Cytokine gene polymorphisms in type I and type II reactions in Hansen's disease.

<bold>Introduction: </bold>Leprosy or Hansen's disease is a chronic debilitating disease caused by Mycobacterium leprae. Host genetics are believed to strongly influence the course of the disease. It is known that cytokines play an important role in leprosy and cytokine gene polymorphisms probably influence the course of the disease.<bold>Methods: </bold>In the present study, we evaluated 70 patients with leprosy and 243 controls. DNA was extracted from the peripheral blood and genotyping was done for the following polymorphisms: IL-1 RA intron 2, IL-1β-511 C/T and TNF-α A/G.<bold>Results: </bold>A strong association of TNF-α-308 G/A polymorphism with Hansen's disease with both genotypes and alleles was found. However, no correlation was identified between the other two polymorphisms and Hansen's disease. A strong association between the IL-1β gene polymorphisms and the type of reactions seen in leprosy was found. In contrast, the other two polymorphisms did not show any such association.<bold>Limitations: </bold>Genetic polymorphisms are association studies. They are not a direct reflection of the transcriptome or proteome and this is a major limitation of this study.<bold>Conclusion: </bold>In conclusion, cytokine gene polymorphisms appear to influence the susceptibility and course of Hansen's disease. An evaluation of the cytokine levels in the skin during lepra reactions would confirm this observation. Possibly, in future, this would be a guide to therapeutic decisions in cases of lepra reactions. [ABSTRACT FROM AUTHOR]