Objective To study the changes of T lymphocyte subsets, immunoglobulin and complements in infants with bronchiolitis and explore the immunopathogenesis of bronchiolitis in in-fants. Methods Sixty-seven infants with bronchiolitis (bronchiolitis group) and forty healthy controls (control group) were enrolled in the study. T lymphocyte subsets were determined by indirected im-munofluorescent assay, and while serum levels of immunoglobulin and complements were determined by timing nephelometry. Results The percentage of CD3+ and CD8+ T cells, the concentrations of se-rum lgA and IgM showed no obvious differences between bronchiolitis group and control group (P>0.05). As compared with those of normal group, the percentage of CD4+ T cells and the ratio of CD4+ to CD8+ were significantly higher (P<0.05 or <0.01) and the levels of serum IgG, C3, C4 were significantly lower in bronchiolitis group(P<0.05 or <0.01). Conclusion Immune function disorder and abnormality occurs in infants with bronchiolitis. T lymphocyte mediated immunity may exert an important antiviral effect. The research from the point of view of cell immunity contributes to evaluation of severity of illness and more effective therapy.

Objective: To describe the current reporting of pneumonia of unknown etiology (PUE) and factors that affect reporting by clinicians in China using the PUE surveillance system in order to provide a reference for improving PUE reporting rates in the future. Methods: Clinicians were recruited via the Sojump platform and requested to complete an anonymous self-administered questionnaire. Multivariate logistic regression analysis was used to assess factors influencing clinicians' reporting activities. Results: This study showed a low PUE case reporting rate and a poor understanding of PUE reporting among the investigated clinicians. Of the 136 clinicians who had diagnosed PUE cases, multivariate logistic regression analysis results showed that clinicians who had attended in-hospital training were more likely to report PUE than those who had not (OR 4.48, 95% CI 1.49-13.46). Clinicians with an expert panel on PUE in their hospital were more likely to report PUE cases than those without (OR 5.46, 95% CI 1.85-16.11). Conclusions: There is a need to promote and reinforce PUE surveillance system training among medical staff. In addition, PUE testing technologies in hospital laboratories should be upgraded, especially in primary and unclassified hospitals, to increase surveillance efficiency and improve PUE reporting rates.