Rituximab in Churg-Strauss syndrome

Churg-Strauss syndrome: evidence for disease subtypes?

PURPOSE OF REVIEW

Churg-Strauss syndrome (CSS) is a rare systemic small-vessel necrotizing vasculitis. Its main clinical characteristics, some potentially life-threatening, are now well known, as are its usual successive phases, from allergic rhinitis to asthma, and finally vasculitis. Conversely, physiopathogenetic mechanisms are not completely elucidated and clearly multiple, thereby suggesting the existence of different disease subtypes.

RECENT FINDINGS

Almost 40% of CSS patients have circulating antineutrophil cytoplasm autoantibodies (ANCAs), mostly directed against myeloperoxidase. ANCA-positive patients suffer more frequently from renal disease, peripheral nervous system involvement and/or alveolar hemorrhage, whereas frequent cardiac involvement, lung infiltrates and/or systemic manifestations are more common in those who are ANCA-negative. However, their respective global outcomes do not clearly differ. Patients might also be categorized according to other, more subtle clinical, radiological and/or biological parameters, for example, cardiac magnetic resonance imaging abnormalities or genetic background.

SUMMARY

Because of its practical and therapeutic repercussions, the priority remains the prompt, relatively easy identification of the most severely affected patients at CSS diagnosis, before searching for and trying to classify subsets. Large, collaborative studies are needed to determine whether other subgroups might be associated with outcomes and warrant different, and possibly new, therapeutic strategies.

Churg-Strauss syndrome successfully treated with rituximab

Churg-Strauss syndrome (CSS) is characterized by small-vessel vasculitis, extravascular granulomatous inflammation, and massive eosinophilia in tissues and blood, and is often accompanied by a history of preclinical asthma and/or allergic rhinitis lasting several years before the syndrome develops its full clinical picture. Corticosteroids, often in combination with cytotoxic agents, comprise standard therapy; however, a number of patients appear to be resistant to treatment and there is a need for more effective regimens. B cell depletion may be an effective treatment option for CSS. Here, we describe two patients resistant to conventional therapy who were treated with rituximab and experienced a rapid and substantial decrease in disease activity and asthmatic symptoms and an increase in physical capacity.

Vasculitis of the upper and lower airway

The pulmonary vasculitides are a heterogeneous group of rare disorders that result from an inflammatory process damaging the vessel wall and consequent impaired blood flow, ischaemia and tissue necrosis. The clinical manifestation of these vasculitides depends on the site, size, type and severity of the inflammatory process. Vasculitis involving the airways is a common feature of the anti-neutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitides (AASVs) and can predate the diagnosis by years. Secondary causes of vasculitis associated with connective tissue disorders are also capable of presenting with pulmonary features. Recognition of involvement, investigation and treatment are important to ameliorate symptoms for patients. This article concentrates on the assessment and specific management of upper and lower airway problems of AASV.

Current status on B-cell depletion therapy in autoimmune diseases other than rheumatoid arthritis

Since the approval of the chimeric anti-CD20 antibody rituximab for the treatment of adults with severe-to-moderate rheumatoid arthritis after an inadequate response to TNF blockade, B-cell depletion therapy has been used for the treatment of a broad range of refractory autoimmune disorders. Based on current experiences and a literature search, a systematic review and evaluation of the current status of B-cell depletion therapy in autoimmune diseases other than rheumatoid arthritis, including rheumatic, nephrologic, dermatologic and neurologic autoimmune entities, was performed by an international group of experts based at several academic centres. Although important questions remain about the value and place of B-cell depletion in autoimmune diseases other than RA, preliminary data indicate the value of this therapeutic approach in otherwise refractory patients. However, given the lack of robust data from large randomised controlled trials, anti-CD20 therapy should be considered on an individual basis in otherwise refractory patients and its use based on a risk/benefit net calculation.

