Renal function at the brush border membrane level has been studied using characteristic enzymes, such as alkaline phosphatase, leucine-aminopeptidase and gamma-glutamyl transpeptidase. Urinary enzyme studies were performed using leprosy patients, classified on the basis of bacteriological index (BI > 3; n = 20, BI < 3; n = 12, BI-ve; n = 10) and compared with control subjects (n = 10). The role of enzymuria in monitoring WHO-recommended multidrug therapy (MDT) has been evaluated in these patients. A significant increase in the enzyme activities (p < 0.01), as well as significant (p < 0.01) proteinurea in 24-hour urine samples of both the smear positive groups (Bf > 3, BI < 3) prior to therapy compared to control subjects, indicates proximal tubular functional impairment at brush border membrane level. In the smear negative (BI-ve) group, no significant difference was observed in enzyme activities as compared with the control group. In a follow-up study (BI > 3; n = 13, BI < 3; n = 4) the activities of all the enzymes decreased significantly in all the groups when compared to a corresponding untreated group. The follow-up study was not carried out on the smear negative group. The surprising finding was the differential behaviour of r-glutamyl transpeptidase, whose activity increased significantly (p < 0.01) even after therapy in BI > 3 group when compared with untreated patients. However in a detailed work-up including hepatic and renal function tests, the serum biochemistry was found to be normal both before and after therapy. Urinary excretion of brush border enzymes seems to be related to bacterial load, and their potential in studying the effect of MDT remains unclear.
