INCREASED URINARY ZINC EXCRETION IN CANCER-PATIENTS IS LINKED TO IMMUNE ACTIVATION AND RENAL TUBULAR CELL DYSFUNCTION

Urinary zinc excretion is known to be increased in cancer patients, bu t the pathogenesis of this phenomenon remains uncertain, Both skeletal muscle catabolism and renal tubular cell dysfunction have been propos ed to explain this observation, We have investigated urinary zinc and N-acetyl-beta-D-glucosaminidase (NAG), an indicator of renal tubular c ell dysfunction, as well as serum neopterin, an index of systemic immu ne activation, in 22 patients with cancer and seven controls, Both ser um neopterin and urinary zinc were significantly elevated in cancer pa tients (15.8 +/- 12.7 versus 7.3 +/- 2.3 nmol l(-1) and 1.77 +/- 0.80 versus 1.21 +/- 0.41 mmol mol(-1) creatinine, P < 0.02 and P < 0.05, r espectively), while NAG was similar in cancer patients and the control s (13.58 +/- 13.80 versus 13.68 +/- 12.19 mu kat mol(-1) creatinine). A significant correlation was observed between serum neopterin and uri ne zinc (rs = 0.5119, P < 0.02), serum neopterin and urine NAG (rs = 0 .6761, P < 0.002), and urinary zinc and NAG (rs = 0.6348, P < 0.002), In conclusion, the present data indicate a link between urinary zinc e xcretion and immune activation as well as renal tubular cell dysfuncti on. In addition, renal tubular cell dysfunction appears to be linked t o immune activation.