Lymphoproliferative responses in recrudescent orofacial herpetic infections

The relationship between antibody (Ab) and lympho-proliferative responses to herpes simplex virus (HSV) and recrudescent orofacial HSV lesions were investigated in 65 patients. All had HSV-specific Ab and cell mediated immune responses (CMIR) demonstrated by ELISA and in vitro lymphoproliferation respectively. Thirteen control subjects were negative in both tests. Thirty-three patients were repeatedly investigated for 6-38 months during which time they suffered 1-8 recrudescences. HSV-induced lymphoproliferation was depressed during recrudescences, rose to a peak several weeks later, and declined slowly to a background level. However, ELISA titres and lymphoproliferative responses to Concanavalin A (Con A) were high throughout and circulating peripheral blood mononuclear cell (PBMC) subsets did not change. Depressed lymphoproliferative responses to HSV antigen (Ag) during recrudescences were enhanced by removal of CD8+ cells from PBMC using either a panning technique or cell sorting; reconstitution of CD8+ cells suppressed the HSV-specific lymphoproliferative response. CD8+ cell depletion affected neither HSV-induced lymphoproliferation recrudescence, nor lymphoproliferative responses to another Ag (PPD) during recrudescence. Depressed HSV-induced lymphoproliferation during recrudescences might thus be due to CD8+ suppressor T cell (Ts) function rather than low numbers of circulating lymphocytes. Suppression or delay of normal CMIR to asymptomatic recurrent epidermal HSV infection by Ts might allow development of recrudescent HSV lesions.