Analysis of serum lactate dehydrogenase and its isozymes during administration of granulocyte colony-stimulating factor in children.

Serum lactate dehydrogenase (LDH) activity is known to become elevated following granulocyte colony-stimulating factor (G-CSF) therapy in some patients, but no extensive studies on this phenomenon have been performed. In 26 children with malignancies in complete remission who received recombinant human G-CSF intravenously after combined chemotherapy, we measured serum LDH and its isozymes (81 episodes) before chemotherapy (pre-Tx), during administration of G-CSF (mid-Tx), and after stopping G-CSF (post-Tx) and compared the obtained data using paired t test. Twelve episodes were excluded from analysis because of liver dysfunction (alanine aminotransferase > 45 IU/L). Serum LDH at mid-Tx (343.1+/-19.8 IU/L; mean +/- SE) was significantly higher than that at pre-Tx (186.9+/-6.7 IU/L) and post-Tx, but this difference was observed only when change in white blood cell counts (WBCs) (WBC at mid-Tx minus WBC at pre-Tx) was greater than or equal to 4000/microL (58 episodes). Percentages of LDH isozymes 3, 4, and 5 at mid-Tx (23.5+/-1.0, 11.7+/-0.8, and 8.3+/-0.7) were significantly increased compared with those at pre-Tx (19.5+/-0.7, 6.3+/-0.3, and 4.2+/-0.5) and post-Tx, resulting in a significant decrease in percentages of LDH isozymes 1 and 2 at mid-Tx. In episodes of change in WBCs > or =4000/microL, change in LDH significantly correlated to changes in WBCs and granulocytes but not to change in lymphocytes or monocytes. These results suggest that serum LDH is significantly elevated during G-CSF administration in accordance with the increase in peripheral granulocytes, which accompanies change in the pattern of percentages of LDH isozymes.