Delayed hypersensitivity skin testing in the Thai adult population.

OBJECTIVE The present study was carried out in healthy Thai subjects to determine the types and concentrations of standard antigens used in delayed-type hypersensitivity (DTH) skin testing as an evaluation of cell-mediated immunity. MATERIAL AND METHOD One hundred subjects were tested with three antigens including tuberculin (purified protein derivative), tetanus toxoid, 1:10 and 1:100 dilutions, and Candida albicans, 1:10 and 1:100 dilutions. RESULTS We found that 92% of the subjects responded to tuberculin and/or tetanus toxoid at a 1:10 dilution, 77% responded to tetanus toxoid at a 1:10 dilution, and 35% responded to a 1:100 dilution. There was only one subject who responded to Candida albicans at a 1:10 dilution, and none to a 1:100 dilution. The size of tuberculin reactions varied from 5 mm to over 20 mm without any evidence of active tuberculosis. CONCLUSION Tuberculin and tetanus toxoid at a 1:10 dilution are probably sufficient to be used in DTH skin testing to evaluate T-cell function.