Quantitation of human peripheral blood T and B lymphocytes

Centrifugation of heparinized peripheral blood on Ficoll-Hypaque under defined conditions is a most common method of lymphocyte purification in clinical studies. A loss of 25-30% of lymphocytes may occur during this procedure due to incomplete recovery of lymphocytes from the plasma layer after the gradient centrifugation and/or to poor recovery during the washing process. The loss is not selective since T and B cells are lost in the same proportions as determied by several different methods for T and B cell identification. Quantitation of T and B lymphocytes in terms of total number/mm-3 of peripheral blood is necessary in order to determine deficiencies in either of these two cell populations. The percentage values are inadequate in clinical evaluations. Thus, patients with chronic lymphocytic leukemia show elevated absolute number of T cells absolute numbers of T and B cells as well as percentages ought to be reported in all clinical studies.