IFIH1 and retinitis pigmentosa 1: In MDA5-positive DM-ILD patients, it was found that CD8 + T cells were reduced more significantly than CD4 + T cells in patients with RP-ILD, and the peripheral blood lymphocyte count was positively correlated with the degree of lung interstitial injury, but negatively correlated with the ratio of CD4:CD8 [9].