Expression profile of Eph receptors and ephrin ligands in healthy human B lymphocytes and chronic lymphocytic leukemia B-cells

Increasing information relates some Eph receptors and their ligands, ephrins (EFN), with the immune system. Herein, we found that normal B-cells from peripheral blood (PB) and lymph nodes (LN) showed a differential expression of certain Eph/EFN members, some of them being modulated upon in vitro stimulation including EFNA1, EFNA4, EphB6 and EphA10. In contrast, PB CLL B-cells showed a more heterogeneous Eph/EFN profile than their normal PB B-cell counterparts, expressing Eph/EFN members frequently found within the LN and activated B-cells, specially EFNA4, EphB6 and EphA10. Two of them, EphB6 and EFNA4 were further related with the clinical course of CLL patients. EphB6 expression correlated with a high content of ZAP-70 mRNA and a poor prognosis. High serum levels of a soluble EFNA4 isoform positively correlated with increasing peripheral blood lymphocyte counts and lymphadenopathy. These findings suggest that Eph/EFN might be relevant in normal B-cell biology and could represent new potential prognostic markers and therapeutic targets for CLL.