Transformation of chronic myelomonocytic leukemia to acute lymphoblastic leukemia: Case report and review of the literature of lymphoblastic transformation of myelodysplastic syndrome

If chronic myelomonocytic leukemia (CMML) transforms into an acute leukemic phase, the blast crisis is invariably myeloid. Occasionally, the other subtypes of myelodysplastic syndrome (MDS) (refractory anemia, refractory anemia with ringed sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation) have been noted to transform into acute lymphoblastic leukemia (ALL). We now report a case of CMML that transformed into ALL and we review the literature of 13 other cases of MDS with ALL transformation. Such cases provide suggestive clinical evidence that MDS can involve a pluripotent stem cell. © 1955 Wiley-Liss, Inc.     

Clinical significance of phenotypic features of blasts in patients with myelodysplastic syndrome

Knowledge of the blast phenotype in myelodysplastic syndrome (MDS) would be valuable, as in other malignancies, but remains sparse. This is mainly because MDS blasts are a minor population in clinical samples, making analysis difficult. Thus, for this blast phenotype study, we prepared blast-rich specimens (using a new density centrifugation reagent for harvesting blasts) from blood and marrow samples of 95 patients with various MDS subtypes and 21 patients with acute leukemia transformed from MDS (AL-MDS). Flow cytometry revealed that a high proportion of the enriched blast cells (EBCs) from almost all patients showed an immunophenotype of committed myeloid precursors (CD34(+)CD38(+)HLA-DR(+)CD13(+)CD33(+)), regardless of the disease subtype. The cytochemical reaction for myeloperoxidase was negative in 58% of the cases. Thus, the EBC phenotype is more immature in MDS than in de novo acute myeloid leukemia. MDS EBCs often coexpressed stem cell antigens and late-stage myeloid antigens asynchronously, but rarely expressed T- and B-lymphoid cell-specific antigens. Markers for myeloid cell maturation (CD10 and CD15) were more prevalent on EBCs from low-risk MDS (refractory anemia [RA] and RA with ringed sideroblasts), whereas markers for myeloid cell immaturity (CD7 and CD117) were more prevalent on EBCs from high-risk MDS (chronic myelomonocytic leukemia, RA with excess blasts [RAEB], and RAEB in transformation) and AL-MDS. A shift to a more immature phenotype of EBCs, accompanying disease progression, was also documented by sequential phenotyping of the same patients. Further, CD7 positivity of EBCs was an independent variable for a poor prognosis in MDS. These data represent new, valuable information regarding MDS.     

The role of aggressive chemotherapy in the treatment of the myelodysplastic syndromes

Fifteen patients with the initial diagnosis of myelodysplastic syndrome (MDS) received aggressive chemotherapy with high dose cytarabine or with a standard acute myeloid leukaemia (AML) regime. Cases treated with aggressive chemotherapy were either younger individuals with refractory anaemia with excess of blasts (RAEB) or patients, irrespective of age in advanced stages of MDS (RAEB in transformation or after evolution to frank AML), who did not have a major infection at the time of presentation. Age seemed to be the most important factor in determining the outcome of aggressive remission induction chemotherapy in MDS: 86% of the patients less than 50 years entered complete remission, compared to only 25% in the older age group. In spite of intensive consolidation therapy the duration of complete remission was short. We conclude that young patients (less than 50 years) with excess of bone marrow blasts should be treated with aggressive chemotherapy even in the early stages of the disease. Elderly patients in advanced stages of MDS should be treated with less aggressive chemotherapy.     

Manifestations systémiques et auto-immunes des syndromes myélodysplasiques

Myelodysplastic syndromes (MDS) can be associated with systemic or autoimmune diseases. Vasculitides (leucocytoclastic, periarteritis nodosa, micropolyangeitis, Wegener's granulomatosis), relapsing polychondritis, and Sweet's syndrome are the most commonly reported. Refractory anemia with excess of blasts (RAEB), transformed RAEB evolving to an acute leukemia, and chronic myelomonocytic leukemia (CMML) are preferentially associated with these vasculitides or systemic diseases. Corticosteroids are generally effective. Immunosuppressive drugs expose these patients to infectious complications and increase the risk of transformation into acute leukemia. Occurrence of relapsing polychondritis in a patient older than 60 years is associated with a myelodysplastic syndrome in 40% of the cases. Sweet's syndrome is associated in 10% of the cases with acute myeloid leukemia and MDS. Polyarthritis or oligoarthritis with systemic manifestations that include fever, skin rash, and more rarely serositis or haemolytic anemia can occur contemporarily to a MDS. Behçet's disease with intestinal involvement has been reported in patients presenting with trisomy 8 associated MDS. Pathogenic mechanisms underlying the association between MDS and autoimmune or systemic disorders remain to be elucidated.     

