Recurrent aphthous stomatitis (RAS) is a common painful, ulcerative oral inflammatory disorder with unknown aetiology. Immune system and aberrant cytokine cascade deemed to be critical in outbreaks of RAS ulcers. Interleukin-1 (IL-1) and IL-6 are the most potent pro-inflammatory cytokines. Single nucleotide polymorphisms (SNPs) of IL-1 and IL-6 genes can affect the secretion of these cytokines. The aim of this study was to investigate the association between RAS and IL-6 and IL-1 in Iranian subjects with minor RAS. Genomic DNA was obtained from 64 Iranian patients with RAS. IL-1α C -889 T, IL-1β C -511 T, IL-1β C +3962 T, IL-1R C pst-I 1970 T, IL-1Ra C Mspa-I11100 T, IL-6 C -174 G and IL-6 A nt +565 G polymorphisms were determined using polymerase chain reaction with sequence-specific primers (PCR-SSP). The frequency of C -174 C genotype in the patients group was significantly different from the healthy control. No other significant differences were found in genotype and alleles frequencies between the two groups. These results indicate that certain SNPs of IL-6 gene at position -174 which located in promoter have association with predisposition of individuals to RAS.

Considering the high frequency of the presence of NLRP3 rs3806265 TT genotype in patients with RAS, it seems that this gene polymorphism could affect individual susceptibility to RAS.

Recurrent aphthous stomatitis (RAS) is a common oral inflammatory disease with unknown etiology in which the immune system seems to have a role in oral tolerance. Interleukin (IL)-10 is a cytokine synthesis inhibitory factor. Single nucleotide polymorphisms (SNPs) of IL10 gene could alter this cytokine production. The aim of this study was to investigate frequencies of IL10 alleles and genotypes in a group of individuals with RAS. Genomic DNA of 60 Iranian patients with RAS were typed for IL10 gene (C/A -1082, C/T -819, and C/A -592), using PCR-SSP method. Frequency of each allele and genotype was compared to control group. A significantly higher frequencies of the T allele at position -819 (p=0.006) and the A allele at position of -592 (p<0.001) were found in the patients with RAS group, when compared to the controls. IL10 GA genotype at position -1082 (p=0.007), CA genotype at position -592 (p=0.001), and CT genotype at position -819 (p=0.001) were significantly higher in the RAS patients. The results of this study suggest that certain SNPs of IL10 gene have association with predisposition of individuals to RAS. However, further multicenter studies should be conducted to confirm the results of this study.