Comparison of the effects of two different whole body hyperthermia protocols on the distribution of murine leukocyte populations

Two predominant WBH protocols presently being used in clinical trials inclu de a low temperature, long duration (LL) WBH, where core body temperature i s raised to 39.5-40 degrees C for 6h or more, and a high temperature, short duration (HS) WBH, where core body temperature is raised to 41.8 degrees C for up to 2h. Here, the effects of LL-WBH and HS-WBH on leukocyte populati ons in the blood, spleen, lymph node (LN) and peritoneal cavity (PerC) of B alb/c mice were compared using flow cytometry. The total numbers of periphe ral blood leukocytes decreased up to 2-fold immediately after LL-WBH, refle cting a decrease of lymphocyte numbers compared to controls. In contrast, t he numbers of blood leukocytes are increased 2.7-fold immediately after HS- WBH compared to controls, reflecting an increase in lymphocytes, monocytes and granulocytes. After both LL-WBH and HS-WBH treatment, leukocyte numbers in the spleen are decreased approximately 2-fold, again reflecting decreas es in lymphocyte numbers. In the PerC, total numbers of leukocytes are also significantly decreased (2-fold) during LL-WBH but not HS-WBH. Total numbe rs of leukocytes in the LNs were unaffected by both LL- and HS-WBH. Overall , these data reveal differential effects of the LL- and HS-WBH protocols on leukocyte populations in the blood, spleen, LN and PerC of Balb/c mice.