To determine which FcR participate in the ADP response induced by the most efficient RTX isotypes; RTX-IgG1 and RTX-IgG3, we treated IFNγ-stimulated monocytes with or without blocking antibodies to human FcγRI, FcγRIIa, and FcγRIIIa prior co-culture with RTX-treated B-cell lymphoma spheroids. This evidence concerns the gene IGHG3 and B-cell non-Hodgkin lymphoma.