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

BLyS antagonists and peptide tolerance induction

The major impediment to drug development for systemic lupus erythematosus (SLE) is its heterogeneity. The unpredictable manner in which lupus targets different organs at varying intensity makes the study of new drugs and the optimization of their administration extremely difficult. With the advent of novel, targeted biologic agents for SLE, it can be hoped that more strategic, lupus-relevant immune modulation will lead to safer and more effective treatments. Two alternative new approaches to lupus treatment are reviewed. The first involves selective inhibition of a single protein (BLyS), which may play a central role in host defense and in the pathogenesis of SLE. Although this approach is finely targeted to the inhibition of a single protein which is known to be upregulated in SLE patients, the positioning of BLyS at a critical hub in the immune response suggests that more global adverse repercussions on immunity might still occur. The second strategy is the use of peptides designed to specifically induce tolerance in limited autoreactive immune responses. Immune repercussions might, at least in theory, be almost nonexistent with this kind of approach. Concerns that limited induction of tolerance might have equally limited impact on the complex immune disorder of SLE are not borne out in preliminary murine data. Specific development programs are ongoing using both of these strategies and have recently entered human trials.

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.

Anti-DNA Ig peptides promote Treg cell activity in systemic lupus erythematosus patients

OBJECTIVE

Treg cells oppose autoreactive responses in several autoimmune diseases, and their frequency is reduced in systemic lupus erythematosus (SLE). In murine lupus models, treatment with anti-DNA Ig-based peptides can expand the number of Treg cells in vivo. This study was undertaken to test the possibility that functional human Treg cells can be induced by exposure to anti-DNA Ig-based peptides.

METHODS

Peripheral blood mononuclear cells were isolated from 36 lupus patients and 32 healthy individuals matched for ethnicity, sex, and age. Short-term culture experiments in the presence of several independent stimuli including anti-DNA Ig peptides were followed by flow cytometric analysis for identification of CD4+,CD25(high) T cells, cell sorting for in vitro suppression assays, and analysis of correlations between the expression of forkhead box P3 (FoxP3) and serologic and clinical characteristics of the SLE patients.

RESULTS

The number of in vitro CD4+,CD25(high) T cells increased after culture with anti-DNA Ig peptides in the SLE patients, but not in the controls. The expanded CD4+,CD25(high) T cells required FoxP3 for cell contact-mediated suppression of proliferation and interferon-gamma production in target CD4+,CD25- T cells. The induction of FoxP3 in SLE Treg cells occurred only in seropositive patients, and was correlated with anti-DNA and IgG serum titers.

CONCLUSION

These results suggest a new modality to reverse the functional deficit of Treg cells in SLE patients with positive autoimmune serology, and identify a new strategy to enhance immunoregulatory T cell activity in human SLE.

Malignant lymphomas in autoimmunity and inflammation: a review of risks, risk factors, and lymphoma characteristics

Certain autoimmune and chronic inflammatory conditions, such as Sjögren's syndrome and rheumatoid arthritis (RA), have consistently been associated with an increased risk of malignant lymphomas, but it is unclear whether elevated lymphoma risk is a phenomenon that accompanies inflammatory conditions in general. Likewise, it is debated whether the increased risk identified in association with some disorders pertains equally to all individuals or whether it varies among groups of patients with different phenotypic or treatment-related characteristics. It is similarly unclear to what extent the increased lymphoma occurrence is mediated through specific lymphoma subtypes. This update reviews the many findings on risks, risk levels, and lymphoma characteristics that have been presented recently in relation to a broad range of chronic inflammatory, including autoimmune, conditions. Recent results clearly indicate an association between severity of chronic inflammation and lymphoma risk in RA and Sjögren's syndrome. Thus, the average risk of lymphoma in RA may be composed of a markedly increased risk in those with most severe disease and little or no increase in those with mild or moderate disease. The roles of immunosuppressive therapy and EBV infection seem to be limited. Furthermore, RA, Sjögren's syndrome, systemic lupus erythematosus, and possibly celiac disease may share an association with risk of diffuse large B-cell lymphoma, in addition to well-established links of Sjögren's syndrome with risk of mucosa-associated lymphoid tissue lymphoma and of celiac disease with risk of small intestinal lymphoma. However, there is also obvious heterogeneity in risk and risk mediators among different inflammatory diseases.

Cellular and molecular mechanisms of regulation of autoantibody production in lupus

The hyperactive interaction between helper T cells and autoimmune B cells in individuals predisposed to systemic lupus erythematosus (SLE) can be interrupted by induction of regulatory and suppressor T cells. Using two strategies-high dose tolerance to an immunoglobulin-derived peptide, and minigene vaccination with DNA encoding T cell epitopes presented by MHC class I molecules-our group has induced at least three types of regulatory/suppressive T cells. They include CD8+ T cells that suppress helper T cells by cytokine secretion, CD8+ T suppressors that kill B cells making anti-DNA antibodies, and peptide-binding CD4+CD25+ regulatory T cells that suppress B cells by direct cell contact. Each of these lymphocyte subsets suppresses anti-DNA antibody production and delays the onset of nephritis in BWF1 lupus-prone mice. Patients with SLE have amino acid sequences similar to those from murine anti-DNA antibodies used in these studies, and at similar locations in the VH regions of anti-DNA immunoglobulins. Therefore, strategies described here might ultimately be useful in therapy of the human disease.

