Genetic Implications of HLA-DR and HLA-DQ Genotype on Tobacco Smoking and Oral Submucous Fibrosis

Purpose: Integration of genetic information into our understanding of oral diseases has fostered the hope to intervene the disease process among genetically susceptible individuals. Oral submucous fibrosis (OSF) (mainly in the Southeast Asia region) and tobacco smoking are two of the major public health problems the world is facing today. With more and more diseases being associated with alleles of the human leukocyte antigen (HLA), the objective of the study was to explore any genetic association of OSF and smoking behaviour with specific HLA Class II DQB1*0503 and HLA DRB1*0301 alleles.

Materials and methods: Genomic DNA was extracted from saliva of 64 patients divided into an OSF group, a tobacco smokers group and a control group. This was followed by polymerase chain reaction (PCR) with sequence-specific primer of HLA-DQB1*0503 and HLA DRB1*0301 allele, visualised under 2% agarose gel.

Results: A statistically significant difference was observed between the OSF group and controls in presence of HLA-DQB1*0503 allele, with 84% of the patients showing the presence. Frequency of HLA DRB1*0301 allele was also found to be significantly higher (72%) among OSF patients (p <0.001). Similar results were shown in tobacco smokers with 28% cases showing presence of HLA DRB1*0301 allele and 13 (52%) of them having DQB1*0503 allele (p <0.001).

Conclusion: HLA-DRB1*0301 and HLA-DQB1*0503 are statistically significantly associated with susceptibility to OSF and smoking behaviour.

Keywords: HLA; OSF; genetics; tobacco.