Then, the cells were pelleted down by centrifugation at 300 g. The supernatants

were collected and stored at −80°C for the measurement of IFN-γ by enzyme-linked immunosorbent assay (ELISA) kits (BD Biosciences), according to the manufacturer’s protocol. All data are represented as the mean ± standard deviation (s.d.). Univariate and multivariate linear regression was Protein Tyrosine Kinase inhibitor applied to calculate the correlation coefficient and significance among different parameters using STATA software (StataCorp, College Station, TX, USA). Statistical significance was assessed by Mann–Whitney U-test and a P-value less than 0·05 was considered statistically significant. The demographic and clinical data of the AS patients were recorded and are summarized in Table 1. The expression profile of 270 miRNAs in T cells from five AS patients and five healthy controls is shown in Fig. 1a. Each scatter-spot represents the average of normalized miRNA levels of T cells from five AS patients and normal controls. We noted that the expression of eight microRNAs, including miR-150, miR-16, miR-342-5p, miR-221, Ensartinib mouse let-7i, miR-99b, let-7b and miR-513-5p, were significantly higher and five microRNAs including miR-218, miR-409-3p, miR-30e, miR-199a-5p and miR-215 were significantly lower in AS T cells than in normal

T cells (fold change >4·5 and P < 0·05; Fig. 1b). Then, we chose only the five most differentially expressed miRNAs (defined as fold change >6 and P < 0·05), including miR-150, miR-16, miR-342-5p, miR-221 and let-7i for further validation. In the second step, T cells from another 22 AS patients and 18 healthy controls were compared. We confirmed that the expression levels of miR-16, miR-221 and let-7i (fold change: 2·34, 2·38 and 3·17, Fludarabine respectively; all the P values < 0·05) were significantly higher in AS T cells than in normal T cells (Fig. 1c). We then intended to correlate

different clinical parameters with the expression levels of miR-16, miR-221 and let-7i in AS T cells by univariate and multivariate linear regression analysis. We found that the expression of miR-221 (P = 0·022) and let-7i (P = 0·031) were associated positively with BASRI of lumber spine. The expression of miR-16 (P = 0·086) was associated positively with BASRI of lumbar spine (Fig. 2). After adjusting for age and gender, the expression of miR-221 (fold change = 1·58, P = 0·033) and let-7i (fold change = 1·75, P = 0·029), but not miR-16 (fold change = 1·67, P = 0·059), were still correlated positively with BASRI of lumbar spine, which reflects inflammatory activity in the lumbar spine (Table 2). However, expression of miR-16, miR-221 and let-7i did not correlate with serum C-reactive protein levels or sacroiliitis by radiography in AS patients (Table 2). Several studies have demonstrated that miR-16, miR-221 and let-7i regulate the protein expression of Bcl-2, c-kit and TLR-4, respectively [29-31].