While anti-PD-1 antibodies have not been directly tested in CVID, clinical improvement was reported in patients who received IL-2 therapy in the past.18, 19 Along with suboptimal proliferation responses, a small number of studies also suggest an impaired apoptotic function contributing to the accumulation of effete T cells.20–22. The gene discussed is PDCD1; the disease is common variable immunodeficiency.