Association between -308 G/A polymorphism in TNF-α gene and lichen planus: A meta-analysis

SummaryBackgroundDifferent studies have conflicting opinions on the association between the -308 G/A polymorphism in TNF-α gene and genetic risk of lichen planus (LP).ObjectiveThe purpose of this meta-analysis is to comprehensively evaluate interactions on this polymorphism and LP risk.MethodsA meta-analysis was employed to assess genetic risk of -308 G/A polymorphism in TNF-α gene for lichen planus. Odds ratios (ORs) with 95% confidence intervals (CIs) were also included.ResultsFive studies including 8 comparisons were involved in this meta-analysis. The result showed that no association was found between this polymorphism and LP risk in combined analyses (OR = 1.42 and 95% CI = 0.85–2.37, P = 0.180 for AA + GA vs. GG model). In the subgroup analysis by subtypes of LP (cutaneous LP and OLP) and OLP (eOLP, neOLP and mixed), no significant connections of risks were obtained from the two groups for AA + GA vs. GG comparison. In the subgroup analysis by ethnicity, significant increased OLP risks were found among population with mixed ethnicity (OR = 3.26, 95%CI = 1.46–7.26, P = 0.004), but not in Asians (OR = 1.19, 95%CI = 0.69–2.05, P = 0.528) and Caucasians (OR = 1.32, 95%CI = 0.41–4.27, P = 0.645) for AA + GA vs. GG comparison. For the population presence or absence of hepatitis C virus (HCV) infection, significant increased risk of OLP was found among patients without HCV infection (OR = 2.16, 95%CI = 1.05–4.43, P = 0.037), but not in LP–HCV +ve patients (OR = 0.48, 95%CI = 0.13–1.69, P = 0.251) and mixed HCV status LP patient (OR = 1.24, 95%CI = 0.62–2.50, P = 0.546). However, the negative results could have been biased because some included papers were lack of some information, which mainly related to HCV-status and clinical variety. That is the limitation of this meta-analysis.ConclusionsThe -308 G/A polymorphism may be a risk factor for OLP patients without HCV infection and those with mixed ethnicity. More studies are needed to validate these associations.