CD4 and viral infectious disease: ISG+ CD4+ T cells have been previously found in the blood and kidneys of patients with lupus nephritis (Arazi et al., 2019; Szabo et al., 2019; Wang et al., 2022), and in mouse during chronic viral infections (Crawford et al., 2014), allergic airway inflammation (Tibbitt et al., 2019), and colonic infection (Kiner et al., 2021).