Burden of abnormal hematopoietic clone in patients with myelodysplastic syndromes

To investigate the role of the burden of abnormal hematopoietic clone in the development of myelodysplastic syndromes (MDS).

The ratio of the bone marrow cells with abnormal chromosomes to the total counted bone marrow cells was regarded as the index of MDS clone burden. The disease severity related parameters including white blood cell count, hemoglobin, platelet count, lactate dehydrogenase level, bone marrow blast, myeloid differentiation index, micromegakaryocyte, transfusion, interleukin-2, tumor necrosis factor (TNF), CD4+ and CD8+ T cells of MDS patients were assayed, and the correlations between those parameters and MDS clone burden were also analyzed.

The clone burden of MDS patients was 67.4% +/- 36.2%. MDS clone burden positively correlated with bone marrow blasts (r = 0.483, P < 0.05), negatively with hemoglobin level (r = -0.445, P < 0.05). The number of blasts, hemoglobin, and erythrocytes in high clone burden (> 50%) and low clone burden ( < or = 50%) groups were 7.78% +/- 5.51% and 3.45% +/- 3.34%, 56.06 +/- 14.28 g/L and 76.40 +/- 24.44 g/L, (1.82 +/- 0.48) x 10(12)/L and (2.32 +/- 0.66) x 10(12)/L, respectively (all P < 0.05). CD4+ T lymphocytes of MDS patients and normal controls were (0.274 +/- 0.719) x 10(9)/L and (0.455 +/- 0.206) x 10(9)/L, respectively (P < 0.05). CD8+ T lymphocytes of MDS patients and normal controls were (0.240 +/- 0.150) x 10(9)/L and (0.305 +/- 0.145) x 10(9)/L, respectively. The serum level of interleukin-2 of MDS patients (6.29 +/- 3.58 ng/mL) was significantly higher than normal control (3.11 +/- 1.40 ng/mL, P < 0.05). The serum level of TNF of MDS patients and normal control group were 2.42 +/- 1.79 ng/mL and 1.68 +/- 0.69 ng/mL, respectively. The ratio of CD4 to CD8 was higher in high clone burden MDS patients (1.90 +/- 0.52) than that in low clone burden patients (0.97 +/- 0.44, P < 0.05).

The quantitive clonal karyotype abnormalities and deficient T cell immunity are important parameters for evaluating MDS severity and predicting its progression.