OBJECTIVES: This study aimed to investigate the relationship between the frequency of CD3 + TCRVα24 + iNKT cells, the proportions of iNKT CD4+, iNKT CD8 + and iNKT CD4-CD8- (DN) subgroups in peripheral blood, and nasal exhaled nitric oxide (NO) levels in patients with allergic rhinitis (AR). METHODS: Peripheral blood samples were collected from 40 AR patients and 40 patients with nasal septal deviation (DNS). The frequencies of the iNKT cell subgroups were analyzed, and nasal exhaled NO levels were measured. Correlation analyses were conducted to assess the associations between these parameters.. RESULTS: The frequency of CD3 + TCRVα24 + iNKT cells was significantly higher in the AR group (0.4863 % ± 0.0874 %) compared to the DNS group (0.4451 % ± 0.0603 %) (p <
0.05). The proportions of iNKT CD4+, iNKT CD8+, and iNKT CD4-CD8- (DN) cells in the AR group were 76.32 % ± 10.24 %, 12.71 % ± 4.34 %, and 11.08 % ± 6.29 %, respectively, while in the DNS group, they were 60.79 % ± 9.04 %, 13.81 % ± 5.56 %, and 25.56 % ± 6.45 %. Significant differences were observed in the proportions of iNKT CD4+ and iNKT CD4-CD8- (DN) cells between the two groups (p <
0.01). Nasal exhaled NO levels were significantly elevated in the AR group (842.33 ± 237.88 ppb) compared to the DNS group (527.37 ± 163.57 ppb, p <
0.01). In the AR group, nasal exhaled NO levels showed a strong positive correlation with the frequency of iNKT cells (r = 0.9, p <
0.01), the iNKT CD4+ subgroup (r = 0.93, p <
0.01), and a negative correlation with the iNKT CD4-CD8- (DN) subgroup (r = -0.877, p <
0.01). These findings suggest that elevated iNKT cells, particularly the iNKT CD4+ subgroup resembling T helper 2 (Th2) cells, may contribute to AR pathogenesis. CONCLUSIONS: The significant correlations between iNKT cell subgroups and nasal exhaled NO levels highlight the role of iNKT cell variations in NO-mediated AR pathogenesis. These findings also suggest the potential diagnostic value of analyzing iNKT cell profiles in AR patients.