Hyperthermic Effects on Peripheral Lymphocytes Isolated from a Chronic Lymphocytic Lymphoma/Leukemia Patient In vitro

Effects of hyperthermia in vitro on the atypical lymphocytes isolated from peripheral blood of a chronic lymphocytic lymphoma/leukemia patient were investigated. Incubation of the isolated lymphocytes at 43 ° C for 5 hr killed 15% of the cells, while more than 95% of the lymphocytes isolated from normal individuals and heated under the same conditions survived. Cultivation of the patient's lymphocytes at 37° C for 4 days after heat treatment at 43 ° C for 5 hr resulted in a viability of less than 50%. Proliferative responses of the patient's lymphocytes to lectins showed 70% more inhibition than did the control when heated at 43 ° C for 1 hr and were abolished completely after 3 hr of hyperthermia. Although, in normal individuals, complete recovery of ( 3 H)‐thymidine uptake of the lymphocytes heated at 43 ° C for 3 hr was observed after 4 days of cultivation at 37 ° C, this recovery did not occur in the patient's cells. Morphological changes in the atypical lymphocytes heated at 43 ° C for 3 hr occurred in the cytoplasmic organelles; in particular, enlargement of mitochondria, increased numbers of cytoplasmic granules and vesicles, probably derived from lysosomes, and hyperproduction of myelin sheath‐like structures around the nuclear membrane were seen.