The Nucleated Red Blood Cell ( NRBC ) Count in Thalassaemia Syndromes

• The Nucleated Red Blood Cell ( NRBC ) Count in Thalassaemia Syndromes

AUTHOR(S)

Paolo DANISE and Giovanni AMENDOLA

Department of Haematology and Oncology, Umberto I Hospital

SUMMARY

The purpose of this study was to evaluate the performance of the automated NRBC count generated by the SYSMEX XE-2100 in a large series of thalassaemia patients under the care of the Division of Pediatric Haematology and Oncology in the Haematology Department of an Italian hospital.

The principle of the automated NRBC count on the XE-2100 by now is well known being accomplished by flow cytometry using a semiconductor red diode laser and a polymethine based fluorescent dye. Mature RBCs are completely lysed. WBC membranes become perforated but the cells retain their original shape. NRBCs are denucleated and shrunken. The polymethine dye stains the intracytoplasmic organelles and the nucleus of the WBCs quite strongly while the staining of the NRBCs is comparatively weak. These different staining characteristics allow clear discrimination between the cell counts and therefore make NRBC counting possible. Imprecision studies and comparison with manual microscopy counts have been reported by Zini et al .

The thalassaemias are the most common monogenic diseases in man. Both historical and recent transmigrations have made the thalassaemias a world wide problem. There are many unresolved issues particularly in relation to population screening, the differential diagnosis between ß-thalassaemia trait and mild thalassaemia intermedia and the management of therapy of thalassaemia major patients. Why specifically count NRBC in the thalassaemia syndromes? A number of reasons have been advanced. The first is to improve the accuracy of the WBC count but, since thalassaemia patients are usually very well known to the clinicians, this is not a very important reason. The second reason is to improve the differential diagnosis between ß-thalassaemia trait and mild thalassaemia intermedia and this may be a rather controversial point. The third reason is to improve the transfusion regimen in transfusion-dependent patients.

KEY WORDS

Nucleated Red Blood Cell, NRBC, Thalassaemia, Red Blood Cell, RBC, XE-2100

NOTE(S)

This article is re-printed from the “Proceedings of the Sysmex European Symposium 2003” pp. 48-56.