Expression of myelomonocytic antigens is associated with unfavourable clinicoprognostic factors in B-cell chronic lymphocytic leukaemia.

The cross-lineage expression of five myelomonocytic antigens (CD11b, CD11c, CD13, CD14, and CD15) was analysed in neoplastic lymphocytes from 100 consecutive B-cell chronic lymphocytic leukaemia (B-CLL) patients. CD14 antigen was detected on lymphocytes from more than 50% of patients whilst smaller percentages of samples were positive for CD11b (21%), CD11c (26%), CD13 (22%), and CD15 (7%). The presence of the CD13 antigen on neoplastic lymphocytes showed a statistically significant association with the two most important unfavourable clinicoprognostic factors in B-CLL: advanced clinical stage (CD13, P less than 0.01 by the Rai staging system; P less than 0.05 by the Binet staging system) and the diffuse pattern of bone marrow infiltration (CD13, P less than 0.001). A multiple logistic regression analysis showed that the increased risk for CD13-positive patients (13.7-fold higher than CD13-negative cases; P = 0.001) of presenting a diffuse pattern of bone marrow infiltration is independent of all other prognostic factors analysed including sex, age, lymphocyte counts, and clinical stage. A statistically significant association of CD11c (P = 0.002) and CD11b (P = 0.032) expression with the pattern of bone marrow infiltration was also found. Our results indicate for the first time a statistically significant association of CD13, CD11c, and CD11b antigens with unfavourable prognostic factors in B-CLL. They suggest that the cross-lineage expression of myeloid-associated surface peptidase (CD13-aminopeptidase N) and/or cell adhesion molecules (CD11c-LeuCAMc, CD11b-LeuCAMb) may influence the biological and clinical behaviour of chronic lymphoproliferative disorders of B cells.