Increased Blood Th2-Like Invariant Natural Killer T Cells In Patients With Asthma

Invariant natural killer T (iNKT) cells might play an important role in the pathogenesis of asthma in humans. Our previous study has shown no difference in the number of blood iNKT cells between asthmatics and controls. However, few studies have reported about the function of blood iNKT cells in human asthma. Twenty asthmatics and eight controls were included. Blood iNKT cells were identified with double staining with both anti-Vα24 and anti-Vβ11mAbs or both 6B11 and anti-Vβ11mAbs. Intracellular IL-4, IL-10 and IFN-γ cytokines were stained in blood iNKT cells with the respective mAbs and isotypes, and their relationships with clinical parameters were analyzed. The number of Vα24+Vβ11+ iNKT cells or 6B11+Vβ11+ iNKT cells did not differ between asthmatics and controls. However, among Vα24+Vβ11+ iNKT cells, the proportion of IL-4+ cells of Vα24+Vβ11+ iNKT cells was increased in 20 asthmatics (7.0 ± 3.0%) compared with 8 controls (0.5 ± 0.4%, p < 0.05). There were no differences in the proportion of IL-10+ or IFN-γ+ cells of iNKT cells between asthmatics and controls. Proportion of IL-4+ cells of 6B11+Vβ11+ iNKT cells was inversely correlated with FEV1 expressed as % predicted value in asthmatics (Rs = -0.64, p < 0.05, n = 19). Blood iNKT cells are thought to be Th2-like type in human asthma, and IL-4-producing iNKT cells may be associated with lung function, indicating that a new drug regulating Th2-like iNKT cells may control refractory asthma in humans.