Association of IL-33, IL1RL1 gene polymorphisms with serum IL-33 levels and risk of asthma in adults and asthmatic bronchitis in children (Chinese)

Figures & data

Table 1. PCR primers used in this study.

SNP	Primers
rs16924159	Forward 5'-ACGTTGGATGCAAAGTATGTGAGGCATGGG-3’ Reverse 5’-ACGTTGGATGACTTTCCAGCTGGCCTGTG-3’ Extension primer 5’-GTTCAGTCACACTAAAACT-3’
rs928413	Forward 5’- ACGTTGGATGGATTCCATGGAGAGATTAGC-3’ Reverse 5’-ACGTTGGATGAATACAGATTCCCTGCCTTG-3’ Extension primer 5’-CGTAGTTAGCTACTTTTTAATAGTTAC-3’
rs1420102	Forward 5’-ACGTTGGATGGATTGGTCAGGAACTCAAAC-3’ Reverse 5’-ACGTTGGATGGGTTGCTTCTAGCTATTGAC-3’ Extension primer 5’-AACTCAAACAAATACTTGGACAC-3’
rs13431828	Forward 5'-ACGTTGGATGCTCGTTGTTGAGATTACTCC-3’ Reverse 5’-ACGTTGGATGGAAGAGTATCACCAACTGCC-3’ Extension primer 5’-ACAGATGAGTCACTGGCATAC-3’

Table 2. Demographics of patients with asthma and controls.

Variables	Controls N = 277 (%)	Asthmatic patients n = 279 (%)
Age (years, mean ± SD)	17.71 ± 17.44	23.50 ± 28.32
Sex
Male	148 (53.4)	140 (50.2)
Female	129 (46.6)	139 (49.8)
IL-33, pg/mL	(n = 59) 11.95 ± 3.92	(n = 70) 22.80 ± 28.49

N Number of subjects; % percentage of sex composition; SD standard deviations; NS not significant.

Figure 1. Serum IL-33 levels in participants with asthma and control subjects.

Table 3. Main characteristics of the four SNPs in the study.

SNP	Position	Region	GSR(%)^a	Alleles^b	MAF^c	ObsHET^d	PredHET^e
rs16924159	6229 417	intron	100	G:A	0.321	0.387	0.436
rs928413	6213 387	promoter	100	A:G	0.076	0.149	0.141
rs1420102	102332 359	intron	99.8	C:T	0.467	0.472	0.498
rs13431828	102338 193	5’UTR	99.8	C:T	0.095	0.171	0.171

^a Genotyping success rate; ^bMinor allele/major allele; ^cMinor allele frequency; ^dObserved heterozygous alleles; ^ePredicted heterozygous alleles.

Figure 2. Mass spectrum scatter plot of rs16924159 (a) and rs928413 (b).

Table 4. Genotype and allele frequency distributions of rs16924159, rs1420102, rs1946131and rs13431828 in patients with asthma and controls.

SNP	Model	Case N = 279(%)	Control N = 277(%)	OR (95% CI)	P-value
rs16924159(IL-33)	Allele
	G	372(66.7)	383(69.1)	1(Reference)
	A	186(33.3)	171(30.9)	1.120(0.870–1.441)	0.378
	Genotype
	GG	141(50.5)	129(46.6)	1(Reference)
	AG	90(32.3)	125(45.1)	0.659(0.459–0.945)	0.023*
	AA	48(17.2)	23(8.3)	1.909(1.100–3.314)	0.022*
	AG+AA	138(49.5)	148(53.7)	0.853(0.612–1.190)	0.349
rs928413 (IL-33)	Allele
	A	333(92.5)	323(92.8)	1(Reference)
	G	27(7.5)	25(7.2)	1.048(0.595–1. 843)	0.872
	Genotype
	AA	154(85.6)	149(85.6)	1(Reference)
	AG	25(13.9)	25(14.4)	0.968(0.532–1.760)	0.914
	GG	1(0.6)	0(0.0)
	AG+GG	26(14.4)	25(14.4)	1.006(0.556–1.821)	0.984
rs1420102(IL1RL1)	Allele
	C	277(49.6)	315(56.9)	1(Reference)
	T	281(50.4)	239(43.1)	1.337(1.056–1.693)	0.016*
	Genotype
	CC	74(26.5)	91(32.9)	1(Reference)
	CT	129(46.2)	133(48.0)	1.193(0.807–1.763)	0.377
	TT	76(27.2)	53(19.1)	1.763(1.107–2.810)	0.017*
	CT+TT	205(73.5)	186(67.1)	1.355(0.941–1.953)	0.103
rs13431828(IL1RL1)	Allele
	C	497(89.4)	508(91.7)	1(Reference)
	T	59(10.6)	46(8.3)	1.311(0.875–1.965)	0.190
	Genotype
	CC	223(80.2)	232(83.8)	1(Reference)
	CT	51(18.3)	44(15.9)	1.206 (0.774–1.878)	0.408
	TT	4(1.4)	1(0.4)	4.161(0.462–37.520)	0.204
	TT+CT	55(19.8)	45(16.2)	1.272 (0.823–1.964)	0.279

Figure 3. Serum levels of IL-33 with three genotypes of rs16924159 in healthy controls (a) and asthmatic patients (b).