Autologous transplantation remains the standard of care for eligible multiple myeloma (MM) patients, yet optimal CD34⁺ cell dose remains unclear. We conducted a retrospective study on MM patients undergoing upfront transplant between 2005 and 2021 and divided them into low (≤2.5 × 10⁶ cells/kg) and high (>2.5 × 10⁶ cells/kg) CD34⁺ dose groups. We included 2479 patients, 95 in the low CD34⁺ group and 2384 in the high CD34⁺ group. Patients in the low CD34⁺ group were older (63.2 vs 61.1 years, p = 0.013), more often had R-ISS III (19% vs 9%, p = 0.014), received plerixafor (60% vs 35%, p < 0.001) and transplanted after 2009 (88% vs 80%, p = 0.047). Time to neutrophil and platelet recovery was longer in the low CD34⁺ group. Median PFS and OS were lower in the low CD34⁺ group (31.6 vs. 43.6 months, p = 0.011 and 76.4 vs. 108.2 months, p < 0.001, respectively). Evaluation of incrementally higher CD34⁺ dose did not show significant improvement in survival at thresholds >2.5 × 10⁶ cells/kg. Multivariable analysis affirmed that CD34⁺ >2.5 × 10⁶ cells/kg was associated with better PFS (HR 0.71, p = 0.008) and OS (0.59, p < 0.001). After propensity score matching, a CD34⁺ dose >2.5 × 10⁶ cells/kg remained a predictor of better OS (0.42, p < 0.001). In conclusion, CD34⁺ dose >2.5 × 10⁶ cells/kg was associated with improved survival, without any additional benefit at incrementally higher doses.

自体移植仍然是符合条件的多发性骨髓瘤 （MM） 患者的标准治疗，但最佳 CD34⁺ 细胞剂量仍不清楚。我们对 2005 年至 2021 年接受前期移植的 MM 患者进行了回顾性研究，并将其分为低 （≤2.5 × 10⁶ 个细胞/kg） 和高 （>2.5 × 10⁶ 个细胞/kg） CD34⁺ 剂量组。我们纳入了 2479 例患者，其中低 CD34 ⁺ 组 95 例，高 CD34 ⁺ 组 2384 例。低 CD34⁺ 组患者年龄较大 （63.2 vs 61.1 岁，p = 0.013），更常患有 R-ISS III （19% vs 9%，p = 0.014），接受普乐沙福 （60% vs 35%，p < 0.001） 和 2009 年后移植 （88% vs 80%，p = 0.047）。低 CD34 ⁺ 组中性粒细胞和血小板恢复的时间更长。低 CD34⁺ 组的中位 PFS 和 OS 较低 （分别为 31.6 个月 vs. 43.6 个月，p = 0.011 和 76.4 vs. 108.2 个月，p < 0.001）。对逐渐升高的 CD34 ⁺ 剂量的评估未显示阈值 >2.5 × 10⁶ 个细胞/kg 的存活率显着改善。多变量分析证实，CD34 ⁺ >2.5 × 10⁶ 个细胞/kg 与更好的 PFS （HR 0.71，p = 0.008 ） 和 OS （0.59，p < 0.001） 相关。 倾向评分匹配后，CD34 ⁺ 剂量 >2.5 × 10⁶ 个细胞/kg 仍然是较好 OS 的预测因子 （0.42，p < 0.001）。 总之，CD34 ⁺ 剂量 >2.5 × 10⁶ 个细胞/kg 与生存率的提高相关，在逐渐升高的剂量下没有任何额外的益处。