Does whole-body hyperthermia therapy involve participation of the immune system?

The effect of micro-wave whole-body hyperthermia on tumor growth and lung metastasis counts was examined in adult BALB/c mice. The effective therapy with hyperthermia prolonging mean survival time of the animals and causing tumor regression resulted in concimitant depression of anti-tumor immunity measured in vivo. The beneficial effect of preimmunization of animals with killed tumor cells on subsequent challenge with live tumor cells was completely abrogated by hyperthermia treatment. It is postulated that this form of therapy is directly related only to heat sensitivity of tumor cells and that there is no profitable participation of the immune system in the anti-tumor effect of wholebody hyperthermia.