MDSCs Aggravate the Asthmatic Progression in Children and OVA-Allergic Mice by Regulating the Th1/Th2/Th17 Responses.

Background. Asthma is a chronic inflammatory disease of respiratory with serious risks for children. This study explored myeloid-derived suppressor cells (MDSCs) on the pathogenesis of asthmatic children and mice. Methods. The clinical study enrolled 30 asthma, 20 pneumonia, and 20 control participants. The MDSCs, Th17 and Th1 cells percentage, and IL-4, IL-12, IL-10, and IFN-γ levels were detected by flow cytometry and ELISA. In experimental asthma, mice were divided into control, ovalbumin (OVA), and OVA + MDSCs groups. The changes in inflammatory cell count and the levels of IL-5, IL-12, and IL-10 in mice BALF and the levels of inflammatory factors, IgE, and IFN-γ in mice were detected by ELISA. The amount of ROS generation and pathological changes and the levels of caspase 1 and caspase 3 were tested by flow cytometry, HE and PAS staining, and immunohistochemistry. The expression of cleaved caspase 1/caspase 1 and cleaved caspase 3/caspase 3 was detected by western blot. Results. In clinical trials, the levels of IL-12, IFN-γ, and Th1 percentage decreased in pneumonia and asthma children's peripheral blood, while the levels of IL-4 and IL-10 and the percentages MDSCs and Th17 increased. In asthma mice, pathological staining showed that asthma caused lung inflammation and damage, while the OVA + MDSC group was severer. Moreover, the percentages of eosinophils, neutrophils, lymphocytes, and the levels of inflammatory factors, IgE, ROS production, caspase 1, caspase 3, cleaved caspase 1/caspase 1, and cleaved caspase 3/caspase 3 increased in OVA + MDSC group, while the percentage of macrophages, IL-12, and IFN-γ levels reduced, illustrating that MDSCs exacerbated asthma. Conclusion. Our study indicated that MDSCs could aggravate asthma by regulating the Th1/Th2/Th17 response. [ABSTRACT FROM AUTHOR]