Chromosome abnormalities in myelodysplastic syndrome

We performed chromosomal analysis in 18 patients with myelodysplastic syndrome (MDS). According to the French-American-British (FAB) cooperative study group and Research Group of Japanese Ministry of Welfare Classification, our cases with MDS were classified into four subtypes as follows; refractory anemia [RA], 6 cases; refractory anemia with excess of blasts [RAEB], 4; chronic myelomonocytic leukemia [CMML], 3; refractory anemia with excess of blasts in transformation [RAEB-T], 4; and refractory cytopenia [RC], 1. Thirteen patients (72%) had chromosomal abnormalities and frequently observed chromosomal abnormalities were trisomy 8, -7/7q-, 20q-, trisomy 1q and 5q-. The mean survival were as follows; RA: 22.5 months, RAEB: 13.2 months, CMML: 15 months, RAEB-T: 5.5 months. Progression to overt leukemia occurred in 5 patients (27.7%): 1 of four patients with RAEB, 1 of three patients with CMML and 3 of four patients with RAEB-T. In conclusion, chromosomal abnormalities were most frequently observed in the patient with RAEB-T who had shortest survival time among the patients with MDS. On the other hand, chromosomal abnormalities were less frequently observed in the patients with RA and they showed relatively better prognosis than the other types of MDS.     

骨髓增生异常综合征中的微环境异常

Myelodysplastic syndrome (MDS) is considered as a preleukemic course, characteristic of hypercellular marrow and pancytopenia. Many studies have demonstrated that defects occur in the heamtopoiet-ic cells from patients with MDS. Recently, many abnormal changes in apoptosis, proliferation, ability of hematopoietic support, cytokine secretion, clonal origin of stromal cells and angiogenesis have also been re-vealed in the bone marrow mieroenvironment of MDS patients.     

Chromosome 11 abnormalities in myelodysplastic syndromes.

Cytogenetic studies were performed in 140 patients with myelodysplastic syndrome (MDS) at diagnosis. Chromosome 11 anomalies were found in 7 cases (5%); 2 of these patients had refractory anemia (RA), 2 had refractory anemia with excess of blasts (RAEB), 1 had RAEB in transformation (RAEB-t), and 2 had chronic myelomonocytic leukemia (CMMoL) according to the French-American-British (FAB) Cooperative Group criteria. The chromosome 11 abnormalities comprised trisomy 11 (2 patients), monosomy 11 (1 patient), del(11)(q23) (2 patients), add(11)(p15) (1 patient), and der(11) t(3;11)(p21;q23) (1 patient). Abnormalities involving band q23 of chromosome 11 occurred in 3 cases and were the most common alteration. However, specific chromosomal alterations were not associated with any FAB classification group. These findings and their implications in the biology of MDS are discussed.     

Combined spectral karyotyping and DAPI banding analysis of chromosome abnormalities in myelodysplastic syndrome.

Spectral karyotyping (SKY) is a new molecular cytogenetic technique that allows simultaneous visualization of each chromosome in a different color. We have used SKY for comprehensive analysis of 20 myelodysplastic syndromes (MDSs) (13 primary MDSs, 3 therapy-related MDSs, and 4 acute leukemias developed from MDS, including 1 cell line established from a secondary leukemia), previously analyzed by G-banding. To locate the chromosomal breakpoints, DAPI-counterstained band images from all metaphases were transformed to G-band-like patterns. By using SKY, it was possible to identify the origin and organization of all clonal marker chromosomes (mar), as well as the origin of all abnormalities defined as additional material of unknown origin (add) or homogeneously staining regions (hsr) by G-banding. In total, SKY identified the chromosomal basis of 38 mar, add, and hsr, corrected 8 abnormalities misidentified by G-banding, and revealed 6 cryptic translocations in 5 cases. Total or partial chromosomal loss (mainly of -5/5q- and -7/7q-) is the most frequent cytogenetic abnormality in MDS. In 3 of 11 cases with -5/5q- and in 4 of 8 with -7/7q-, lost material was detected by SKY in unbalanced translocations. A total of 60 chromosomal losses were identified by G-banding in 16 cases with multiple chromosome abnormalities involving at least 3 chromosomes. For 26 of these losses (43%), SKY analysis suggested that the losses were not complete, but had been translocated to a variety of partner chromosomes. Moreover, SKY analysis revealed that a ring chromosome in a case of acute leukemia developed from MDS contained three to six segments that originated from chromosome 21 material. Fluorescence in situ hybridization showed the amplification of the AML1 gene on regions derived from chromosome 21, providing the first evidence of amplification involving this gene in MDS. Genes Chromosomes Cancer 26:336-345, 1999.     

