Associations of IL-2 and IL-4 Expression and Polymorphisms With the Risks of Mycoplasma pneumoniae Infection and Asthma in Children.
BACKGROUND
Asthma is an inflammatory disorder of the airways and the symptoms of asthma could be exacerbated by Mycoplasma pneumoniae infection. Interleukin-2 and interleukin-4 have been implicated in immune and inflammatory reactions. We examined the associations of IL2 and IL4 polymorphisms and expression with the risks of asthma and M. pneumoniae infection in children.


METHODS
392 asthmatic children and 849 controls were recruited into the study. Eight polymorphisms in IL2 and IL4 were genotyped with Sequenom MassARRAY platform. M. pneumoniae infection and copy number was determined with fluorescence PCR. IL-2 and IL-4 serum expression levels were determined by using ELISA.


RESULTS
We found a significant association of IL2 rs6534349 polymorphism with increased asthma risk (heterozygotes, P=.029; homozygous variants; P=.013) and of IL4 rs2227284 polymorphism with reduced asthma risk (heterozygotes, P=.026; homozygous variants; P=.001). Besides, the association of other polymorphisms, except rs2070874 polymorphism, became apparent when the asthmatic children were grouped according to GINA classification of asthma control and severity. In addition, IL-2 and IL-4 serum expression levels were significantly higher in M. pneumoniae negative (P=.038) and positive (P=.011) subjects respectively. This observation holds true among asthmatic patients (P=.016 for IL-2 and P=.042 for IL-4), but only the IL-4 observation remained correct among non-asthmatic controls (P=.032). We also observed that the rs6534349 GG genotype was significantly associated with increased odds of getting high load M. pneumoniae infection (P=.0376).


CONCLUSIONS
IL2 and IL4 could be important biomarkers for estimating the risks of asthma and M. pneumoniae infection in children.
Department of Pediatrics, Yiwu Maternity and Child Care Hospital, Zhejiang, China.
Rong-Shan
RS
Wang
Department of Pediatrics, Yiwu Maternity and Child Care Hospital, Zhejiang, China.
Hong-Xing
HX
Jin
Department of Pediatrics, Laboratory of the Children's Hospital of Zhejiang Province, Zhejiang, China. Electronic address: shiqiangshang945@gmail.com.
Shi-Qiang
SQ
Shang
Department of Pediatrics, Yiwu Maternity and Child Care Hospital, Zhejiang, China.
Xi-Yong
XY
Liu
Department of Pediatrics, Yiwu Maternity and Child Care Hospital, Zhejiang, China.
Shu-Jun
SJ
Chen
Department of Pediatrics, Yiwu Maternity and Child Care Hospital, Zhejiang, China.
Zhi-Biao
ZB
Jin
D000293:Adolescent; D001249:Asthma / Q000453:epidemiology / Q000235:genetics*; D001980:Bronchi / Q000382:microbiology; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis / Q000097:blood / Q000235:genetics*; D015847:Interleukin-4 / Q000096:biosynthesis / Q000097:blood / Q000235:genetics*; D008297:Male; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification; D010614:Pharynx / Q000382:microbiology; D011019:Pneumonia, Mycoplasma / Q000453:epidemiology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012306:Risk; D013183:Sputum / Q000382:microbiology
C508598:IL4 protein, human; D007376:Interleukin-2; D015847:Interleukin-4
Asma; Asthma; Children; Interleucina-2; Interleucina-4; Interleukin-2; Interleukin-4; Mycoplasma pneumoniae; Niños