Plasma chitotriosidase activity in patients with beta-thalassemia.

Variable increases in chitotriosidase levels have been reported in Italian patients with beta-thalassemia major and intermedia. We measured plasma chitotriosidase levels in Israeli patients with beta-thalassemia to ascertain its use as a universal marker of disease and/or response to therapy. Chitotriosidase levels in 39 adults (16-53 years; 30 with beta-thalassemia major, 9 with intermedia), and in 14 children (0.7-15 years; 12 with beta-thalassemia major, 2 with intermedia) were compared with other measures of disease, such as ferritin, hemoglobin, liver function tests, and genotype. Plasma chitotriosidase levels were normal (0.37 +/- 0.04 mU/mL) in all children. Twelve adults (31%) had elevated levels (>1.33 mU/mL): 11 patients (37%) with thalassemia major and 1 patient (11%) with thalassemia intermedia. A significant correlation was only found between plasma chitotriosidase levels and ferritin levels, and with mean number of transfusions per year. The patient with the highest chitotriosidase (1,440 nmol/mL/hr) had the highest ferritin (5,175 microg/L), required the most transfusions per year (40), and had abnormal liver tests. Normal chitotriosidase levels in the pediatric cohort and increased levels in only some adults may reflect status of iron overload in macrophages; thus there may be a role for monitoring chitotriosidase in patients with beta-thalassemia. Our results confirm results of the Italian cohort; however, in the latter, a more universal correlation was noted and chitotriosidase levels were much higher.