Peripheral T Levels and Transforming Growth Factor-β (TGFβ) in Patients with Psoriatic Arthritis: A Systematic Review Meta-Analysis.

Introduction: Studies on the level of regulatory T (T) cells in psoriatic arthritis (PsA) have been controversial, leading to disagreement regarding the role T cells play in the pathogenesis of the disease. To clarify the status of T cells in patients with PsA, we performed a meta-analysis to determine the levels of T cells and serum T-associated cytokines in PsA patients.

Methods: According to published data from PubMed, Web of Science, Embase, Clinical Trials.gov, MEDLINE, Web of Knowledge, Cochrane Library, and FDA.gov, we determined the T and T cytokine levels in patients with PsA. The effect estimates were pooled using a random-effects model.

Results: This meta-analysis included 12 studies. Compared to healthy controls (HCs), the proportions of T cells had no significant difference in patients with PsA (based on standardized means[SMD] = - 1.038, 95% confidence intervals[CI] =  - 2.165 to 0.089, p = 0.071). On the basis of subgroup analysis, patients with PsA had a lower percentage of CD4 T cells (SMD = - 1.501, 95% CI - 2.799 to - 0.202, p = 0.023) than OKT8 T (SMD = 0.568, 95% CI - 2.127 to 3.263, p = 0.679). Besides, CD4CD25FoxP3 T cells and CD4CD25CD127 T cells were both significantly decreased on the levels of PBMCs in patients with PsA (SMD = - 0.764, 95% CI - 1.404 to - 0.125, p = 0.019; SMD = - 5.184, 95% CI - 6.955 to - 3.412, p < 0.001). CD4CD25FoxP3 T cells were particularly more abundant in the synovial fluid thanin peripheral blood (SMD = 3.288, 95% CI 2.127 to 4.449, p < 0.001). No significant difference was observed in the proportion of CD4CD25 T cells in peripheral blood and CD4CD25FoxP3 T cells in CD4 T cells (SMD = - 2.498, 95% CI - 7.720 to 2.725, p = 0.349; SMD = - 0.719, 95% CI - 2.525 to 1.086, p = 0.435). PsA patients had decreased cytokines such as transforming growth factor-β (TGFβ) (SMD = - 2.199, 95% CI - 3.650 to - 0.749, p = 0.003).

Conclusions: T definition markers influence the scale of T cells in patients with PsA. Pathogenesis of PsA may be attributed to an insufficient or malfunctioning T population.