[Expression of interferon-λ1 in respiratory epithelial cells of children with RSV infection and its relationship with RSV load].

OBJECTIVE: To investigate the expression of IFN-λ1 in respiratory epithelial cells of children with respiratory syncytial virus (RSV) infection and its relationship with RSV load. METHODS: The nasopharyngeal swabs were collected from the children who were hospitalized with respiratory tract infection from June 2015 to June 2016. A direct immunofluorescence assay was used to detect the antigens of seven common respiratory viruses (including RSV) in the nasopharyngeal swabs. A total of 120 children who were only RSV positive were selected as the RSV infection group. A total of 50 children who had negative results in the detection of all viral antigens were selected as the healthy control group. Fluorescence quantitative real-time PCR was used to determine the RSV load and the expression of IFN-λ1 mRNA in the nasopharyngeal swabs of children in the two groups. RESULTS: The expression of IFN-λ1 in the RSV infection group was significantly higher than that in the healthy control group (P<0.05). The expression of IFN-λ1 was positively correlated with RSV load (r=0.56, P<0.05). CONCLUSIONS: RSV can induce the expression of IFN-λ1 in respiratory epithelial cells, suggesting that IFN-λ1 may play an important role in anti-RSV infection.

[A preliminary study on the disappearance time of influenza virus antigen].

OBJECTIVE: To investigate the antigen clearance time, time to symptom disappearance, and the association between them using immunofluorescence assay for dynamic monitoring of influenza virus antigen in children with influenza. METHODS: A total of 1 063 children suspected of influenza who visited the Hunan People's Hospital from March to April, 2016 were enrolled. The influenza A/B virus antigen detection kit (immunofluorescence assay) was used for influenza virus antigen detection. The children with positive results were given oseltamivir as the antiviral therapy and were asked to re-examine influenza virus antigen at 5, 5-7, and 7 days after onset. RESULTS: Of all children suspected of influenza, 560 (52.68%) had an influenza virus infection. A total of 215 children with influenza virus infection were followed up. The clearance rate of influenza virus antigen was 9.8% (21 cases) within 5 days after onset. The cumulative clearance rate of influenza virus antigen was 32.1% (69 cases) within 5-7 days, and 98.1% (211 cases) within 7-10 days after onset. Among these children, 6 children (2.8%) achieved the improvement in clinical symptoms within 3 days after onset. The cumulative rate of symptom improvement was 84.7% (182 cases) within 3-5 days after onset, and 100% achieved the improvement after 5 days of onset. CONCLUSIONS: The time to improvement in symptoms after treatment is earlier than antigen clearance time. Almost all of the children achieve influenza virus antigen clearance 7-10 days after onset. Therefore, it is relatively safe for children to go back to school within 7-10 days after onset when symptoms disappear.