Folate Activity in Malignant Blood Diseases.

Abstract

Basal serum folate activity, serum folate clearance and folate output in the urine after folic acid loading, urocanic acid and formiminoglutamic acid output in the urine after histidine loading were determined on 27 patients with malignant blood diseases in therapeutic remission. The mean values for basal serum folate activity and for serum folate activity and urinary folate output after folic acid loading were significantly lower than normal, both in chronic myeloid leukemia and in Hodgkin's disease. On the contrary, in chronic lymphatic leukemia only after folic acid loading urinary folate output was significantly lower than normal. The median values for urinary excretion of histidine derivatives after histidine loading was higher than normal in Hodgkin's disease and in chronic lymphatic leukemia. Folate deficiency was observed in 16 out of the 27 patients under study. Comparative analysis of multiple test results showed different response patterns which can be attributed to different types of deficiency, namely tetrahydrofolate deficiency from primary folate deficiency and possibly tetrahydrofolate deficiency from folate metabolic abnormalities. Folate deficiency appeared to correlate with the activity of disease when expressed by such parameters as performance status and erythrocyte sedimentation rate. This applies to all patients as a group, and, as far as performance status is concerned, to the chronic lymphatic leukemia patients as a subgroup. Folate deficiency did not appear to correlate with other parameters of disease nor to induce, in the majority of patients, the typical hematologic features. Folate deficiency in malignant blood diseases is likely to be somehow related to the abnormal cell proliferation, through several possible mechanisms which are analysed and discussed.