OX40/OX40L signaling pathway gene variants and preeclampsia risk: a case-control study with combined genotype analysis

Preeclampsia (PE) is a serious pregnancy disorder with a complex immunological basis. The OX40/OX40L interaction plays a critical role in T-cell activation, survival, and immune regulation. This study investigated the association between OX40 rs17568 and OX40L rs1234313 polymorphisms and PE susceptibility in an Iranian population. This case-control study included 560 pregnant women (280 with PE and 280 normotensive controls) from Zahedan, southeastern Iran. Genotyping was performed using PCR-RFLP. Demographic and clinical data were recorded. Associations were assessed using logistic regression to calculate odds ratios (ORs) with 95% confidence intervals (CIs). Bonferroni correction was applied for multiple comparisons separately for each analysis table (Table 2 total: α = 0.005; Table 2 subgroups: α = 0.0025; Table 3: α = 0.0025; Table 4, and 5: α = 0.002–0.003). Hardy-Weinberg equilibrium (HWE) was tested for both polymorphisms. The two groups were well-matched for age, body mass index, and family history of PE ( p > 0.05 for all comparisons). For OX40L rs1234313, carriers of the GA and AA genotypes showed a significantly increased risk of PE compared to those with the GG genotype, with adjusted ORs of 1.85 ( p < 0.001) and 2.22 ( p = 0.003), respectively. The A allele was also associated with higher PE susceptibility (OR = 1.55, p < 0.001). For OX40 rs17568, the GA genotype was associated with a nominally significant decreased risk of severe PE (OR = 0.58, p = 0.017), though this did not survive Bonferroni correction. Subgroup analysis based on disease severity and onset timing revealed stronger associations for OX40L rs1234313 in mild and early-onset PE cases. Combined genotype analysis showed that the GG-GA combination (OX40 GG and OX40L GA) was associated with a 3.8-fold increased risk of total PE and a 4.9-fold increased risk of severe PE; however, these findings should be interpreted with caution due to small sample sizes in some subgroups. All genotype distributions were in HWE in the control group. This study provides the first evidence that OX40L rs1234313 is significantly associated with PE susceptibility in an Iranian population. The A allele of OX40L rs1234313 confers increased risk, while specific combinations of OX40 and OX40L variants may modulate PE risk. However, these findings are preliminary and require replication in independent cohorts and functional validation.