IFNγ+ NKT-like cells are associated with increased incidence of atrial fibrillation in elderly women.

Abstract

Aims: T cells are present in atrial tissue from atrial fibrillation (AF) patients. However, prospective studies of T cells and AF development are few. The current aim was to investigate if T-cell subsets are associated with the risk of developing AF.

Methods and results: T-cell subsets, measured by flow cytometry of cryopreserved mononuclear leucocytes isolated from blood at baseline, were analysed for associations of incident AF in 669 subjects from a population-based cohort. Subjects were followed for incidence of AF for 18.6 (11.5-21.7) years during which 145 subjects were diagnosed with AF. Incident AF cases had higher levels of CD3⁺CD56⁺ NKT-like cells. No differences in CD3⁺, CD3⁺CD4⁺, CD3⁺CD8, Th1, Th2, or regulatory T cells between incident AF cases and non-cases were observed. Women had higher levels of NKT-like cells than men. High numbers of NKT-like cells were associated with an increased risk of developing AF in women [HR (95% CI) 1.88 (1.10-3.23) above vs. below median], but not in men or in the total cohort. The majority of NKT-like cells were IFNγ⁺ after stimulation. High numbers of IFNγ⁺ NKT-like cells were associated with increased risk for developing AF in women. Median fluorescence intensity of IFNγ for NKT-like cells was higher in cases of incident AF in women, but not in the total cohort or in men.

Conclusion: High levels of IFNγ⁺ NKT-like cells in blood are associated with increased risk of incident AF in women, supporting a role for T cells in development of AF and emphasizing sex differences in this context.