Teresa Vallespi

Diagnosis and classification of myelodysplastic syndrome: International Working Group on Morphology of myelodysplastic syndrome (IWGM-MDS) consensus proposals for the definition and enumeration of myeloblasts and ring sideroblasts

This article details the proposals of the IWGM-MDS for the definition of myeloblasts, promyelocytes and ring side-roblasts in patients with myelodysplastic syndrome. The classification of myelodysplastic syndromes is based on the morphological criteria proposed by the French-American-British (FAB) and World Health Organization (WHO) groups. Accurate enumeration of blast cells, although essential for diagnosis of myelodysplastic syndrome and for assignment to prognostic groups, is often difficult, due to imprecise criteria for the morphological definition of blasts and promyelocytes. An International Working Group on Morphology of Myelodysplastic Syndrome (IWGM-MDS) of hematopathologists and hematologists expert in the field of myelodysplastic syndrome reviewed the morphological features of bone marrows from all subtypes of myelodysplastic syndrome and agreed on a set of recommendations, including recommendations for the definition and enumeration of blast cells and ring sideroblasts. It is recommended that (1) agranular or granular blast cells be defined (replacing the previous type I, II and III blasts), (2) dysplastic promyelocytes be distinguished from cytologically normal promyelocytes and from granular blast cells, (3) sufficient cells be counted to give a precise blast percentage, particularly at thresholds that are important for diagnosis or prognosis and (4) ring sideroblasts be defined as erythroblasts in which there are a minimum of 5 siderotic granules covering at least a third of the nuclear circumference. Clear definitions and a differential count of a sufficient number of cells is likely to improve precision in the diagnosis and classification of myelodysplastic syndrome. Recommendations should be applied in the context of the WHO classification.

Cytogenetic risk stratification in chronic myelomonocytic leukemia

Background The prognostic value of cytogenetic findings in chronic myelomonocytic leukemia is unclear. Our purpose was to evaluate the independent prognostic impact of cytogenetic abnormalities in a large series of patients with chronic myelomonocytic leukemia included in the database of the Spanish Registry of Myelodysplastic Syndromes. Design and Methods We studied 414 patients with chronic myelomonocytic leukemia according to WHO criteria and with a successful conventional cytogenetic analysis at diagnosis. Different patient and disease characteristics were examined by univariate and multivariate methods to establish their relationship with overall survival and evolution to acute myeloid leukemia. Results Patients with abnormal karyotype (110 patients, 27%) had poorer overall survival (P=0.001) and higher risk of acute myeloid leukemia evolution (P=0.010). Based on outcome analysis, three cytogenetic risk categories were identified: low risk (normal karyotype or loss of Y chromosome as a single anomaly), high risk (presence of trisomy 8 or abnormalities of chromosome 7, or complex karyotype), and intermediate risk (all other abnormalities). Overall survival at five years for patients in the low, intermediate, and high risk cytogenetic categories was 35%, 26%, and 4%, respectively (P<0.001). Multivariate analysis confirmed that this new CMML-specific cytogenetic risk stratification was an independent prognostic variable for overall survival (P=0.001). Additionally, patients belonging to the high-risk cytogenetic category also had a higher risk of acute myeloid leukemia evolution on univariate (P=0.001) but not multivariate analysis. Conclusions Cytogenetic findings have a strong prognostic impact in patients with chronic myelomonocytic leukemia.

Standardization of flow cytometry in myelodysplastic syndromes: a report from an international consortium and the European LeukemiaNet Working Group

Flow cytometry (FC) is increasingly recognized as an important tool in the diagnosis and prognosis of myelodysplastic syndromes (MDS). However, validation of current assays and agreement upon the techniques are prerequisites for its widespread acceptance and application in clinical practice. Therefore, a working group was initiated (Amsterdam, 2008) to discuss and propose standards for FC in MDS. In 2009 and 2010, representatives from 23, mainly European, institutes participated in the second and third European LeukemiaNet (ELN) MDS workshops. In the present report, minimal requirements to analyze dysplasia are refined. The proposed core markers should enable a categorization of FC results in cytopenic patients as ‘normal’, ‘suggestive of’, or ‘diagnostic of’ MDS. An FC report should include a description of validated FC abnormalities such as aberrant marker expression on myeloid progenitors and, furthermore, dysgranulopoiesis and/or dysmonocytopoiesis, if at least two abnormalities are evidenced. The working group is dedicated to initiate further studies to establish robust diagnostic and prognostic FC panels in MDS. An ultimate goal is to refine and improve diagnosis and prognostic scoring systems. Finally, the working group stresses that FC should be part of an integrated diagnosis rather than a separate technique.

