Association of interferon-gamma gene polymorphisms with susceptibility to oral lichen planus in the Thai population.

OBJECTIVE

Interferon-gamma (IFN-γ) is highly expressed in oral lichen planus (OLP). The IFN-γ (+874 in intron 1, rs2430561) TT genotype, which has been reported to be associated with high IFN-γ production, was hypothesized to be associated with susceptibility to OLP in the Thai population.

DESIGN

Genomic DNA samples from 74 OLP and 268 healthy controls were evaluated for IFN-γ polymorphisms by polymerase chain reaction with sequence-specific primers (PCR-SSP) and direct sequencing method.

RESULTS

The T allele was significantly associated with an increased risk of OLP development as compared to the A allele (OR=1.76, P=0.004; P(c)=0.02). The effect of the T allele was similar to an autosomal recessive disorder; the presence of TT genotype (when compared to AA and AT) conferred an OR of 2.61, P=0.008; P(c)=0.04.

CONCLUSIONS

We found an association between IFN-γ +874A/T polymorphism and susceptibility to OLP. However, an association study utilising a larger sample size and patients from other races apart from the Asian population should be performed to further verify these findings.