A clinical and serological study of linear IgA bullous dermatosis without linear immunoglobulin deposition other than IgA at the basement membrane zone using direct immunofluorescence.

BACKGROUND: Linear IgA bullous dermatosis (LABD) is a heterogeneous disease. Different diagnostic criteria have been used in different reports. OBJECTIVES: To reappraise the characteristic features of LABD with only IgA deposition at the basement membrane zone (BMZ) with direct immunofluorescence (DIF). METHODS: We retrospectively collected data from 101 patients from our archival records from 1 January 1996 to 31 December 2014 who had: (i) blisters on the skin and/or mucous membranes; (ii) subepidermal blisters in a biopsy specimen; and (iii) linear IgA deposition along the BMZ with/without linear C3 deposition at the BMZ with DIF. Most patients were referred for serological evaluation. Patients who showed concurrent linear IgG and/or IgM deposition at the BMZ under DIF were excluded. Clinical manifestations and serological findings were analysed. RESULTS: Heterogeneity of autoantigens in LABD was confirmed. Fifty-four of 101 patients (53%) had IgG antibodies detected either by indirect immunofluorescence, immunoblotting or enzyme-linked immunosorbent assays (ELISA). No statistical difference in clinical manifestations was found between patients in the IgG antibody-possessing group and patients in the other group. CONCLUSIONS: An association of IgG anti-BMZ antibodies with LABD may increase if new IgG immunoblotting or ELISA techniques become available. Consensus for diagnostic criteria for LABD is desired for prospective data storage, although it may be arbitrary.