Tumour necrosis factor alpha gene polymorphisms in women with recurrent pregnancy loss: a meta-analysis

Role of tumor necrosis factor-alpha -238 G>A promoter region polymorphism on recurrent miscarriage: An association study and meta-analysis

BACKGROUND

Recurrent miscarriage (RM) is defined as the loss of two or more consecutive pregnancies. A functional SNP, -238G>A in the promoter region of TNF-α, affects the gene transcription activity with implications on human pregnancy. Previous limited studies, linking the TNF-α -238 G>A to the risk of recurrent miscarriage have been inconclusive.

MATERIAL AND METHOD

The PCR-RLFP technique was used to evaluate this polymorphism in 199 RM cases and 215 control women from Amritsar, Punjab. For a meta-analysis, a total of 13 eligible studies (including the present study) comprising 2947 cases and 2933 controls were included. To evaluate the association among different genetic models, odds ratio with a 95% confidence interval (CI) and chi-square were used.

RESULTS

Genotype and allelic frequency did not differ significantly between both groups (p = .07 and p = .24, respectively). In the present meta-analysis, a significant association was found with the recessive model (OR-1.78 CI:1.24-2.55, p = .002).

CONCLUSION

Although, TNF-α -238 G>A polymorphism did not provide any risk in the case-control study but provided risk towards the development of RM with the recessive genetic model in the pooled analysis.

Impact of TNF-α profile in recurrent pregnancy loss pathogenesis: A patient based study from Assam

BACKGROUND

Lacunae exist in understanding the underlying etiology in majority of recurrent pregnancy loss (RPL) cases. Given the significance of regulated immune-modulation in pregnancy, and the central role of pro-inflammatory TNF-α plays in it; this study targeted to appraise the significance of TNF-α profile in RPL pathogenesis in an ethnically distinct population from Assam, India.

METHODS

Term delivery, medically terminated pregnancy (MTP) and RPL cases (based on ASRM criteria) were enrolled with no anatomical and chromosomal abnormalities or pathological infections; and blood and/or placenta/product of conceptus (POC) tissue samples were collected with informed consent. Serum level and tissue level TNF-α expression profile were screened using specific molecular tools, and was correlated with TNF-α -308 G/A genotype; for its association with RPL predisposition.

RESULTS

A significant gestation specific increase in serum TNF-α levels was observed in MTP cases (19.932 ± 4.407 pg/mL) compared to term delivery subjects (p = 0.001), while a comparable levels were observed with RPL cases (22.709 ± 5.833 pg/mL) (p = 0.646). A site specific (POC) increased expression was observed in RPL compared to MTP cases at both at transcript (6.37 ± 3.714 folds) and protein levels. The TNF-α -308 variant genotype was associated with increased predisposition to RPL (OR = 1.721) compared to MTP as well as significantly increased serum TNF-α levels (p = 0.017); especially in subjects with a homozygous TNF-α -308 A/A genotype.

CONCLUSION

Our data emphasizes on the importance of site specific TNF-α expression levels in RPL pathogenesis in the studied population, and underlines its importance in screening, clinical stratification, and therapeutics by molecular targeting using TNF-α inhibitors.