Relationship between disease activity and Th17/regulatory T cells level in peripheral blood of patients with synovitis acne pustulosis hyperostosis osteitis syndrome

Abstract

Objective To investigate whether the proportions of Th17/Treg balance were impaired in the peripheral blood of patients in different phases of synovitis acne pustulosis hyperostosis osteitis (SAPHO) syndrome. Methods We studied 22 cases diagnosed as SAPHO syndrome and 11 healthy controls. According to the scores of VAS pain, BASDAI and BASFA, the 22 patients were divided into active group and stable group. By means of flow-cytometry, the frequencies of total and different subsets of Th17 and Treg cells in peripheral blood mononuclear cell of different groups of SAPHO syndrome and healthy controls were studied. The values of Th17/Treg balance were analyzed. The relationship was analyzed with Kruskal-Wallis test, Mann-Whitney test and Pearman's test. Results The mean percentage of Th17 cells was markedly higher in the active group [(2.74± 0.25)%] than in the stable group [(1.16±0.09)%] (U=0.000, P<0.01) and healthy controls [(1.13±0.11)%] (U= 0.000, P<0.01). No differences were found among active group [(2.10±0.20)%], stable group [(2.51±0.20)%] and control group [(2.44±0.22)%] (χ2=2.16, P=0.339 4). The ratio of Th17 cells to Treg cells was markedly higher in active group [(1.48 ± 0.25)% ] than in the other two groups [(0.47 ± 0.03)% ] (U=0.000, P<0.01).We also found the positive correlation of the ratios of Th17/Treg cells with the values of VAS in SAPHO syndrome patients (r=0.752 7, P<0.01). Conclusion The results demonstrate that the development of SAPHO syndrome is closely related to the imbalance of systemic Th17/Treg cells. Increased ratio of Th17/Treg cells may be the main factor that cause disease recurrence, and then, lead to the manifestations of high levels of inflammation and joint pain. Key words: Acquired hyperostosis syndrome; T-lymphocytes; T-lymphocytes, helper-inducer; Flow cytometry