Increase in Mitochondrial Mass of Lymphocyte Subsets in Anti-MDA5 and TIF1-γ-Positive Dermatomyositis Patients.

Objectives: The mitochondrial function in anti-MDA5 and TIF1-γ-positive dermatomyositis (DM) is relatively unknown. This study attempted to explore mitochondrial mass within the peripheral lymphocyte subsets of anti-MDA5 and TIF1-γ-positive DM. Methods: This cross-sectional study enrolled 109 DM patients and 32 healthy controls (HCs). The mitochondrial mass of peripheral lymphocyte subsets was analyzed via flow cytometry using median fluorescence intensity assessment. Results: Compared with HCs, there was an abnormal change in peripheral lymphocyte subsets in anti-MDA5 and anti-TIF1-γ-positive DM patients. Anti-MDA5 and anti-TIF1-γ-positive DM patients also exhibited a significantly elevated mitochondrial mass in peripheral lymphocyte subsets. Furthermore, anti-MDA5 antibody levels were positively associated with the mitochondrial mass of most lymphocyte subsets in anti-MDA5-positive DM patients. Univariate logistic regression analysis indicated that the increased mitochondrial mass in some peripheral lymphocyte subsets was related to the occurrence of anti-MDA5-positive DM and presence of anti-MDA5 antibodies. Similar results were obtained in anti-TIF1-γ-positive DM patients. Conclusions: Abnormal lymphocyte subset counts and percentages as well as altered mitochondrial mass in anti-MDA5 and TIF1-γ-positive DM patients were associated with anti-MDA5 and TIF1-γ antibodies. We believe that these results may provide novel mitochondria-based insights into DM pathogenesis. [ABSTRACT FROM AUTHOR]