Immunologic responses following serial skin testing

Twenty volunteers underwent intradermal skin testing with tetanus toxoid (TT) and varicella-zoster (VZ) antigens weekly for 7 weeks. In addition to measurements of delayed hypersensitivity skin test responses, in vitro antigen specific lymphocyte stimulation and antibody levels were monitored. Data for TT exhibited more variability than VZ, demonstrating a marked boost in antibody titers after the first skin test and a shift in the kinetics of the skin test reaction to later maximum responses after the first 3 weeks. In contrast, serial skin testing with VZ was not associated with changes in cellular immune assays. Following the initial VZ skin test there was a slight rise in antibody levels for one-third of studied individuals. These observations suggest that VZ skin test antigen is ideal for monitoring immune function and that repeated testing should not significantly influence in vitro assays.