MAb treatment, Treg cells themselves can maintain the tolerant state in a dominant way in the absence of the therapeutic MAb or other immunosuppressive agents, and are able to recruit other T cells into the regulatory pool--a process named infectious tolerance.

High-dose intravenous immunoglobulins: an option in the treatment of systemic lupus erythematosus

Despite encouraging reports on the efficacy of intravenous immunoglobulin (IVIG) therapy in systemic lupus erythematosus (SLE), the clinical value of this treatment is not well established, and most of the data are based on case reports and small series of patients. IVIG has been used successfully to treat SLE patients with a broad spectrum of clinical manifestations, such as refractory thrombocytopenia, pancytopenia, central nervous system (CNS) involvement, secondary antiphospholipid syndrome, and lupus nephritis. The beneficial effects of IVIG on overall disease activity are usually prompt, with marked improvement within a few days, but they are often of limited duration. Improvement lasts for several weeks after the last infusion, although clinical response could be maintained by continuous monthly IVIG infusions. IVIG therapy immunomodulates autoimmune diseases by interacting with various Fcgamma receptors in such a way that it downregulates activating FcRIIA and FcRIIC and/or upregulates inhibitory FcRIIB. However, in SLE, additional mechanisms include inhibition of complement-mediated damage, modulation of production of cytokines and cytokine antagonists, modulation of T- and B-lymphocyte function, induction of apoptosis in lymphocytes and monocytes, downregulation of autoantibody production, manipulation of the idiotypic network, and neutralization of pathogenic autoantibodies. At present, IVIG in SLE is indicated either in severe cases that are nonresponsive to other therapeutic modalities, or when SLE can be controlled only with high-dose steroids; in such patients, IVIG thus becomes a useful steroid-sparing agent. However, this needs to be confirmed in double-blind, placebo-controlled studies.

Hypersensitivity to Mycophenolate Mofetil in Systemic Lupus Erythematosus: Diagnostic Measures and Successful Desensitization

Despite therapeutic advances in the treatment of systemic lupus erythematosus (SLE), several patients are still afflicted with severe and uncontrolled symptoms. Recently, mycophenolate mofetil (MMF) has been introduced in the treatment of SLE, with a significant therapeutic benefit, and minor side effects have been reported. Data on the adverse effects of MMF in SLE are lacking. We present an SLE patient who developed urticaria during MMF treatment. Rechallenge with MMF established the diagnosis of MMF-induced urticaria. As MMF was considered a necessary therapy, a desensitization protocol was devised, which successfully induced tolerance to MMF. This is the first published protocol for MMF desensitization, which induced tolerance in an SLE patient previously reacting with generalized urticaria.

Peptide-based immunotherapy of systemic lupus erythematosus

Current drug-based therapy for systemic lupus erythematosus (SLE) are non-specific and often counterbalanced by adverse effects. Current research aims at developing specific treatments that target deleterious cells only and not the whole immune system. This strategy requires the identification of sequences derived from major lupus autoantigens, responsible for the activation of autoreactive B and T cells. This review summarizes the identification and characterization of peptides, which are able to modulate T cells ex vivo, and describes the promising results obtained after administration of some of these peptides in lupus mice. Although these therapeutic trials are encouraging, the precise mode of action of peptide-based immunotherapy is still elusive. Here, we discuss the possible mechanisms leading to T-cell tolerance induction and the feasibility of extending the success of peptide-based therapy from animal models to human.

Novel Approaches to Therapy for SLE

Systemic lupus erythematosus (SLE) is an autoimmune disease manifested by multi-organ involvement and elevated titers of anti-DNA antibodies. Current therapies for SLE are broadspectrum, and include steroids and immunosuppressive cytotoxic agents that are counterbalanced by the toxicity and side effects of the medications. One of the goals is to target therapies by altering specific known mechanisms of inflammation and autoimmunity. Although the inciting antigen is still unknown in SLE, it may be possible to alter the regulation of the immune response by targeted molecular therapy. Methods under investigation, which may be beneficial, are manipulation of second-signal stimulation of the immune response (anti-CD40L), manipulation of cytokines (monoclonal anti-IL-10), inducing tolerance by administration of blocking peptides (LJP394), and the manipulation of idiotypes (IVIg). In this article, we also discuss modalities that are steroid-sparing (MTX), and selective immunosuppression (stem-cell restoration and MMF). We review the ongoing literature from 2000-2002, utilizing the MEDLINE search. Controlled trials, open trials, and trials in phase I and II have been included, and anecdotal reports were excluded. The major advances have been with mycophenolate mofetil (MMF) and LJP 394.

Treatment of systemic lupus erythematosus by immunoadsorption in a patient suffering from tuberculosis

We report on a 40-year-old man, admitted with fever and weight loss, in whom systemic lupus erythematosus (lupus nephritis World Health Organization type IV) and concomitant acute lung tuberculosis were diagnosed. Conventional treatment of diffuse proliferative nephritis with cytotoxic drugs was thought to be too dangerous in the presence of active tuberculosis. A combination of immunoadsorption and steroids was instituted for the treatment of systemic lupus erythematosus. Antibodies against double-stranded DNA decreased, and proteinuria decreased from 10 g/24 hours to less than 1 g/24 hours. Tuberculosis was treated initially with quadruple-drug therapy, then a triple-drug protocol. Primarily enlarged lymph nodes decreased to normal size after 3 months. The combined treatment modality of steroids and immunoadsorption was effective and safe, even in this patient with active tuberculosis.

High-dose intravenous immunoglobulins for lupus nephritis--a salvage immunomodulation

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease with a great diversity of clinical manifestations which is difficult to manage. IVIGs represent promising immunoregulatory agents with the ability to control SLE without subsequent predisposition to infectious complications. Despite the implied risk of developing renal failure due to IVIG, considerable beneficial effects on lupus nephritis are reported. In this review, the clinical and adverse effects, and mechanism of action, with special emphasis on modulation, of idiotypic network is discussed.