Introduction: Recurrent aphthous stomatitis (RAS) is a disorder, which is characterized by ulcers restricted to oral mucousa. Regarding the inspection of histological similarities between peptic ulcers and recurrent oral aphthous and the response of RAS to the broad-spectrum antibiotic treatment such as tetracycline and the identified role of H.pylori in peptic ulcers, the possibility of bacterial involvement in the progression of oral aphtous ulcers has been suggested. Hence, there are limited evidence available for colonization of H. pylori and its probable role in induction of oral aphthouse ulcers.Objective: We aimed to distinguish the probable presence of H.pylori in brushed sample of oral aphthous ulcers by PCR method. Materials and Methods: In this study, we sampled the oral aphtous ulcers with the toothbrush in patients with RAS. PCR which is a very precise and sensitive technique for isolation of H. pylori in ulcer samples of recurrent aphthous stomatitis and in samples from other parts of the oral cavity. Serologic tests such as ELISA were also done in all patients for determination of IgG antibody. Both PCR and ELISA were done in all patients. Evaluated patients were people presenting to the laboratory with the diagnosis of RAS, from the beginning of 2001 till the end of 2002.Results: Study patients were between 18 to 60 years old and the average age among them was 32/38 ± 11/30. 26 patients (52%) had positive ELISA test and we obtained H.pylori DNA in one patient (2%) in a total of 50 evaluated patients.Conclusion: According to the results of this study, H. Pylori DNA cant be found in aphthous ulcers of these patients, even in those with positive anti H. Pylori, anti body (IgG) results. And it is probable that these bacteria aren't involved in oral recurrent aphthous ulcers.

Background: Recurrent Aphthous Stomatitis (RAS) is a common oral inflammatory disease with unknown pathogenesis. Although the immune system alterations could be involved in predisposition of individuals to oral candidiasis, precise ethiologies of RAS have not been understood yet. Considering the inflammatory nature of interleukin (IL) -17F and RAS, we aimed to sequence the gene in a number of patients with RAS to identify any disease-associated mutation.Methods: Sixty-two Iranian patients with RAS and fifty healthy subjects enrolled in this study. After DNA extraction from the whole blood, amplification was accomplished by polymerase chain reaction for IL-17F.Finding: The results of sequencing revealed a missense, heterozygous mutation, converting a threonine to proline in a patient with RAS. The Polyphen software suggested a damaging probability predicting this substitution to have a harmful effect on IL-17F protein function. Nevertheless, this substitution was predicted to change the β-aggregation propensity using TANGO software. Such mutation was not detected in any control subject. In addition, one of the IL-17F SNPs is associated with the RAS.Conclusion: This is a first study showing a mutation that seems to be associated with susceptibility to RAS. Further studies on more patients with RAS are required to confirm this finding.

Recurrent aphthous stomatitis (RAS) is a common oral disorder that despite extensive researches, the etiology of this phenomenon is still unknown. Because this phenomenon has been observed more often in families than in individual cases, genetic influence has been investigated in most researches.Purpose: The aim of the present study was to evaluate the association between Human Leukocyte Antigen (HLA) and aphthous stomatitis more precisely.Materials and Methods: In this study, 60 patients with RAS were examined for HLA-A and HLA- B types and 37 of them were examined for HLA- DR and HLA-DQ types. The results were compared through Fisher test with those of 25 healthy control subjects, aged more than 30 years.Results: A significant decrease in the frequency of some antigens such as HLA-DQW 3 and HLA-A 26 in subjects with RAS was observed. Therefore, according to the results of this study, these antigens were considered as resistant antigens to recurrent aphthous stomatitis. In contrast, there was no significant increase in the frequency of any HLA antigens in the test group, compared to the control group. This finding is in contrast with the multiple reports about Behest's disease. (Because a high frequency of HLA-B 51 has been found in Behcet"s syndrome.)Conclusion: According to the findings of this study, it is suggested that the pathogenicity of aphthous ulcerations in Behest's disease and recurrent aphthous stomatitis is not the same. However, further studies are necessary to prove this theory.