Immunity in herpes gestationis: inhibition of mixed lymphocyte culture by patients' sera.

The families of four patients with herpes gestationis (HG) (pemphigoid gestationis) and five patients with polymorphic eruption of pregnancy (PEP) were HLA typed. Anti-HLA-D antibodies in the maternal sera were sought using mixed lymphocyte culture (MLC) inhibition test. Two of the four patients with HG had Dw3, one of which was combined with Dw4. One of the fathers had Dw2. The sera of the four patients with HG strongly inhibited (48-100%) the MLC reaction of maternal cells against cells of the father or the child. This kind of inhibition could not be shown in the patients with PEP. We conclude that patients with HG often seem to have MLC inhibiting factors which obviously are antibodies directed against HLA-D region determinants. Their pathogenic role is still obscure.