Fig. 3

Mucosal-associated invariant T (MAIT) cell activation and correlation of CD69⁺ MAIT cell frequency with disease activity in systemic lupus erythematosus (SLE). CD69 expression on MAIT cells (a) and other T-cell subsets (b), including γδT cells, CD4⁺ T cells, and CD8⁺ T cells, were analyzed by flow cytometry. a Representative examples of CD69 expression on MAIT cells and the percentages of CD69⁺ cells among each MAIT cell population in patients with SLE are shown. The gray histogram indicates isotype control. The relative levels of CD69⁺ MAIT cells are increased in patients with SLE with active disease compared with healthy control subjects (HCs). *p < 0.05, ** p < 0.01 (Kruskal-Wallis test followed by Dunn’s multiple comparisons test). Each symbol represents the value of one individual. The box plot indicates the first and third quartiles, and the middle line indicates the median. Whiskers indicate the minimum and maximum. c Correlations between Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score and CD69⁺ MAIT cells or CD69 expression on MAIT cells. Symbols represent individual subjects. There was a positive correlation between the percentages of CD69⁺ cells among MAIT cells and the SLEDAI score. Correlations were analyzed using Spearman’s correlation analysis. MFI Mean fluorescence intensity