Metabolism of fibrinogen in children with acute lymphoblastic leukaemia.

The metabolism and in vivo kinetics of fibrinogen were studied using homologous 125I-labelled fibrinogen in 21 children with acute lymphoblastic leukaemia (ALL). Ten patients were undergoing induction therapy, 11 children were in complete remission on maintenance therapy. Results in the patients undergoing induction therapy were: plasma fibrinogen levels were normal in all except one patient, the plasma fibrinogen pool was elevated in six cases, seven patients had a shortened fibrinogen half-life and increased fractional catabolic rate for fibrinogen. The absolute catabolic rate for fibrinogen was elevated in six cases. This shortened fibrinogen half-life together with the correcting effect of heparinisation on the fibrinogen turnover indicated that fibrinogen was consumed by chronic disseminated intravascular coagulation. Inhibition of the fibrinolytic system with epsilon-aminocaproic acid in five patients had no influence on the fibrinogen half-life in three of them but resulted in its prolongation in two patients. All except two children in complete remission had normal fibrinogen levels. Six patients had elevated plasma fibrinogen pools and in all of the cases survival and fractional catabolic rate of fibrinogen were normal. The absolute catabolic rate for fibrinogen was normal in eight, elevated in three of the patients. This observation indicates that fibrinogen synthesis remains accelerated in some cases of ALL in complete remission, but the cause of this is not known.