This observation is in line with previous work demonstrating a rapid loss of Th1 cell formation and function during chronic viral infection (Fahey et al., 2011; Yamada et al., 2016), as well as our recent finding that this decline in CXCR6+ Th1 cell accumulation is accompanied by an increase in the formation of a Slamf6+ memory-like CD4+ T cell subset (Zander et al., 2022). This evidence concerns the gene SLAMF6 and viral infectious disease.