Significance of Natural Killer Cell Subsets, their Receptors, and Inflammatory Cytokines in Peripheral Blood of Children with Hand, Foot, and Mouth Disease

Background Hand, foot, and mouth disease (HFMD) is a self-limited disease caused mainly by enterovirus 71 and coxsackievirus A16; however, some cases have severe neurological complications, pulmonary edema, and fetal death. In this study, we analyzed the changes in natural killer (NK) cell subsets, their receptors, and serum inflammatory cytokines in children with HFMD. Methods Peripheral blood samples were collected from 70 HFMD pediatric patients admitted Department of Infectious Diseases of our hospital from July 2016 to November 2017 and from 16 healthy children receiving physical examination in the disease control and prevention center as the healthy control group. The changes in three NK cell subsets and their receptors, and serum inflammatory cytokines were detected via flow cytometry. Results The distribution of CD3-CD16+CD56+ and CD3-CD16+CD56- NK cell subsets in the HFMD group increased significantly compared with that in the healthy control group, while CD3-CD16-CD56+ NK cell subset showed no significant difference in the two groups. Besides, the distribution of the CD3-CD16+CD56+ NK cell subset was significantly higher than the CD3-CD16+CD56- NK cell subset. The distribution of the NKG2A receptor on the CD3-CD16+CD56+ NK cell subset in the HFMD group was significantly higher than that in the healthy control group. Moreover, the serum levels of IL-17A, IL-10, IL-6, and IL-2 in the HFMD group were higher than those in the healthy control group. Conclusions The results showed that the positive distribution of NKG2A in the NK cell subset and the content of inflammatory cytokines could be of diagnostic value for early detection of HFMD in patients and prediction of the severity of the disease.