Quantification of Leishmania infantum kinetoplast DNA for monitoring the response to meglumine antimoniate therapy in visceral leishmaniasis.

Meglumine antimoniate (Glucantime) remains the therapeutic cornerstone of visceral leishmaniasis (VL). Twenty-one VL patients were treated with Glucantime, extending for 1 week after defervescence. For monitoring the response, Leishmania infantum kinetoplast DNA loads were evaluated using real-time polymerase chain reaction (PCR) assay in the blood. The maximum duration of treatment was 14 days. The loads before treatment ranged from 8 to 1,300,000 parasites/mL (mean = 73,095 parasites/mL), and the mean values on days 3, 7, 14, 28, and 90 were 4,902, 506, 6.33, 0.26, and 0.14, respectively. The loads decline to < 1 parasite/mL for 16 (76%) and 20 (95%) patients on days 14 and 28, respectively, and they decline for all patients by day 90. Results showed a dramatic decrease of the parasite loads, although complete clearance was not accomplished at the end of treatment. Only one relapse (4.5%) was observed. The parasite load can also serve as a dependable index for monitoring the response to Glucantime.