[Apoptotic characteristics of CD34 positive cells in myelodysplastic syndromes]

To investigate the apoptotic situation of CD(34) positive cells in myelodysplastic syndromes (MDS).

In 36 MDS patients, immunocytochemical technique was used for the detection of the expression of CD(34) antigen and DNA in situ end labelling (ISEL) (fluorescein) for the apoptotic signals. Fourteen cases of iron deficiency anemias (IDA) were used as controls.

(1) CD(34) expression in MDS group was much higher than that in controls (49.2 +/- 38.5 vs 10.2 +/- 9.7, P < 0.01), and MDS cases had an obviously higher apoptotic rate than control did (69.1 +/- 28.2 vs 17.8 +/- 11.2, P < 0.01). (2) Expression of CD(34) was higher in transforming group (P < 0.05) than in non-transforming and post-transforming groups. Apoptotic rates in both non-transforming/transforming group were higher than in post-transforming group (P < 0.02 and < 0.05 respectively). (3) No apoptosis was found in CD(34) positive cells in MDS; (4) Both CD(34) positive cells and apoptotic cells formed into small or large clusters but did not co-distributed in a given area.

There is overexpression of CD(34) antigen on hematopoietic cells in MDS. High CD(34) expression accompanied high apoptosis coexisted in the process of transformation from MDS to AML. Apoptosis-resistance of these CD(34) positive cells suggested that they came from malignant hematopoietic cell clones.