Interleukin-33 in children with asthma: A systematic review and meta-analysis.

BACKGROUND: Previous studies have shown that serum interleukin 33 serving as an "alarmin" is increased in children with asthma. The objective of this study was to assess the validity of serum IL33 test for early diagnosis of childhood asthma.

METHODS: A literature search was performed in June 2016 using PubMed, Embase, the Cochrane Library and other Chinese Medical Databases to identify studies. The search terms used were "cytokine", "interleukin-33", "asthma" and "children". The meta-analysis was performed using Review Manager 5.3 software. Random-effects model was used to estimate the standardized mean differences (SMDs) with 95% confidence intervals (CIs).

RESULTS: A total of eight studies were included into this meta-analysis, involving 330 asthmatic children and 248 healthy children. The meta-analysis results revealed that the serum IL33 level was higher in asthmatic children compared to that in healthy children (SMD=1.29, 95%CI=0.53-2.05, P=0.0009), with significant heterogeneity across studies (I2 =94% and P<0.00001).

CONCLUSIONS: The meta-analysis showed that serum IL33 is a helpful biomarker for early diagnosis of childhood asthma. However, owing to lack of enough data, the increased serum concentration of IL33 cannot be an indicator for the asthma severity.