In situ localization of IgG in epidermolysis bullosa acquisita by immunogold technique

Clinical features and diagnosis of epidermolysis bullosa acquisita

INTRODUCTION

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune blistering disease of skin and mucous membranes. EBA is caused by autoantibodies against type VII collagen, which is a major component of anchoring fibrils, attaching epidermis to dermis. Binding of autoantibodies to type VII collagen leads to skin fragility and, finally, blister formation. The clinical picture of EBA is polymorphic, with several distinct phenotypes being described. Despite recent progress in understanding the pathophysiology of EBA, its diagnosis is still challenging. Areas covered: This review provides an update on the clinical manifestations and diagnostic methods of EBA. We searched PubMed using the terms 'epidermolysis bullosa acquisita' covering articles in English between 1 January 2005 and 31 May 2016. Relevant older publications were retrieved form cited literature. Expert commentary: While the clinical picture is highly variable, diagnosis relies on direct immunofluorescence (IF) microscopy of a perilesional skin biopsy. Linear deposits of IgG, IgA and/or C3 along the dermal-epidermal junction with an u-serrated pattern are diagnostic for EBA alike the detection of serum autoantibodies against type VII collagen. Several test systems for the serological diagnosis of EBA have recently become widely available. In some patients, sophisticated diagnostic approaches only available in specialized centers are required.

Epidermolysis bullosa acquisita in childhood

This case report of an 11-year-old girl describes a juvenile form of epidermolysis bullosa acquisita, an autoimmune disease of IgG antibodies to basement membrane type 7 collagen. Our case illustrates an unusually severe, acute inflammatory presentation of this condition with prominent mucosal and constitutional features requiring admission to a paediatric burns unit. The treatment consisted of supportive topical and systemic agents, prednisolone and dapsone. She responded to dapsone alone and the course of the illness was uneventful.

Intravenous immunoglobulin treatment in therapy-resistant epidermolysis bullosa acquisita

Epidermolysis bullosa acquisita is an uncommon autoimmune bullous disease of the skin and mucous membranes. It is chronic, disabling, and difficult to treat. We describe a case of severe epidermolysis bullosa acquisita of 7 years' duration that had been treated with azathioprine, corticosteroids, chlorambucil, plasma exchanges, cyclophosphamide, cyclosporine, and colchicine without any lasting effect. Seven cycles of treatment were administered with immunoglobulin given intravenously at a low dose, 40 mg/kg body weight daily for 5 days. The patient was free of disease for 10 months after the initiation of therapy. We suggest that low-dose regimens of immunoglobulins may be as effective in this disease as the high-dose regimens suggested in the literature, and at much lower cost.

New applications of electron microscopy techniques in dermatopathology

The application of immunostaining techniques to electron microscopy specimens has led to a renewal of interest in electron microscopy in biological research in general, as well as in dermatopathology. Refinements in the preparative procedures have made easier the immunolocalization of antigens both in chemically-fixed and frozen unfixed tissues, embedded in plastic and sectioned. Application of these methods has led to the demonstration of the bullous pemphigoid antigen inside basal keratinocytes. HMB-45 antigen has been found to be present in premelanosomes. Recently, Factor XIIIa has been localized not only in dermal dendrocytes but also in endothelial cells and mast cells.

Ultrastructural immunogold studies in two cases of linear IgA dermatosis. Are there two distinct types of this disease?

It has been suggested that patients with homogeneous linear IgA deposits at the basement membrane zone constitute a distinct bullous disorder called linear IgA dermatosis (LAD) of adults or children. The results of the present ultrastructural immunogold study in two patients with LAD suggest that LAD is not a single disease entity. LAD in a 10-year-old girl was found to be ultrastructurally similar to an IgA-type pemphigoid. IgA was detected in the uppermost lamina lucida underlying the basal cell plasma membrane. In a second patient, an 86-year-old man, IgA deposits were present within the lamina densa and the anchoring plaques. The distribution of IgA in this patient was ultrastructurally identical with that of IgG in epidermolysis bullosa acquisita skin and with that of the non-collagenous globular terminus of collagen VII within the basement membrane zone of normal skin. By using the immunogold technique, we could distinguish two distinct types of LAD according to the IgA binding sites in the diseased skin. We suggest that different labelling patterns may correspond to different clinical pictures.