Personality factors, stress and immunity

Stress has been shown to have an association with immune changes. In this study, the effects of examination stress were studied in a group of 10 postgraduate students. Parameters measured included the seriousness of illness rating scale, the test of trait anxiety and the subjective appraisal of stressfulness of exams. Immunological parameters assessed included full blood counts, enumeration of lymphocytes and their subsets; lymphocyte proliferative responses to mitogens (phytohaemagglutinin, concavalin A, pokeweed mitogen) and antigen (purified protein derivative); neutrophil phagocytosis; intracellular killing ability and oxidative mechanisms of intracellular killing by assessing the reduction of nitroblue tetrazolium (NBT). Biochemical parameters assessed included glucose, cortisol, TSH, prolactin, ACTH and DHEA levels in serum. The results suggest a positive association between phagocyte functions (early phagocytosis and NBT reduction) and both trait anxiety and the perception of threat. Decreased lymphocyte proliferation in response to mitogens and antigen was associated with trait anxiety. These results suggest that students who are anxious and see exams as a threat display more efficient phagocyte functions, but decrease proliferation of their lymphocytes at a time of stress.