Autologous stem cell transplantation (auto-SCT) is an established treatment option in patients with non-Hodgkin lymphoma (NHL). In this prospective multicenter study, the effect of infused blood graft cellular composition on post-transplant outcome was analyzed in 129 NHL patients. Higher graft CD34⁺ cell content (>2.5 × 10⁶/kg) correlated with better progression-free survival (PFS) (p=.009) and overall survival (OS) (p=.004). Higher graft CD34⁺CD133⁺CD38^– counts (>0.08 × 10⁶/kg) were also linked with better PFS (p=.03) and OS (p=.004), and these survival benefits retained in multivariate analyses. Higher infused CD3⁺CD4⁺ cell count (>37 × 10⁶/kg) predicted better PFS (p=.013) and OS (p=.007) in multivariate analysis. Autograft cellular composition seems to impact outcome in NHL patients. These observations regarding composition of optimal graft in autologous setting should be validated in an independent patient series or in a randomized study.

Background: Autologous stem cell transplantation (auto‐SCT) is a widely used treatment option in multiple myeloma (MM) patients. The optimal graft cellular composition is not known.Study design and methods: Autograft cellular composition was analyzed after freezing by flow cytometry in 127 MM patients participating in a prospective multicenter study. The impact of graft cellular composition on hematologic recovery and outcome after auto‐SCT was evaluated.Results: A higher graft CD34⁺ cell content predicted faster platelet recovery after auto‐SCT in both the short and long term. In patients with standard‐risk cytogenetics, a higher graft CD34⁺ count (>2.5 × 10⁶/kg) was linked with shorter progression‐free survival (PFS; 28 vs. 46 months, p = 0.04), but there was no difference in overall survival (OS) (p = 0.53). In a multivariate model, a higher graft CD34⁺CD133⁺CD38⁻ (>0.065 × 10⁶/kg, p = 0.009) and NK cell count (>2.5 × 10⁶/kg, p = 0.026), lenalidomide maintenance and standard‐risk cytogenetics predicted better PFS. In contrast, a higher CD34⁺ count (>2.5 × 10⁶/kg, p = 0.015) predicted worse PFS. A very low CD3⁺ cell count (≤20 × 10⁶/kg, p = 0.001) in the infused graft and high‐risk cytogenetics remained predictive of worse OS.Conclusions: Autograft cellular composition may impact outcome in MM patients after auto‐SCT. More studies are needed to define optimal graft composition.

BACKGROUND Autologous stem cell transplantation is an established treatment option for patients with multiple myeloma (MM) or non‐Hodgkinʼs lymphoma (NHL). STUDY DESIGN AND METHODS In this prospective multicenter study, 147 patients with MM were compared with 136 patients with NHL regarding the mobilization and apheresis of blood CD34+ cells, cellular composition of infused blood grafts, posttransplant recovery, and outcome. RESULTS Multiple myeloma patients mobilized CD34+ cells more effectively (6.3 × 10⁶/kg vs. 3.9 × 10⁶/kg, p = 0.001). The proportion of poor mobilizers (peak blood CD34+ cell count <20 × 10⁶/L) was higher in NHL patients (15% vs. 3%, p < 0.001). Plerixafor was added to rescue the mobilization failure in 17 MM patients (12%) and in 35 NHL patients (26%; p = 0.002). The infused grafts contained more natural killer (NK) and CD19+ cells in MM patients. Blood platelet and NK‐cell counts were higher in MM patients posttransplant. Early treatment‐related mortality was low in both groups, but NHL patients had a higher late (>100 days) nonrelapse mortality (NRM; 6% vs. 0%, p = 0.003). CONCLUSIONS Non‐Hodgkinʼs lymphoma and MM patients differ in terms of mobilization of CD34+ cells, graft cellular composition, and posttransplant recovery. Thus, the optimal graft characteristics may also be different.

Early lymphocyte recovery as manifested by an absolute lymphocyte count at d+15 (ALC-15) ≥ 0.5 × 10⁹/L after autologous hematopoietic stem cell transplantation (AHCT) has been associated with a better outcome. This prospective multicenter study aimed to clarify factors associated with ALC-15 ≥ 0.5 × 10⁹/L after AHCT among 178 patients with non-Hodgkin lymphoma. The mobilization capacity, as manifested by peak blood CD34⁺ cell numbers > 45 × 10⁶/L correlated with higher ALC-15 levels (p = 0.020). In addition, the amount of CD3⁺CD4⁺ T cells > 31.8 × 10⁶/kg in the infused graft predicted ALC-15 ≥ 0.5 × 10⁹/L (p < 0.001). Also, the number of infused graft CD3⁺CD8⁺ T cells > 28.8 × 10⁶/kg (p = 0.017) and NK cells > 4.4 × 10⁶/kg was linked with higher ALC-15 (p < 0.001). The two-year progression-free survival after AHCT was significantly better in patients with ALC-15 ≥ 0.5 × 10⁹/L (74 vs. 57%, p = 0.027). The five-year OS in patients with higher ALC-15 was 78% vs. 60% in those with lower ALC-15 (p = 0.136). To conclude, the mobilization capacity of CD34⁺ cells and detailed measures of graft cellular content mark prognostic tools that predict ALC-15 ≥ 0.5 × 10⁹/L, which is associated with a better outcome in NHL patients after AHCT.