Enzymes Degrading Adenine, Nucleotides in Erythrocytes of Patients with Chronic Renal Failure

Abstract

Uraemia is associated with immunoincompetence, where both cellular and humoral immunity are disturbed. The exact pathophysiology of such incompetence is not known. However, uraemic toxins, urea, creatinine, together with nutritional deficiencies, especially zinc and pyridoxal phosphate have been incriminated as participating factors. The present study was undertaken to confirm the presence of such incompetence by measurement of activity levels of adenosine deaminase and 5-nucleotidase in blood plasma of patients with chronic renal failure at presentation together with IgG, zinc and vitamin B6 levels. The study revealed that the plasma levels of the two enzymes of purine metabolism, namely ADA and 5'-nucleotidase are significantly decreased in the blood plasma of these patients. Such decrement would reflect decreased activity levels in lymphocytes of these patients. This decrease results in raised intracellular levels of adenosine concentrations and thus, inhibition of DNA synthesis, through reduction of synthesis of purine and pyrimidine synthesis. With inhibition of ADA, 5'-nucleotidase would also be inhibited, since it was deprived of its own substrate. The net result is block of nucleic acid synthesis and lymphopenia could supervene.