Purine metabolism in normal and pathologic lymphoid cell differentiation

Intact purine metabolism is pivotal for proper functioning of (lymphoid) cells. During the generation of immunocompetent lymphocytes of T- or B-cell lineage, and during subsequent differentiation into effector cells, cell divisions occur which require DNA synthesis. Studies of the causal relationship between deficiency of certain purine nucleotide metabolizing enzymes and deficiencies in immune function, revealed several privileged pathways in purine metabolism (Fig. 1). These pathways are different for T- and B-cells in different stages of maturation, and are related to purine enzyme activities [1, 2]. Assessment of purine nucleotide metabolizing enzymes in lymphoreticular malignancies [3, 4] showed enzyme activities that could be related to normal lymphoid cell differentiation. In addition, the purine enzyme make-up of lymphoid cells may be applied in malignant cell typing and permits estimation of the effectiveness of enzyme-directed chemotherapy. This survey focuses on these different aspects.