Biology of myelodysplastic syndromes

A case of erythema nodosum and serositis associated with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a heterogenous group of stem cell disorders usually characterized by progressive refractory cytopenias, which could progress to acute myeloid leukemia. MDS may be associated with a wide spectrum of skin lesions, including neoplastic cell infiltration, Sweet's syndrome, pyoderma gangrenosum, erythema elevatum diutinum, vasculitis, and panniculitis. However, erythema nodosum is rarely associated with MDS. Unusual rheumatologic manifestations in patients with MDS also have been reported, which range from asymptomatic serological abnormalities to classic connective tissue disorders such as Sjögren's syndrome, relapsing polychondritis, systemic lupus erythematosus, rheumatoid arthritis and mixed connective tissue disease. However, concurrent erythema nodosum and serositis has rarely been reported. We describe a case of MDS with erythema nodosum and immune-mediated pericardial effusion in a 34-year-old woman.

Decreased amount of mpl and reduced expression of glycoprotein IIb/IIIa and glycoprotein Ib on platelets from patients with refractory anemia: analysis by a non-isotopic quantitative ligand binding assay and immunofluorescence

Using a non-isotopic ligand binding assay and immunofluorescence, we examined the amount of mpl, glycoprotein IIb/IIIa (gpIIb/IIIa) and glycoprotein Ib (gpIb) on platelets from healthy volunteers and patients with refractory anemia (RA). For the analysis of mpl expression, we applied both a non-isotopic ligand binding assay and immunofluorescence using anti-mpl monoclonal antibody, and compared the results from both methods. The non-isotopic ligand binding assay has been developed in our laboratory and is suitable for the quantitative analysis of a small amount of cytokine receptors such as mpl on platelets. In platelets from patients with RA, the amount of mpl expressed by the D value was 0.05+/-0.03 (mean+/-standard deviation), and was significantly lower than that in healthy volunteers (0.15+/-0.05, p<0.0001). The mean fluorescence intensities (MFI) of gpIIb/IIIa and gpIb on platelets from RA patients were 28.8+/-8.8 and 20.8+/-7.7, respectively, and were significantly lower than those on normal subjects (93.2+/-22.6 and 67.4+/-9.1, p<0.0001 and p<0.0001, respectively). There was a good correlation between the amount of mpl and the MFI of gpIIb/IIIa (p=0.794, p<0.0001) or gpIb (p=0.774, p<0.0001), and between those of gpIIb/IIIa and gpIb (p=0.728, p<0.0001). We demonstrated a decreased amount of mpl as well as a reduced expression of gpIIb/IIIa and gpIb on platelets from RA patients.

Hematopoietic progenitor cells from patients with myelodysplastic syndromes: in vitro colony growth and long-term proliferation

It is known that the levels of hematopoietic progenitor cells (HPC) are greatly reduced in the majority of patients with myelodysplastic syndromes (MDS). To date, however, only limited information exists on the growth kinetics of these cells in long-term marrow cultures (LTMC), particularly in terms of erythroid and multipotent progenitors. In the present study, we have determined the HPC content in the bone marrow of 12 MDS patients and followed the proliferation kinetics of myeloid (including granulocyte, macrophage and granulocyte macrophage), erythroid (including early and late) and multipotent progenitor cells in LTMC throughout a 7-week culture period. Both the non-adherent and adherent fractions of the cultures were analyzed, so we were able to look at progenitor cells in suspension and those that physically associated to the stromal cell layer developed in culture. All 12 patients were grouped based on their FAB subtype and the in vitro growth of the HPC was analyzed accordingly. The results presented here indicate that in the majority of MDS patients, pronounced deficiencies exist both in the content and the long-term proliferation of marrow HPC. Such deficiencies were particularly evident for multipotent progenitors and those committed to the erythroid lineage, in which alterations in the maturation process also seem to be present. Our results suggest that, at least in some patients, HPC--besides showing an impaired proliferative capacity--lose their ability to adhere to the stromal cell layers developed in culture. RA patients showed the less affected in vitro HPC growth, whereas HPC from RAEB and RAEB-t showed a markedly deficient growth in culture. Interestingly, myelopoiesis was significantly increased in cultures of CMML patients. These results give some new insights into the biology of MDS-derived HPC.

Analysis of bone marrow and peripheral blood immunoregulatory lymphocytes in patients with myelodysplastic syndrome

