A colchicine-sensitivity test for leukaemic lymphocytes.

Non-dividing lymphocytes from patients with chronic lymphocytic leukaemia were more sensitive than normal lymphocytes to reagents as prednisolone, cytarabine, vincristine and colchicine. The maximum difference was obtained when the cells were incubated with colchicine at 37 degrees C for 20 h. The sensitivity was measured by a 'sensitivity index' which was an estimate of the average percentage of lymphocytes killed by 1.0 and 0.1 mug/ml of colchicine. The index was 0-15% for lymphocytes from the blood of 14 normal persons and was 61-98% for 23 of 25 leukaemic patients with absolute lymphocyte counts of 8,000 X 10(9)/l or more. 3 of 4 untreated patients with presumptive diagnoses of early leukaemia had low absolute counts of 3,300 to 7,600 X 10(9) lymphocytes/l and high sensitivity indices of 41 to 83%. Tests on treated patients with lymphocytes counts less than 8,000 X 10(9)/l suggested a correlation of the index with remission and relapse. Hairy cells from 3 patients with hairy cell leukaemia were resistant to colchicine. Sensitivity to colchicine seemed useful at a test for leukaemic lymphocytes and as an aid in the haematologic evaluation of patients with chronic lymphocytic leukaemia and malignant lymphoma.