Ricerc@Sapienza

Tubular disfunction in a patient with a recent kidney transplant.The case reports about a patient who underwenta kidney transplantation for chronic disease of unknown cause. The clinical course showed a delayed graft functionand acute tubular necrosis. Urine microscopy confirmed a tubular disfunction: presence of renal epithelial cells,cylindruria and crystals. The microscopy images showed brownish-colored crystals that, under polarized light,suggested a 2.8-dihydroxyadenine (DHA) urolithiasis, rare and underdiagnosed pathology, due to the deficiency ofadenine-phosphoribosyltransferase (APRT). The specific analysis, i.e. the determination of the enzyme activity onerythrocyte lysate, did not confirm our initial hypothesis, excluding de facto a DHA urolithiasis. Analysis of purine andpyrimidine profile confirmed the presence of a purine dysmetabolism. The patient was treated with allopurinol, whichimproved the clinical picture. This case underlines the need for more extensive studies of crystal and/or metabolicnephropathies before renal transplantation. The microscopy study was however useful to trigger investigations thathave then influenced the therapy and the clinical progress of the patient.