Blood Th17 cells and IL‐17A as candidate biomarkers estimating the progression of cognitive impairment in stroke patients

BACKGROUND: T helper (Th) cells regulate immunity and inflammation to engage in cognitive impairment in several neurological diseases, while their clinical relevance in stroke patients is not clear. The current study intended to assess the relationship of Th1 cells, Th17 cells, interferon‐gamma (IFN‐γ), and interleukin (IL)‐17A with cognitive function in stroke patients. METHODS: One hundred twenty stroke patients and 40 controls were enrolled in this muticenter study. Th1 and Th17 cells in peripheral blood were assessed by flow cytometry; meanwhile, IFN‐γ and IL‐17A in serum were detected by enzyme‐linked immunosorbent assay. Cognitive function of stroke patients was evaluated by Mini‐Mental State Examination (MMSE) score at enrollment (baseline), year 1, year 2, and year 3. RESULTS: Th1 cells (p = 0.037) and IFN‐γ (p = 0.048) were slightly increased, while Th17 cells (p < 0.001) and IL‐17A (p < 0.001) were greatly elevated in stroke patients compared with controls. Th17 cells (r (s) = −0.374, p < 0.001) and IL‐17A (r (s) = −0.267, p = 0.003) were negatively correlated with MMSE score at baseline, but Th1 cells and IFN‐γ were not. Meanwhile, Th17 cells (p = 0.001) and IL‐17A (p = 0.024) were increased in patients with cognitive impairment compared to those without cognitive impairment. Notably, Th17 cells were positively associated with 1‐year (r (s) = 0.331, p < 0.001), 2‐year (r (s) = 0.261, p = 0.006), and 3‐year (r (s) = 0.256, p = 0.011) MMSE decline; IL‐17A was positively correlated with 1‐year (r (s) = 0.262, p = 0.005), 2‐year (r (s) = 0.193, p = 0.045), but not 3‐year MMSE decline. However, both Th1 cells and IFN‐γ were not linked with MMSE decline. CONCLUSION: Th17 cells and IL‐17A estimate the progression of cognitive impairment in stroke patients.