IMMUNOPURINOGENIC ENZYMATIC ACTIVITY IN THE ACQUIRED IMMUNODEFICIENCY SYNDROME: 132

Abstract

Deficiencies of the purine catabolic enzymes adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) have been described in association with severe combined immunodeficiency disease and selective T-cell immunodeficiency disease respectively. Recently a selective T-cell acquired immunodeficiency syndrome has been described in homosexuals, drug addicts,Haitians and hemophiliacs. In an attempt to explore further metabolic mechanisms to account for this disorder we have quantitated erythrocyte and lymphocyte ADA and PNP activities using highly sensitive radiochemical methods in controls and seven patients with AIDS. Our results are as follows: 1) Erythrocyte ADA activity in controls and AIDS patients was 0.66 n mol/min/mg protein and 0.80 n mol/min/mg protein respectively. 2) Lymphocyte ADA activity was 6.86 n mol/min/mg protein for controls and 5.57 n mol/min/mg protein in AIDS. 3)Erythrocyte PNP activity was 2680 n mol/hr/mg protein for controls and 1618 n mol/hr/mg protein in the patients (p<.0005) 4)Lymphocyte PNP activity was 5892 n mol/hr/mg protein and 2740 n mol/hr/mg protein for controls and AIDS patients respectively (P<.0025). We conclude that: (1) Abnormalities in purine catabolic enzymes should be included in the disease spectrum of AIDS. (2) The causal relationship of decreased PNP activity in perpetuating the abnormal T-cell function in these patients remains to be determined (3) Alternatively the decreased PNP activity in AIDS may be secondary to the profound selective T-cell lymphopenia in this syndrome.