Reactivity of monoclonal antibodies OK-CLL (anti-CD5) with peripheral blood cells of patients with B cell lymphoproliferative disorders.

Reactivity of OK-CLL monoclonal antibodies that can identify CD5 antigen on peripheral blood mononuclear cells, was investigated in 172 patients with B cell chronic lymphocytic leukemia (B-CLL) in clinical stages RAI O-I and RAI II-IV and in patients with non-Hodgkin's lymphomas, classified according to the Working formulation into high and low grade histologic type. The OK-CLL reactivity with B-CLLs in the initial (RAI O-I), as well as in advanced stages of disease (RAI II-IV) was significantly higher than in controls. Peripheral blood cells of lymphoma patients, regardless of histological type, showed a much lower values of the CD5 positive population than chronic lymphocytic leukemia (CLL) patients, and a non significant discrepancy between the number of cells stained with anti-CD5 and those stained with other T cell markers. In spite of the showed considerable decrease of CD5 positive cells in CLL patients during therapy, elevated number of this population compared to normal individuals, after chemotherapy, was found. However, in lymphoma patients of both types of malignancies, CD5 positive population increased concomitantly with therapy. These results may suggest that analysis of CD5 antigen expression on peripheral blood cells of patients with B cell lymphoproliferative malignancies may have diagnostic, or, in correlation with some relevant clinical parameters, a potential predictive value in the treatment of those patients.