Incorporation of purine nucleosides in cultured fibroblasts from a patient with purine nucleoside phosphorylase deficiency and associated T‐cell immunodeficiency

Cultured skin fibroblasts from a patient with T‐cell immune deficiency and an absence of purine nucleoside phosphorylase activity in red cells were assayed for their capacity to metabolize inosine and guanosine. The cultured fibroblasts were lacking activity of nucleoside phosphorylase and, compared to normal fibroblasts, could incorporate only 2% and 4% of 14 C‐inosine and 3 H‐guanosine, respectively, into acid precipitable material. Autoradiography visually confirmed the failure of the NP deficient cell line to incorporate the nucleosides into nuclear material. The physiological mechanism by which the deficiency of purine nucleoside phosphorylase causes T‐cell dysfunction remains unclear.