L-asparaginase effect on antithrombin-III levels.

The effect of L-asparaginase (L-asp) therapy on circulating antithrombin-III (AT-III) was monitored in three patients with acute lymphoblastic leukemia. Serial determination for AT-III by both a functional assay and an immunologic assay demonstrated a rapid decrease in serum AT-III levels, followed by a protracted recovery beyond the period of L-asp exposure. One of the three patients developed a reversible venous thrombosis of the arm. The mechanism of the L-asparaginase effect may be related to peripheral degradation of AT-III or to inhibition of production.