Reduced expression of adhesion molecules and cell signaling receptors by chronic lymphocytic leukemia cells with 11q deletion

Deletions in chromosome bands 11q22-q23 were recently shown to be one of th e most frequent chromosome aberrations in B-cell chronic lymphocytic leukem ia (B-CLL). Patients suffering from B-CLL with 11q deletion are characteriz ed by extensive lymphadenopathy, rapid disease progression, and short survi val times. Phenotypic and functional characteristics of B-CLL cells with 11 q deletion that may help to explain the pathophysiology of this entity are yet unknown. In the present study, B-CLL cells with (n = 19) and without (n = 19) 11q deletion were analyzed for their expression of functionally rele vant cell surface molecules (n = 57). B-CLL cells with 11q deletion carried significantly lower levels of the adhesion molecules CD11a/CD18 (integrin alpha(L)/beta 2), CD11c/CD18 (integrin alpha(X)/beta 2), cD31 (PECAM-1), CD 48, and CD58 (LFA-3). Furthermore, B-CLL cells with 11q deletion expressed less the cell signaling receptors CD45 (leukocyte common antigen [LCA]), CD 6, CD35 (complement receptor 1), and CD39. Reduced CD45 levels and low-leve l expression of CD49d correlated with decreased overall survival. B-CLL cel ls with or without 11q deletion did not differ in their growth fractions, e xpression levels of transcription factor NF-kappa B, or their response to m itogenic stimuli. Decreased levels of functionally relevant adhesion molecu les and of cell signaling receptors may contribute to the pathogenesis of t he subgroup of B-CLL characterized by 11q22-q23 deletion. (C) 1999 by The A merican Society of Hematology.