A patient with subcorneal pustular dermatosis was found to have a circulating monoclonal IgA kappa immunoglobulin. Direct immunofluorescence studies revealed IgA kappa deposits in the subcorneal zone of the epidermis. Circulating IgA kappa reacting with the subcorneal zone of normal human epidermis was demonstrated by indirect immunofluoresence. It is speculated that IgA deposition might be implicated in the pathogenesis of subcorneal pustular dermatosis.

ABSTRACT. The clinically normal skin of the lower back of 30 patients with diabetes mellitus was examined, using the direct immunofluorescence technique. No deposit of immunoglobulins or complement (C3) could be demonstrated, while other authors have previously reported lupus‐like deposits in diabetes mellitus. As other discrepant studies of skin immunofluorescence have been published, it is suggested that the standards of the various immunopathology laboratories are different. This may explain why the actual value of the lupus band test remains controversial.