IMMUNE-RESPONSES DURING AN ANTARCTIC SUMMER

The immune status of 29 members of the Australian National Antarctic R esearch Expeditions (ANARE) was investigated before, during, and after a 56 day summer voyage to Antarctica and correlated with psychologica l and physiological parameters. All subjects were healthy. Expedition personnel demonstrated decreased cell mediated immune responses (CMI) assessed by the CMI Multi-test; 21% were hypoergic. The major associat ed observation was a significant negative correlation with anxiety in Antarctica. However, perceived anxiety was greater before and after th e voyage. No significant changes were found in T and B lymphocyte subs ets, immunoglobulin and complement components and cutaneous blood flow , nor was there any clinical evidence of illness. Of the hormones exam ined only cortisol was low predeparture which may reflect increased pe rceived anxiety at that time. Changes in immune control mechanism were apparent as shown by reduced CMI responses and lowered tetanus antibo dy levels. Stress factors are postulated to induce depression of the i mmune response in Antarctica. The association with anxiety suggests th at brain peptides or associated cytokines may have a role in mediating these immune events. Such alterations in immune status have implicati ons for health management in isolated and extreme conditions.