Dysregulated CD38 expression on T cells was associated with rapidly progressive interstitial lung disease in anti-melanoma differentiation-associated gene 5 positive dermatomyositis.

Background: Anti-melanoma differentiation-associated gene 5 positive dermatomyositis (MDA5+ DM) is a life-threatening disease due to rapidly progressive interstitial lung disease (RP-ILD). We aimed to investigate the expression profile of T cell subsets in MDA5+ DM patients, seeking for possible disease-causing T cell subsets and potential biomarkers to distinguish ILD, especially RP-ILD patients. Methods: Peripheral blood T cell subpopulations were immunophenotyped in 24 MDA5+ DM patients and 21 healthy controls (HCs) by flow cytometry. The proportion of T cell subsets and clinical characteristics were analyzed. The quantitative determination of cytokines in the plasma was measured by using a microsphere-based immunofluorescence assaying kit. Results: The proportion of naïve and CD38+ T cells were much higher, whereas the proportion of central memory T cells were lower in MDA5+ DM patients than in HCs. Notably, the proportion of CD38+CD4+ T cells and CD38+CD8+ T cells on T cells in in RP-ILD group were significantly elevated compared to C-ILD, non-ILD group and HCs. Moreover, serum IFN-α levels were significantly increased in MDA5+ DM patients with RP-ILD. Further, the frequencies of CD38+CD4+ T cells and CD38+CD8+ T cells were positively correlated with IFN-α levels. Finally, ROC analysis indicated that CD38+CD4+ T cells and CD38+CD8+ T cells could be potential biomarkers for predicting ILD/RP-ILD in MDA5+ DM patients. Conclusion: Dysregulated CD38 expression on T cell subsets was associated with lung involvement, especially RP-ILD in MDA5+ DM patients. CD38+ T cell subsets could be used as potential biomarkers for predicting ILD/RP-ILD in MDA5+ DM patients.