Although we did not measure the well known exhaustion markers PD-1, CD95, and TIM-3 (43), there is recent evidence that CD69 may act as marker for lymphocyte exhaustion and is an immunoregulatory marker in addition to being an early activation marker (44): A study in mice showed that T cell infiltration and killing of tumor cells was upregulated in the presence of antibodies to CD69 and also in CD69 knockout mice. The gene discussed is FAS; the disease is neoplasm.