Expression of lymphocyte function-associated antigen (LFA)-1 in B-cell chronic lymphocytic leukemia.

We investigated the expression of the lymphocyte function associated (LFA)-1 adhesion molecule, recognized by the CD11a and CD18 monoclonal antibodies, in 53 patients with B-cell chronic lymphocytic leukemia (B-CLL) and in 37 controls. The mean percentage of control lymphocytes expressing CD11a and CD18 positivity was 92 +/- 5.5 and 90 +/- 8.7, respectively and, in patients with B-CLL, 14.2 +/- 10.3 and 14.8 +/- 10.3 respectively (p < 0.001). No statistical difference was found between CD11a and CD18 expression and the Rai clinical stages. In our experience a decrease of LFA-1 is a constant finding in B-CLL, in the early stages of the disease. It may, therefore, be useful to differentiate between slight increases of neoplastic cells and reactive blood lymphocytosis.