Advances in the prognostication and management of advanced MDS in children

Advanced myelodysplastic syndrome (MDS) in children includes refractory anaemia with excess blasts (RAEB) and RAEB in transformation (RAEB-T) according to the paediatric modification of the World Health Organization classification. Clinical features and cytogenetics are essential to make a diagnosis because blast count alone is insufficient to differentiate MDS from acute myeloid leukaemia (AML). Little is known about molecular genetics in paediatric MDS but hypermethylation seem to be frequent. Monosomy 7 is the most common cytogenetic aberration but prognostic neutral whereas those with structural complex karyotype have a very poor outcome. Haematopoietic stem cell transplantation (HSCT) is the treatment of choice and results in cure rates of around 60%. Intensive chemotherapy prior to HSCT provides no survival benefit for children with RAEB and RAEB-T and can generally not be recommended. Intensive chemotherapy before HSCT should be considered in patients with myelodysplasia-related-AML (MDR-AML).     

Bmi-1 is useful as a novel molecular marker for predicting progression of myelodysplastic syndrome and patient prognosis

The International Prognostic Scoring System (IPSS) has been widely used to predict the prognosis of patients with myelodysplastic syndrome (MDS). However, IPSS does not always provide a sufficiently precise evaluation of patients to allow the appropriate choice of clinical interventions. Here, we analyzed the expression of Bmi-1, which is required to regulate the self-renewal in CD34+ cells from 51 patients with cases of MDS and acute myeloid leukemia preceded by MDS (MDS-AML). Higher positivity rate of Bmi-1 was preferentially seen in refractory anemia with excess blasts (RAEB), RAEB in transformation (RAEB-T), and MDS-AML compared with refractory anemia (RA) and RA with ringed sideroblasts (RARS). IPSS score was positively correlated with the percentage of Bmi-1 expression. Patients with RA and RARS with a higher percentage of Bmi-1+ cells showed disease progression to RAEB. Here, we propose Bmi-1 as a novel molecular marker to predict the progression and prognosis of MDS.     

Lineage conversion from acute lymphoblastic leukemia to acute myeloid leukemia on rearrangement of the IgH gene in a patient with Down syndrome

A patient with Down syndrome (DS) at the time of diagnosis of acute lymphoblastic leukemia (ALL) had a relapse with acute myeloid leukemia (AML) after 4 years of complete remission. Although the diagnosis was AML, the leukemic blasts at relapse showed an immunoglobulin H rearrangement that turned out to be identical to that of the initial ALL blasts. It is thought that the leukemic precursor cells of this patient had the potential to differentiate into both lymphoid and myeloid lineages. This case is important for investigating target cells for leukemogenesis in DS.     

Acute leukemia after a primary myelodysplastic syndrome: immunophenotypic, genotypic, and clinical characteristics.

We studied the nature of blast cells in 41 patients with acute leukemia following a previous primary myelodysplastic syndrome (MDS) by a combined multiparameter analysis including morphologic, immunophenotypic, and molecular genetic (Igs, T-cell receptor (TCR)-beta, -gamma, and -delta and the major breakpoint cluster region [M-bcr]) investigations. In addition, the clinical and hematologic characteristics according to the immunophenotype of blast cells were analyzed. Our results show that, although the granulocytic and/or monocytic lineages are those most commonly involved in these acute leukemias, other cell components, including the megakaryocytic and lymphoid, may be present (12% and 15% of the cases, respectively). Moreover, both morphologic and phenotypic studies show the frequent coexistence of two or three cell populations. Interestingly, in all cases the lymphoblastic component constantly displayed an early B phenotype (CD19+, CD10-, TdT+). Upon analyzing whether the type of MDS conditioned any differences in the immunophenotype of blast cells, we observed that, although the lymphoid lineage may be involved in all MDS subgroups, some differences emerge within the myeloid leukemic transformations. Thus, the refractory anemias with excess of blasts (RAEB) and RAEB in transformation displayed a significantly higher incidence of myeloblastic and megakaryoblastic transformations, while in the RA, RA with ring sideroblasts and chronic myelomonocytic leukemia, the granulo-monocytic phenotype predominated. In addition, our results show that the clinical and hematologic characteristics of these patients may be partially related to the immunophenotype of the blast cells. Ig heavy chain gene rearrangements were found in two of 19 patients analyzed (11%), one with a hybrid leukemia (lymphoid-myeloid) and the other with a granulo-monocytic phenotype. Two other hybrid transformations analyzed were in germline configuration. Gamma and delta gene rearrangements were found in 21% and 37% of these acute transformation, respectively. The TCR-beta and M-bcr were in germline configuration in all 19 cases studied. In summary, immunophenotype and molecular studies point to a pluripotent stem cell with preferential myeloid commitment as the target cell of leukemias following a primary MDS.     

