FcγRIIb expression in early stage chronic lymphocytic leukemia

Abstract

In normal B-cells, B-cell antigen receptor (BCR) signaling can be negatively regulated by the low-affinity receptor FcγRIIb (CD32b). To better understand the role of FcγRIIb in chronic lymphocytic leukemia (CLL), we correlated its expression on 155 samples from newly-diagnosed Binet A patients with clinical characteristics and outcome. FcγRIIb expression was similar in normal B-cells and leukemic cells, this being heterogenous among patients and within CLL clones. FcγRIIb expression did not correlate with well known prognostic markers [disease stage, serum beta-2 microglobulin (B2M), IGHV mutational status, expression of ZAP-70 and CD38, and cytogenetics] except for a weak concordance with CD49d. Moreover, patients with low FcγRIIb expression (69/155, 44.5%) required therapy earlier than those with high FcγRIIb expression (86/155, 55.5%) (median 151.4 months vs. not reached; p=.071). These results encourage further investigation on the role of FcγRIIb in CLL biology and prognostic significance in larger series of patients.

Keywords:

• Chronic lymphocytic leukemia
• FcγRIIb
• B-cell receptor
• treatment-free survival
• B-cell activation

Acknowledgements

We would like to acknowledge Ignasi Gich for his support with statistical analysis. We would also like to thank Elena Serrano and Iris Rodriguez for their technical support in the collection and cryopreservation of CLL samples.

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article online at http://dx.doi.org/10.1080/10428194.2017.1307981.

Additional information

Funding

This work was supported by grants from Ministerio de Economia y Competividad [RD12/0036/0071 to J.S. and FIS11/01740 to C.M.], Agència de Gestió d’Ajuts Universitaris i de Recerca [2014 SGR1281 to J.S.], National Cancer Institute [RO1 CA 81554 to N.C.], Fundación Cellex y Fundación Científica Asociación Española Contra el Cáncer.