Biomarkers of the early response to treatment of visceral leishmaniasis: A prospective cohort study.

BACKGROUND: Early biomarkers of the response to treatment are lacking and may help to reduce mortality by the vector-borne disease visceral leishmaniasis (VL). METHODS: A prospective cohort study was conducted to investigate plasma cytokines and clinical laboratory data as biomarkers of the early response to specific treatment for VL in 36 patients. RESULTS: The mean interleukin 6 (IL-6) concentration on the 7th day was 2.3% of the pre-treatment concentration, interleukin 10 (IL-10) was 8.0%, and interleukin 8 (IL-8) was 8.2%. On the 7th day, IL-10 was below half of the pre-treatment concentration in 100.0%, IL-8 in 95.5% and IL-6 in 90.9%. The spleen and liver sizes, haemoglobin, interleukin 1 beta (IL-1ß) and tumour necrosis factor alpha (TNF-α) showed a slower recovery. Fever disappeared in 91% on the 7th day, 69.4% had a normal white cell count, and 77.8% had a normal platelet value by this time. CONCLUSIONS: The plasma cytokines IL-6, IL-10 and IL-8 were demonstrated to be excellent markers of the early response to VL treatment and if tested before the 7th day, will likely prove to be better than fever measurement.