Fig. 2

Tregs in PB and lung tissue were significantly lower than IPF patients. (a) We evaluated immune infiltration using gene expression profiles from the GSE28221, GSE33566, and GSE15197 datasets from the GEO database, which include IPF samples and healthy controls. The results showed a significant decrease in Tregs scores in IPF compared to healthy controls. (b-c) The expression of the CD25/IL2RA gene was significantly decreased in IPF compared to healthy controls in both array and sequencing data. (d) The Tregs-associated negative marker gene CD127 showed a significant increase in IPF patients in the sequencing data. (e) PB was collected from healthy individuals and patients with IPF. The fibrosis-related proteins in serum were analyzed by ELISA. The expression of relevant genes in PBMCs was analyzed using qPCR. Additionally, CD4⁺ T cells in PBMCs was analyzed using FCM. (f) The protein expression levels of HAase and LN-5 in PB were analyzed by ELISA. (g-i) QPCR was used to analyze the relevant gene expression of the Tregs, including IL-10, Foxp3 and CTLA4. (j-k) Flow cytometric analysis was performed on PBMCs to determine the percentages of Tregs (CD4⁺ CD25⁺ Foxp3⁺). Contour plots showing the cell populations from the indicated gates. (l) Correlation analysis between the expression of HAase and the proportions of Tregs. (m-n) By using immunofluorescence to stain human lung tissue paraffin sections with Foxp3 and DAPI, Tregs number in the lung tissues of healthy individuals and IPF patients was counted, followed by statistical analysis between the two groups