Myelodysplastic syndrome transformed into Acute Lymphoblastic Leukaemia (FAB:L3)

Myelodysplastic syndrome (MDS) is recognized as a preleukaemic disorder with a variable risk of transformation to acute myeloid leukaemia. Usually the blast cells in leukaemia are transformed after MDS displays a myeloid phenotype. Even though lymphoid progression had been reported previously, most displayed myeloid-lymphoid hybrid or early B phenotype. We report a case of an elderly man who had MDS transformed into Acute Lymphoblastic Leukaemia (ALL:L3) which is a rare lymphoid transformation.     

Progression from myelodysplastic syndrome to acute lymphoblastic leukaemia with Philadelphia chromosome and p190 BCR-ABL transcript

We describe a patient with Philadelphia chromosome (Ph¹)-positive acute lymphoblastic leukaemia (ALL) who developed it 2.5 years after being diagnosed with myelodysplastic syndrome (MDS). The patient initially had refractory anaemia (RA), but progressed to refractory anaemia with excess blasts (RAEB) 2 years later, that terminated in ALL. An immunophenotypic analysis of the lymphoblasts revealed CD10 and CD19 positive cells. The karyotype was normal 46,XY in RA phase, 46,XY,20q– during the RAEB phase, and 46,XY, t(9;22)(q34;q11), 20q– during the ALL phase. Furthermore, p190 BCR-ABL mRNA was detected in the ALL blasts. These findings indicate that this ALL arose from the MDS clone through multiple cytogenetic evolutions, the final event of which was the acquisition of p190 BCR-ABL type Ph¹     

Humoral immune responses against Wilms tumor gene WT1 product in patients with hematopoietic malignancies

Wilms tumor gene WT1 is expressed at high levels in hematopoietic malignancies, such as leukemias and myelodysplastic syndromes (MDS), and in various kinds of solid tumors, including lung cancer, and it exerts an oncogenic function in these malignancies. IgM and IgG WT1 antibodies were measured by means of dot blot assay in 73 patients with hematopoietic malignancies (16 acute myeloid leukemia [AML], 11 acute lymphoid leukemia [ALL], 13 chronic myeloid leukemia [CML], and 33 MDS) and 43 healthy volunteers. Immunoglobulin IgM, IgG, and IgM+IgG WT1 antibodies were detected in 40 (54.8%), 40 (54.8%), and 24 (32.8%), respectively, of the 73 patients with hematopoietic malignancies, whereas 7 (16.2%), 2 (4.7%), and none of the 43 healthy volunteers had IgM, IgG, or IgM+IgG WT1 antibodies, respectively. Furthermore, immunoglobulin isotype class switching of WT1 antibodies from IgM to IgG occurred in conjunction with disease progression from refractory anemia (RA) to RA with excess of blasts (RAEB), and further to RAEB in transformation (RAEB-t) in MDS patients. These results showed that humoral immune responses against the WT1 protein could be elicited in patients with WT1-expressing hematopoietic malignancies, and they suggested that the helper T-cell responses needed to induce humoral immune responses and immunoglobulin isotype class switching from IgM to IgG were also generated in these patients. Our findings may provide new insight into the rationale for elicitation of cytotoxic T-cell responses against the WT1 protein in cancer immunotherapy using the WT1 vaccine.     

