Evaluation of interleukin 17: A polymorphism in patients with visceralleishmaniasis

Visceral leishmaniasis (VL) is an infectious disease that it has spread in more than 60 countries, in Iran it is caused by Leishmania infantum. The infection is transmitted bysand flies, often affects children under 10 years of age, and it can be fatal if no treatment isundertaken. The progression of leishmaniasis infection in the host depends on cellularimmunity. Studies have associated immune responses against leishmaniasis to host genotype,resistance due to Th1 and T CD8 cells, and responses leading to macrophage activation andparasite killing. The parasite can stimulate the production of interleukin 17A (IL-17A) byTh17. It was shown that IL-17A is strongly and independently associated with protectionagainst VL. Moreover, it seems that IL-17A has a complementary role in human protectionagainst VL.
Blood samples were collected from 259 people among whom 88 were patients withhistory and clinical symptoms of leishmaniasis and 171 were healthy controls with no signs of infection. All participants were residents in an endemic area of VL in east Azerbaijanprovince, Iran. DNA extraction was performed using salting out method. Then, the controlgroup was divided into two groups of seropositive and seronegative by IFA (indirectfluorescent antibody) test, and for detecting polymorphism of IL-17A (197A\G) ARMS-PCR(Amplification refractory mutation system-Polymerase chain reaction) was used.
The result showed that the G allele was more frequent than the A allele among thegroups, but this difference was not statistically significant (P = 0.8). In addition, the GG genotype was more frequent than genotype A/G and A/A among the groups, but thisdifference was not statistically significant (P = 0.7).
On the basis of the results, there was no significant association between VL andpolymorphism of IL-17A (197A\G).