Although decreased peripheral T cells are often observed in DM patients with anti-MDA5+, T cell lymphopenia and upregulated expression of RIG-I were also observed in 5 patients without anti-MDA5 antibody (2 patients for anti-SAE+, 1 patient for anti-TIFγ+ 2, 1 patient with Mi2+, and 1 patient for MSA−) in our study. Here, IFIH1 is linked to lymphopenia.