Associations of IL-4, IL-6, and IL-12 levels in peripheral blood with lung function, cellular immune function, and quality of life in children with moderate-to-severe asthma

BACKGROUND: Pediatric asthma has gained increasing concerns with poorly understood pathogenesis. The purpose of this study was to explore the associations of interleukin-4 (IL-4), IL-6, and IL-12 levels in peripheral blood (PB) with lung function, cellular immune function, and children's quality of life (QOL) with moderate-to-severe asthma. METHODS: A total of 1158 children with moderate-to-severe asthma (the experimental group) and 1075 healthy children (the control group) were recruited for our study. Enzyme-linked immunosorbent assay was used to detect IL-4, IL-6, and IL-12 levels. T lymphocytes were detected by alkaline phosphatase antialkaline phosphatase, and erythrocyte immune was measured by red blood cell C 3b receptor (RBC-C3bR) rosette-forming test. The forced expiratory volume in 1 second (FEV1) and peak expiratory flow (PEF) were detected, after which FEV1/forced vital capacity (FVC) was calculated before and after treatment. PedsQL3.0 was used to measure the effect of asthma on QOL of children, and the correlation between IL-4, IL-6, and IL-12 levels and the lung function and QOL was measured. Logistic regression analysis was applied to detect related factors of moderate-to-severe asthma of children. RESULTS: After treatment, the decreased IL-4 and IL-6 levels and increased IL-12 level were revealed in the experimental group. The cellular immune function's disorder was significantly decreased, and an elevated CD(3), CD(4), CD(8), and declined CD(4)/CD(8) level was performed in T lymphocytes. RBC-C3bR was increased, and red blood cell immune complex (RBC-IC) was reduced in erythrocyte immune in comparison with those before treatment. Lung function parameters all increased. After treatment, the symptoms of asthma in children reduced with scores of increased QOL. IL-4 was positively related to RBC-IC, but negatively associated with the QOL score. IL-6 showed negative connection with CD(4)/CD(8), RBC-C3bR, FEV1/FVC, and QOL score, and had positive connection with PEF. In addition, IL-12 was negatively correlated with PEF. The levels of IL-4, RBC-C3bR, FEV1/FVC, and PEF were independent risk factors for the prognosis of treatment for children with moderate-to-severe asthma. CONCLUSION: This study demonstrated that IL-4, IL-6, and IL-12 levels in PB were associated with lung function, cellular immune function, and QOL in children with moderate-to-severe asthma.