Pathogenesis of herpes simplex labialis: correlation of vesicle fluid interferon with lesion age and virus titer.

Of 51 patients with herpes simplex labialis, 50 had detectable interferon (IFN) in samples of lesion vesicle fluid. The median titer of vesicle fluid IFN was 8,200 U. and the range of values was 400 to 63,600 U. The amount of vesicle fluid IFN was correlated with lesion age (r = 0.32, P = 0.024) and vesicle fluid virus titer (r = 0.59, P = 0.00004), but not with the clinical severity of the disease. The presence of vesicle fluid IFN (1,500 to 28,600 U) in 15 lesions less than 12 h old emphasizes the need for early treatment in studies of antiviral agents for herpes simplex labialis.