Cell-mediated immunity in healthy adults in Antarctica and the sub-Antarctic.

Cell-mediated immune responses were studied in 2 Antarctic and sub-Antarctic groups at quarterly intervals over a wintering year, using the cutaneous CMI Multitest. The sub-Antarctic population at Macquarie Island (M.I.) had levels of responsiveness and hypoergy comparable to other healthy populations in temperate regions. The Antarctic group at Mawson showed decreased scores and total number of positive responses to antigens, and a significantly elevated incidence of anergy and hypoergy. Quarterly skin testing showed considerable variability in subject responsiveness to specific antigens at different times over the year. However, only 2 antigens at M.I., trichophyton and proteus, showed a significant seasonal variation in score. There was no statistically significant seasonal variation in antigen scores at Mawson. It is concluded that environment and stress factors in Antarctic expeditions are responsible for the decreased immunological responsiveness.