Psychologically mediated effect on the delayed hypersensitivity reaction to tuberculin in humans

Recent research with animals has indicated a central nervous system effect on the immune system. This report describes findings of a possible psychologically mediated effect on the delayed hypersensitivity reaction to tuberculin in humans. Seven tuberculin positive subjects evidenced a decreased response to tuberculin (as measured by erythema and induration) when a paradigm similar to behavioral conditioning was followed where the subjects expected their reactions to be negative.