CSF2 and neoplasm: High international prognostic index score (p = 0.012), and high tumor burden (p = 0.005) appeared to be independent prognostic factors for worse PFS.<h4>Conclusions</h4>The maintenance therapy of R<sup>2</sup>  + GM-CSF regimen may improve survival in high-risk BCL patients, which might be modulated by amplification of natural killer cells.