Stress and psychosocial factors: effects on primary cellular immune response.

Life stress is associated with decreases in some immune functions, but little is known about the effect of stress on immune response to active immunization. We examined the relationships between stressful events, psychosocial, and biologic factors and primary immune response to a novel antigen-keyhold limpet hemocyanin (KLH). Lymphocyte proliferation (LP) was measured prior to immunization and 3 and 8 weeks following KLH immunization. At 3 weeks, LP was significantly lower in subjects reporting more "bad" stress and those experiencing more psychological distress, while "good" stress and social support tended to be associated with higher LP. There was a trend toward the more stressed subjects having lower baseline, but higher 8-week, LP responses. The model that best fits these data suggests that psychosocial processes mediate the relationship between stressful events and primary immune response, while biologic factors, such as recent weight gain, show direct independent effects on immune response.