Background: IFN-&lambda3 (IL-28B) is a new cytokine from the type III interferons. Its role in several biologic activities, such as regulation of immune responses, tumor and metastasis, or its functions in HBV and HCV diseases, has been shown. The present study evaluated the frequency of rs8099917 allele polymorphism in IFN-&lambda3 gene in Iranian population.

Materials and Methods: In this laboratory-experimental study, after collecting blood samples from 118 unrelated Iranian subjects, DNA extraction was performed according to the kit protocols. Evaluation of rs8099917 allele polymorphism was done by Nested-PCR and RFLP method using BsrDI and Tsp451 restriction enzymes.

Results: After running the tests and data analysis, the frequencies of GG genotype (2.5%), GT genotype (31.4%), and TT genotype (66.1%) were obtained. Allele frequencies were 71.22% for G allele and 81.78% for T allele.

Conclusion: The results of this study showed that TT genotype and T allele are the dominant frequencies of rs8099917 allele of IFN-&lambda3 gene in Iranian population. Regarding the different established functions of IFN-&lambda3, frequency determination of this variant can be helpful in different studies, designs, evaluations, and treatment procedures in some diseases, such as tumors and hepatitis, in Iranian patients.