Concentrations of free amino acids and other blood components in a lymphoma patient during intensive hemodialysis

Abstract

L‐Asparaginase is used as a therapeutic enzyme to selectively destroy asparagine‐dependent cancer cells. This study explores alternate means for depriving cancer tissues of L‐asparagine and other specific amino acids or vital substrates required by normal and cancer cells. Hemodialysis, employing an artificial kidney, was used to remove free amino acids from the blood of a patient with lymphoblastic lymphosarcoma. Approximately 1200 mg, the equivalent of the patient's total amino acid pool, was removed every 100 minutes while the patient was on the artificial kidney. Despite this impressive clearance capacity, the dialyzer was not able to completely overcome the endogenous amino acid influx of the patient. The combined data indicate that hemodialysis is theoretically capable of removing specific amino acids to a therapeutic level, but that the clearance efficiency of the artificial kidney must be significantly increased or the endogenous amino acid influx must be effectively blocked before hemodialysis can be successfully applied to cancer patients. An unexpected finding was that the malignant lymphocyte population was strikingly increased during dialysis but returned to the original levels when dialysis was temporarily discontinued. The presence of a nonprotein inhibiting factor capable of suppressing an increase in the peripheral malignant lymphocyte population could be an explanation. This postulated factor behaved during dialysis as though its molecular weight was relatively low, possibly less than 500.