Lymphocyte subpopulations and immunodeficiency in calves with acute lymphocytic leukemia

The frequency of surface immunoglobulin (SIg), a B lymphocyte marker, was studied on peripheral blood lymphocytes (PBL) obtained from 2 calves with acute lymphocytic leukemia (ALL). Approximately 19% of PBL from normal age matched calves demonstrated SIg, and these were classified as B lymphocytes, whereas less than 1% of the PBL from calves affected with ALL had SIg and these were classified as B lymphocytes. The mitogenic activity of phytohemagglutinin (PHA) and pokeweed mitogen (PWM) was studied on PBL from normal calves and cows and from the 2 calves with ALL. Lymphocytes from the 2 calves with ALL were unresponsive to PHA and PWM, as indicated by the degree of stimulation. The value of these findings and possible explanations are discussed.