Immunohistochemical localization of epidermal basement membrane laminin and type IV collagen in bullous lesions of dermatitis herpetiformis.

Antibodies against the human basement membrane proteins, laminin and the 7-S domain of type IV collagen, were used to study the epidermal basement membrane in lesional skin from four patients with dermatitis herpetiformis. The staining pattern of both antigens was mostly fragmented and sometimes absent on papillary microabscesses, but when present it was attached to the epidermal basal cells. On papillary microblisters and larger blisters the staining of both antigens showed discontinuities and was located in the floor of the blister, except for two cases where tiny fragments of laminin staining were also seen in the roof of larger blisters. These results suggest that blister formation in dermatitis herpetiformis takes place between the epidermal basal cells and the basement membrane.