Purine and Phosphoribosylpyrophosphate Metabolism of Lymphocytes and Erythrocytes of an Adenosine Deaminase Deficient Immunocompetent Child

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Abstract

Summary

Purine metabolism and phosphoribosylpyrophosphate content of lymphocytes and erythrocytes were studied in an immunocompetent black male child with a total deficiency of erythrocyte and partial deficiency of lymphocyte adenosine deaminase. The partial genetic deficiency of adenosine deaminase was demonstrated in intact lymphocytes, and was approximately one third of the deaminating activity of control lymphocytes. Intact lymphocytes of the patient did not incorporate adenosine at a faster rate than those of control lymphocytes. The patient's erythrocytes deaminating activity was low and adenine ribonucleotide synthesis from adenosine was increased several fold, while adenine incorporation into purine ribonucleotides was comparable to that of control erythrocytes. Transfusion with packed erythrocytes temporarily improved the deaminating capacity of circulating erythrocytes, but did not reduce the elevated incorporation of adenosine into purine ribonucleotides.

Summary

Phosphoribosylpyrophosphate content of the patient's lymphocytes and erythrocytes was not diminished. Incubation of erythrocytes with adenosine lowered phosphoribosylpyrophosphate content while incubation with phosphate increased phosphoribosylpyrophosphate content to the same extent in mutant and control erythrocytes.

Speculation

The finding that the patient's lymphocytes can deaminate adenosine to some extent may explain why the rate of adenosine incorporation into purine ribonucleotides of his lymphocytes is not increased and immune function is not impaired. Deficiency of erythrocyte adenosine deaminase results in increased adenosine incorporation, but does not appear to interfere with immune functions.

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