Frequency of IL-17-positive CD4 T cells in PBMC, SFMC, and synovium (SVMC) of RA patients versus PBMC of healthy donors. Cells were stimulated with PMA and ionomycin in the presence of brefeldin A. A) Representative plots of IL-17 staining on PBMC of healthy controls (HC), RA PBMC, and RA SFMC are shown against CD3. Cells were first gated on CD3 and CD4 expression. The percentages of IL-17 positive cells are indicated. B) The frequency of IL-17-positive CD4 T cells was compared between RA and healthy control samples. Data from healthy control PBMC (n = 13), RA PBMC (n = 44) and SFMC samples (n = 14) are shown. C) Data from healthy control PBMC (n = 13), RA paired PBMC and SFMC samples (n = 14) and paired RA PBMC and SVMC samples are shown (n = 10). D) The frequency of IL-17-positive CD4 CD45RO T cells was compared between healthy donor PBMC (n = 13), RA PBMC (n = 44) and RA SFMC (n = 14). Bars representing the medians are shown within the dot plots. P-values less than 0.05 were considered significant.