Targeting the B cell in vasculitis

The treatment of severe vasculitides, such as antineutrophil cytoplasmic autoantibodies (ANCA)-associated vasculitis, is associated with both short- and long-term toxicities that limit its use in paediatric patients and is complicated by refractory and relapsing disease that requires increased exposure to these toxic therapies. B cells have been implicated in the pathogenesis of autoimmune diseases, including vasculitis, and represent a potential target for new therapies that may have a more acceptable toxicity profile. The use of rituximab, a biologic therapy directed against B cells, has provided valuable insight into the potential role of B-cell targeted therapies for vasculitis. Rituximab appears to be a potentially useful treatment for vasculitis in adult patients, but randomized evidence comparing it to cyclophosphamide in terms of both efficacy and toxicity is lacking, as is long-term safety data. Several other B-cell-directed therapies are in development and may offer rational alternatives or adjunctives to traditional treatments.

[Anti-B-cell strategies in vasculitides and collagenoses]

B-cells play a central role in the pathogenesis of autoimmune diseases. As already discussed in other articles, besides the production of potentially pathogenic autoantibodies, B-cells may function as antigen-presenting cells, may induce T-cell activation and produce various cytokines. The feasibility of targeting B-cells in patients with severe and refractory autoimmune disorders, especially in patients with vasculitis or connective tissue diseases, has met growing interest among rheumatologists in recent years. The use of rituximab as a monoclonal antibody directed against CD20 positive B-cells has been reported in case reports and small patient series; however, these are hard to compare as different diseases are described and different doses and schedules of rituximab were used. It has to be considered that positive reports are more likely to be reported than patients who do not improve or experience side effects. Data on only a few indications from randomized, double-blind studies are available; however, even these results should be evaluated critically.

B-cell-directed therapy for inflammatory skin diseases

The basic understanding of inflammatory dermatoses and autoimmune-mediated skin disorders has greatly advanced and broadened our understanding of underlying immune mechanisms that shape the complex network of chronic inflammation and autoimmunity. The new treatment options for psoriasis exemplify how new insights into (auto)immune responses, especially the role and function of various immune cells and proinflammatory cytokines, may lead to new therapeutic strategies. The concept of targeting B cells in autoimmune-mediated disorders is closely related to the discovery of autoantibodies and their cellular origin. However, the appreciation of B cells in autoimmunity has significantly changed and is not limited to their role as progenitors of autoantibody secreting plasma cells. Recent investigations of various inflammatory skin diseases, that is, autoimmune blistering disorders, collagen vascular diseases, and atopic dermatitis, actually support the concept that B cells might be as important as T cells in the etiopathogenesis of these disorders. The striking clinical improvement seen in patients with rheumatoid arthritis following B-cell depletion with the anti-CD20 mAb rituximab has tremendously catalyzed the interest in B-cell-targeted therapies in different autoimmune diseases. Future translational and clinical investigations are mandatory to precisely define the role and the contribution of impaired B-cell function in (auto)immune-mediated skin diseases.

Treatment strategies for a rheumatoid arthritis patient with interstitial lung disease

This review article describes our present understanding of interstitial lung disease (ILD) complicating rheumatoid arthritis (RA). It discusses its high prevalence and clinical relevance, our recent improvement in understanding both its pathology and physiology, and our expectations of ongoing research into the immunology and genetics of the disease. An important section relates to the effects of drugs routinely used in the treatment of the articular manifestations of RA on the lung, especially in the presence of ILD. The major focus of the article is on therapeutic intervention, and here we discuss traditional and often unsuccessful approaches to treatment, leading on to discuss newly introduced therapeutic options such as anticoagulation and oral N-acetylcysteine. In the later sections, we focus our attention on several promising new therapeutic agents, including mycophenolate and new monoclonal antibody therapies, reviewing the limited literature available to support the use of these agents, concluding with a number of other aspects of treatment that are worthy of consideration.

Churg-Strauss syndrome: 2005-2008 update

Churg-Strauss syndrome (CSS) is a rare necrotizing small-vessel vasculitis associated with eosinophil-rich granulomatous inflammation of tissues and vessels and is also associated with asthma and eosinophilia. Epidemiologic studies continue to show that CSS is the rarest of the necrotizing small-vessel vasculitides. However, it is not possible to know with any certainty if there has been an increase in incidence. There has been an attempt to divide the patients with CSS into an antineutrophil cytoplasmic antibody-positive and cytoplasmic antibody-negative group. The former group has an increased frequency of renal involvement, parenchymal pulmonary disease, constitutional symptoms, and peripheral and central nervous system involvement, whereas the latter group has more frequent cardiac disease. The role of eosinophils and antineutrophil cytoplasmic antibodies remains poorly defined but provocative. Leukotriene receptor antagonists do not appear to induce CSS but facilitate the tapering of glucocorticoids, which unmasks the condition. Glucocorticoids and cyclophosphamide remain the foundation of treatment for vasculitis, but there are other promising and less toxic alternatives on the horizon.

