Clinical correlations of linear IgA deposition at the cutaneous basement membrane zone

To determine the specificity of linear IgA deposition at the cutaneous basement membrane zone for primary bullous disease, we reviewed the results of all direct immunofluorescence studies of skin biopsy specimens taken from patients seen at Mayo Clinic during the period 1982 through 1986. Of 4642 specimens submitted for direct immunofluorescence during this 5-year period, 44 from 42 patients showed linear IgA deposition at the basement membrane zone, with or without other immunoglobulins. Of these 42 patients, 36 (86%) had primary subepidermal bullous disease. Of the 36, 20 had linear IgA without IgG at the basement membrane zone (10 with clinical adult linear IgA bullous dermatosis, 2 with chronic bullous disease of childhood, and 8 with cicatricial pemphigoid). Sixteen had linear IgA and IgG at the basement membrane zone (10 with clinical cicatricial pemphigoid, 5 with bullous pemphigoid, and 1 with epidermolysis bullosa acquisita). There was a high frequency of mucosal involvement (67% of the 36 patients) and a somewhat higher frequency of ocular involvement in patients with cicatricial pemphigoid who had linear IgA without IgG at the basement membrane zone (6 of 8) than in those who had both immunoglobulins at the basement membrane zone (4 of 10). These results show that the direct immunofluorescence finding of linear IgA deposition at the basement membrane zone correlates with primary subepidermal bullous disease in a high percentage of patients but reflects a heterogeneous group of blistering disorders.