Purine Nucleoside Phosphorylase Deficiency: Improved Metabolic and Immunologic Function with Erythrocyte Transfusions

DEFICIENCY of the purine enzyme nucleoside phosphorylase is associated with a severe T-lymphocyte immune deficiency. 1 2 3 4 5 6 The abnormality in the immune system results from the accumulation of purine metabolites that inhibit lymphocyte function. 7 8 9 10 11 Correction of T-lymphocyte deficiencies by stem-cell transplantation is limited by the availability of suitable donors, but treatment of the metabolic disorder by enzyme-replacement therapy may provide a useful alternative. Transfusion therapy is effective for about half the patients with severe combined immunodeficiency associated with adenosine deaminase deficiency. 12 13 14 In nucleoside phosphorylase deficiency transfusion therapy has been reported to produce partial improvement or no improvement in immune function. 4 , 15 16 17 In this . . .