[Churg-Strauss syndrome]

Churg-Strauss syndrome is a systemic ANCA-associated vasculitis arising almost exclusively in patients with a pre-existent asthma. Common clinical manifestations are marked blood eosinophilia, asthma, chronic sinusitis, cardiomyopathy, pulmonary infiltrates, gastrointestinal complaints and a multiplex neuropathy. The morphological substrate is an eosinophilic necrotizing vasculitis. Other eosinophilic disorders such as parasitic diseases, allergies and idiopathic hyper-eosinophilic syndrome have to be excluded. The mainstay of therapy is high-dose corticosteroids with the addition of cytotoxic drugs in patients with poor prognosis.

[Progress in pathogenesis and therapy of vasculitis syndrome]

Since antineutrophil cytoplasmic autoantibody (ANCA) was found, the researches in the pathogenesis of vasculitis syndrome have been developing. Proinflammatory cytokines including tumor necrosis factor-alpha are induced by certain infections, by which ANCA that binds to granule components of cytoplasm adhesions to endothelial cells. These endothelial cells produce proteolytic enzymes and oxygen radicals, which leads to vasculitis. It might be contributed in the production of ANCA that bacterial organisms are mimicry to the peptide sequences of granule components. The multicentric randomized clinical trials undertaken by the European Vasculitis Study Group (EUVAS) optimized that cyclophosphamide-corticosteroid combination therapy was useful to ANCA-associated vasculitis. It is increasing evidences that biologics are useful to ANCA-associated vasculitis, although it is necessary to take care of severe adverse effects.

[Results of biological treatments in autoimmune diseases]

The use of the biological therapies has revolutionized in the last years the handling of numerous autoimmune processes. It has taken to numerous physicians and investigators to try to apply these therapies in other diseases (lupus, Sjögren, vasculitis, etc). From the introduction of corticosteroids and immunosupressives, vasculitis were no more a mortal diseases, and it was possible to obtain high rates of remission. Nevertheless, they are delayed, they are not sustained, and require of the use of maintained drugs. Against this background, the new biological drugs have to surpass the challenge to induce an earlier and permanent remission that diminishes irreversible organ damage, to reduce (or to eliminate) the exposition to steroids and immunesupressives and to improve the patient function. This article reviews data present until now in literature with respect to the utility of biological drugs in systemic vasculitis.

Targeting B lymphocytes as therapy for ANCA-associated vasculitis

This article focuses on the initial results achieved with the more selective immunosuppressive approach of B-lymphocyte depletion in patients who fail cyclophosphamide or have contraindications for its use in the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This novel approach has sparked hope for patients and physicians in their search for effective, well-tolerated therapy for AAV. B-cell depletion is now undergoing rigorous investigation in randomized clinical trials.

Targeted biologic approaches to the treatment of systemic vasculitis

The introduction of biological agents in the treatment of systemic vasculitis offers the promise of targeted therapy with greater efficacy and fewer side effects than conventional treatments. In this paper, we review the rationale for biological strategies in vasculitis and discuss the results of clinical studies to date. The biotherapies discussed include immune-cell-depleting agents, both B- and T-cell targeted; costimulatory blockade; and cytokine blockade. Although most of these agents remain unproven until ongoing randomized clinical trials are complete, their introduction heralds a new era of vasculitis treatment and has provided novel insights into disease pathogenesis.

The potential utility of B cell-directed biologic therapy in autoimmune diseases

Increasing awareness of the importance of aberrant B cell regulation in autoimmunity has driven the clinical development of novel B cell-directed biologic therapies with the potential to treat a range of autoimmune disorders. The first of these drugs-rituximab, a chimeric monoclonal antibody against the B cell-specific surface marker CD20-was recently approved for treating rheumatoid arthritis in patients with an inadequate response to other biologic therapies. The aim of this review is to discuss the potential use of rituximab in the management of other autoimmune disorders. Results from early phase clinical trials indicate that rituximab may provide clinical benefit in systemic lupus erythematosus, Sjögren's syndrome, vasculitis, and thrombocytopenic purpura. Numerous case reports and several small pilot studies have also been published reporting the use of rituximab in conditions such as myositis, antiphospholipid syndrome, Still's disease, and multiple sclerosis. In general, the results from these preliminary studies encourage further testing of rituximab therapy in formalized clinical trials. Based on results published to date, it is concluded that rituximab, together with other B cell-directed therapies currently under clinical development, is likely to provide an important new treatment option for a number of these difficult-to-treat autoimmune disorders.

