PDCD1 and lymphoma: The 2016 WHO revision acknowledged this overlap by creating ‘AITL and other nodal lymphomas of TFH origin’ as an umbrella category specifically to highlight the spectrum of lymphomas which share a TFH phenotype, given the similarities of the genetic abnormalities within these two groups, particularly that of identified pan-TFH antigens including CD279/PD1, CD10, BCL6, CXCL13, ICOS, SAP, and CCR5.