Direct and indirect immunofluorescence for the diagnosis of bullous autoimmune diseases

DIF and IIF evaluates in vivo bound and circulating autoantibodies and are the preferred methods for diagnosing AIBDs. In pemphigus diseases and dermatitis herpetiformis, the titer of circulating autoantibodies reflects the disease activity. In patients with a classical clinical picture, the DIF confirms the diagnosis. Furthermore, this technique is essential in subtypes of AIBDs with atypical clinical manifestations (eg, no blisters or erosions) or clinically similar presenting manifestations, such as bullous pemphigoid, MMP, or EBA. A direct or indirect SSST is often crucial for the differential diagnosis between subtypes of these diseases, leading to proper treatment for severely affected patients.     

The use of intravenous immunoglobulin in autoimmune bullous diseases

Intravenous immunoglobulin (IVIG) has been shown to be effective in the treatment of autoimmune blistering diseases and may be an option if disease is refractory to conventional treatment. IVIG effectiveness appears to increase when administered concurrently with a cytotoxic drug and used in multiple treatment cycles (though a single cycle may give benefit). Tapering administration may improve the duration of remission and subcutaneous injections may be an option. This article provides an introduction to the make-up and use of IVIG, and reviews previous studies.     

Indirect immunofluorescence testing in bullous diseases

Sera from patients with bullous pemphigoid, pemphigus vulgaris and other bullous conditions have been tested for auto-antibodies by the indirect immunofluorescence (IIF) method. Positive confirmation of the initial diagnosis was obtained in approximately 75% of both pemphigus and pemphigoid cases. It is suggested that the major source of error in the IIF test lies in the existence of ‘pemphigus-like antibodies’; and clinically, in diagnosing some cases of dermatitis herpetiformis as pemphigoid.     

Immunosuppressive therapy for autoimmune bullous diseases

Adjuvant immunosuppressive drugs are widely used to minimize corticosteroid-related adverse effects in the short-term and long-term management of cautoimmune bullous diseases. In bullous pemphigoid and pemphigus vulgaris, azathioprine and mycophenolate mofetil seem to be equally effective when used in combination with oral corticosteroids, but mycophenolate mofetil is less myelosuppressive and hepatotoxic. Due to a better safety profile, mycophenolate mofetil or enteric-coated mycophenolate sodium may gradually replace azathioprine as the first-line adjuvant of choice in the treatment of moderate to severe autoimmune bullous diseases, including epidermolysis bullosa acquisita and cicatricial pemphigoid. Cyclophosphamide still has a place in the treatment of severe relapsing autoimmune bullous diseases. Continuous oral cyclophosphamide provides optimal immunosuppression, but it also produces the highest cumulative dose. Several pulsed cyclophosphamide regimens have, therefore, been developed and are reported to be effective in severe forms of pemphigus. Randomized controlled studies are needed to compare the efficacy and safety of cyclophosphamide with newer treatment options, such as rituximab and immunoapheresis, and to define optimal dose ranges and duration of available immunosuppressive treatments in different stages of autoimmune bullous diseases.     

免疫球蛋白在自身免疫性大疱病的研究进展

免疫球蛋白作为人体内具有活性的免疫效应分子,在自身免疫性大疱病的发病、诊断及治疗中发挥着重要的作用。人免疫球蛋白可以分为IgG、IgA、IgM、IgD、IgE5大类,除IgD外其他都在自身免疫性大疱病的发病过程中存在并发挥不同的作用。IgG可通过激活补体、活化白细胞、释放蛋白水解酶等诱发水疱形成,其不同亚型也有所区别。IgA可引起粒细胞迁移从而导致水疱脓疱的发生。IgE与荨麻疹样红斑、嗜酸性粒细胞浸润相关。IgM多见于巴西落叶型天疱疮。这些都为自身免疫性大疱病的诊断和治疗提供了新的思路。     

Recommendations for the use of immunoapheresis in the treatment of autoimmune bullous diseases

Despite the use of high‐dose systemic corticosteroids in combination with other immunosuppressants, in some patients with autoimmune bullous diseases only insufficient improvement is achieved. In these cases and in acute severe disease, adjuvant immunoapheresis has been increasingly used. A consensus meeting was held in mid‐2005 in Hamburg, aiming at developing guidelines for the use of immunoapheresis in the treatment of autoimmune bullous diseases.This paper summarizes the experts‘ recommendations.     

