Analysis of circulating immune cells in patients with rheumatoid arthritis and positive for hashimoto thyroiditis antibodies

To examine the differences in the proportions of circulating peripheral helper T cells (Tph), follicular helper T cells (Tfh), regulatory T cells (Treg), and Treg subtypes between patients with rheumatoid arthritis positive for Hashimoto thyroiditis antibodies (RA-HT) and those with rheumatoid arthritis alone (RA). To investigate the correlations between these cell types and clinical indicators, and evaluate their potential as biomarkers for diagnosing and predicting RA-HT, thereby providing directions for more detailed mechanistic studies. The study enrolled 50 RA-HT patients, 53 RA patients, and 10 healthy controls. Fresh peripheral blood was collected for flow cytometry analysis, and clinical data were gathered for correlation studies. The diagnostic performance of the cells was analyzed using the receiver operating characteristic (ROC) curve. In the RA-HT group, there were significant increases in circulating Tph, Tfh, Treg, and memory Treg cells compared to the RA group (<i>p</i> < 0.0001, <i>p</i> < 0.01, <i>p</i> < 0.05, <i>p</i> < 0.05), while activated Treg cells decreased significantly (<i>p</i> < 0.0001). ROC curve analysis showed that the area under the curve of the combined prediction model of Tph, Tfh, Treg, and activated Treg cells was 0.905, with a sensitivity of 78.00% and a specificity of 90.57%. The increase in the proportions of Tph and Tfh cells and the imbalance in the proportions of Treg cell subtypess, may contribute to the pathogenesis of RA-HT. The combined prediction model of Tph, Tfh, Treg, and activated Treg cells demonstrates diagnostic potential for RA-HT.