While B cell non-Hodgkin’s-lymphoma (NHLs) predominantly arise in aged individuals, and age-related T-cell changes—such as cytotoxic CD4+ T-cell accumulation, increased circulating TFH (cTFH) frequencies, and elevated pre-TFH formation in mice—have been documented (6, 39–41), these alterations do not fully recapitulate the disease-specific TFK cell expansion observed in lymphomas. Here, CD4 is linked to lymphoma.