The glycan-binding protein galectin-1 expressed by nurse-like cells promotes the differentiation of CLL cells”

D. CROCI; C. CAÑONES,; M TOSCANO,; P. MORANDE,; M. BORGE,; R. F. BEZARES,; J. SÁNCHEZ AVALOS,; M. NARBAITZ,; R. GAMBERALE,; G.A. RABINOVICH; M. GIORDANO

Barcelona, España,

Workshop; 2nd. Workshop Chronic Lymphocytic Leukemia,; 2009

Society of CLL

Accumulation of neoplastic cells in chronic lymphocytic leukemia (CLL) is conditioned by a variety of signals delivered by accompanying cells in lymphoid tissues, which provide an appropriate niche for differentiation and survival. Here we examined the relevance of galectin-1 (Gal-1), a glycan-binding protein with immunoregulatory activity, within the CLL microenvironment. Exposure to Gal-1 promoted the differentiation of CLL cells in a saccharide-dependent manner by up-regulating the expression of CD86 and CD25, and favoring the release of IL-10. Of note, Gal-1 did not modify any of these parameters when added to tonsillar normal B lymphocytes although it markedly bound to these cells. Adherent nurse-like cells (NLC) differentiated in vitro and CD68+ myeloid cells tracked in the bone marrow of CLL patients were found to be the main source of Gal-1. These results provide the first evidence of a role for Gal-1 in CLL cell differentiation and its selective expression in accompanying myeloid cells.