Association of polymorphisms in the human IFN-λ and IL-4 gene with oral lichen planus:: A study in an ethnic Chinese cohort

Cytokines have an important role in the pathogenesis and disease progression of oral lichen planus (OLP). The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-gamma) and interleukin- 4 (IL-4), on OLP in an ethnic Chinese cohort. We investigated IFN-gamma gene (IFNG) and IL-4 gene (IL-4) polymorphisms in 151 patients with OLP and 143 healthy controls using the polymerase chain reaction with sequence-specific primers (PCR-SSP) method. Each genotype was also validated by direct DNA sequencing methods to further guarantee the significance of our findings. The data revealed that there were highly significant increases in +874 IFNG2 genotype distributions and allele T frequencies in both the OLP patient group (p = 0.033, 0.003) and the more progressive subtype group (eOLP) (p = 0.013, 0.001) compared with those of normal controls There was no difference between the OLP patient and healthy control groups in frequencies of both the IL-4 allele (p = 0.053) and genotype (p = 0.197), although the frequencies of the IL4-590 C allele (p = 0.001) and the CC genotype (p = 0.024) in patients with nonerosive OLP (neOLP) were significantly greater than the corresponding values in the control group. Our study suggests that IFN-gamma and IL-4 gene polymorphisms seem to have a positive influence on disease susceptibility and progression of OLP in this ethnic Chinese cohort.