The high expression of PD-1 in AITL was confirmed as early as 2007 (Shimauchi et al., 2007), and subsequent studies also found an increased number of PD-1-expressing cells in 93% of AITLs and 62% of follicles outside PTCL-NOS, leading to an immunosuppressive microenvironment (Krishnan et al., 2010). The gene discussed is PDCD1; the disease is angioimmunoblastic T-cell lymphoma.