CD4 and neuroblastoma: Studies have also found that treatment with anti-PDL1 and/or PD-1 antibodies in concert with anti-CD4 antibody, anti-CTLA4 mAb, anti-GD2 antibody, or a CSF-R1 inhibitor can significantly decrease tumor growth compared to monotherapy alone in neuroblastoma models in vivo (19, 54, 67, 68).