High dose prednisolone treatment of leprosy patients undergoing reactions is associated with a rapid decrease in urinary nitric oxide metabolites and clinical improvement.

Evidence is accumulating that nitric oxide (NO) produced by macrophages has a role in the pathogenesis of reactions in leprosy. We followed the urinary levels of the metabolites of NO [nitrite (NO2-) and nitrate (NO3-)] and the clinical response to prednisolone treatment in leprosy patients (n = 9) admitted to ALERT leprosy hospital Addis Ababa, Ethiopia, because of reversal reaction (RR) or erythema nodosum leprosum (ENL). In untreated reactional leprosy patients, the levels of urinary NO metabolites (1645 +/- 454 microM, n = 9, ENL = 4, RR = 5) decreased significantly 2 weeks after high dose prednisolone treatment (1075 +/- 414 microM, P < 0.05), and remained stable 4 (895 +/- 385 microM, P < 0.02) and 6 weeks following treatment initiation (1048 +/- 452 microM, P < 0.02). This decrease was also present when the reactional patients were subdivided according to the type of reaction (ENL, RR) and coincided with a clinical improvement. In patients showing a poor clinical response to steroids, no or minor effects on the urinary NO metabolite levels were observed. We conclude that there is a correlation between the decrease in urinary NO metabolites and a favourable clinical response after high dose prednisolone treatment of reactional leprosy patients.