Evaluation of a Newly Available ELISA for Envoplakin Autoantibodies for the Diagnosis of Paraneoplastic Pemphigus.

IMPORTANCE: Paraneoplastic pemphigus (PNP) is routinely diagnosed by the presence of autoantibodies for desmoplakin by indirect immunofluorescence (IIF) on rat bladder epithelium (RBE). IIF on RBE has recently been found to be positive in select cases of other blistering disorders. A new ELISA that detects envoplakin autoantibodies has recently been developed for the diagnosis of PNP. In this study, we measure the specificity of IIF on RBE and compare it to the new ELISA. OBSERVATIONS: We measured the specificity of IIF on RBE to be 86% which is on the lower end of the previously reported specificity of 83% to 98.9%. The ELISA for envoplakin autoantibodies has a technical sensitivity of 100%, diagnostic sensitivity of 83%, and specificity of 91%. CONCLUSIONS AND RELEVANCE: This ELISA for envoplakin autoantibodies is now commercially available and technically easier to perform then the immunoblot. We recommend that this new ELISA serves as a confirmatory test in cases of a positive IIF on RBE given its higher specificity.

Comparisons of pathologic and normal skin reactive autoantibodies and the interference phenomenon.

Immunofluorescent serum studies of the roles of the two groups of normal complement-fixing autoantibodies in psoriasis are complicated by the interference phenomenon. Both antibodies have the potential to react in vivo at sites of trauma and in psoriasiform lesions. In serum tests, only one or the other reacts, as demonstrated by immunofluorescent serum tests and absorption studies with isolated stratum corneum antigen. In tests of 15 normal sera, only one consistently reacted with the soluble carbohydrate antigens; the rest consistently reacted with the glycoproteins of the keratin intermediate filaments. This appears to be due to an antibody interference reaction that permits only one of two or more antibodies to react on a given tissue section.

Neonatal linear immunoglobulin a bullous dermatosis: a rare presentation.

Linear immunoglobulin A bullous dermatosis (LABD) is an autoimmune blistering disease that most commonly presents in preschool-aged children. There have been few neonatal reports, all of which had life-threatening aerodigestive complications requiring mechanical intervention and systemic therapy. We present a case of LABD in a neonate who had an uncomplicated course and was treated conservatively with only low-potency topical corticosteroids and wound care before resolution of his skin lesions.

A case of bullous disease limited to the skin illustrates the spectrum of neoplasia-induced autoimmunity.

Although the initial report of paraneoplastic pemphigus described individuals with mucocutaneous blistering disease, subsequent reports identified patients with lichen planus or graft versus host disease-like changes. We describe a patient with fatal autoimmune blistering disease with absence of mucous membrane lesions. The pattern of complement indirect immunofluoresence helped identify the prognosis prospectively. This case illustrates yet another presentation of the neoplasia-induced autoimmunity.