Detection and diagnostic applicability of human urinary kininogen in kala-azar patients

The present study was aimed to detect urinary proteins excreted in kala-azar patients. Urinary proteins were isolated by ammonium sulfate precipitation and purified by Amicon ultra using 3 kDa cutoff membrane device. The proteins were resolved on 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis and blots were developed with the patients sera. The excretion of urinary proteins was differential in kala-azar patients. A total eight proteins of molecular weights 25, 28, 46, 54, 57, 60, 72, and 95 kDa were detected in the urine of visceral leishmaniasis (VL) patients. On blot, the 57 kDa protein was found to be host origin and characterized as human kininogen. All other proteins were leishmanial origin. Out of 50 urine samples analyzed, the kininogen was detected in 45 urine samples. Following treatment, this protein was not detectable in the urine samples of any patient. The appearance of kininogen in urine of VL patients offers a novel possibility for the development of diagnostic tool and a test of cure.