Objective: Pneumonia is a common disease in infants that has been a major cause of death in children worldwide. Although studies have suggested that T cell subsets and cytokines in the Bronchoalveolar Lavage Fluid (BALF) may reflect the severity of pneumonia, the exact connection remains un-clarified. This study aimed to elucidate the changes of T cell subsets and cytokines in BALF in paediatric pneumonia.
Patients and Methods: A total of 90 cases of pneumonia children who were examined in our hospital between January 2015 and January 2016 were selected in this study. The patients were divided into mild-to-moderate (n=36) and severe pneumonia group (n=54). Thirty children without any lung diseases were used as controls. The bronchial secretion was collected and analyzed by flow cytometry to determine the expression of surface activation marker of CD3+ T cell subpopulation (CD69, CD25 and HLA-DR). The expression of IL-6, IL-17 and HMGB1 was measured by ELISA.
Results: The expression of CD69, CD25 and HLA-DR in BALF in patients was significantly higher compared with controls (P=0.033). The level of IL-6, IL-17 and HMGB1 in patients was also significantly higher than that in control (P=0.026). The expression of CD69, CD25 and HLA-DR as well as IL-6, IL-17 and HMGB1 in severe pneumonia group was significantly higher compared with mild-tomoderate pneumonia group (P <0.05).
Conclusions: The significant increase in the surface activation markers and cytokines in BALF suggested the immune dysfunction in pneumonia patients. The positive correlation between cytokine expression and the severity of pneumonia indicated their role as biomarkers in immunotherapy.