Lymphocyte and IgG responses to different herpes simplex virus antigens in patients with frequent HSV-1 reactivations

Seventeen patients with a history of frequent clinical herpes simplex (HSV) reactivations and 13 HSV seropositive controls were monitored for 6 months. The patients had 4-8 clinical reactivations during the study. No clinical HSV reactivations were observed in the controls. IgG subclasses directed against HSV-1 nucleocapsid, membrane and glycoprotein C (gC) antigens were determined after the study period. Anti-HSV IgG4 directed against gC was found more often in the patients (65%) than in the controls (8%, P less than 0.025). The same trend was seen for IgG4 against HSV nucleocapsid antigen (88 and 46%, n.s.) and HSV membrane antigen (82 and 38%, n.s.). In both patients and controls IgG3 was found more often against nucleocapsid antigen compared to membrane or gC antigens (P less than 0.001). Lymphocytes were stimulated with the different antigens and the anti-HSV IgG subclass responses and cellular proliferation were determined. Lymphocyte produced IgG4 against HSV nucleocapsid antigen was found more often in patients than in controls (47 and 8%, P = 0.05) and membrane antigen (41 and 0%; P less than 0.025). No differences were found in the magnitude of lymphocyte proliferation responses between patients and controls. Lymphocyte proliferation responses were stronger to nucleocapsid antigen than to membrane or gC antigens (P less than 0.01).