IgG autoantibody reactivity against bullous pemphigoid (BP) 180 and BP230 in elderly patients with pruritic dermatoses

Background Pruritic dermatoses of the elderly often pose a diagnostic and therapeutic challenge. Specifically, a prodromal phase of bullous pemphigoid (BP) has to be considered in patients with pruritic lesions of polymorphic appearance. These conditions frequently do not fulfil all the clinical, histological and immunopathological criteria for establishing the diagnosis of BP. Objectives To investigate IgG reactivity against the autoantigens of BP, BP180 and BP230, by enzyme-linked immunosorbent assay, in elderly patients affected with various pruritic disorders who had never experienced clinically apparent blisters. Methods The sera of 15 elderly patients with pruritic disorders (group I) were tested for IgG reactivity against BP180 and BP230. Also included were 30 patients with full-blown BP (group II) and 25 age-matched patients with immediate-type allergic reactions (group III). Results Thirty-three per cent of the patients with pruritic disorders (group I) showed IgG against BP230 and/or BP180: four of 15 patients had IgG against BP230 while two of the 15 group I patients were BP180 reactive. All the BP sera (group II) showed IgG reactivity against BP180 and/or BP230. Notably, two of 25 control sera (group III) showed IgG reactivity against either BP180 or BP230. Conclusions The present findings suggest that IgG reactivity against BP230 (i.e. the COOH terminus), and to a lesser extent against BP180, is a common finding in pruritic disorders of the elderly with a wide clinical spectrum. IgG-mediated autoimmunity against the intracellular BP230 may facilitate a chronic, inflammatory response eventually leading to full-blown BP which is presumably associated with IgG against BP180.