Herpes gestationis (HG) occurs during pregnancy, puerperium, and, more seldom, in association with trophoblastic neoplasms. Association of HG with choriocarcinoma is rare, and in only one reported case1 the diagnosis was confirmed using direct immunofluorescence. Furthermore, Kelly et al2 used indirect immunofluorescence (IIF) to detect circulating anti–basement membrane zone (BMZ) IgG1 autoantibodies in serum samples from patients with HG that fix to a complement called the HG factor.
Paula do Valle Chiossi M, Silva Costa R, Ferreira Roselino AM. Titration of Herpes Gestationis Factor Fixing to C3 in Pemphigoid Herpes Gestationis Associated With Choriocarcinoma. Arch Dermatol. 2000;136(1):129-130. doi: