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Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. GISTs are believed to be related to mutational activation of receptor tyrosine kinases, KIT, or platelet-derived growth factor receptor-alpha. The coexistence of GISTs with other neoplasms has been extensively addressed in the literature. The most common second neoplasms are colorectal cancer, prostate cancer, and neoplasms derived from lymphoid tissue. In this case report, we describe a patient affected by GIST and acute myeloid leukemia preceded by myelodysplastic syndrome with refractory anemia. The clinicopathological characteristics of the patient are discussed and the literature is reviewed.

A clonal origin of hematopoiesis was studied by investigation of X-chromosome inactivation patterns (XCIP) in isolated granulocyte, CD14(+) and CD3(+) subpopulations obtained from bone marrow and peripheral blood of 36 female patients with primary myelodysplastic syndrome (MDS). Clonality was assessed by PCR amplification of polymorphic short tandem repeats of the human androgen receptor (HUMARA) gene and by investigation of silent polymorphism of iduronate sulphatase (IDS) or p55 genes. On the basis of results in a control group of 20 healthy age related females, a ratio of at least 9:1 between the two alleles was considered a significant marker of monoclonal hematopoiesis. Ten of the 11 patients with advanced forms of MDS (RAEB, RAEB-T, CMML) had clonal granulocytes and CD14(+) cells in peripheral blood. In patients with early disease, only 2 out of 11 patients (18%) with RA or RARS, according to WHO classification, had clonal granulocytes and CD14(+) cells in peripheral blood and bone marrow and 2 other patients with 5q-syndrome exhibited extremely oligoclonal granulocyte subpopulation in bone marrow. In contrast, we found clonal granulocytes in 12 out of 14 patients (86%) with refractory cytopenia with multilineage dysplasia (RCMD) and 8 of them simultanously exhibited clonal CD14(+) cells. Estimated 3 years survival of patients with early disease and clonal cell subpopulations was 61% as compared with 88% in patients without clonal hematopoiesis. Karyotype abnormalities were detected in 11 of the 25 females with early disease. Clonal patterns were present in 7 out of 8 patients with abberations diagnosed by routine cytogenetics, nevertheless, FISH revealed 5q deletion in 3 patients without signs of clonality in XCIP assay. No correlation was found between the presence of clonal subpopulations and the degree of telomere shortening in early MDS. Despite some limitations, the measurement of XCIP remains a sensitive tool for diagnosis of the first transforming mutation in the clonal development of MDS especially when combined with FISH and when an age related group is used to establish an appropriate allele ratio to exclude constitutional or acquired skewing. The occurrence of clonal cell subpopulations in most of the RCMD patients in contrast to RA may reflect a proposed multistep pathogenesis of MDS with dysplastic changes limited to erythropoiesis in early step and with subsequent development of multilineage dysplasia. The results also support the usefulness of separation of RCMD from 'pure' RA; however, a more complex insight combining different molecular techniques performed in a large number of patients is needed for refined classification of MDS on the basis of new molecular prognostic factors and for indication of more effective targeted therapy.

There is a growing interest in studying cell cycle and apoptosis in the myelodysplastic syndromes (MDS). p53 has been a major target of several studies. We examined the impact of antibody selection on p53 overexpression in bone marrow (BM) biopsies of 28 patients with refractory anemia (RA) in addition to 10 cases of aplastic anemia (AA) using three antibodies DO-7, PAb 1801, and PAb 240. DO-7 was positive in 68%, PAb 1801 in 18% and PAb240 in 4% of RA patients. All three antibodies were negative in AA. We conclude that antibody selection is an important variable in studying p53 in MDS regardless of the method of fixation or decalcification of BM trephine biopsies.

CD34/QBEND10 immunostaining has been assessed in 150 bone marrow biopsies (BMB) including 91 myelodysplastic syndromes (MDS), 16 MDS-related AML, 25 reactive BMB, and 18 cases where RA could neither be established nor ruled out. All cases were reviewed and classified according to the clinical and morphological FAB criteria. The percentage of CD34-positive (CD34 +) hematopoietic cells and the number of clusters of CD34+ cells in 10 HPF were determined. In most cases the CD34+ cell count was similar to the blast percentage determined morphologically. In RA, however, not only typical blasts but also less immature hemopoietic cells lying morphologically between blasts and promyelocytes were stained with CD34. The CD34+ cell count and cluster values 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), in 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 with increased risk of progression of the disease. We conclude that CD34 immunostaining in BMB is a useful tool for distinguishing RA from other anemias, assessing blast percentage in MDS cases, classifying them according to FAB, and following their evolution.

Purpose: To investigate whether the abnormalities observed on femoral marrow magnetic resonance images are related to the development of leukemia and survival of patients with myelodysplastic syndromes (MDS)., Patients and Methods: The findings on magnetic resonance images of the femoral marrow were evaluated over periods of 1 to 92 months (median, 18 months) in 42 consecutive adult patients with newly diagnosed MDS. Magnetic resonance images were obtained by the T1-weighted spin echo method and the short T1 inversion recovery technique., Results: Magnetic resonance images showed that the femoral marrow patterns changed from fatty, faint, or nodular to scattered or uniform as the disease progressed. Development of acute myeloid leukemia was observed in only 13 patients whose marrow exhibited a scattered or uniform pattern. The overall survival of the 29 patients with a scattered or uniform marrow pattern was significantly shorter than that of the 13 patients with a fatty, faint, or nodular marrow pattern (10.7% v 73.3% at 7 years; P < .01). The period of leukemia-free survival was also significantly shorter in the patients with a scattered or uniform marrow pattern versus a fatty, faint, or nodular pattern (37.7% v 100% at 7 years; P < .01)., Conclusion: Magnetic resonance images of the femoral marrow can provide valuable information for assessing the prognosis and determining the most appropriate management of patients with MDS.

Myelodysplastic syndromes (MDS) may be accompanied by systemic mastocytosis. The mechanisms which play a role in the evolution of mastocytosis, however, are not well understood. We report on a case of refractory and anemia with ringed sideroblasts (RARS), and co-existing bone marrow mastocytosis. Compact mast cell (MC) infiltrates were detected in bone marrow sections by immunohistochemistry using an antibody to tryptase. In addition, the MC were found to express c-kit, the tyrosine kinase receptor for MGF (mast cell growth factor = stem cell factor, SCF). Activating point mutations in the kinase domain of c-kit (often found in mastocytosis) were not detectable. However, the mononuclear cells (MNC) of the bone marrow expressed mRNA specific for MITF, a transcription factor that regulates expression of c-kit and differentiation of MC. Surprisingly, the c-kit ligand SCF was found to augment expression of MITF mRNA in bone marrow MNC. Whether this augmentation represents a general response (preventing loss of growth factor receptor expression during cell maturation) common to all types of hemopoietic progenitors, or is confined to (some forms of) mastocytosis, remains unknown.

A previously healthy 74-year-old patient without a prior history of hematological disease presented with an acute respiratory infection. Peripheral pancytopenia led us to perform a bone marrow biopsy, and the diagnosis of undifferentiated acute myelogenous leukemia (AML, 61% blasts) was made. Following antibiotic treatment and resolution of the infection, the blast count in the bone marrow fell to 2%, leaving a clinicopathologic picture consistent with myelodysplastic syndrome (MDS, French-American-British type refractory anemia), and the patient survived for a total of 16.5 months following the initial presentation with cytokine support. A preterminal blast proliferation occurred during a bacterial ear infection and rapidly responded to a withdrawal of cytokine support, antibiotic therapy, and hydroxyurea. The patient succumbed ultimately to an apparent myocardial infarct. Clinicians should consider transient acceleration of MDS in their differential diagnosis when confronted with apparent AML and acute infection.

Myelodysplastic syndromes (MDS) characterized by multilineage cytopenias and dysplasia but lacking an increase in blasts, with no Auer rods or monocytosis, do not exactly fit any of the categories of the French-American-British (FAB) classification of MDS and are often diagnosed as refractory anemia (RA), refractory anemia with ringed sideroblasts (RARS), or 'unclassifiable' MDS. It has been suggested that these 'unclassifiable' cases form a distinct subset with a clinical behavior more like that of refractory anemia with excess of blasts (RAEB) than that of RA or RARS, but few studies have been undertaken that characterize this group. We compared the clinical, hematologic, morphologic and cytogenetic features of 18 such patients - for whose disease we propose the designation 'refractory cytopenia with multilineage dysplasia' (RCMD) - to those of 42 patients meeting the FAB criteria for RA or RARS (14 patients) and RAEB (28 patients). Our results show that cytopenias in RCMD are more severe than those in RA or RARS, but are similar to those in RAEB. Erythroid hyperplasia and dyserythropoiesis are the main findings in bone marrow specimens of RA or RARS, but the major features in RCMD are multilineage proliferation and dysplasia, which, except for the lack of increased blasts resemble the findings in RAEB. Only 1/14 patients (7%) with RA or RARS had an abnormal karyotype, whereas RCMD resembled RAEB in terms of the frequency (41 vs 50%, respectively) and type of karyotypic lesions. Abnormalities of chromosomes 5 and 7 (excluding del(5q) as an isolated finding) or complex aberrations were seen only in RCMD and RAEB. in RCMD, the median survival was 24 months, with a 4-year survival rate of48 +/- 13%, intermediate between the findings in RA/RARS (107 months and 77 +/- 12%, respectively) and RAEB (18 months and 27 +/- 9%, respectively). Our data indicate that RCMD is a distinct subset of MDS, with an unfavorable clinical outcome. The designation 'refractory cytopenia with multilineage dysplasia' emphasizes the differences between such cases and the primarily dyserythropoietic, indolent subgroups of MDS, such as RA or RARS.

Purpose: Myelofibrosis is a common, poor-prognosis feature of myelodysplastic syndromes (MDS). The aim of this work was to evaluate quantitatively the extent of the juxtatrabecular fibrosis in primary MDS and in secondary myelodysplasias, along with the presence of immature precursor cells in anomalous position, that is, the displacement of granulopoiesis from the paratrabecular area to central positions., Patients and Methods: Twenty-seven bone marrow samples were examined: 9 from primary MDS, 9 from secondary myelodysplasias, and 9 normal. The percentage of myeloblasts and promyelocytes with nucleoli located in the central areas was estimated, in an attempt to correlate such feature with the degree of juxtatrabecular fibrosis. The analysis of data was performed with the Kruskal-Wallis test, values of p < 0.01 being significant., Results: Sectorial juxtatrabecular fibrosis was present in all the myelodysplastic samples, ranging from 6% to 55% of the trabecular surface; the highest values found in the controls were about 3.6% (p < 0.01). Although the juxtatrabecular fibrosis figures are higher in secondary MDS, the difference is not significant with regard to the primary MDS in the number of patients studied here. The count of myeloblasts and promyelocytes with nucleoli present in the MDS was significantly greater than that of the control group. The number of promyelocytes with nucleoli was significantly higher in the primary MDS with respect to the secondary ones, whereas no significant difference was seen between the two types of MDS regarding the myeloblast count., Conclusions: The increased number of central immature precursor cells in MDS was not directly correlated with the extent of the juxtatrabecular fibrosis. Although the number of cases is small, the fact that the juxtatrabecular fibrosis was higher in the two deceased patients in the series (49% and 56%, respectively) suggests a poor-risk prognosis for such finding.

A patient with myelodysplastic syndromes (MDS) developed eosinophilia during treatment with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). To study the mechanism of this eosinophilia, we investigated the proliferation of eosinophil colony-forming units (CFU-Eo) in nine patients and four healthy controls. Eosinophil clusters increased significantly in the patients (P < 0.01) compared with controls, but eosinophil colonies were not different between controls and MDS patients. In addition, the eosinophil clusters were significantly increased with rhGM-CSF in MDS patients compared with controls, although serum GM-CSF concentrations were similar in both groups. These results suggest that eosinophil clusters are increased in MDS either through abnormal progenitor proliferation or hypersensitivity to GM-CSF.

We describe a patient with basophilic leukaemia following a 2-year period with myelodysplastic syndrome (refractory anaemia). The marrow showed 59.4% of blasts with 25.0% of mature and immature basophils. The leukaemic blasts contained granules, positively stained with toluidine blue but negative for peroxidase. The basophilic differentiation was confirmed by ultrastructural analysis demonstrating immature basophil granules. In addition, a morphological transition from immature blasts to more mature basophils was observed. Immunophenotypic analysis of blasts and basophils showed positive for CD5, CD7, CD13, CD33 and CD34. Cytogenetic investigation showed an abnormal karyotype, 46,XY,del(5)(q31q35), in 11% of the cells examined when the initial diagnosis of refractory anaemia was made. However, expansion of the same clone up to 100% was observed concomitantly with transformation to basophilic leukaemia.

In this study we used magnetic resonance imaging (MRI) to examine the axial bone marrow of 11 patients with myelodysplastic syndromes (MDS). T1 weighted images showed a reduction in signal intensity in all patients. The degree of reduction in signal intensity correlated with bone marrow cellularity rather than percentage blasts or French-American-British Co-operative group (FAB) classification. T2 weighted images showed an increase in signal intensity in 10 out of 11 patients; however, reliable grading was not possible using this sequence. Both T1 and T2 weighted images indicated a homogeneous pattern of disease within the axial skeleton in MDS. We have also shown that iron deposition in multiply transfused patients is a significant factor influencing signal reduction. The results of this study suggest that MRI may have a diagnostic role in MDS but is unlikely to be of value in staging.

We report the youngest cases of myelodysplastic syndrome (MDS) in two brothers aged 7 and 2 years. The maternal grandfather and maternal grandmother had been exposed to radioactive fallout after the atomic bomb attack on Hiroshima in 1945. The elder brother demonstrated pancytopenia with < 1% blast cells in his peripheral blood and < 5% in his bone marrow at diagnosis. The younger brother was thrombocytopenic without increased blasts. The karyotype of bone marrow cells from the elder brother was 46,XY, -7, +der (7), t(1:7) (lqter-lq11::7q11-7pter), but the younger brother's karyotype was normal. Immature myeloid cells in the bone marrow from both brothers were morphologically abnormal. A diagnosis of refractory anaemia (RA) was made in both brothers. Atavism due to radioactive poisoning was suspected in the development of MDS in these two cases.

We statistically analyzed the hematologic findings of patients with refractory anemia (RA) to identify parameters associated with a poor prognosis. We first separated the RA patients into two groups: one group with disease progression and one without. The patients with disease progression were predominantly male and had a significantly higher percentage of bone marrow (BM) blasts at the time of diagnosis (3.06 +/- 1.29% vs. 1.44 +/- 1.38%, P < 0.005). This finding was confirmed when the patients were separated into the two groups; those who survived and those who expired (BM blasts: 2.68 +/- 1.59% vs. 1.37 +/- 1.27%, P < 0.005). The survival probabilities were calculated depending on whether or not the RA patients had > or = 3% BM blasts. The RA patients with > or = 3% BM blasts had a significantly worse prognosis (P < 0.01) than the patients with < 3% BM blasts. Notably, the RA patients with > or = 3% BM blasts did not show any significant differences in the incidence of disease progression, mortality rate, or survival probability, when compared with the patients with RA with an excess of blasts (RAEB). The present findings indicate that RA patients are heterogeneous with regard to prognosis, and the RA patients with > or = 3% BM blasts might have a poorer prognosis than those with fewer BM blasts. Thus we propose a general approach in predicting the prognosis of RA patients: those with complex chromosomal changes will expire shortly. Secondly, when the patients do not have any complex changes, the prognosis might be linked to the percentage of BM-blasts at the MDS diagnosis.

The in vitro colony-forming capacities of marrow CD34-positive (CD34+) cells from 25 patients with myelodysplastic syndromes (MDS) were studied. In all patients this purified cell population showed erythroid (burst-forming unit erythroid; BFU-E) or non-erythroid colony growth, both of which were more restricted than non-purified mononuclear cell population under stimulation with erythropoietin (EPO) or granulocyte/macrophage colony-stimulating factor (GM-CSF) alone. MDS patients examined were put into two groups; refractory anemia (RA) or RA with ringed sideroblasts (RA/RARS) and RA with excess of blasts (RAEB) or RAEB in transformation (RAEB/RAEB-t). The CD34+ cells of both RA/RARS and RAEB/RAEB-t exhibited a similarity to the cells of normal individuals in their responsiveness to the addition of interleukin 6 (IL-6), IL-3 or stem cell factor (SCF). SCF caused powerful but highly variable responses in both erythroid and nonerythroid colony formation as compared with IL-6 or IL-3. We demonstrated that MDS marrow hematopoietic progenitor cells reactive to GM-CSF or EPO were additionally stimulated with early-acting hematopoietic growth factors including IL-6, IL-3 and SCF in a fashion similar to those of normal individuals.

We report two patients who had been initially diagnosed as having a myelodysplastic syndrome but subsequently progressed into a leukothrombocytosis state which mimicked a chronic myeloproliferative disorder. Both patients had anemia and mild neutropenia without thrombocytopenia at the time of their diagnosis of myelodysplastic syndrome, and dyshematopoietic features were present in the bone marrow. After treatment with vitamin D3 for 7 and 18 months, respectively, they developed leukothrombocytosis which responded to hydroxyurea. We speculate that these and other similar patients with this unusual course might constitute an entity distinct from the typical myelodysplastic syndromes or chronic myeloproliferative disorders.

In vitro colony growth was studied on bone marrow cells from 51 patients with myelodysplastic syndromes (MDS), using a cell culture method with the unique feature of daily feeding, in an effort to gain insight into the pathophysiology of MDS and to assess the clinical utility of this cell culture assay. The colony growth pattern of MDS marrow cells is remarkably similar to that of acute myeloid leukemia but quite dissimilar from that of normal marrow, in support of a common pathophysiological mechanism for these two disorders. In particular, L-ascorbic acid (LAA) enhanced colony growth in 30% and suppressed growth in 16% of cases, a finding also similar to that in acute myeloid leukemia, indicating a unique growth requirement which may be explored for therapeutic purposes. Further, these LAA effects have prognostic value, with LAA-sensitive (both LAA-enhanced and LAA-suppressed) cases displaying shorter survivals than LAA-insensitive cases (median survival of 5 months versus 18 months; P = 0.011). This prognostic value is independent of, and more powerful than, bone marrow blasts; the median survival was 18 months for less than 5% bone marrow blasts and 8 months for greater than 5% bone marrow blasts (P = 0.044). These two risk factors can be used together to identify patients with an extremely good or an extremely poor prognosis. This study establishes the clinical usefulness of the LAA effect in MDS as a prognostic factor and provides a new lead to explore in understanding differential biochemical/molecular events and, possibly, a new therapeutic approach to the management of MDS.

Chromosome analyses of bone marrow and peripheral blood cells were performed in a total of 51 patients with myelodysplastic syndromes (MDS) simultaneously with histopathological examination of resin-embedded bone marrow biopsies. Diagnosis of MDS was established by histopathology according to the French-American-British (FAB) classification, and reassessed by haematological data and clinical course. Clonal karyotypic changes were found in 30 of the 51 patients (59%): in 15 of 19 (79%) patients with refractory anaemia, 7 of 11 (64%) with refractory anaemia and excess of blasts (RAEB), 6 of 10 (60%) with RAEB in transformation, and 2 of 11 (18%) with chronic myelomonocytic leukaemia. The following three features of the histopathology revealed positive correlations with karyotype abnormalities: all cases of myelofibrosis in MDS (7/51) were accompanied by chromosome aberrations, microforms of megakaryocytes with reduced nuclear lobulation were observed in 18 of 30 cases with karyotype changes, and hypocellularity of haematopoiesis was associated with aberrations of chromosome 7 in 2 of 4 cases. No positive correlations were revealed between abnormal karyotypes and the transformation to acute leukaemia. The survival times were significantly decreased in patients with complex (3 and more) karyotype changes, when compared with patients with single (1-2) chromosome aberrations or normal karyotype, independently of the FAB classification.

Dysmegakaryocytopoiesis is an integral component of myelodysplastic syndrome (MDS), and has been shown in some studies to be an independent prognostic factor. Megakaryocytic hypogranulation, a feature we have noticed for some time to be fairly common in MDS and acute myeloid leukaemia (AML), has received little attention in the literature as a dysplastic feature of megakaryocytes. This study was performed to determine how frequently this feature was observed in MDS and the specificity of its occurrence. On review of archival materials, hypogranular megakaryocytes were observed in 80.3% of MDS, 30.6% of AML and 1.4% of controls. On the other hand, the other well-recognized dysmegakaryocytopoietic features (hypolobulation, multiple separate nuclei, micromegakaryocyte), though frequent in MDS or AML, were also observed in 20% of controls. We therefore propose including megakaryocytic hypogranulation as a cytological feature of myelodysplasia.

In 23 patients with myelodysplasia syndromes cytomorphological examinations of peripheral red blood cells and bone marrow cells were carried out. Apart from anisocytosis and poikilocytosis observed in all patients, the most frequent changes were macrocytosis and megalocytosis or erythrocytes and their precursors, presence of erythroblasts in peripheral blood and disturbances of megakaryopoiesis. None of these changes was characteristic in a given type of these syndromes.

Responsiveness of bone marrow erythropoietic stem cells (CFU-E and BFU-E) to recombinant human erythropoietin (rh-Ep) was examined in vitro in 23 patients with aplastic anemia and 14 with myelodysplastic syndrome (MDS) to investigate the clinical use of rh-Ep for these diseases. Bone marrow mononuclear cells were cultured by methylcellulose methods for CFU-E and BFU-E assays. In normals, the CFU-E numbers reached a plateau of increase at Ep doses of almost 2-5 units, and no further increase was observed with the addition of larger Ep doses. In aplastic anemia, the responses of CFU-E to Ep were relatively good in nonsevere type and generally poor in severe type. However, the CFU-E numbers increased with increasing doses of Ep in some of the patients with aplastic anemia. Among the patients with MDS, the responses of CFU-E to Ep were relatively good in primary acquired refractory anemia (PARA) and primary acquired sideroblastic anemia. On the other hand, the responses of CFU-E to Ep were poor in refractory anemia with an excess of blasts (RAEB) and RAEB in transformation among the MDS patients. BFU-E responses to Ep were poor in severe aplastic anemia, RAEB, and RAEB-T. However, there are Ep responsive patients in some of aplastic anemia and PARA. High titers of rh-Ep were suggested to be effective clinically in some patients with aplastic anemia and those with PARA.

Myelodysplastic syndrome (MDS) is frequently associated with monocytosis in the blood and myelomonocytic dysplasia in the bone marrow. In two groups of patients with MDS, all subtypes excluding CMML, the authors demonstrated that monocytosis was present in 15% of the patients in group I according to the haemogram at the time when the diagnosis was established and in 19% in group II where it was required that at least in half the haemograms throughout the course of the disease there were more than 10% monocytes. No difference was found in the prognosis of patients with monocytosis, as compared with patients with monocytopenia as regards the life span and frequency of transformation into AL. The cytogenetic and cultivation findings did not differ either. In some instances, in particular in patients with RA and RAS significant monocytosis was not associated with the expected proliferation of monocytoid cells in bone marrow. The authors assume that proliferation and differentiation of germ cells in the monocytic series is easier than in the granulocytic series and that monocytosis can be considered a manifestation of substituted neutropenia. The work indicates the difficulties associated with the differential diagnosis of RA, RAS and RAEB with monocytosis, MDS with a dominating change of the type of myelomonocytic dysplasia and CMML proper.

Cultural, ultrastructural, cytochemical and histological investigations of bone marrow tissue were conducted in 26 patients with varying types of preleukemia states. A number of early structural, morphological and functional signs of hemopoietic disorders of different character and manifestation degree have been revealed. Particularly, a relationship has been established between the pathologic changes appearing in the bone marrow stroma and disorders in the morphological and functional state of the hemopoietic cells.

One hundred and one patients with refractory cytopenia were reviewed for morphological classification (using bone marrow, BM, imprints for cytology and Jamshidi biopsies for BM cellularity) and clinical course. Final diagnoses were: moderate aplastic anemia (MAA), myelodysplastic syndromes (MDS) and hypoplastic acute leukemia (HAL). Ninety-two patients received high dose testosterone enanthate (TE) as first treatment (starting dose = 7-10 mg/week i.m. for at least three months). Median survival was significantly longer in MAA than in MDS and in HAL. Among MDS patients, those with primary acquired sideroblastic (AISA) and refractory (RA) anemia had median survival similar to those with MAA, but distinctly longer (p = 0.01) than patients with RA with an excess of blasts (RAEB), RAEB in transformation (RAEBtr) and chronic myelomonocytic leukemia (CMMoL). Acute leukemia (AL) developed more rarely (p less than 0.02) in MAA, AISA and RA than in RAEB, RAEBtr and CMMoL. Response to TE was seen in about two thirds of MAA and in a half of MDS and HAL patients. Among MDS patients, those with hypocellular BM developed leukemia less frequently, responded to androgens more often and survived longer than those with normocellular and, especially, with hypercellular BM. These data indicate that the cytohistological classification of refractory cytopenias identifies essentially two groups with different clinical behaviour, one (MAA, AISA and RA) having long life expectancy and a low probability of developing AL and the other (RAEB, RAEBtr, CMMoL) with a short survival and relatively frequent leukemic complication. Bone marrow hypocellularity seems to be a favourable prognostic factor in MDS. Patients with refractory cytopenias, especially those with a hypocellular BM, can be advantageously treated with androgens.

The bone marrow adipocyte colony-forming capacity (Adipo-CFC) in patients with aplastic anemia (AA), myelodysplastic syndrome (MDS) and iron deficiency anemia (IDA) was studied. Before treatment, Adipo-CFC in IDA was higher than that in AA and MDS. After treatment, Adipo-CFC decreased in IDA, but it increased in AA and MDS only at the responsive stage. In this context, it is suggested that increase of Adipo-CFC occurs during not only regenerating hemopoiesis but also accelerated erythropoiesis such as severe IDA. Colony-stimulating activity (CSA) production by marrow stromal cells (MSC) in AA was lower than that in normal subjects. Low Adipo-CFC and defective CSA production by MSC may explain in part the pathogenesis of microenvironmental defect in AA.

Erythroid and myeloid colonies were grown from the bone marrow of 81 patients with myelodysplasia and the median number of colonies correlated with the FAB classification and Bournemouth score. CFU-GM were increased in CMML compared to RAEB and RAEBt. BFU-E were higher in RA than in the other FAB subgroups. Patients with a high Bournemouth score had poorer CFU-GM and BFU-E growth than those with a low score.

Peripheral blood and bone marrow mononuclear cells from patients with refractory anemia (RA) or RA with sideroblasts (defined according to the revised French-American-British classification with less than 5% blast cells in the bone marrow) were analyzed using a panel of monoclonal antibodies directed against leukocyte antigens on B lymphocytes, T lymphocytes, monocytes, and myeloid cells. In the peripheral blood an increased proportion of T lymphocytes (and correspondingly a decreased proportion of B cells) could be demonstrated. However, when expressed in terms of absolute numbers, the T cell component was depressed because of severely decreased numbers of T4+ helper cells. In contrast, the absolute numbers of T8+ suppressor cells were either normal or increased in the majority of the patients. This resulted in markedly decreased ratios of T4+/T8+ cells, which were closely correlated to the number of transfusions given to the patients because of their refractory anemia. Finally, nearly all of the patients exhibited decreased numbers of cells reactive with the N901 natural killer (NK) antibody, thus explaining our earlier finding of decreased NK activity in these patients. In the bone marrow increased proportions of myeloid cells reactive with monoclonal antibodies present on immature myeloid cells (My7 and My9) were found, suggesting the presence of malignant clones. Indeed, when the numbers of My7+ cells and the morphologic evaluations of bone marrow smears at the time of diagnosis were compared to the progression of the disease, a group of patients with high numbers of My7+ cells and normal morphology could be identified that had a high probability of progression to refractory anemia with an excess of blasts or to overt acute myeloid leukemia. Thus, the use of antibodies defining leukocyte differentiation antigens might be of significant value in the diagnosis and prognostication of the myelodysplastic syndromes. These findings are discussed in relation to the pathogenesis of this potentially premalignant condition with special emphasis on possible defects in the immunologic defense mechanisms against early neoplasias.

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.

Megakaryocytic colony formation by precursor cells from the bone marrow was investigated in 10 patients with a myelodysplastic syndrome. All but one exhibited abnormal colony formation: four showed no colony formation at all, while a decreased number of colonies was noticed in five. All of the patients showed defective colony formation by erythroid progenitors, but only four showed clearly abnormal granulocyte-macrophage colony formation. The defect in megakaryocytic progenitors seems to be more akin to the defects occurring in erythroid progenitors than to the defects seen in the granulocyte-macrophage lineage.

The role of peripheral blood mononuclear cells (PB-MNC) on the growth of bone marrow (BM) CFU-GM was investigated in refractory anaemia (RA) patients. Whereas normal donor PB-MNC were found to inhibit autologous day 7 CFU-GM, PB-MNC from RA patients exhibited little modulatory effect on autologous or allogeneic day 7 CFU-GM. In contrast, patient PB-MNC inhibited autologous CFU-GM at day 10 at a time where no significant inhibition was seen in the PB-MNC/RA CFU-GM combination. The identity of the inhibitory cells was investigated using anti-T8+ and anti-N901+ subsets purified by immune-rosette depletion with a panel of monoclonal antibodies. The activity of these subsets was tested on immature myeloid cells enriched for MY7+ cells, and it was found that cells highly enriched for NK cells were responsible for the inhibition. Further support for NK cells as the inhibitory cells was obtained in experiments where a positive correlation between the level of PB NK cytotoxicity against K562 cells and the degree of CFU-GM inhibition was demonstrated. Thus, these data suggest the presence of a specialized subset of NK cells with a capacity to inhibit autologous CFU-GM. Since RA is a potentially premalignant disease, in which a significant number of cases transform into AML, these findings also suggest a physiological role for NK cells in suppression of newly arisen clonogenic cells at least in early stages of the disease.

34 patients with primary myelodysplastic syndrome (MDS), initially diagnosed as subtypes refractory anaemia (RA) and RA with ringed sideroblasts (RA-S), were followed to investigate the distribution of lymphoid and myeloid differentiation antigens in the blood and bone marrow in search of potential prognostic significance with regard to progression to RA with an excess of blasts (RAEB) or acute myeloid leukaemia, and for relations to clinical, morphological and cytogenetic findings. Patients who later progressed to RAEB had significantly decreased percentages of anti-T8 positive T-suppressor cells in the blood at diagnosis compared to those who did not (p = 0.05). Sequential analysis showed a decrease with time also in the percentages of anti-T8-positive cells (p = 0.05). In the bone marrow, progressing patients initially showed significantly increased percentages of anti-My9-positive immature myeloid cells (p less than 0.001), and the percentages of anti-My9-positive cells in the bone marrow increased with time (p less than 0.005). Analysis of the pooled data revealed a statistically significant relation between increasing percentages of anti-My9-positive cells and the frequencies of clonally abnormal (p less than 0.001) and abnormal (p = 0.004) metaphases.