Myelodysplastic syndrome with karyotype abnormality is associated with elevated F-cell production

A sensitive F-cell assay has been used to examine the production of fetal haemoglobin (Hb F) in a group of 77 adult patients with myelodysplastic syndrome (MDS), and a control group composed of 100 normal blood donors. Although the mean F-cell percentage in the MDS group (6.0%) is not statistically different from that in the normal blood donors (3.1%), a higher proportion of myelodysplastic patients have elevated F-cell values and the magnitude of the increases is greater than that observed in blood donors. In order to investigate the association further, the karyotypes of the MDS patients have been examined. 13/21 (61.9%) of the MDS patients with karyotypic abnormalities have F-cell values > 5%, compared to only 6/56 (10.9%) of the MDS patients with a normal karyotype and 11/100 (11%) of the blood donors. The observed difference in the distributions of F cells between the two subgroups of patients with MDS is highly significant (P < 0.0001).