Abstract:Objective To investigatethe clinical levels of serum microRNA-24 (miR-24) mRNA, chitinase-3- like-1 protein (YKL-40) in children with virus infectious pneumonia and their relationship with pulmonary function and clinical outcomes. Methods A total of 117 children (in 2 to 11 years old) with virus infectious pneumonia in our hospital from September 2018 to April 2019 were enrolled into the study. At the same time, 30 healthy children were selected as healthy control group. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect serum miR-24 mRNA. ELISA assay was used to analyze serum YKL-40 protein. The time necessary to reach the peak expiratory flow in tidal breathing over the total expiratory time (tPTEF/tE) was detected in tidalbreath pulmonary function test. Results Compared with control group, there were lower miR-24 mRNA levels and higher YKL-40 protein in children with virus infectious pneumonia (P < 0.05). And there were furtherly lower miR-24 mRNA levels and higher YKL-40 protein levels in severe pneumonia children than that in mild pneumonia children (P < 0.05). After treatment, serum miR-24 mRNA levels in fully recovered or improved children were increasing than before treatment (P < 0.05), meanwhile YKL-40 protein levels were decreasing (P < 0.05). But the differences of miR-24 mRNA and YKL-40 protein before and after treatment in invalid group were lower than those in cured group and effective group (P < 0.05). Before treatment, miR-24 mRNA was negatively related with YKL-40 (r = -0.297, P = 0.000), and positively related with tPTEF/tE (r = 0.422, P = 0.000). Besides, YKL-40 was negatively related with tPTEF/tE (r = -0.394, P = 0.000). Conclusions To a certain degree, miR-24 and YKL-40 would reflect the severity of disease, pulmonary function and clinical effect in children with virus infectious pneumonia, which can be provide a clinical supervision.