Objective: Gestational trophoblastic diseases (GTDs) consist of a spectrum of disorders characterized by an abnormal proliferation of trophoblastic tissue. IL-18 is a pleiotropic cytokine with a capacity for both ThI and Th2 polarization. Considering the association of IL-18 promoter polymorphisms at positions -607 (A/C) and -137 (C/G) with pregnancy events and some cancers, we sought to examine these polymorphisms in Iranian patients with GTD, their association with disease subtypes, and IL-18 serum level.
Study design: Single nucleotide polymorphisms (SNPs) were analyzed by allele-specific polymerase chain reaction in 92 patients with GTDs and 103 healthy pregnant controls. IL-18 serum level was determined using ELISA method.
Results: No significant association was found between the allele, genotype, genotype combination and haplotype distribution of these SNPs and GTDs or its subgroups. Mean IL-18 serum level was significantly higher in patients with choriocarcinoma and pregnant controls compared with nonpregnant controls (p = 0.04, 0.04 and 0.001, respectively). -137 GG genotype pregnant controls had a significantly higher IL-18 serum level compared with CC genotype.
Conclusion: IL-18 promoter polymorphisms do not confer susceptibility to GTDs or its variants; however, their functional significance is demonstrated in this study. Furthermore, IL-18 serum level increases in GTDs and in normal pregnancy.