Systemic lupus erythematosus—2005 annus mirabilis?

We are about to enter a new era in the treatment of patients with systemic lupus erythematosus (SLE). For the past 40 years hydroxychloroquine sulfate and corticosteroids, together with varying combinations of immunosuppressive drugs, have been the main treatments for SLE. Although effective for many patients, some patients fail to respond to these drugs and even more suffer from major side effects due to the generalized nature of the immunosuppression. In this article we review the remarkable confluence of new therapies ranging from newer immunosuppressive drugs with fewer side effects, such as mycophenolate mofetil, to the more targeted approaches offered by biological agents. These agents have been designed to block molecules such as CD20, CD22 and interleukin-10 that are thought to have an integral part in the development of SLE. This wolf might not yet be about to become extinct but its survival is increasingly under threat!

Manipulation of immune regulation in systemic lupus erythematosus

Production of autoantibodies by B cells in systemic lupus erythematosus (SLE) can be interrupted via induction of regulatory and suppressor T cells. We have used the strategy of tolerizing lupus-prone (NZBxNZW)F(1) mice with an artificial peptide based on sequences common to several anti-double stranded (ds)DNA antibodies to induce regulatory and suppressor T cells that block production of anti-DNA antibodies and prolong their survival. At least one type of suppressor T cells (CD8+) and one type of regulatory T cell (CD4+ expressing the IL-2 receptor alpha chain CD25) are raised under this condition. While CD8+ suppressors (TS) require soluble factors to block help of T cells to B cells, regulatory CD4+CD25+ T cells (TR) curb the production of anti-DNA antibodies from B cells via cell contact through molecules that include membrane-bound TGFbeta and GITR. Moreover, CD8+ suppressors seem to act independently on antigen specificity, while TR act in an antigen-specific fashion. We hypothesize that the differences between these two lymphocyte subsets that share the common ability to dampen production of autoantibodies might underlie significant temporal and teleological advantages for optimal control of autoimmune reactivity.

Tolerogenic treatment of lupus mice with consensus peptide induces Foxp3-expressing, apoptosis-resistant, TGFbeta-secreting CD8+ T cell suppressors

Lupus-prone (NZB x NZW)F1 mice spontaneously develop elevated titers of anti-DNA Abs that contain T cell determinants in their V(H) regions. We have previously shown that tolerization with an artificial peptide based on these T cell determinants (pConsensus (pCons)) can block production of anti-DNA Abs and prolong survival of the mice. In this study, we show that this protection depends in part on the generation of peripheral TGFbeta- and Foxp3-expressing inhibitory CD8+ (Ti) cells. These CD8+ Ti cells suppress anti-DNA IgG production both in vitro and in vivo and require up-regulated expression of both Foxp3 and TGFbeta to exert their suppressive function, as indicated by microarray analyses, small interfering RNA inhibition studies, and blocking experiments. Additionally, CD8+ Ti cells from pCons-tolerized mice were longer-lived suppressors that up-regulated expression of Bcl-2 and were more resistant to apoptosis than similar cells from naive mice. These data indicate that clinical suppression of autoimmunity after administration of pCons depends in part on the generation of CD8+ Ti cells that suppress secretion of anti-DNA Ig using mechanisms that include Foxp3, TGFbeta, and resistance to apoptosis.

SLE: translating lessons from model systems to human disease

Systemic lupus erythematosus (SLE, lupus) results from immune-mediated damage to multiple organs. Its pathogenesis should be viewed as a series of steps, beginning with impaired immune regulation that permits self-reactive T-B-cell activation, which results in the production of autoantibodies. Activated T and B cells then infiltrate tissues, which along with autoantibody and immune complex deposition, triggering local events that ultimately cause organ damage. Although improved understanding of early autoimmune events might open up avenues for disease prevention, future investigations must focus on the mechanisms of end-organ damage in model systems and how to translate this knowledge into human disease. Understanding the mechanisms of each pathogenetic step would provide a rational basis for the development of disease stage-specific diagnostic markers and treatments.

Recent developments in immunomodulatory peptides in juvenile rheumatic diseases: from trigger to dimmer?

PURPOSE OF REVIEW

Current therapy for juvenile rheumatic diseases is based on general immune suppression or blocking inflammatory pathways. These treatments do not induce long-term disease remission and have a risk of side effects; this is especially unfavorable in children. It is better to focus on induction of tolerance mechanisms than on suppression of inflammation. This promotes epitope specific immunotherapy as a possible safe treatment option.

RECENT FINDINGS

In the search for specific peptides for immunotherapy in autoimmunity, the focus is shifting from purported triggers of disease to peptides that regulate the ongoing inflammation. These so-called 'immunomodulatory peptides' are important in every healthy immune system. Several juvenile rheumatic diseases have been linked to certain immunomodulatory peptides. In juvenile dermatomyositis, peptides from human skeletal myosin play a role in the perpetuation of the disease. In systemic lupus erythematosus, the focus is mostly on DNA-derived peptides and peptides from anti-DNA antibodies. In juvenile idiopathic arthritis, heat shock proteins have been shown to contain important immunomodulatory epitopes.

SUMMARY

Immunomodulatory peptides play an important role in juvenile rheumatic diseases. Promising candidates for immunotherapy have been identified. This opens the possibility of clinical testing in rheumatic diseases of childhood.