Purine metabolism in lymphocytes from patients with primary hypogammaglobulinaemia.

The previous report of low levels of purine 5'-nucleotidase activity in peripheral blood mononuclear cells (lymphocytes and monocytes) from patients with non-familial adult onset `variable' primary hypogammaglobulinaemia has been confirmed and the observation extended to include patients with other types of primary immunodeficiency. Patients with sex-linked congenital hypogammaglobulinaemia have values for mononuclear cell 5'-nucleotidase activity which are in the normal range, whereas most cases of non-familial adult onset `variable' primary hypogammaglobulinaemia have clearly subnormal values. The three patients with isolated IgA deficiency who were tested also had subnormal values. Evidence that the measured enzyme activity is in fact 5'-nucleotidase and independent of interfering phosphatase activities is presented. No significant or consistent alterations in the activities of the following enzymes were detected in mononuclear cells or erythrocytes: adenosine deaminase, purine nucleoside (inosine) phosphorylase, hypoxanthine phosphoribosyltransferase, adenine phosphoribosyltransferase, phosphoribosylpyrophosphate (PRPP) synthetase. The erythrocyte PRPP content and the mononuclear cell PRPP amidotransferase activity were normal in the small number of patients in which they were measured. These findings are discussed in the light of the current interest in the inter-relationship between some disorders of purine metabolism and the immunological deficiency syndromes.