379 Clinica Chimica Acta, 60 (1975) 379-383 @ Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands CCA 7031 LDH ISOZYMES OF HUMAN T AND B LYMPHOCYTES S. RINGOIRa and J. PLUMb =Department of Medicine and bDepartment of Microbiology, University Hospital, De Pintelaan 135, B-9000 Ghent (Belgium) (Received November 28, 1971) Summary Peripheral lymphocytes were obtained from five normal healthy adults. T and B lymphocytes were separated by rosette formation. LDH (L-lactate:NAD+ oxidoreductase, EC 1 .l .1.27) isozymes were studied on both populations after agar gel electrophoresis. The mean B lymphocyte pattern was: LDH-1, 7.2%; LDH-2, 25.0%; LDH-3, 39.2%; LDH-4, 21.9%; LDH-5, 6.6%. The mean T lymphocyte pattern was: LDH-1, 25.8%; LDH-2, 35.1%; LDH-3, 28.3%; LDH-4, 9.4%; LDH-5,1.3%. This makes the T lymphocytes look more aerobic than the B lympho- cytes. Daudicells had the following pattern: LDH-1, 8.4%; LDH-2, 19.1%; LDH-3, 26.6%, LDH-4, 24.9%; LDH-5, 20.9%. Introduction The LDH (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) isozymes of human chronic lymphocytic leukemic and normal lymphocytes have been studied by Bottomley et al. [l] , Starkweather et al. [2] and Rabinowitz and Dietz [3]. These reports do not agree as they found, respectively, the LDH-3, the LDH-5 and the LDH-1 to be the most important fractions. The authors had not separated the T and B lymphocytes. The circulating lymphocytic population which has a dual origin could, therefore, influence the LDH pattern in an opposite way. We studied the LDH isozymes of human peripheral lymphocytes after separation in order to see whether a different pattern could be found for T and B lymphocytes.