Herpes simplex antigen in immune complexes of patients with erythema multiforme: presence following recurrent herpes simplex infection.

Serum samples from patients with erythema multiforme (EM) were examined for the presence of herpes simplex virus (HSV) antigen in immune complexes using the Raji cell radioimmunoassay. Raji-cell-bound immune complexes from eight of 12 patients with EM after HSV infection and four of four patients with EM of uncertain cause had increased anti-HSV binding, while patients with EM after drug exposure and patients with recurrent HSV infections without EM had binding in the same range as controls. Viral cultures for HSV of immune complexes eluted from Raji cells were negative. Sucrose density gradient ultracentrifugation studies of serum samples of patients with EM after HSV infection showed HSV antigen in large molecular weight fractions. The HLA typing of lymphocytes from 16 patients with EM after HSV infection was not different from that of controls. Immune complexes composed of antibody and HSV antigen are present in serum samples of patients with EM after HSV infection and some cases of EM of uncertain cause and may mediate the pathogenesis of these disorders.