Interleukin-4 gene polymorphism is not involved in the risk of recurrent pregnancy loss

PROBLEM: Enhanced secretion of type-2 T-helper (Th2) cytokine is a characteristic feature in normal physiological pregnancy. A study has demonstrated defective production of interleukine-4 (IL-4) and other Th2 cytokine in women with recurrent pregnancy loss (RPL). Several studies have suggested that IL-4 variable number of tandem repeat (VNTR) gene polymorphism is probably associated with different IL-4 production. METHODS OF STUDY: The IL-4 VNTR genotypes were assessed in 109 Japanese women with RPL and 210 ethnically matched women experiencing at least one live birth and no spontaneous abortion. RESULTS: No significant differences in IL-4 VNTR genotype frequencies were found between the RPL and the control [B1B1 genotype (reference); B1/B2 and B2/B2 genotypes, odds ratio, 0.91; 95% confidence interval, 0.58-1.45]. CONCLUSION: The present study suggests that the IL-4 VNTR allele is not a major genetic regulator in RPL.