Primary myelodysplastic syndrome in children--clinical, hematological and histomorphological profile from a tertiary care centre in India

We describe the clinical, hematological and histomorphological features in children of primary myelodysplastic syndrome (MDS) seen at the All India Institute of Medical Sciences over three years (Jan 2001-Jan 2004). Twenty-one patients of primary MDS aged 17 year or less were classified using the latest proposed WHO classification for Pediatric MDS. The median age was 9 years with male predominance (80%). Pallor was present in all the cases while fever and bleeding diathesis was present in more than 50% of the cases. Morphological assessment of the peripheral blood showed macrocytosis in 50%, pancytopenia in 15% and blast cells in 45% of cases. A complete analysis of clinical features in conjunction with the bone marrow profile revealed 8 cases of refractory cytopenia (RC), 3 cases of refractory anemia with excess blasts (RAEB), 5 cases of refractory anemia with excess blasts in transformation (RAEB-T), 4 cases of Juvenile myelomonocytic leukemia (JMML) and a solitary cases of acute myeloid leukemia (AML) in Downs syndrome.These children were followed up from 1-36 months (mean 15 months). Three patients of RAEB-T progressed to AML within 3-4 months. RC had the best prognosis and all are alive and under regular follow up. The solitary case of AML of Downs syndrome died 1.5 months after initial diagnosis. All 3 cases of RAEB are under regular follow-up and doing well. Three cases of RAEB-T died (all had progressed to AML); the remaining 2 cases were lost to follow up. Of the 4 cases of JMML 1 died within 6 months of diagnosis; the other 3 cases are under regular follow up of whom 1 has a progressively increasing blast count.We conclude that the latest proposed WHO classification for Pediatric MDS can be successfully applied to all cases of primary MDS.     

Transformation of severe aplastic anemia to myelodysplastic syndrome with monosomy 7 in a patient who achieved transfusion independence after immunosuppressive therapy

A 72-year-old woman was given a diagnosis of severe aplastic anemia, and treated with anabolic steroid and cyclosporin A starting in October 1996. Because this treatment was ineffective, anti-thymocyte globulin (ATG) therapy was started in September 1997. In May 1998, chromosome analysis revealed transformation to myelodysplastic syndrome (MDS), refractory anemia with excess of blasts with monosomy 7 in 60% of metaphase cells. The patient showed gradual hematologic improvement and became transfusion independent. Despite progression to acute myeloid leukemia (FAB-M6) with monosomy 7 in 100% of metaphase cells in December 1998, the hemoglobin level recovered to 13.2 g/dl. In May 1999 the blasts increased rapidly and transformation to acute myelomonocytic leukemia (FAB-M4) was diagnosed. The patient was treated with low-dose Ara-C and aclarubicin with no improvement and died in August 1999. This case demonstrated the transformation of severe aplastic anemia to acute myeloid leukemia via MDS with monosomy 7 associated with transfusion independence after immunosuppressive therapy. These findings suggested a close relationship between aplastic anemia and hypoplastic MDS and the possibility of hematologic improvement based on the growth advantage of abnormal clones.     

Therapy-related myelodysplastic syndrome with monosomy 5 after successful treatment of acute myeloid leukemia (M2)

We describe a patient who developed myelodysplastic syndrome over 2 years after achieving complete remission of acute myeloid leukemia (AML). The patient was treated in July 1998 with anthracycline, etoposide, and behenoyl cytarabine chemotherapy for AML (French-American-British classification, M2; World Health Organization classification, AML with maturation) and achieved complete remission. At presentation, no chromosomal abnormalities were detected. In December 2000, the patient's peripheral blood revealed pancytopenia, and his bone marrow was hypocellular with trilineage myelodysplasia and no blasts. Chromosomal analysis revealed complex karyotypic abnormalities, including monosomy 5. The patient was diagnosed with high-grade myelodysplastic syndrome (MDS)/refractory anemia with excess blasts (RAEB) subtype. The pancytopenia progressed rapidly, and he died 2 months after the diagnosis of MDS. Therapy-related MDS and AML (t-MDS/t-AML) developing after treatment for acute leukemia is unusual; the primary leukemia associated with most cases of t-MDS/t-AML is acute promyelocytic leukemia (APL). This unusual case suggests that AML excluding APL should be considered a primary hematologic malignancy for t-MDS/t-AML.     

