CD34 and myelodysplastic syndrome: For example, a score that identifies at least two of the following criteria – increased CD34+ progenitors in nucleated BM cells, a decrease in B cell progenitors among CD34+ cells, change in CD45 expression on myeloid progenitor cells as compared with lymphocytes, and a decrease in sideward light scatter (SCC) of neutrophils compared with lymphocytes – demonstrated a specificity of over 90% in patients with low risk MDS (25, 26).