Transient hyperphosphatasemia observed in a boy with acute lymphoblastic leukemia

: A detailed time course of alkaline phosphatase (ALP; EC3.1.3.1) activity of transient hyperphosphatasemia (TH) in a 9-year-old boy with acute lymphoblastic leukemia (ALL) is described. The patient's serum ALP activity rose transiently to 49 times the upper limit of normal adult, without any evidences of hepatic and bone disease. The half-life of ALP activity was calculated about 10 days. We characterized ALP isoenzymes by usual electrophoresis using cellulose acetate membrane (Titan III iso-vis) and polyacrylamide disc gel (AlkPhor), and isoelectric focusing using polyacrylamide slab gel. The former two methods showed typical two bands (fast-alpha 2 and alpha 2 beta bands) and the latter one method revealed more basic bands of liver and bone, suggesting the extensive sialylation. The patient complained fever and diarrhea. Enterococcus faecium was detected from his stool. Etiologically, two more patients in the same ward showed TH in the same period. It suggested TH would be occurred by infectious states. Awareness of such benign forms of hyperphosphatasemia not related to malignancy will aid the physician in the differential diagnosis of elevated ALP activity.