Primary myelodysplastic syndrome in children—clinical,hematological and histomorphological profile from a tertiary care centre in India

We describe the clinical, hematological and histomorphological features in children of primary myelodysplastic syndrome (MDS) seen at the All India Institute of Medical Sciences over three years (Jan 2001–Jan 2004). Twenty-one patients of primary MDS aged 17 year or less were classified using the latest proposed WHO classification for Pediatric MDS. The median age was 9 years with male predominance (80%). Pallor was present in all the cases while fever and bleeding diathesis was present in more than 50% of the cases. Morphological assessment of the peripheral blood showed macrocytosis in 50%, pancytopenia in 15% and blast cells in 45% of cases. A complete analysis of clinical features in conjunction with the bone marrow profile revealed 8 cases of refractory cytopenia (RC), 3 cases of refractory anemia with excess blasts (RAEB), 5 cases of refractory anemia with excess blasts in transformation (RAEB-T), 4 cases of Juvenile myelomonocytic leukemia (JMML) and a solitary cases of acute myeloid leukemia (AML) in Downs syndrome.

These children were followed up from 1–36 months (mean 15 months). Three patients of RAEB-T progressed to AML within 3–4 months. RC had the best prognosis and all are alive and under regular follow up. The solitary case of AML of Downs syndrome died 1.5 months after initial diagnosis. All 3 cases of RAEB are under regular follow-up and doing well. Three cases of RAEB-T died (all had progressed to AML); the remaining 2 cases were lost to follow up. Of the 4 cases of JMML 1 died within 6 months of diagnosis; the other 3 cases are under regular follow up of whom 1 has a progressively increasing blast count.

We conclude that the latest proposed WHO classification for Pediatric MDS can be successfully applied to all cases of primary MDS.     

低增生骨髓增生异常综合征的由来和转归

目的探讨低增生骨髓增生异常综合征（ＭＤＳ）的由来和发展。方法对我院１０年中确诊的２５例低增生ＭＤＳ进行了系统分析,对其中１７例患者进行长期追访。结果（１）低增生ＭＤＳ占同期确诊为ＭＤＳ的２１９例患者中１１．４％,确诊时平均年龄为（４４．８±１４．７）岁。（２）ＦＡＢ分型：难治性贫血（ＲＡ）１１例,难治性贫血伴原始细胞增多（ＲＡＥＢ）１４例。（３）低增生ＭＤＳ很可能是ＭＤＳ患者病程中一个阶段,其骨髓增生活跃和低下可以相互转化,这种转化不但可以发生在同一ＦＡＢ亚型内,也可以发生在不同亚型相互转化时。（４）长期随访的１７例患者中有７例转为急性白血病,占４１．２％,６例为急性粒细胞白血病,１例为急性淋巴细胞白血病;７例中３例转为低增生白血病,４例为增生活跃或极度活跃白血病。（５）１７例患者中７例自低增生ＲＡＥＢ转为急性白血病时间为１～７４个月,中数为２７个月。（６）低增生ＭＤＳ的产生与治疗药物无明显相关。结论低增生ＭＤＳ很可能为ＭＤＳ病程中一个阶段而非一种特殊类型。     

Methylation of the p15(INK4B) gene in myelodysplastic syndrome: it can be detected early at diagnosis or during disease progression and is highly associated with leukaemic transformation

To investigate the time sequence of occurrence of p15(INK4B) gene methylation in myelodysplastic syndrome (MDS) and its correlation with leukaemic transformation and survival of patients, the methylation status of the p15(INK4B) promoter region was analysed in 50 patients and was serially studied in 22 of them. Of the 50 patients, 17 (34%) showed p15(INK4B) gene methylation, first demonstrated at diagnosis or during follow-up. When FAB subtypes at the time of study were used in the analysis, the incidence of (p15INK4B) methylation in each risk group of MDS remained stable throughout the course: 0% for low-risk MDS [refractory anaemia (RA) and RA with ring sideroblasts] and from 23% at diagnosis to 30% for high-risk MDS [RA with excess of blasts (RAEB), RAEB in transformation and chronic myelomonocytic leukaemia] respectively. The incidence of p15(INK4B) methylation rose to 60% at initial study and, finally, to 75% in cases of acute myeloid leukaemia (AML) evolved from MDS. Most patients (69%) with p15(INK4B) methylation showed disease progression to AML; it could be detected before, at the time or after the diagnosis of leukaemic transformation. p15(INK4B) methylation in MDS patients implicated a shorter survival time in univariate analyses, but its prognostic significance disappeared in multivariate analyses. In conclusion, p15(INK4B) methylation can be detected early at the diagnosis of MDS or acquired during disease progression. It may play an important role in the pathogenesis of some high-risk MDS and is related to leukaemic transformation of MDS.     

