Bigoni R, Cuneo A, Milani R, Cavazzini F, Bardi A, Roberti M G, Agostini P, della Porta M, Specchia G, Rigolin G M, Castoldi G
Section of Hematology, Department of Biomedical Sciences, University of Ferrara, Italy.
Haematologica. 2001 Apr;86(4):375-81.
A pluripotent progenitor cell was demonstrated to be involved in myelodysplastic syndromes (MDS) with normal karyotype or with numerical chromosome aberrations, but the pattern of lineage involvement by the 5q31 deletion in the 5q- syndrome is unknown. We performed this study in order to define the distribution pattern of the 5q- anomaly better in the non-lymphoid cell compartment
Bone marrow (BM) smears from 8 patients with the 5q- syndrome were studied by a modification of the fluorescent in situ hybridization (FISH) technique that allowed direct visualization of cell morphology. A commercial LSI EGR1 probe (Vysis Inc.) for the 5q31 band was used simultaneously in dual-color experiments with a chromosome-5-centromeric probe (Vysis Inc.) on BM smears from 8 patients with the 5q-syndrome. As additional internal controls a chromosome-7-centromeric probe and a 7q31 probe were used. To establish the sensitivity limit of this approach 5 normal BM smears were studied. All 8 patients had the 5q- chromosome as the sole anomaly in 45% to 75% of the interphase cells.
For each patient 20-40 erythroblasts were analyzed: they were mostly proerythroblasts and basophilic erythroblasts. In all patients a clone carrying the 5q31 deletion was detected (35-50% of the cells, median 45%). Between 20-50 granulocyte precursors were scored; the 5q31 deletion was found in 40%-50% (median 45%) in all cases. The proportion of neutrophils carrying the 5q deletion was consistently lower than the corresponding value in promyelocytes (28.7% vs 45.6%). In the 20-25 megakaryocytes analyzable in all patients, the overall incidence of 5q31 deletion was 52-68%. Equal proportions of large multilobular megakaryocytes and hypolobular megakaryocytes characteristic of the 5q- syndrome were scored: the latter cells showed the 5q31 deletion more frequently than the former cells (93.6% vs 19.3% of the cells). In 66% to 100% of the cases (median 83%) a few cells with uncondensed nuclear chromatin pattern, and two or three prominent nucleoli with cytoplasmatic hypogranulation were seen in each sample carrying the 5q31 deletion.
We arrived at the following conclusions: i) the transformation in the 5q- syndrome involves an early progenitor cell retaining the ability to proceed along multiple differentiation pathways; ii) there is a preferential distribution of the 5q31 deletion within immature cells and morphologically abnormal megakaryocytes.
已证实一种多能祖细胞参与核型正常或有染色体数目畸变的骨髓增生异常综合征（MDS），但5q-综合征中5q31缺失所涉及的谱系受累模式尚不清楚。我们开展本研究以更好地明确5q-异常在非淋巴细胞区室中的分布模式。
采用改良的荧光原位杂交（FISH）技术对8例5q-综合征患者的骨髓涂片进行研究，该技术可直接观察细胞形态。在双色实验中，将用于5q31带的商用LSI EGR1探针（Vysis公司）与染色体5着丝粒探针（Vysis公司）同时用于8例5q-综合征患者的骨髓涂片。作为额外的内部对照，使用了染色体7着丝粒探针和7q31探针。为确定该方法的灵敏度极限，研究了5份正常骨髓涂片。所有8例患者在45%至75%的间期细胞中，5q-染色体是唯一异常。
对每位患者分析了20 - 40个成红细胞：大多为早幼红细胞和嗜碱性成红细胞。在所有患者中均检测到携带5q31缺失的克隆（占细胞的35% - 50%，中位数为45%）。对20 - 50个粒细胞前体进行计数；在所有病例中，5q31缺失见于40% - 50%（中位数为45%）。携带5q缺失的中性粒细胞比例始终低于早幼粒细胞中的相应值（28.7%对45.6%）。在所有患者可分析的20 - 25个巨核细胞中，5q31缺失的总体发生率为52% - 68%。对5q-综合征特征性的大分叶巨核细胞和低分叶巨核细胞进行了同等比例的计数：后者细胞显示5q31缺失的频率高于前者细胞（分别为93.6%对19.3%）。在66%至100%的病例（中位数为83%）中，在每个携带5q31缺失的样本中可见一些核染色质模式松散、有两三个明显核仁且细胞质颗粒减少的细胞。
我们得出以下结论：i）5q-综合征中的转化涉及一个早期祖细胞，其保留了沿着多种分化途径进展的能力；ii）5q31缺失在未成熟细胞和形态异常的巨核细胞中存在优先分布。
