Elevated Serum Levels of Thymic Stromal Lymphopoietin in Wheezing Children Infected with Human Metapneumovirus.

Our aim was to study the epidemiology and clinical manifestations of human metapneumovirus (hMPV) infection in children in the Suzhou area, China, and to investigate the effect of thymic stromal lymphopoietin (TSLP) on wheezing in hMPV-infected children. The study included 13,533 children with respiratory tract infections who were admitted to the Children's Hospital of Soochow University between January 2009 and December 2014. Clinical data were recorded. Plasma levels of TSLP, interleukin (IL)-4, and IL-2 were compared among 35 wheezing children with single hMPV infection, 15 non-wheezing children with hMPV infection, and 35 wheezing children with other viral infections. The annual rates of hMPV infection from 2009 to 2014 were 2.33%, 6.41%, 3.29%, 3.52%, 0.23%, and 0.64%, respectively, peaking in 2010. The number of CD3-/CD16+/CD56+ cells was significantly lower in inpatients with hMPV infection than that in patients with other viral infections. Serum levels of TSLP and IL-4 in wheezing children with hMPV infection were significantly higher than the levels in the other 2 groups. hMPV is a common viral pathogen that causes respiratory infections in children in Suzhou, but annual rates have declined since 2010. Infection with hMPV may affect cell-mediated immunity. Serum TSLP levels were elevated after hMPV infection.