Expression of EVI1 in myelodysplastic syndromes and other hematologic malignancies without 3q26 translocations

The EVI1 gene encodes a zinc-finger, DNA-binding protein originally described as the transforming gene associated with a common ecotropic viral insertion site in myeloid leukemias. Previous studies demonstrated EVI1 expression in human leukemias in cases with 3q26 translocations, but not in normal blood or bone marrow. These studies also suggested an association between EVI1 expression and chromosome 7 deletion (del). Because of this association, we examined expression of EVI1 using RNA polymerase chain reaction (PCR) in patients with myelodysplastic syndromes (MDS) and acute leukemia with and without 3q26 translocations. EVI1 RNA was expressed in 29% of 34 (95% confidence interval, 20% to 50%) patients with the MDS subtypes refractory anemia (RA), refractory anemia with excess blasts (RAEB), or refractory anemia with excess blasts in transformation (RAEB-T). The vast majority of these cases occurred in patients with RAEB and RAEB-T. EVI1 expression was not detected in patients with chronic myelomonocytic leukemia (CMML), normal bone marrow or cord blood, or a variety of other hematologic malignancies. EVI1 RNA was detected in three of 18 patients with acute myelogenous leukemia (AML) and in two of four patients with acute promyelocytic leukemia (APL). Karyotypes showed that only one AML patient had karyotype 3q26 abnormalities, indicating that EVI1 expression is associated with cases that do not have structural abnormalities involving chromosome 3q26. These studies document for the first time the abnormal expression of EVI1 RNA by patients with MDS, and suggest an important role for EVI1 in the pathogenesis or progression of some myeloid malignancies.     

Appearance of Sweet's syndrome in a patient with myelodysplastic syndrome (MDS) without relation to the hematological findings of MDS

Sweet's syndrome is known often to associate with non-lymphocytic leukemia (ANLL); however, there have been very few reports of Sweet's syndrome associated with myelodysplastic syndrome (MDS). It was reported that improvement and exacerbation of these two syndromes occurred simultaneously. We present here a 49-year-old male with Sweet's syndrome developed in RAEB in T. He complained of fever and infiltrative eruptions on the trunk and legs. At the time of admission to Tsukuba University Hospital, the peripheral blood showed leukocytopenia (WBC 2,000/microliter: Blast 9%, PMN 51%) and anemia (Hb 6.5 g/dl). Pseudo-Pelger anomaly of neutrophils was found on the blood smear. From the hematological findings and the result of skin biopsy, the patient was diagnosed as having MDS (RAEB in T) complicated by Sweet's syndrome. Prednisolone was effective to improve his fever and eruptions. However, when treated with low-dose Ara-C and when transformed into acute myelogenous leukemia, there was no correlation between the condition of Sweet's syndrome and the percentages of blasts in the marrow. We suggest that eruptions of Sweet's syndrome associated with MDS are not always a good index of exacerbation of MDS.     

骨髓增生异常综合征免疫表型分析

目的：探讨免疫表型测定在骨髓增生异常综合征（MDS）诊断及分型中的价值。方法：采用一组系列相关单克隆抗体和流式细胞术对19例MDS患者免疫表型进行检测，并对其中的10例进行了细胞遗传学检查。结果：MDS患者骨髓单个核细胞（MNC）CD13，CD33抗原表达率平均分别为36．69％和41．86％，而T淋巴系抗原CD3的表达平均仅为14．49％，且随着低危的难治性贫血（RA）向高危的难治笥贫血伴原始细胞增多（RAEB）或难治性贫血伴原始细胞增多－转变型（RAEB-t)的进展，较早期的髓系抗原CD13，CD33及干（祖）细胞抗原CD34的表达升高，并伴有T淋巴系抗原CD3的表达降低。10例进行了细胞遗传学检查的患者中，5例有染色体核型异常，染色体核型异常的患者与染色体核型正常的患者在抗原表达上存在区别。结论：对MDS患者进行免疫表型检查有助于MDS的诊断分型研究。