Objective: To examine the frequency and phenotype of Th17 cells in the peripheral blood of patients with early non-radiographic axial SpA (early nrSpA).
Methods: CD4(+) T cells were isolated from the peripheral blood of 30 early nrSpA patients, 11 AS patients and 41 age- and sex-matched healthy controls by Ficoll-Hypaque gradient and magnetic negative selection. After polyclonal stimulation, the frequency of Th17 and Th1 cells and of cells producing TNF-α or IL-10 was determined by cytometry and concentrations of IL-17, IL-22, IFN-γ, TNF-α, IL-10 and IL-4 were measured by ELISA.
Results: Early nrSpA but not AS patients demonstrated a significantly lower percentage of circulating Th17, Th1 and Th17/Th1 cells, together with lower CD4-derived IL-17 and IFN-γ secretion, as compared with controls. In contrast, the percentage of circulating cells producing IL-10 or TNF-α, and the secretion of CD4-derived IL-10, TNF-α, IL-22 and IL-4 in early nrSpA were not different from controls. All Th17 cells were CD45RO(+)CD45RA(-) and CCR6(+). The frequency of circulating Th17, Th1 and Th17/Th1 was negatively correlated with BASDAI, BASFI, ASDAS-CRP, ASDAS-ESR, AS quality of life (ASQOL) and patient's global assessment in HLA-B27(+) but not in HLA-B27(-) early nrSpA patients. A positive correlation between circulating Th17 cells and BASDAI was observed in AS.
Conclusion: A decreased percentage of Th17, Th1 and Th17/Th1 cells is apparent in peripheral blood CD4(+) T cells from early nrSpA. Th17, Th1 and Th17/Th1 cell numbers are related to disease activity indices in HLA-B27(+), but not in HLA-B27(-), early nrSpA patients.