Natural cytotoxic cell activity linked to time of recurrence of herpes labialis

Peripheral blood mononuclear leucocytes from patients with recurrent oral herpes labialis showed an enhanced spontaneous cytotoxic activity against HSV-1 infected target cells during the acute episode. A heightened cytotoxicity persisted for several weeks during prospective follow-up study of the donors, but fell to low levels during the last week before the next episode of herpes labialis. A correlation between natural cytotoxicity against HSV infected targets and pre-recurrence intervals was noted (r = 0.715, P less than 0.05). In parallel, recurrence of herpes labialis was accompanied by a marked increase in the percentage of T cells with Fc IgG receptors and in the percentage of natural cytotoxic lymphocytes, as defined by a newly described monoclonal antibody, HNC-1A3. Both these populations were significantly decreased during the last week before the next herpes labialis episode, suggesting a role for these cells in defence mechanisms involved in anti-HSV immunity.