Diagnosis of autoimmune bullous diseases

Autoimmune bullous disorders (AIBDs) are a heterogeneous group of rare diseases clinically characterized by erosions and/or blisters on the skin and mucous membranes. AIBDs can be categorized into two groups: pemphigus diseases, characterized by intraepidermal blistering and autoantibodies against desmosomal proteins such as desmoglein (Dsg) 1, Dsg3, members of the plakin family, and subepidermal AIBDs, comprised of pemphigoid diseases and dermatitis herpetiformis. Autoantibodies in dermatitis herpetiformis target transglutaminases 2 and 3, while in pemphigoid disease, autoantibodies are directed against structural proteins of the dermal‐epidermal junction. Although analysis of a perilesional biopsy with direct immunofluorescence (IF) microscopy is still the diagnostic gold standard, several assays have become widely available that allow serological diagnosis in the majority of patients. Standard serological diagnosis includes indirect IF on monkey esophagus and salt‐split human skin. Assays to further characterize autoantibody specificity include ELISA systems based on recombinant forms of the immunodominant regions of the target antigens as well as multivariant indirect IF microscopy tests with several miniature substrates. These serological assays are complemented by various in‐house assays using immunoblotting and ELISA, which are only available in specialized laboratories. Here we review new developments in the diagnosis of AIBDs and describe state‐of‐the‐art diagnostic procedures for this group of diseases.     

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-Hodgkin's 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.     

Oral involvement in autoimmune bullous diseases

The oral mucosa is frequently involved by autoimmune bullous diseases and often this is the first site of manifestation. In this site the lesions are very similar, making the clinical diagnosis difficult; therefore, the definition of the immunohistopathologic characteristics of each one becomes essential for a differential diagnosis. The authors review the clinical-pathological and therapeutic aspect of these oral injuries in order to help in the diagnosis, treatment and prognosis of the oral conditions of those diseases.     

Significance of immunofluorescence in the diagnosis of autoimmune bullous dermatoses

Direct immunofluorescence study remains the diagnostic gold standard in the assessment of patients with bullous disorders, despite novel immunoserologic tests such as enzyme-linked immunosorbent assay and immunoblotting. This contribution provides an update of the classification of autoimmune bullous diseases and diagnostic procedures, with an emphasis on immunofluorescence findings.     

Ultrastructural immunocytochemistry of autoimmune bullous diseases

Advanced immunopathological assays have been developed to elucidate the pathophysiology and provide more precise nosological definitions of the immunobullous diseases. Forty-seven patients suffering from autoimmune bullous diseases (intra- or subepidermal) were studied by immunoelectron microscopy (direct and indirect). Peroxidase staining was revealed by diaminobenzidine (determination of immune deposit location) in the majority of the cases of subepidermal bullous diseases, but in less than half of the cases of intraepidermal bullous diseases. Immunoelectron microscopy features contributed in verifying the diagnosis of rare entities such as cicatricial pemphigoid, paraneoplastic autoimmune bullous disease, linear IgA disease and epidermolysis bullosa acquisita.     

Spectrum of autoimmune bullous diseases in Kuwait

BACKGROUND: Autoimmune bullous diseases (ABDs) are a rare but significant group of dermatoses that pose great challenges to the treating dermatologist. Most epidemiological studies have focused on a single ABD. Few surveys have been carried out to describe the whole spectrum of ABDs in a region, and no such studies are available from the Arabian Peninsula. OBJECTIVES: To determine the clinico-epidemiological features of various ABDs in Kuwait, and to compare the results with those reported elsewhere. METHODS: A total of 128 cases of ABDs were studied over a span of 11.5 years. The diagnosis in all cases was confirmed by histopathology, and direct and indirect immunofluorescence (IMF). The diagnosis of various subepidermal ABDs was further confirmed by indirect IMF on salt-split skin (SSS) and that of pemphigus by desmoglein 1 and 3 enzyme-linked immunosorbent assay (ELISA). RESULTS: Eighty seven per cent of patients were of Arab ethnicity. Pemphigus was observed to be the commonest ABD (47%), followed by pemphigoid (22%), pemphigoid gestationis (PG) (19%), linear IgA bullous disease (LABD) (7%), lichen planus pemphigoides (LPP) (3%), and epidermolysis bullosa acquisita (EBA) (2.3%). The minimum estimated incidence in the local population was 4.6, 2.14, 1.83, 0.69, 0.30, and 0.23 cases per million per year, respectively. Pemphigus patients were observed to have a younger age of onset (36.50 +/- 11.36 years) than reported elsewhere. BP, although the second commonest ABD, was less prevalent than in Europe and Singapore, and BP patients were observed to have a striking female predominance (85%). The prevalence of PG was much higher than that reported elsewhere. LABD was the fourth commonest ABD, and 89% of patients were children. CONCLUSIONS: The study suggests that similar surveys from different regions would expand our understanding of ABD.     

自身免疫性疱病与银屑病的相关性

自身免疫性疱病（AIBD）和银屑病的发病机制有部分相似性。近年来,多项研究报道银屑病与AIBD之间具有相关性,以大疱性类天疱疮多见,还包括寻常型天疱疮、红斑型天疱疮、线状IgA大疱性皮病等,多数AIBD在银屑病发病后发生,部分患者两病同时出现或AIBD先出现。本文综述AIBD与银屑病发病的相关性及可能存在的机制。