Myelodysplastic syndromes: a study of 101 cases according to the FAB classification

Summary. The myelodysplastic syndromes (MDS) are a group of closely related disorders characterized by chronic cytopenias with cellular marrow, poor prognosis and refractoriness to treatment. We studied 101 consecutive cases of MDS diagnosed over a 7–year period. Peripheral blood (PB) and bone marrow (BM) samples were reviewed and classified according to the proposals of the French–American–British (FAB) cooperative group for MDS. The combined analysis of the initial laboratory features and qualitative haematological abnormalities readily allowed the distinction between the different subgroups. Thirty‐two of 79 cases (40.5%) evolved towards other diseases, frequently acute leukaemia (24/79, 30%), or transformed into other MDS (7/79, 9%). In five cases, initially classified as refractory anaemia (RA) or refractory anaemia with ring sideroblasts (RAS), a transitory change to another type of MDS—two chronic myelomonocytic leukaemias (CMML), two refractory anaemias with excess of blasts (RAEB) and one refractory anaemia with excess of blasts ‘in transformation’(RAEB‐t)—was observed before the evolution towards acute leukaemia. This provides a new link between all these syndromes and increases the number of transitions to other MDS. Overall prognosis was very poor, with differences between subgroups. RA had the best prognosis whereas RAEB‐t had the worst one. This study shows that the FAB classification is readily usable and defines well‐characterized subgroups of MDS, although there are frequent transitional forms, and as the natural history of the MDS unfolds they may convert into another. The actual poor prognosis and the frequent evolution towards acute leukaemia makes necessary to investigate new methods of treatment for these disorders.

Impact of adjunct cytogenetic abnormalities for prognostic stratification in patients with myelodysplastic syndrome and deletion 5q.

This cooperative study assessed prognostic factors for overall survival (OS) and risk of transformation to acute myeloid leukemia (AML) in 541 patients with de novo myelodysplastic syndrome (MDS) and deletion 5q. Additional chromosomal abnormalities were strongly related to different patients’ characteristics. In multivariate analysis, the most important predictors of both OS and AML transformation risk were number of chromosomal abnormalities (P<0.001 for both outcomes), platelet count (P<0.001 and P=0.001, respectively) and proportion of bone marrow blasts (P<0.001 and P=0.016, respectively). The number of chromosomal abnormalities defined three risk categories for AML transformation (del(5q), del(5q)+1 and del(5q)+⩾2 abnormalities) and two for OS (one group: del(5q) and del(5q)+1; and del(5q)+⩾2 abnormalities, as the other one); with a median survival time of 58.0 and 6.8 months, respectively. Platelet count (P=0.001) and age (P=0.034) predicted OS in patients with ‘5q−syndrome’. This study demonstrates the importance of additional chromosomal abnormalities in MDS patients with deletion 5q, challenges the current ‘5q−syndrome’ definition and constitutes a useful reference series to properly analyze the results of clinical trials in these patients.

Chronic lymphocytic leukaemia: prognostic value of lymphocyte morphological subtypes. A multivariate survival analysis in 146 patients

Summary. Among other patient and disease characteristics, different morphological lymphocyte subtypes were analysed in 146 patients with chronic lymphocytic leukaemia (CLL) to establish their clinical significance and prognostic value. The univariate analysis selected, among other well‐known variables, the following lymphocyte subtypes as significant in prognosis: prolymphocytes, granulated lymphocytes, cleaved lymphocytes and small‐size lymphocytes. The presence of prolymphocytes and cleaved lymphocytes was correlated with a poor prognosis, whereas granular lymphocytes and small‐size lymphocytes were related to a good prognosis. A multivariate regression analysis showed that, besides clinical stages, haemoglobin level. WBC count, age, percentage of bone marrow erythroid cells, and sex, only prolymphocytes had independent prognostic significance. Prolymphocyte percentage correlated positively with characteristics expressing tumour mass such as WBC count, blood absolute lymphocyte count, serum lactate dehydrogenase level. number of enlarged lymph nodes, splenomegaly, and a high number of lymphocytes in bone marrow aspirate. Finally, a prolymphocyte threshold of 5 × 109/l was found to be useful not only to separate two different groups of patients in the whole series but also in Rais stages II and III + IV, and in Binets stages A and C.

