[Serum interferon level and (2'-5')-oligo(A) synthetase activity in pityriasis rosea, basalioma, melanoma and molluscum contagiosum].

In various skin diseases with a possible viral and/or autoimmune etiology, the peripheral lymphocytes were studied with regard to serum interferon levels and the interferon-induced activity of (2'-5')-oligoadenylate synthetase (OAS). This enzyme is a sensitive marker of interferon and can be detected even some days after the clearance of interferon from the blood. In patients with pityriasis rosea (n = 13), basal cell carcinoma (n = 12), malignant melanoma (n = 11), and molluscum contagiosum (n = 13), the serum interferon levels were not increased. In comparison to healthy persons, 5 patients with melanoma (Clark's levels I, I-II and II) showed a significantly elevated activity of OAS. In 6 other patients with melanoma (Clark's level III, III-IV and IV), the OAS activity was not increased. Although the elevated activity of OAS found in patients with melanoma of lower Clark's levels indicates a participation of the interferon system in the course of the disease, our results do not allow a clear statement regarding a viral and/or an autoimmune etiology of the skin disease.