Depressed specific cell-mediated immunity to Herpes simplex virus type 1 in patients with recurrent herpes labialis.

Cell-mediated immunity to herpes simplex virus type 1 (HSV-1) was assessed by a lymphocytotoxicity 51-Cr-release microassay procedure, using the MA-160 human prostatic adenoma cell line chronically infected with HSV-1 and its parent cell line as control. The specific immune release mean plus or minus standard deviation for nine asymptomatic patients with recurrent HSV-1 infections was 13.7 plus or minus 8.1%, compared to 28.9 plus or minus 8.4% in seven normal seropositive controls (P is less than 0.01). In four additional patients studied serially, the cell-mediated immunity was significantly increased during the recrudescence of herpetic infection, with a mean specific immune release value of 51.7 plus or minus 27.8%, compared to 8.7 plus or minus 1.5% during the convalescent period 2 to 10 weeks later (P is less than 0.05). These findings suggest that patients with recurrent HSV-1 infections have vigorous cellular immune responses during the acute phase but a specific impairment of cell-mediated immunity during the quiescent period, which may in part account for their susceptibility to recurrent herpetic infections.