The significance of an IgM band at the dermo-epidermal junction.

We studied 190 patients with an IgM band at the dermo-epidermal junction demonstrated by direct immunofluorescence. In 55% of patients the final diagnosis was lupus erythematosus, 49% discoid lupus erythematosus, and 6% systemic lupus erythematosus. In 45% of patients the presence of an IgM band was associated with a number of other diagnoses. The finding of an IgM band at the dermo-epidermal junction in a cutaneous biopsy is not sufficient evidence to make a diagnosis of lupus erythematosus without supporting clinical, histological and serological evidence.