Fibrinopeptide A in acute leukemia: relationship of activation of blood coagulation to disease activity.

Plasma fibrinopeptide A (FPA) levels were determined in 20 unselected adult patients with acute nonlymphocytic and lymphocytic leukemia. The mean FPA level in patients with active disease (15.0 ng/ml) was significantly higher than during clinical remission (2.4 ng/ml, p less than 0.01). Elevated FPA levels were observed in patients with all morphological forms of acute leukemia. In the group of patients in clinical remission, 20/47 FPA values remained elevated beyond the normal range, suggesting that low-grade intravascular coagulation was present even when no leukemic cells were observed. Sequential studies revealed reduction of FPA levels to the normal range in five patients who entered clinical remission after chemotherapy and rapid elevation of the levels in eight patients who entered relapse after clinical remission. FPA levels rose significantly in five patients studied during induction chemotherapy. Thus, subclinical activation of blood coagulation, as defined by elevation of plasma FPA level, may occur commonly in acute leukemia. Plasma FPA generation may relate to leukemic disease activity.