RESUMO
In this study we sought to determine if there is alteration in nitric oxide (NO) production and adenosine deaminase (ADA) activity among patients with visceral leishmaniasis (VL) and the effect of four weeks of chemotherapy on these levels. Fifty-three VL patients diagnosed clinically and by direct demonstration of the LD bodies in the bone marrow smear were studied. They were treated with Sodium Stibogluconate and sampled at the baseline and four weeks. Forty-three healthy individuals coming from the same endemic area were taken as control. Total nitrite (NO2- and NO3-) as an index of NO production and ADA activity was measured spectrophotometrically. Serum nitrite level decreased significantly in patients as compared to the healthy individuals but significantly increased following 4 weeks of chemotherapy. Conversely, Increased ADA activity was observed in the beginning of treatment and decreased significantly with successive 4 weeks of chemotherapy. It seems a negative correlation between NO level and ADA activity. This result indicates parasite induced evasion of NO and activation of T lymphocytes during immunopathogenesis of VL. Therefore, assessment of NO metabolites may be useful marker in the evaluation of the effector mechanism of macrophages and clinical manifestation of patients.