As IFNα has been reported to decrease the number of CLL cells in the circulation at early disease stages (A and B), its production after reovirus treatment could generate significant bystander effects by direct cytotoxicity as well as activation of antitumour immunity.49, 50 Cytokine production (interleukin-6 and tumour growth factor-β) from malignant CLL cells can inhibit T and NK cells,51, 52, 53 and PD-1/PD-1L expression may also inhibit immune cell functions;54 future work will elucidate the effect of reovirus-induced IFNα production on these suppressive mechanisms. This evidence concerns the gene IFNA1 and B-cell chronic lymphocytic leukemia.