The Th1:Th2 Dichotomy of Pregnancy and Preterm Labour

Table 1

Cytokine polymorphism associations with preterm labour (PTL).

Gene	Polymorphism	Th1/Th2	Function	Reference
IFN-γ	+874A>T	Th1	Classic Th1 cytokine. Proinflammatory. No clear association between IFN-γ polymorphisms and PTL	[104, 105]
TNF-α	−308G>A	Th1	Regulatory role in PG synthesis elevated at maternal fetal interface controversial link between PTL and TNF-α polymorphisms	Refute association [104, 106, 107]; Support association [108, 109]
IL-4	−590	Th2	Classic Th2 cytokine. The IL-4 590 C/C genotype is associated with preterm birth but unclear. IL-4-590 SNP has been associated with both low and high IL-4 expression. Link also exists between IL-4 promoter polymorphisms and preterm birth in multiple pregnancies; however, polymorphism actually associated with increased IL-4	[110, 111]
IL-10	−1082G>A; −819C>T; −592C>A	Th2	Anti-inflammatory Th2 cytokine inhibits production of cytokines, chemokines, and prostaglandins in LPS stimulated amnion, choriodecidual, and placental explants [112–114]. However, no clear association between IL-10 polymorphisms and PTL or adverse neonatal outcome	[104–106, 115].