Small-vessel vasculitis: Therapeutic management

Small-vessel vasculitis is defined by the presence of blood vessel inflammation involving the arterioles, venules, or capillaries. This can be seen in a broad spectrum of settings, but it is most commonly associated with Wegener's granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome. Although prednisone combined with cyclophosphamide induces remission and prolongs survival in these diseases, this regimen is toxic and does not prevent relapse. Current therapeutic approaches seek to minimize cyclophosphamide exposure through the use of staged induction-maintenance regimens or cyclophosphamide alternatives for induction of nonsevere disease. Emerging trials with biologic agents are exploring new treatment options.

Treatment for Churg-Strauss syndrome: induction of remission and efficacy of intravenous immunoglobulin therapy

Churg-Strauss syndrome (CSS) is characterized by the presence of asthma, eosinophilia, and small-vessel vasculitis with granuloma. It is a distinct entity, as determined from all classifications of systemic vasculitis. The poor prognostic factors in CSS are renal insufficiency, cardiomyopathy, severe gastrointestinal (GI) tract, and central nervous systems (CNS) involvement. The initial management of CSS should include a high dose of a corticosteroid: prednisone at 1 mg/kg/day or its equivalent for methylprednisolone with tapering over 6 months. In patients with severe or rapidly progressing CSS, the administration of methylprednisolone pulse at 1 g/body/day for 3 days is recommended. When corticosteroid therapy does not induce remission, or when patients have poor prognostic factors, immunosuppressive cytotoxic therapy is indicated. However, some patients with severe CSS often show resistance to conventional treatment. We think that IVIG therapy is a hopeful candidate for second-line treatment for CSS patients, particularly in the case of neuropathy and/or cardiomyopathy, which are resistant to conventional therapy. However, there is not much evidence supporting the effectiveness of IVIG in CSS, and the mechanisms underlying the action of IVIG remain unclear. Now we are performing clinical trials of IVIG therapy for CSS patients who are resistant to conventional treatment, through a nationwide double-blinded placebo-controlled study in Japan.

Churg-Strauss syndrome

PURPOSE OF REVIEW

Churg-Strauss syndrome is a small-vessel necrotizing vasculitis typically characterized by asthma, lung infiltrates, extravascular necrotizing granulomas and hypereosinophilia. The most recent clinical studies on its pathogenesis and therapeutic management are reviewed here.

RECENT FINDINGS

French and Italian clinical studies found that the clinical characteristics of patients with Churg-Strauss syndrome differed according to their antineutrophil cytoplasmic autoantibody status: cardiomyopathy predominated in antineutrophil cytoplasmic autoantibody-negative patients while necrotizing glomerulonephritis was more often observed in antineutrophil cytoplasmic autoantibody-positive patients. These histologically documented findings suggest the existence of different Churg-Strauss syndrome subtypes, characterized by the predominance of distinct pathogenetic mechanisms. To date, following the therapeutic recommendations for Churg-Strauss syndrome (i.e. corticosteroids and, when required, immunosuppressants), patient outcomes are good, with 5-year survival exceeding 90%, but often with the need to continue low-dose corticosteroids to control residual asthma.

SUMMARY

The precise pathogenetic mechanisms of Churg-Strauss syndrome are only partly elucidated. Recent results suggest that antineutrophil cytoplasmic autoantibodies are probably more involved in the vasculitic manifestations of Churg-Strauss syndrome (e.g. glomerulonephritis) whereas eosinophil tissue infiltration and associated cytotoxicity would be responsible for cardiomyopathy. If confirmed, these results could support individual therapeutic stratification according to the clinical pattern. Furthermore, some patients may benefit from new biologic therapies under development, for example antiinterleukin-5 or antiimmunoglobulin E monoclonal antibodies.