Immunocytochemical investigation of normal and chronic lymphocytic leukaemia lymphocytes reveals unexpectedly frequent reactivity with some myelomonocytic associated antibodies

Information about the expression of some myelomonocytic markers in lymphocytes of patients with B-CLL is scarce. We studied the CD13, CD14, CD11c and CD68 surface antigens in 42 controls and in 38 patients with B-CLL to detect their possible reactivity. Eighty-nine percent of B-CLL expressed very strongly the CD14 antigen; on the contrary, the other myelomonocytic antigens tested were very weakly expressed. Forty-one of 42 controls showed a few CD14-positive lymphocytes with a statistical difference between normal and CLL lymphocytes. No statistical difference was recorded either between CD14 expression and Rai's staging system or Binet's stages, nor between CD14 and bone marrow involvement and doubling time or between CD14 and heavy or light chain expression. A minor B lymphocytic subset in humans coexpresses the CD14 and CD5 antigens, it being increasingly speculated that B chronic lymphocyte leukaemias originate precisely from this B CD5- and CD14-positive cells. Just as the CD5 antigen is regarded as an excellent B-CLL marker, it seems to us that a strong expression of the CD14 antigen might have the same diagnostic relevance.