CD34/QBEND10 immunostaining in bone marrow biopsies: an additional parameter for the diagnosis and classification of myelodysplastic syndromes

CD34/QBEND10 immunostaining has been assessed in 150 bone marrow biopsies ( BMB) including 91 myelodysplastic syndromes (MDS), 16 MDS-related AML, 25 r eactive BMB, and 18 cases where RA could neither be established nor ruled o ut. All cases were reviewed and classified according to the clinical and mo rphological FAB criteria. The percentage of CD34-positive (CD34+) hematopoi etic cells and the number of clusters of CD34+ cells in 10 HPF were determi ned. In most cases the CD34+ cell count was similar to the blast percentage determined morphologically. In RA, however, not only typical blasts but al so less immature hemopoietic cells lying morphologically between blasts and promyelocytes were stained with CD34. The CD34+ cell count and cluster val ues were significantly higher in RA than in BMB with reactive changes (p<0. 0001 for both), in RAEB than in RA (p=0.0006 and p=0.0189, respectively), i n RAEBt than in RAEB (p=0.0001 and p=0.0038), and in MDS-AML than in RAEBt (p<0.0001 and p=0.0007). Presence of CD34+ cell clusters in RA correlated w ith increased risk of progression of the disease. We conclude that CD34 imm unostaining in BMB is a useful tool for distinguishing RA from other anemia s, assessing blast percentage in MDS cases, classifying them according to F AB, and following their evolution.