DECREASED PHAGOLYSOSOMAL FUSION OF PERIPHERAL-BLOOD MONOCYTES FROM PATIENTS WITH THALASSEMIA MAJOR

We evaluated the phagolysosomal fusion of peripheral blood monocytes f rom 15 patients with thalassemia major and 10 thalassemia major carrie rs using a cytomorphological method with acridine orange as fusion mar ker. The monocyte phagolysosomal fusion of thalassemic patients was de creased (49.6 +/- 8.6%, mean +/- SD) and differed significantly (p < 0 .05) from those of carriers and normal controls (65.7 +/- 11.4% and 74 .6 +/- 5.7%, respectively). In vitro deferoxamine partially improved m onocyte phagolysosomal fusion of patients with thalassemia major, and did not affect monocyte function in carriers and healthy subjects. Fur thermore, in vitro addition of ferrous sulfate decreased normal phagol ysosomal fusion. We conclude that the monocyte phagolysosomal fusion d ysfunction of thalassemic patients could be related to iron overload.