Bullous pemphigoid: Interaction of interleukin 5, anti-basement membrane zone antibodies and eosinophils. A preliminary observation

Bullous pemphigoid (BP) is an autoimmune blistering skin disease characteri zed by the presence of autoantibodies to normal components of the hemidesmo some (BPAg1 and BPAg2), Histology of skin lesions demonstrate a subepiderma l vesicle and a predominantly eosinophilic dermal cellular infiltrate, Inte rleukin 5 (IL-5) plays a major role in eosinophil recruitment and function. Using an ELISA, we investigated the levels of IL-5 in the sera and blister fluid of BP patients with active disease and those in prolonged clinical r emission treated with intravenous immunoglobulin, and compared it to that i n normal controls. Significantly increased levels of IL-5 were detected in the serum and particularly the blister fluid of patients with active diseas e (P=0.0043) when compared to levels in normal controls. There was no signi ficant difference in IL-5 levels in patients in prolonged clinical remissio n compared to normal control serum. Tn an immunoblot assay, using bovine gi ngival lysate as substrate, we determined the presence of Ige and IgE autoa ntibodies specific to basement membrane zone proteins in blister fluid and serum of BP patients. IgG autoantibodies to BPAg1 and BPAg2 were detected i n both blister fluid and serum of patients, whereas IgE autoantibodies, in much lower titers, were detected to only BPAg1, Elevated levels of blood an d tissue eosinophilia were observed in these patients. Based on these data, we present a preliminary hypothesis for the initiation, progression and lo calization of blister formation in BP. (C) 2001 Academic Press.