On the contrary, the programmed cell death protein-1 (PD-1) antibody Nivolumab demonstrated efficacy in the treatment of refractory or relapsed Epstein-Barr virus (EBV)-HLH in a pilot study, most likely due to expansion of PD-1 positive T-cells and restoring the defective anti-EBV response [7]. The gene discussed is PDCD1; the disease is hemophagocytic syndrome.