The association between lymphocyte subsets and several psychopathological variables which had proved to be able to affect immune cell count in other conditions was investigated in bulimia nervosa patients. Sixty-seven female bulimia nervosa patients and 29 female healthy controls were assessed for nutritional status (weight, blood cells, lymphocyte subsets, biochemical parameters and hormones) and psychopathology (anxiety, depression, hostility, impulsivity and borderline personality traits). A negative correlation between impulsivity and helper T-cells (CD4(+)) was found in controls. In the bulimia nervosa group, the patients with higher anxiety had the lower lymphocyte count, and anxiety and hostility were negatively related to CD4(+) count. In addition, helper/cytotoxic T-cell ratio negatively correlated in this group with impulsivity, hostility and depression. In the light of these results, the potential influence of psychopathology on lymphocyte subset counts seems to be specific in bulimia nervosa patients, and more relevant than in healthy controls.