Immune abnormalities in myelodysplastic syndromes

The immune states of 52 patients with myelodysplastic syndromes classified according to the FAB criteria were studied. Serum electrophoresis and immunoelectrophoresis, direct Coombs test, and tests for organ and non-organ specific antibodies were performed. Twenty six patients had immunoglobulin abnormalities: six (11.5%) had monoclonal gammopathy; 17 (32.6%) had polyclonal increases in serum immunoglobulin; while in three (5.8%) immunoglobulin concentrations were decreased. The distribution of immunoglobulin abnormalities among the five myelodysplastic syndrome subtypes was fairly uniform. Results of direct Coombs test were negative in all cases. Organ specific antibodies were not detected in any of the patients tested, although two patients were found positive for antinuclear antibodies. The presence of immunoglobulin abnormalities indicates an involvement of the lymphoplasmatic system in myelodysplastic syndromes.     

Red cell aplasia in myelodysplastic syndrome.

Six cases of red cell aplasia occurring in patients with myelodysplastic syndromes (MDS) showed a diversity of clinical course and prognosis. In some patients red cell aplasia may have represented an evolution of MDS while in others autoimmune destruction of erythoblasts may have been the mechanism. A proliferative phase is seen in many of these patients, the clinical importance of which is uncertain.     

组合探针荧光原位杂交检测骨髓增生异常综合征常见染色体异常

目的：评价组合探针荧光原位杂交（fluorescence in site hybridization,FISH)在检测骨髓增生异常综合征（myelodysplastic syndrome,MDS）常见染色体异常中的价值。方法：应用YAC248F5（5q31)、YAC938G5（7q32）、CEP8、YAC912C3（20q12）4种DNA探针，对核型未知的20例MDS患者进行FISH检测－5／5q-、－7／7q-、＋8、20q－等常见染色体异常，并与常规细胞遗传学分析结果相比较。结果：20例MDS患者中，组合探针FISH检出13例有常见染色体异常（其中5例＋8，1例－5／5q-，5例20q-,1例5q-合并20q-，复杂异常1例）；而常规细胞遗传学发现5例常见染色体异常，1例＋21，复杂异常1例，标记染色体1例，正常5例。结论：组合探针FISH是筛查MDS患者常见染色体异常的有效手段。     

6;9 translocation in myelodysplastic syndrome.

The 6;9 chromosomal translocation [t(6;9)] is usually associated with acute nonlymphocytic leukemia, and carries a poor prognosis. We present a case of refractory anemia with excess of blasts (RAEB) accompanied by t(6;9). Review of the literature revealed an additional ten patients in which myelodysplastic syndrome (MDS) was associated with the chromosomal translocation 6;9. The patients tend to be younger then the average MDS patient and, unlike leukemia, in which this translocation is associated with a poor prognosis, these patients tend to have the same overall RAEB and refractory anemia with excess of blasts in transformation (RAEBt) prognosis. It is therefore possible that this chromosomal aberration should not be considered as an unfavorable prognostic factor in MDS.     

Double 20q- anomaly in myelodysplastic syndrome.

Two patients with myelodysplastic syndrome (MDS) whose bone marrow (BM) cells contained duplicate 20q- chromosomes are reported. No particular differences between the hematologic findings of four patients with single 20q- and the two patients with double 20q- chromosomes were noted. No differences in breakpoints on the 20q- chromosome were noted in these six patients, and the breakpoint was identified as 20q11. The presence of double 20q- chromosomes in MDS patients suggests, however, that the deleted chromosome has oncogenic activity.     

