Enno Schmidt

Prospective analysis of the incidence of autoimmune bullous disorders in Lower Franconia, Germany

Background: Only limited epidemiologic data are available on autoimmune bullous diseases. Improved diagnostic tools should have led to an increased incidence. To test this hypothesis, all patients with autoimmune bullous disorders who were treated in the Department of Dermatology at the University of Würzburg, Germany, between January 2001 and June 2002 were analysed prospectively.

Definitions and outcome measures for bullous pemphigoid: recommendations by an international panel of experts

Our scientific knowledge of bullous pemphigoid (BP) has dramatically progressed in recent years. However, despite the availability of various therapeutic options for the treatment of inflammatory diseases, only a few multicenter controlled trials have helped to define effective therapies in BP. A major obstacle in sharing multicenter-based evidences for therapeutic efforts is the lack of generally accepted definitions for the clinical evaluation of patients with BP. Common terms and end points of BP are needed so that experts in the field can accurately measure and assess disease extent, activity, severity, and therapeutic response, and thus facilitate and advance clinical trials. These recommendations from the International Pemphigoid Committee represent 2 years of collaborative efforts to attain mutually acceptable common definitions for BP and proposes a disease extent score, the BP Disease Area Index. These items should assist in the development of consistent reporting of outcomes in future BP reports and studies.

Safety and clinical outcomes of rituximab therapy in patients with different autoimmune diseases: experience from a national registry (GRAID)

IntroductionEvidence from a number of open-label, uncontrolled studies has suggested that rituximab may benefit patients with autoimmune diseases who are refractory to standard-of-care. The objective of this study was to evaluate the safety and clinical outcomes of rituximab in several standard-of-care-refractory autoimmune diseases (within rheumatology, nephrology, dermatology and neurology) other than rheumatoid arthritis or non-Hodgkins lymphoma in a real-life clinical setting.MethodsPatients who received rituximab having shown an inadequate response to standard-of-care had their safety and clinical outcomes data retrospectively analysed as part of the German Registry of Autoimmune Diseases. The main outcome measures were safety and clinical response, as judged at the discretion of the investigators.ResultsA total of 370 patients (299 patient-years) with various autoimmune diseases (23.0% with systemic lupus erythematosus, 15.7% antineutrophil cytoplasmic antibody-associated granulomatous vasculitides, 15.1% multiple sclerosis and 10.0% pemphigus) from 42 centres received a mean dose of 2,440 mg of rituximab over a median (range) of 194 (180 to 1,407) days. The overall rate of serious infections was 5.3 per 100 patient-years during rituximab therapy. Opportunistic infections were infrequent across the whole study population, and mostly occurred in patients with systemic lupus erythematosus. There were 11 deaths (3.0% of patients) after rituximab treatment (mean 11.6 months after first infusion, range 0.8 to 31.3 months), with most of the deaths caused by infections. Overall (n = 293), 13.3% of patients showed no response, 45.1% showed a partial response and 41.6% showed a complete response. Responses were also reflected by reduced use of glucocorticoids and various immunosuppressives during rituximab therapy and follow-up compared with before rituximab. Rituximab generally had a positive effect on patient well-being (physicians visual analogue scale; mean improvement from baseline of 12.1 mm).ConclusionsData from this registry indicate that rituximab is a commonly employed, well-tolerated therapy with potential beneficial effects in standard of care-refractory autoimmune diseases, and support the results from other open-label, uncontrolled studies.

Recommendations for the use of rituximab (anti-CD20 antibody) in the treatment of autoimmune bullous skin diseases.

Autoimmune bullous skin disorders are induced by autoantibodies against distinct adhesion complexes of the epidermal and dermal‐epidermal junction. Since most of these disorders are characterized by a severe, potentially lethal course,they require long‐term immunosuppressive treatment to reduce the de novo synthesis of pathogenic autoantibodies by B lymphocytes. Rituximab, a chimeric monoclonal antibody against CD20 on B lymphocytes, has shown promise in several case reports or cohort studies in the treatment of paraneo‐plastic pemphigus,refractory cases of pemphigus vulgaris and foliaceus and in other autoimmune bullous disorders.Treatment with rituximab leads to depletion of pathogenic B‐cells which may last up to 12 months resulting in a reduction of plasma cells secreting pathogenic autoantibodies.Rituximab is usually administered in an adjuvant setting at a dose of 375 mg/m2 i.v.in weekly intervals for four consecutive weeks in addition to the standard immunosuppressive treatment.The present consensus statement of German‐speaking derma‐tologists,rheumatologists and oncologists summarizes and evaluates the current evidence for the use and mode of application of rituximab in autoimmune bullous skin disorders.

Modern diagnosis of autoimmune blistering skin diseases

The diagnostic gold standard of autoimmune bullous diseases is the detection of autoantibodies in skin or mucous membranes by direct immunofluorescence microscopy of a perilesional biopsy. The molecular characterisation of several target antigens within the last 10 years has, however, fostered the development of sensitive and specific diagnostic tools that allow the serological diagnosis in about 90% of patients. Based on the recombinant immunodominant portions of the target antigens, ELISA systems are commercially available for the detection of circulating antibodies against desmoglein 1, desmoglein 3, envoplakin, BP180, and BP230. Autoantibodies against the soluble ectodomain of BP180 (LAD-1), laminin 332, type VII collagen, and most recently, laminin γ1 can be detected by Western blotting with recombinant or cell-derived forms of these proteins. The definite differentiation between the various immunobullous disorders that comprise about a dozen entities is increasingly important since more diverse treatment options are employed. Exact diagnosis is also pivotal for the prognosis, since some autoimmune bullous diseases may indicate an underlying tumor. Association with a malignancy has been shown in paraneoplastic pemphigus (in 100%) and anti-laminin 332 mucous pemphigoid (in 25%) In pemphigus vulgaris, pemphigus foliaceus, and bullous pemphigoid, autoantibodies to desmoglein 3, desmoglein 1, and BP180, respectively, have been shown to correlate with the disease activity. The detection of serum autoantibodies during the course of the disease may thus be helpful in guiding treatment decisions in these patients.

