目的  分析骨髓红系比例≥50%的骨髓增生异常综合征（myelodysplastic syndrome，MDS）患者临床特征及预后。

方法 收集2014年5月至2023年6月于中国医学科学院血液病医院确诊的1436例MDS初治患者病例资料，回顾性分析骨髓红系比例≥50%的骨髓增生异常综合征（MDS-E）患者临床特征及预后。

结果 ① MDS-E患者共337例（23.5%），与红系比例<50%患者（MDS-NE）相比，MDS-E患者更年轻 [52（41~61）岁 对56（44~64）岁，P=0.001]，中性粒细胞计数[0.99（0.60~1.72）×10⁹/L对1.15（0.66~2.06）×10⁹/L，P= 0.001]、血小板计数[ 58 （28~104）×10⁹/L对63（33~132）×10⁹/L，P=0.023]、骨髓原始细胞比例[2（1~6）%对3（1~8）%，P=0.001]和EPO水平[176（61~729）mIU/ml对302（73~758）mIU/ml，P=0.011]更低，骨髓纤维化（MF2~3级）发生率更低[22例（6.7%）对159例（14.7%），P<0.001]。MDS-E相较于MDS-NE患者20q-染色体异常比例更高（15.1% 对8.7%，P=0.001），多打击TP53（12.5% 对 7.1%，P=0.002）、BCOR（7.4% 对3.7%，P=0.005）、STAG2（4.5% 对2.4%，P=0.044）基因突变率更高，ASXL1（14.5% 对20.5%，P=0.015）、SRSF2（2.4% 对5.8%，P=0.011）、ZRSR2（0.3% 对3.1%，P=0.004）基因突变率更低；② 在115例MDS-RS患者中，MDS-E患者42例（37%），MDS-NE 73例（63%），与MDS-NE患者相比，MDS- E复杂核型的检出率显著减低（0% 对11.9%，P=0.048），TP53基因突变率更低（2.4% 对 15.1%，P=0.053）；③在195例TP53突变患者中，MDS-E 50例（26%），MDS-NE 145例（74%），MDS-E患者复杂染色体核型比例（87.5% 对63.3%，P=0.002）及多打击TP53突变率（84.0%对53.4%，P<0.001）均显著高于MDS-NE患者。④在MDS-RS患者中，MDS-E组的中位总生存（overall survival，OS）较MDS-NE组更佳[未达到 对 63（53~73）月，P=0.044]。在TP53突变且原始细胞增多的MDS患者中，MDS-E组中位OS较MDS-NE组更差[7（4.4~9.6）对12（8.6~15.4）月，P=0.022]。

结论  MDS-RS患者中，骨髓红系比例≥50%与更低的复杂核型占比及TP53突变率相关，MDS-E组OS显著延长。TP53突变患者中，红系比例≥50%与复杂核型和多打击TP53突变相关，TP53突变伴原始细胞增多患者中，MDS-E组OS显著缩短。

Objective To analyze the clinical characteristics and prognosis of patients with myelodysplastic syndrome with bone marrow nucleated erythroid cell ratio greater than or equal to 50%.

Methods The clinical characteristics and prognostic factors of patients with myelodysplastic syndrome with bone marrow nucleated erythroid cell ratio greater than or equal to 50%(MDS-E) were retrospectively analyzed by collecting the case data of 1436 newly treated patients with MDS diagnosed in the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences from May 2014 to June 2023.

Results ① 1436 newly diagnosed patients with complete data were included in the study, of which 337 (23.5%) patients with bone marrow nucleated erythroid cell ratio greater than or equal to 50% had a younger age of onset than those with erythroid cell ratio less than 50%(MDS-NE) [52(41-61) years vs 56(44-64) years, P=0.001], lower neutrophil[0.99 (0.60-1.72) × 10⁹/L vs 1.15 (0.66-2.06) × 10⁹/L, P = 0.001]and platelet counts [58 (28-104) × 10⁹/L vs 63 (33-132) × 10⁹/L, P = 0.023], lower bone marrow blasts proportion [2 (1-6) % vs 3 (1-8) %, P = 0.001] and erythropoietin levels [176 (61-729) mIU/ml vs 302 (73-758) mIU/ml, P =0.011], lower incidence of myelofibrosis (grade 2-3 fibrosis) [22(6.7%) vs 159(14.7%), P<0.001]. The frequency of 20q- chromosome abnormality was higher in MDS-E (15.1% vs 8.7%, P = 0.001). Compared with MDS-NE group, the multi-hit TP53 mutation (12.5% vs 7.1%, P = 0.002), BCOR (7.4% vs 3.7%, P = 0.005), STAG2 (4.5% vs 2.4%, P = 0.044) mutation were more enriched in MDS-E group, ASXL1 (14.5% vs 20.5%, P = 0.015), SRSF2 (2.4% vs 5.8%, P = 0.011), and ZRSR2 (0.3% vs 3.1%, P = 0.004) were less mutated.②In 115 patients with MDS-RS, there were 42 (37%) MDS-E patients and 73 (63%) MDS-NE patients, the frequency of complex karyotypes (0% vs 11.9%, P = 0.048) and the TP53 mutation rate (2.4% vs. 15.1%, P = 0.053) in MDS-E were significantly lower than their counterparts. ③In 195 patients with TP53 mutations, there were 50 (26%) cases of MDS-E and 145 (74%) cases of MDS-NE. the frequency of complex karyotypes (87.5% vs 64.6%, P = 0.003) and multi-hit TP53 mutation (84.0% vs 54.2%, P < 0.001) were significantly higher than that of MDS-E. ④Survival analysis in MDS-RS patients found that the overall survival(OS) of MDS-E was better than that of MDS-NE [not reached vs 63 (53-73) months, P = 0.044]. In TP53 mutated patients with excess blasts, the OS of MDS-E was worse than that of MDS-NE [7(4.4-9.6) months vs 12(8.6-15.4) months, P=0.022]. 

Conclusion Among MDS-RS patients, bone marrow nucleated erythroid cell ratio greater than or equal to 50% was strongly associated with a lower proportion of complex karyotypes and TP53 mutation, and OS of the MDS-E group was longer than their counterparts. Among patients with TP53 mutation, bone marrow nucleated erythroid cell ratio greater than or equal to 50% was strongly associated with complex karyotypes and multi-hit TP53 mutation, and OS of the MDS-E group was shorter among TP53 mutated patients with excess blasts.