Chromosomal abnormalities in secondary myelodysplastic syndromes and leukemias

Secondary leukemias group essentially together myelodysplastic syndromes and acute leukemias, therapy-related (chemo- or radio-), or consecutive to environmental factors. It's now proven that some recurrent abnormalities are associated with effects of therapeutic agents, as -5/del(5q), -7/del(7q) linked to alkylating agents, or 11q23 and 21q22 abnormalities linked to inhibitors of Topoisomerase II. Even if important differences between secondary and "de novo" forms exist, the discrimination between these 2 categories is not always obvious: many common chromosomal abnormalities, "de novo" leukemias in older patients having characteristics close to those of postalkylating leukemias, neonatal forms possibly secondary to maternal affect. Recent studies identified some others chromosomal abnormalities in the secondary leukemias and confirmed the poor prognosis of these hemopathies. This review sums up criterions, circumstances and cytogenetic abnormalities.     

骨髓增生异常综合征中的T细胞免疫

骨髓增生异常综合征(myelodysplastic syndromes,MDS)是一组肿瘤性疾病,以骨髓无效造血并向急性髓系白血病转化的风险为特点.流行病学显示自身免疫性疾病的患者发生MDS风险增加,为二者存在共同病因的假设提供了依据.MDS骨髓微环境中存在T细胞过度活化的现象.部分低危组MDS治疗药物具有抑制T细胞免疫机制,而高危组MDS的去甲基化药物则增强T细胞的抗肿瘤免疫反应,特别是免疫检查点抑制剂正在MDS中进行临床实验.因此,MDS中T细胞免疫失调的双重作用值得深思,充分认识T细胞免疫异常在M D S发病机制中的作用是形成新治疗方法的理论基础.     

Spontaneous remission in myelodysplastic syndrome. A case report

A patient with refractory anemia with excess blasts (RAEB) and pancytopenia is reported. He was red blood cell (RBC)-transfusion dependent. Karyotype analysis showed a complex cytogenetic abnormality consisting of loss of chromosome 7 and trisomy 8. Without cytotoxic treatment, his complete blood count (CBC) subsequently became normal. He is no longer transfusion dependent and repeat cytogenetic analyses are normal.     

Prothrombotic coagulation abnormalities preceding the hemolytic-uremic syndrome.

BACKGROUND: The hemolytic-uremic syndrome is a thrombotic complication of Escherichia coli O157:H7 infection. It is not known whether the coagulation abnormalities precede, and potentially cause, this disorder. METHODS: In 53 children infected with E. coli O157:H7, we measured a panel of markers indicating activation of the clotting cascade and renal function within four days after the onset of illness. These markers were measured again in as many as possible of the 16 children in whom the hemolytic-uremic syndrome developed. RESULTS: The children in whom the hemolytic-uremic syndrome subsequently developed had significantly higher median plasma concentrations of prothrombin fragment 1+2, tissue plasminogen activator (t-PA) antigen, t-PA-plasminogen-activator inhibitor type 1 (PAI-1) complex, and D-dimer than children with uncomplicated infection. These abnormalities preceded the development of azotemia and thrombocytopenia. When the hemolytic-uremic syndrome developed, the urinary concentrations of beta2-microglobulin and N-acetyl-beta-glucosaminidase rose significantly (P=0.03 for both increases); the plasma concentrations of t-PA antigen, t-PA-PAI-1 complex, D-dimer, and plasmin-antiplasmin complex also increased significantly. The concentration of t-PA antigen correlated with that of the t-PA-PAI-1 complex in a linear regression model (squared correlation coefficient, 0.80; P<0.001). CONCLUSIONS: In the hemolytic-uremic syndrome, thrombin generation (probably due to accelerated thrombogenesis) and inhibition of fibrinolysis precede renal injury and may be the cause of such injury.