Bone marrow biopsy in myelodysplastic syndromes : morphological characteristics and contribution to the study of prognostic factors

Ten characteristics of bone marrow (BM) biopsies in paraffin sections, obtained at diagnosis from patients with myelodysplastic syndromes (MDS) classified according to the FAB criteria, were analysed to identify both the most relevant morphologic data and any possible influence on survival.

Two groups of chronic myelomonocytic leukaemia: myelodysplastic and myeloproliferative. Prognostic implications in a series of a single center

The clinical records of 70 patients seen at our hospital between 1976 and 1998 and diagnosed as suffering from chronic myelomonocytic leukaemia (CMML) were reviewed in order to confirm the validity of the classification into two forms of disease that the French-American-British Co-operative Leukaemia Group (FAB) proposed in 1994: myelodysplastic (MD) and myeloproliferative (MP), depending on the peripheral white blood cell count (WBC) (less or more than 13 x 10(9)/l, respectively). After the rejection of incomplete records and lost to follow up patients, our study population consisted of 49 records. Our results confirm that, even though this classification is useful in order to separate two classes of patients, it is not enough to predict the prognosis in an accurate manner. A lot of studies have tried to find some prognostic factors, but the results have been discordant. The multivariate analysis of our group of patients showed three prognostic factors: serum lactate dehydrogenase (LDH) >1.5 times normal level, blasts in bone marrow >5%, and peripheral blood leukocytes >10 x 10(9)/l. A second multivariate analysis led us to distinguish two groups: high risk (2-3 risk factors) and low risk (0-1 risk factors) (median survival 7 and 44 months, respectively) with a very high statistic significance (P<0.0001). This score should be applied to other series of CMML patients in order to confirm its validity.

Complex, Not Monosomal, Karyotype Is the Cytogenetic Marker of Poorest Prognosis in Patients With Primary Myelodysplastic Syndrome

PURPOSE Complex karyotype (CK) is the poorest risk factor in patients with myelodysplastic syndrome (MDS). It has recently been reported that monosomal karyotype (MK) worsens the prognosis of patients with CK. PATIENTS AND METHODS; We analyzed 1,054 adult patients with MDS with an abnormal karyotype from the Spanish Registry of MDS. The aim of the study was to describe the incidence, characteristics, and prognosis of MK; the main end points were overall survival (OS) and leukemia-free survival. RESULTS MK was identified in 172 patients (16%), most of whom (88%) presented with CK. Variables significantly associated with OS were age (hazard ratio [HR], 1.90; P < .001), bone marrow (BM) blast percentage (HR, 1.05; P < .001), hemoglobin level (HR, 1.71; P < .001), platelet count (HR, 1.41; P < .001), karyotype complexity (CK [three abnormalities]: HR, 1.81; P = .003; very CK [> three abnormalities]: HR, 2; P < .001), and abnormalities of chromosome 5 and/or 7 (HR, 1.89; P < .001). Variables significantly related to the risk of transformation to acute myeloid leukemia (AML) were higher BM blast percentage (HR, 1.12; P < .001) and karyotype complexity (CK: HR, 2.53; P = .002; very CK: HR, 2.77; P < .001). CONCLUSION After accounting for karyotype complexity, MK was not associated with OS or evolution to AML. In conclusion, these results demonstrate that the prognostic value of MK in MDS is not independent and is mainly the result of its strong association with number of chromosomal abnormalities.

Morphological evaluation of monocytes and their precursors

This study establishes morphological definitions so that monocytes, including immature monocytes, can be reliably separated from the spectrum of monocyte precursors. The monocyte is still the most difficult cell to identify with confidence in the peripheral blood or in the bone marrow in healthy individuals as well as in patients with infections, and in those with leukemic proliferations. The goal of this study was to establish morphological definitions so that monocytes, including immature monocytes, could be separated from the spectrum of monocyte precursors. Cells from peripheral blood or bone marrow were selected to provide a large panel of normal and leukemic cells at different maturational stages and were submitted to 5 experts, who had previously reached a consensus, on the basis of microscopy, in defining 4 subtypes: monoblast, promonocyte, immature monocyte, mature, monocyte. They achieved a good concordance rate of 76.6% and a high κ rate confirming that the criteria for defining the 4 subtypes could be applied consistently. It has now to be established whether these monocyte subtypes correlate with immunological or molecular markers and are clinically relevant.