CD4+ TRM cells have a superior functional capacity to circulating T cells and mediate protection against a number of viral infections in multiple organs.1 15 To assess the functional potential of CD69HICD4+ TRM and CD69INTCD4+ T cells, intrahepatic leukocytes from a subset of livers were first prestained for CD69 expression to rule out stimulation-induced changes to CD69 expression and then were stimulated to assess their capacity for cytokine production. Here, CD4 is linked to viral infectious disease.