E-rosette forming lymphocytes in acute leukemia before and after cell incubation with human serum thymic factor.

The Authors studied the effect of the human serum thymic factor on the peripheral blood leukocytes from ALL patients, by testing the frequency of the E+ cells by means of the E rosette assay before and after cell incubation with this factor. In four out of twenty-four patients tested, the thymic factor incubation of peripheral blood mononuclears increased the number of E+ cells. The shift from E- to E+ cells caused by the human serum thymic factor occurred among null cells (E-, SM-Ig-). The possible value of the test in investigating whether a T0 leukemia might really exists is pointed out, as well as its prospective importance in monitoring the variations of the immature T cell counts in relationship to the patient's treatment and his disease course.