731 PURINE NUCLEOSIDE PHOSPHORYLASE (PNP) DEFICIENCY WITH CELLULAR IMMUNE DEFICIENCY

Abstract

Inherited deficiencies in purine metabolism can be associated with immunologic abnormalities. We report the 5th family deficient in PNP and cellular immunity. The proband, a 5-yr-old, had .08% of normal erythrocyte PNP. He presented at 3½-yrs with a history of mild increase in frequency of infections. He had a severe autoimmune hemolytic anemia and at 4½-yrs developed severe ataxia and tremor. He was lymphopenic (<300/mm3) had an absolute decrease in T- and B-lymphocytes and was unresponsive to phytohemagglutinin in vitro. Response to allogeneic cells was normal. IgG and IgM were increased and a monoclonal gammopathy (IgG4λ) was present. Other antibody functions were intact (non-reactive Schick test, normal isoagglutinins, and development of influenza antibodies after infection). Erythrocyte adenosine deaminase was normal. Serum uric acid was 1.9 mg/dl and plasma and urine inosine were increased (38 μM, 13.3 mmole/gm creatinine). Urine guanosine was also increased (4.15 mmole/gm creatinine). This patient confirms the role of purine catabolism in T-lymphocyte function. Also, the unusual neurological findings, monoclonal gammopathy and hemolytic anemia suggest that clinical manifestations of PNP deficiency may be more heterogenous than previously appreciated.