The cell surface phenotype of immunoregulatory lymphocytes in bone marrow (BM) and peripheral blood (PB) in myelodysplastic syndrome (MDS), a stem cell disorder, was analyzed. Mononuclear cells from 25 patients with refractory anemia (RA) and nine with RA with an excess of blasts (RAEB) were characterized by two-color flow cytometry using various monoclonal antibodies. No significant change of CD3+, CD4+, and CD8+ cells in PB, but a decrease of the percent of positive cells for CD8++ among the total lymphocyte (%CD8++) was noticed in RA patients. On the other hand, in BM of RA patients, a decrease in the number of CD4+ cells, but not CD8++ cells, was noted. In RAEB patients, the absolute numbers of CD3+, CD4+, CD8+, and CD8++ cells in BM were decreased; however, the ratio of these lymphocytes was not changed. No change was observed among the CD4+ subsets in PB of RA or RAEB patients. In BM, a decrease in percentage of CD4+CD45RA+ (%CD4+CD45RA+; naive cell) and increases in CD4+CD45RO+ (%CD4+CD45RO+; memory cell) and CD4+CD29+ (%CD4+CD29+; helper/inducer) among CD4+ cells were found in both RA and RAEB patients. Analysis of the CD8++ subset showed an increased number of CD8++CD11a+ cells (activated CTL) in both BM and PB of RA patients, but not of RAEB patients. Furthermore, increments in CD56+ and CD16+ cells among CD3- cells (natural killer; NK cells) were seen in RA patients but not in RAEB patients. It remains unclear whether lymphocytes in MDS patients were involved in the abnormal (MDS) clones, but our results regarding the increments of CD8++CD11a+ and NK cells in RA patients suggest that the mechanism of immune surveillance against the abnormal MDS clones was activated in these RA patients, but not in RAEB patients. Further investigation is required to clarify the functions of these immunoregulatory lymphocytes in MDS patients.

Myelodysplastic syndromes in childhood: description of seven cases

Seven children with a primary myelodysplastic syndrome were seen at our center over a 9-year period. Two presented with refractory anemia, three with refractory anemia with excess of blasts, and two with refractory anemia with excess of blasts in transformation. All children received supportive therapy, including blood transfusions in five of them. Three patients developed acute myeloid leukemia and were treated with intensive chemotherapy, followed by allogeneic or autologous marrow transplantation in the two responders. All three died of either infection or progressive disease. The other four patients are still alive a median of 71 months (range 38-130) after diagnosis. These results confirm the difficulties in managing patients with myelodysplastic syndromes.

MDS-macrophage derived inhibitory activity on myelopoiesis of MDS abnormal clones

We studied the effect of myelodysplastic syndrome (MDS)-derived adherent cells on colony formation of granulocyte-macrophage progenitors (CFU-GM) in both normal and MDS bone marrow cells. MDS-adherent cells suppressed the growth of normal CFU-GM colony formation. Antibodies against ferritin almost totally neutralized the haematopoietic inhibitory activity. Antibody against gamma-interferon (gamma-IFN) did not have such effect. By cytogenetic analysis using G-staining method, MDS-derived CFU-GM colony showed abnormal clones. MDS have been recognized to be a mosaic of normal and abnormal clones. MDS-macrophages suppressed the growth of progenitor cells derived from normal clones by soluble factors, but did not suppress the growth of those from abnormal clones. It is suggested that progenitor cells derived from abnormal clones are freed from the negative myelopoietic regulator that may be related to the progress of leukaemia.

Ineffective hemopoiesis in the myelodysplastic syndromes (MDS) as studied by daily in situ observation of colony-cluster formation

Daily in situ observation of individual proliferating cells was performed to examine ineffective hemopoiesis in vitro. Bone marrow mononuclear cells (BMMNC) from 24 myelodysplastic syndrome (MDS) patients and 12 controls were cultured for granulocyte-macrophage progenitor (CFU-gm) assays using methylcellulose. Individual proliferating cells were mapped at 3 days of culturing and their fates were followed by daily in situ cell counting contained within each cell aggregate until day 8. By retrospective analysis of the daily growth of the cells, a significantly greater proportion of noncolony-forming cells in MDS were found to proliferate initially, but failed to do so thereafter and degenerated in the culture. Cells showing these abnormal growth characteristics apparently contributed to ineffective granulopoiesis. The present method may be useful for clarifying ineffective granulopoiesis.

A phase II trial of recombinant human granulocyte colony-stimulating factor in the myelodysplastic syndromes

We conducted a phase II study of the intravenous administration of a glycosylated recombinant human granulocyte colony-stimulating factor (rhG-CSF) for 7-14 d in 41 patients with the myelodysplastic syndromes (MDS). Administration of rhG-CSF elicited striking rises in both leucocyte and neutrophil counts in the majority of the patients irrespective of the FAB subtypes of MDS. The rises in neutrophil counts were dose dependent and 5 micrograms/kg/d of rhG-CSF yielded approximately an 8-fold increase in neutrophil counts. Leucocytes and neutrophil counts started to increase shortly after the first injection of 5 micrograms/kg, was maintained at significantly elevated levels during 14 d of treatment, and returned to the pretreatment levels within several days following discontinuation of rhG-CSF. The action of rhG-CSF was specific for neutrophils since leucocytosis was due exclusively to neutrophilic increase associated with an increased marrow myeloid maturation. There were no consistent changes in the monocyte, eosinophil, lymphocyte, platelet or reticulocyte counts. After treatment, the percentage of marrow blast cells was reduced in eight of 13 evaluable patients with refractory anaemia with an excess of blasts (RAEB) or RAEB in transformation (RAEB-t). No patients developed acute leukaemia during the treatment or in the immediate follow-up period. The treatment was well tolerated with only minimal toxicity. The results suggest that rhG-CSF is a safe and effective way to promptly improve neutropenia in MDS patients.

