Cell-mediated immunity to varicella-zoster virus as assessed by the migration inhibition test

The migration inhibition method was used to test cell-mediated immunity to varicella-zoster (VZ) virus in 10 varicella and 11 herpes zoster patients. Control groups consisted of eight children susceptible to VZ infection on serological evidence and 49 normal persons of different age categories. Depending on the positivity criterion adopted, positive results during disease were obtained in 43% or 90% or all tests performed in varicella patients and 47% or 74% in herpes zoster patients. Irrespective of which criterion of positivity was applied, a high rate of positive results was obtained in the normal control groups; in the age range from 20--44 years it was comparable to that for patients. This finding would suggest a high activity of VZ virus among the human population. Since a positive result in migration inhibition test offers evidence of recent contact with antigen, either exogeneous contact with VZ infection or endogenous contact with latent VZ virus must have been involved.