Serum immunoreactive trypsin in beta-thalassaemia major.

To assess the exocrine pancreatic function in beta-thalassemia major with iron overload, serum immunoreactive trypsin (IRT) was measured in 38 patients with this condition. In 23 (60%) patients' IRT was abnormal: it was subnormal in 16 patients and supranormal in seven. Whereas subnormal IRT concentrations were more frequent in patients of more than 12 years old, supranormal IRT concentrations were more frequent in younger patients. These data provide the first antemortem evidence of exocrine pancreatic damage in this condition. They also suggest that this acinar cell damage is initially associated with a rise in IRT which is followed by a fall in the serum concentration of this enzyme.