Myelodysplastic syndrome (MDS)-associated inhibitory activity on haemopoietic progenitor cells

We studied MDS-associated inhibitory activity, which inhibited colony formation in vitro of granulocyte-macrophage progenitors (CFU-GM). Macrophages obtained from MDS bone marrow mononuclear cells (BM-MNC) when pretreated with granulocyte-macrophage colony stimulating factor (GM-CSF) suppressed the growth of normal CFU-GM. These macrophages were designated as 'MDS-derived inhibitory macrophages'. Media conditioned by MDS-derived inhibitory macrophages (MDS-CM) also suppressed the growth of normal CFU-GM. In the MDS-CM, high levels of prostaglandin E2 (PGE2) and ferritin were found. However, MDS-CM did not contain detectable levels of tumour necrosis factor (TNF) or gamma-interferon (gamma-IFN). Antiserum against human placental ferritin and/or against PGE2 blocked the haemopoietic inhibitory activity to some extent. These results suggest that inhibitory macrophages may be responsible for the suppression of granulopoiesis in patients with MDS and that the suppression may be mediated by soluble factors including PGE2 and ferritin.

Clinical characteristics of hybrid leukemia: report of five cases

We studied clinical and biological features of five cases of hybrid leukemia. Three of the five patients were classified as biphenotypic leukemia because of the coexpression of myeloid/B lymphoid markers in patients 1 (FAB M2) and 2 (FAB CMMoL) and myeloid/T lymphoid markers in patient 3 (FAB M4). Patient 4 was identified as bilineal-biphenotypic leukemia because acute myelogenous leukemia (AML) (FAB M4) and acute lymphoblastic leukemia (ALL) (FAB L1) coexisted and each population coexpressed myeloid and T lymphoid markers. Patient 5 was identified as bilineal leukemia due to the conversion from AML (FAB M1) to ALL (FAB L1) at an interval of 3 months. The Philadelphia (Ph1) chromosome was negative in all cases. A leukemic blast colony formation using cell line 5637 conditioned medium as a stimulator was obtained in all four patients examined. Three of the five patients had been suffering from so-called stem cell disorders such as aplastic anemia in patient 2, trilineage myelodysplasia in patient 4 and refractory anemia with excess of blasts in transformation in patient 5. The pre-existing impairment of pluripotent stem cell was probably the background of these hybrid leukemia. Hybrid leukemia appears to have an inferior prognosis: an AML-directed chemotherapy resulted in a low remission rate (2/5) with a short duration of relapse free survival (1/2) and an ALL-directed chemotherapy produced no remission (0/3). Chronological phenotypic analysis revealed that hybrid features of leukemic blasts disappeared at the time of relapse in patient 1 and progression to AML in patient 2. Monitoring of lineage-associated markers should be required for the management of hybrid leukemia.

Cooperative effects of gamma-interferon and 1 alpha, 25-dihydroxyvitamin D3 on in vitro differentiation of the blast cells of RAEB and RAEB-T

We added recombinant human gamma-interferon (gamma-IFN) and 1 alpha, 25-dihydroxyvitamin D3 (1 alpha, 25 (OH)2D3) to the bone marrow cells from six patients with RAEB or RAEB-T in liquid suspension cultures. After cultivation for 7 to 9 days, numerical, morphological and functional changes of the cells were assessed. gamma-IFN and 1 alpha, 25 (OH)2D3 additively suppressed cell growth, especially the number of blast cells decreased. The expression of alpha-naphthylbutyrate esterase (NBE) activity appeared to be promoted but that of naphthol AS-D chloroacetate esterase (NAE) activity was apparently suppressed by the addition of gamma-IFN and/or 1 alpha, 25 (OH)2D3. The percentage of NBT reduction-positive cells and latex-phagocytizing cells was only slightly increased by both agents. These results indicate that gamma-IFN and 1 alpha, 25 (OH)2D3 cooperate to induce monocytoid differentiation of the patients' blast cells. Combination therapy with both agents merits further study.

Refractory myelodysplastic anaemias with hypocellular bone marrow

Thirty three patients with refractory myelodysplastic anaemias (RMDA) with marrow hypocellularity were reviewed to see whether they differed from those with normocellular or hypercellular marrows. The median age was 65 years with a male:female ratio of 26:7. There were 11 cases of refractory anaemia (RA), four of refractory anaemia with ringed sideroblasts (RARS), and 18 of refractory anaemia with excess of blasts (RAEB). All presented with peripheral cytopenias, mostly pancytopenia or bicytopenia dysplasia in one or more cell lineages, and a marrow biopsy specimen with less than normal numbers of nucleated cells for the age. Twenty four patients died, including 14 of the 16 who developed acute non-lymphocytic leukaemia (ANLL). The results suggest that patients with hypocellular RMDA have a similar prognosis to those with normocellular or hypercellular marrows at presentation.