Clinical implications of immunophenotypic abnormalities of bone marrow myeloid cell compartment in myelodysplastic syndromes.

PURPOSE

to evaluate the biological and clinical implications of immunophenotypic abnormalities of bone marrow myeloid cell compartment in patients with primary myelodysplastic syndromes (MDS).

METHODS

analysis of cell surface antigen profiles was performed by flow cytometric immunophenotyping on bone marrow mononuclear cell (BMMNCs) specimens from 39 adult MDS patients and 5 healthy individuals. Expression of cell surface antigen profiles was correlated with FAB subtype, cytogenetics, CFU-GM colony growth, overall survival (OS) and leukemic transformation (LT).

RESULTS

expression levels of early differentiation and myelo-monocytic antigens (CD38, CD13, CD33, CD14 and CD15) on myeloid cell compartment of BMMCs were significantly higher in MDS patients in comparison to healthy control group, suggesting maturational left shift of bone marrow myeloid cell compartment in MDS. CD34 antigen expression was in a positive linear correlation with HLA-DR antigen expression (r=0.652; p=0.0004), and in negative correlation with the expression of CD11b and CD15 antigens (r=-0.48; p=0.014 and r=-0.564; p=0.0033, respectively). Myeloid antigen ratio (HLA-DR/CD11b) was 2.5 fold higher in patients with MDS in comparison to control group. Patients with advanced disease had significantly higher myeloid antigen ratio than patients with low risk MDS (p<0.05). The type of CFU-GM colony growth and the presence of chromosomal aberrations were unrelated to the proportion of CD34(+) cells and elevated myeloid ratio. Patients with elevated proportion of CD34(+) BMMNCs or elevated myeloid ratio had significantly shorter OS and higher LT rate in comparison to patients whose proportion of CD34(+) BMMNCs and myeloid ratio were within normal range.

CONCLUSION

the presence of abnormalities in antigen expression profiles of bone marrow myeloid cell compartment has clinical implication in MDS, with particular contribution in predicting the patient outcome. Elevated proportion of CD34(+) BMMNCs and elevated myeloid ratio of bone marrow myeloid compartment are useful immunophenotypic tools for estimation of prognosis in this very heterogeneous disorder group.