TH17 AND REGULATORY B CELLS PROFILE IN PATIENTS WITH HASHIMOTO‘S THYROIDITIS ASSOCIATED WITH SYSTEMIC SCLEROSIS

Objectives: Hashimoto’s thyroiditis (HT) is highly prevalent in women with systemic sclerosis (SSc). HT is characterized by a Th17/Th1 polarization and an increased number of B regulatory (Breg) cells. Previous studies described an increased amount of naïve B cells with a decrease of memory B cells in isolated SSc. The aim of the study has been to characterize Th17 and Breg cell subsets in patients with HT associated with SSc. Methods: A total of 49 patients (44W/5M; mean age: 48 years) were selected: of these, 19 (17W/2M) had isolated HT and 12 patients (11W/1M) had SSc; seven of these latter also had Hashimoto’s thyroiditis (SSc+HT). Eighteen healthy donors (HD) (16W/2M) represented the reference group. Freshly PBMCs were assessed by FACS to characterize Th17 and Breg lymphocytes phenotypes. Moreover, activated Breg (IL-10+) have been measured upon stimulation with CpG oligonucleotide. Result: Mean percentage of Th17+ lymphocytes was 2.4±1.7% in isolated HT and significantly lower when associated with SSc (0.9±0.9%;p=0.0109). Breg cells (CD24hi CD38hi) were increased in patients affected by SSc, both isolated (4.6±2.9%) or associated with HT (4.6±3.2%), as compared to both patients with isolated HT (2.4±0.9%) and HD (2.0±0.7%; p=0.033). Following stimulation, the percentage of Breg cells was significantly higher in patients with SSc (13.6±5.6%) and SSc+HT (10.4% ± 4.9) than in HD (p<0.001 and p=0.0002) and isolated HT (p=0.0027 and p=0.0008). However, despite this increase, the cells producing IL-10 were lower in patients with SSc and SSc+HT (0.5±0.4% and 0.8±1.2%) than in HD (2.4±1.1% p=0.0231 and p=0.0015) and in isolated HT (3.9±1.8%; p=0.012 and p=0.0008). Conclusions: In patients with HT and SSc there was a reduction of Th17 and an increased percentage of Breg cells, but a clear reduction of IL-10+ Breg, as compared with those in isolated HT patients.