Clonality of cell populations in refractory anaemia using combined approach of gene loss and X-linked restriction fragment length polymorphism-methylation analyses.
Abrahamson G., Boultwood J., Madden J., Kelly S., Oscier DG., Rack K., Buckle VJ., Wainscoat JS.
We have used X-linked restriction fragment length polymorphism (RFLP)-methylation and gene deletion analyses to investigate the nature of the progenitor cell of origin in the myelodysplastic syndromes (MDS). Gene deletion studies were performed on the granulocyte and T-lymphocyte fractions of six women with refractory anaemia (RA) and either a partial deletion of the long arm of chromosome 5 (5q-) or monosomy 7. All six showed gene loss in the granulocyte but not the T-lymphocyte fractions, indicating monoclonality of the granulocytes but not the T-lymphocytes. In order to further investigate this finding, we subsequently performed X-RFLP-methylation studies using the probe M27 beta, and also a probe for the phosphoglycerate kinase (PGK) gene. These studies have confirmed the monoclonality of the granulocytes and the polyclonality of the T-lymphocytes in these cases. Our findings suggest that in this group of patients with MDS the T-lymphocytes were not involved in the disorder, and furthermore, in the one case where B-lymphocytes were also available, that the progenitor cell of origin was restricted to the myeloid lineage.