title: Circannual changes in immune function.
abstract: Adrenocortical activity varies on a circannual basis with increased secretion in the winter and decreased secretion in the summer. One consequence of this variation is a circannual pattern in immune function. Adrenal corticosteroids, especially glucocorticoids, depress cellular immune function and seem to be more effective against T-suppressor cells. Thus, when adrenocortical activity is elevated, T-cell activity is depressed and B-cell activity is elevated. To the extent that T-cell "surveillance" is depressed in winter, there should be increased lymphoproliferative cancer risk during winter and in regions characterized by cold climates. This article presents data which suggest: (1) a winter, adrenal-corticoid induced, depression of T-cell function which is accompanied by elevated B-cell function; (2) elevated serum immunoglobulin levels in the winter; and (3) an inverse relationship between ambient temperature and serum immunoglobulin levels. The circannual pattern in immune function could help explain increased lymphoproliferative cancer risk, as a side effect of immunosuppression therapy during organ transplants, and as a function of latitude.
mesh_terms: D000305:Adrenal Cortex Hormones / Q000378:metabolism / Q000502:physiology; D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D006801:Humans; D007108:Immune Tolerance; D007109:Immunity; D007136:Immunoglobulins / Q000378:metabolism; D010507:Periodicity; D012306:Risk; D012621:Seasons; D013601:T-Lymphocytes / Q000502:physiology; D013696:Temperature
chemical_list: D000305:Adrenal Cortex Hormones; D007136:Immunoglobulins