Efficacy and safety of combined immunosuppressive therapy plus umbilical cord blood infusion in severe aplastic anemia patients: A cohort study

Umbilical Cord Blood-Derived Cells Can Reconstruct Hematopoiesis in an Aplastic Anemia Animal Model

Objectives

To explore the efficacy and the mechanism of the umbilical cord-derived cells combined with cyclosporine A (CsA) in treating aplastic anemia (AA) in mice.

Methods

Immune-mediated AA model mice were treated with CsA + UC mesenchymal stem cells (UC-MSC), CsA + umbilical cord blood regulatory T cells (UCB-Treg), UC-MSC, UCB-Treg, CsA alone, or blank control, respectively (n = 9 mice/group). CsA and the cell infusion was administered on d0. Routine peripheral blood testing was performed once weekly; bone marrow colony culture, bone marrow cell flow cytometry, peripheral blood T cell subsets, and serum inflammatory cytokines tests were performed on d14. Transcriptome sequencing was performed for cells from CsA + UC-MSC, CsA + UCB-Treg, and CsA groups to detect the possible related genes. Gene function cluster and signal pathway enrichment analysis were also performed.

Results

Blank control mice died due to pancytopenia within 21 days, whereas mice in other groups survived for >28 days. On d14, the CsA + UC-MSC and CsA + UCB-Treg groups had higher white blood cell (WBC) counts than the other groups (p < 0.05), along with higher burst-forming unit (BFU) and colony-forming unit-granulocyte, macrophage (CFU-GM) counts (p < 0.01). The CsA + UC-MSC group had the highest BFU count (p < 0.01). The CsA + UC-MSC and CsA + UCB-Treg groups exhibited the highest bone marrow CD34+ cell proportion (9.68% ± 1.35% and 8.17% ± 0.53%, respectively; p < 0.01). Tumor necrosis factor (TNF)-α and interleukin (IL)-2 levels in the CsA + UC-MSC group (p < 0.05) and TNF-α, interleukin-2, and interferon (INF)-γ levels in the CsA + UC-Treg group (p < 0.01) were lower than those in the CsA group. Compared with CsA treatment, CsA + UC-MSC significantly downregulated the histone methylation pathway (p < 0.05), whereas CsA + UCB-Treg significantly upregulated energy metabolism processes (p < 0.05). Treatment with CsA + UC-MSC upregulated superoxide dismutase activity compared with CsA + UCB-Treg treatment.

Conclusions

Adding UC-MSC or UCB-Treg to CsA markedly enhanced the reconstruction of hematopoiesis in AA mice, with UC-MSC eliciting greater efficiency than UCB-Treg. Accordingly, the addition of these cells could further improve immune abnormalities.

Cord blood infusion-accelerated hematopoietic recovery after combined immunosuppressive therapy with fludarabine and rabbit ATG in severe aplastic anemia

Immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG) and cyclosporine A (CsA) is currently the standard treatment for patients with severe aplastic anemia (SAA) who have no suitable donor or are ineligible for allogeneic stem cell transplantation. However, the delayed hematopoietic recovery, which accounts for most early deaths, remains a key problem. Thus, we designed an IST protocol with fludarabine, rabbit ATG, and CsA followed by unrelated cord blood (UCB) infusion to study whether hematopoiesis could be accelerated. Nineteen patients were enrolled in this study. The median neutrophil recovery time was 22 days and the treatment-related mortality within 3 months was 5.3%. The median platelet recovery time was 180 days. Six patients had transient or sustained UCB engraftment and the median platelet recovery time of these patients was significantly shorter than those who had no UCB engraftment (46 days vs 206 days, p = 0.006). The cumulative incidence of response rate at 12 months was up to 88.7% with CR rate of 72.2%. The overall survival at 2 years and 5 years was 94.7% and 78.9%, respectively. These results suggest that UCB infusion may play an important role in accelerating hematopoietic recovery in this protocol.