Leukocyte alkaline phosphatase (LAP). A useful marker of zinc status in beta-thalassemic patients.

Intensive desferrioxamine treatment may negatively affect zinc stores in thalassemic patients. Two groups of young thalassemic patients, with good and poor compliance to desferrioxamine treatment, and a control group were investigated. Leukocyte alkaline phosphatase (LAP), zinc content in neutrophils, plasma zinc levels, and urinary zinc excretion were determined. LAP score, and neutrophil zinc and plasma zinc levels of the good compliance patients were statistically lower than those seen in the controls and in the poor compliance patients. Urinary zinc excretion was statistically higher in good compliance patients than in controls and poor compliance patients only during high-dose intravenous desferrioxamine. On the contrary, poor compliance patients had LAP scores, neutrophil zinc, plasma zinc, and urinary zinc excretion values within the normal range. We conclude that high-dose desferrioxamine produces a reduction of zinc stores in thalassemic patients. LAP scores determinations, which are a reliable and inexpensive marker of body zinc, could become a routine test for monitoring thalassemic patients undergoing hypertransfusion programs.