Rituximab in refractory autoimmune bullous diseases

Treatment of autoimmune blistering diseases consists of systemic glucocorticosteroids usually in combination with additional immunosuppressants such as azathioprine and mycophenolate mofetil or immunomodulators such as dapsone, antibiotics, intravenous immunoglobulins, and immunoadsorption. In some patients, these treatment regimens are not sufficient to control disease activity and/or lead to intolerable adverse events. Rituximab, originally developed for the treatment of non‐Hodgkins lymphoma, is an anti‐CD20 humanized monoclonal antibody leading to transitory B‐cell depletion. For this indication, rituximab is widely employed, and severe side‐effects rarely observed. Subsequently, the B‐cell‐depleting effect of rituximab has been exploited successfully in various autoimmune disorders, including autoimmune blistering diseases. Here, we review the effect of rituximab in such diseases. To date, application of rituximab has been reported in 26 treatment‐resistant patients with the vulgaris, foliaceus, and paraneoplastic variants of pemphigus as well as in bullous pemphigoid and epidermolysis bullosa acquisita. All but a single patient showed clinical improvement with reduction of lesion formation. In about a third, a clinical remission requiring further immunsuppressive medication was achieved, and in about a quarter, complete remission was induced. In addition, the mode of action and adverse events of rituximab as well as adjuvant immunosuppressive treatments, and the effect on levels of circulating autoantibodies in these patients are discussed.

Cicatricial pemphigoid : IgA and IgG autoantibodies target epitopes on both intra- and extracellular domains of bullous pemphigoid antigen 180

Background Cicatricial pemphigoid (CP) is an autoimmune subepidermal blistering disease where autoantibodies target various components of the dermal–epidermal junction, including the bullous pemphigoid antigen 180 (BP180).

Enzyme-linked immunosorbent assay using multimers of the 16th non-collagenous domain of the BP180 antigen for sensitive and specific detection of pemphigoid autoantibodies.

Abstract:  Bullous pemphigoid (BP) and pemphigoid gestationis (PG) are acquired autoimmune subepidermal blistering diseases characterized by autoantibodies against the hemidesmosomal proteins BP180/type XVII collagen and BP230. In the vast majority of BP and PG patients, these autoantibodies bind to epitopes clustered within the 16th non‐collagenous domain of BP180. An ELISA system for the detection of these autoantibodies was developed and evaluated using 16th non‐collagenous domain (NC16A) tetramers instead of monomers. In contrast to antigens fused to large proteins used in the past for the detection of autoantibodies against type XVII collagen, tetrameric antigen fragments bearing a small hexahistidine tag allow for high expression levels without the need to cleave off the fusion partner. Using tetrameric BP180 NC16A, positive reactions were found in 106 (89.8%) of 118 randomly selected BP sera and in all of 20 (100%) randomly selected PG sera, whereas only 2.2% of a large cohort of control subjects were positive in this assay, including patients with rheumatoid arthritis (two of 107), progressive systemic sclerosis (two of 50), systemic lupus erythematosus (one of 72), and healthy blood donors (10 of 494). Thus, the sensitivity and specificity of the new anti‐tetrameric NC16A ELISA were 89.9% and 97.8% respectively. Levels of circulating autoantibodies against BP180 paralleled disease activity in the pemphigoid patients. In conclusion, the use of tetrameric NC16A in ELISA results in a sensitive and specific tool for diagnosis and monitoring of BP and PG.

Protein A immunoadsorption: a novel and effective adjuvant treatment of severe pemphigus

Summary Background Pemphigus foliaceus (PF) and pemphigus vulgaris (PV) are autoimmune blistering skin diseases usually treated with high‐dose systemic corticosteroids and other immunosuppressants that may cause severe side‐effects. Plasmapheresis also has been demonstrated to be of benefit in the treatment of pemphigus. In contrast to plasmapheresis, staphylococcal protein A immunoadsorption (PA–IA) specifically removes immunoglobulin from the circulation, allows treatment of larger plasma volumes, and does not require the substitution of plasma components.

Pemphigoid diseases: Pathogenesis, diagnosis, and treatment

Pemphigoid diseases (including bullous pemphigoid, mucous membrane pemphigoid, pemphigoid gestationis, linear IgA dermatosis, lichen planus pemphigoides, and anti-p200 pemphigoid) are a subgroup of autoimmune bullous skin diseases characterized by an autoantibody response toward structural components of the hemidesmosome resulting in subepidermal blistering. By the use of different in vitro systems and experimental animal models, the pathogenic relevance of these autoantibodies has been demonstrated. Recent advances in the understanding of autoantibody responses have led to novel diagnostic tools and a more differentiated therapeutic approach for these disorders. This review covers the most recent understanding of the pathophysiology, diagnosis, and treatment of this group of autoimmune diseases.