Human aggression and enumerative measures of immunity

Objective: A pattern of clinical, behavioral, and experimental findings sug gests that individual differences in aggressive behavior may be related to immunologic processes. We evaluated two conflicting models of the relations hip: 1) A positive association stems from an adaptive mechanism protecting aggressive individuals from increased exposure to immune stimuli and 2) a n egative association is due to potential immunosuppressive effects of high t estosterone levels. Methods: We investigated the models using enumerative m easures of cellular and humoral immunity in a sample of 4415 men aged 30 to 48 years who were interviewed and underwent a medical examination. Results : Analysis revealed positive land curvilinear) associations between aggress ive behavior and enumerative measures of helper/inducer and suppressor/cyto lytic T lymphocytes and B lymphocytes. The aggression-immunity relationship was independent of testosterone level, age, current health status, and neg ative health behaviors and was most pronounced for helper/inducer T cells. There was no evidence of a negative association between testosterone and an y immune measure. Conclusions: In a large sample of men, individual differe nces in aggressive behavior were positively associated with enumerative mea sures of cellular immunity.