Importance of L. Infantum H2B Recombinant Antigen for Serodiagnosis of Visceral Leishmaniasis

Background: Visceral leishmaniasis (VL) can lead to death in more than 95% of cases if left untreated. Accurate and early diagnosis has an important role in reducing mortality rate of this disease. Objective: To express recombinant H2B antigen from an Iranian isolate of Leishmania Infantum and evaluate its efficacy in the diagnosis of VL. Methods: The recombinant H2B antigen was produced in a prokaryotic system, and its efficacy for VL diagnosis was evaluated by ELISA. The serum samples from 80 VL patients, 100 individuals from endemic and non-endemic regions of VL, and 58 non-VL patients were collected. VL cases were confirmed based on the clinical sign, positive IFAT (>64), real time PCR, and response to treatment. Results: The H2B gene sequence of the Iranian L. infantum isolate had about 4% diversity in comparison with the H2B gene of the L. infantum counterpart. ELISA, using the produced H2B recombinant antigen, showed sensitivity of 71.25% (95% CI: 60.05%-80.82%) and specificity of 69.62% (95% CI: 61.81%-76.68%) regarding VL diagnosis. Conclusion: Recombinant H2B antigen expressed in the prokaryotic system had suboptimal performance for the serological diagnosis of VL. It seems that the production and expression of recombinant H2B antigen in a eukaryotic system may enhance the performance of this antigen in the diagnosis of VL in Iran.