Human serum thymic factor in detecting acute T cell leukemia

In acute leukemia, the frequency of the E+ cells among the blood mononuclears before and after their incubation with human serum thymic factor was investigated by means of the E rosette assay. In 4 of 24 patients tested, the thymic factor incubation of their peripheral blood cells increased the number of the E+ cells among the mononuclears. Prospective importance of the test either in investigating whether a T0 leukemia might really exist, or in monitoring possible variations of the immature T cell counts in relationship to the patient's treatment and his disease course, are discussed.