IN-VITRO INDUCTION OF BASAL KERATINOCYTE MY7 ANTIGEN EXPRESSION IN CUTANEOUS T-CELL LYMPHOMA IS ASSOCIATED WITH RESPONSE TO INTERFERON-ALFATHERAPY

Background: Normal basal cell keratinocytes express an antigen recogni zed by monoclonal antibody MY7. This expression is lost in cutaneous T -cell lymphoma (CTCL) and may be reinduced under interferon-alfa-2a th erapy. We investigated whether similar modulation of MY7 antigen could be obtained in vitro and determined the relationship between in vitro modulation and clinical response. Subjects: We studied MY7 expression by basal cell keratinocytes in reconstituted skin specimens from 10 p atients with CTCL and from skin specimens from five control patients a nd determined its modulation by interferon-alfa-2a and interleukin 1 u sing the indirect immunofluorescence technique. Concurrently, clinical examination and in vivo immunologic study on cutaneous biopsy specime ns were carried out for these 10 patients before and while receiving i nterferon-alfa-2a therapy. Results: In vitro studies showed that in fi ve control specimens MY7 expression by basal cells was constant withou t modulation by interferon-alfa-2a or interleukin 1. Two of 10 CTCL sp ecimens spontaneously expressed MY7 antigen while an additional five d id so after incubation with interferon-alfa-2a and the last three neve r did. Conclusions: The three patients with CTCL for whom no MY7 expre ssion was observed in reconstituted skin studies were ''poor responder s'' to interferon-alfa-2a therapy. The five patients with CTCL for who m in vitro MY7 expression was induced by interferon-alfa-2a were respo nders. For the last two patients, results were variable. Thus, in vitr o MY7 antigen is expressed in normal basal cell keratinocytes, absent in CTCL basal cell keratinocytes, but can be induced by interferon-alf a-2a. Moreover this in vitro modulation appears to be possibly correla ted with interferon-alfa efficacy in vivo.