The impact of infused red blood cell volume on major and bidirectional ABO-mismatched bone marrow transplantation.

BACKGROUND AIMS: ABO incompatibility does not hinder bone marrow transplantation (BMT), but it has been associated with worse outcomes and additional adverse events. This study aimed to verify the impact of incompatible red blood cells (iRBCs) in allogeneic BMT and to determine a safe number of iRBCs to be infused. METHODS: We compared ABO-incompatible (iABO) allogeneic BMT (n = 42) with ABO-compatible allogeneic BMT (n = 44) and evaluated the impact of the number of infused iRBCs on outcomes and adverse events. RESULTS: The iABO patients demonstrated delayed time to transfusion independence at 30 days and 60 days, increased requirement for red blood cell (RBC) transfusion and greater hemolysis signals and incidence of pure red cell aplasia. Neutrophil/platelet engraftment, length of hospitalization post-transplant, platelet units required, graft-versus-host disease occurrence and overall survival were similar in both groups. Patients in the iABO group received 1.03 × 1010 iRBCs/kg (range, 0.36-3.88). Infusion of iRBCs >1.0 × 1010 /kg was related to graft failure or death before neutrophil engraftment or platelet engraftment or both as well as increased plasma requirement and increased creatinine. Our results also suggest that antibody titers impact the transplantation scenario. CONCLUSIONS: The iABO transplantation showed some unfavorable outcomes. It is important to monitor the value of iRBCs to be infused, considering the recipient antibody titers. We propose using the number of iRBCs (iRBCs/kg) as a dose parameter with regard to infused iRBCs. Further studies are necessary to clarify the maximum safe number of iRBCs in iABO transplants.

Non-cryopreserved peripheral blood stem cells as a safe and effective alternative for autologous transplantation in multiple myeloma.

BACKGROUND: Autologous stem cell transplantation is the standard procedure for multiple myeloma and the grafts are usually cryopreserved. Previous studies reported advantages in the use of fresh peripheral blood stem cells (PBSC) autotransplantation compared to cryopreservation of the grafts. This study compared the transplant-related outcomes of two graft preservation methods: fresh storage (4°C/72 h) and cryopreservation (-80°C). STUDY DESIGN AND METHODS: We performed an analysis of 45 patients with multiple myeloma under autotransplantation (17 fresh and 28 cryopreserved) from 2017 to 2021. Fresh PBSC were maintained in the refrigerator for three days in a concentration up to 300 × 103 TNC/µL. Cryopreserved PBSC were concentrated by plasma reduction after centrifugation (950 g/10 min/4°C) and an equal volume of cryoprotection solution was added for a final concentration of 300 × 103 TNC/µL, 5% DMSO, 6% hydroxyethyl starch, and 3% human albumin. RESULTS: Neutrophil engraftment was significantly faster with fresh PBSCs (10 vs. 11.5 days, p = 0.045). Adverse effects were more common in cryopreserved PBSC transplantation (75% vs. 35.3% patients; p = 0.013). Post transplantation hospital stay was 20 and 22 days for fresh and cryopreserved PBSCs respectively (p = 0.091). There was no difference in platelet engraftment time (10.5 days for both; p = 0.133), number of antibiotics used after transplantation (3 for fresh and 2.5 for cryopreserved; p = 0.828), days of antibiotic use after transplantation (12.2 days for fresh and 13.3 days for cryopreserved, p = 0.579), and overall survival (p = 0.736). CONCLUSION: The infusion of fresh PBSC refrigerated for up to three days is effective and safe for autologous transplantation in patients with multiple myeloma, which is a useful alternative to cryopreserved PBSC.

An Experimental Study Comparing the Expansion of Peripheral Blood Natural Killer (NK) Cells Cultured with Artificial Antigen-Presenting Cells, in the Presence or Absence of Bone Marrow Mesenchymal Stem Cells (MSCs).

NK cells have been seen as potential agents in adoptive immunotherapy for cancer. The main challenge for the success of this approach is to obtain a great quantity of activated NK cells for adoptive transfer. The present study had aimed to evaluate the effect of a feeder layer of irradiated MSCs in the in vitro expansion of NK cells. MSCs were obtained from the bone marrow (BM) cells remaining in the bag and filter used in the transplantation of hematopoietic stem cells. NK cells were obtained from peripheral blood (PB) of healthy volunteers. NK expansion and activation were stimulated by culture with artificial antigen-presenting cells (aAPCs) and IL-2, in the presence or absence of BM-MSCs. NK cell proliferation, phenotypic expression and cytotoxic activity were evaluated. Both culture conditions showed high NK purity with predominance of NK CD56brightCD16+ subset post expansion. However, cultures without the presence of MSCs showed higher NK proliferation, expression of activation markers (CD16 and NKG2D) and related cytotoxic activity. In this experimental study, the presence of a feeder layer of irradiated BM-MSCs interfered negatively in the expansion of PB-NKs, limiting their growth and activation. Further investigation is needed to understand the mechanisms of NK-MSC interaction and its implications.

Comparison of human mesenchymal stromal cells from four neonatal tissues: Amniotic membrane, chorionic membrane, placental decidua and umbilical cord.

BACKGROUND: Mesenchymal stromal cells (MSCs) are being investigated as a potential alternative for cellular therapy. This study was designed to compare the biological characteristics of MSCs isolated from amniotic membrane (A-MSCs), chorionic membrane (C-MSCs), placental decidua (D-MSCs) and umbilical cord (UC-MSCs) to ascertain whether any one of these sources is superior to the others for cellular therapy purposes. METHODS: MSCs were isolated from amniotic membrane, chorionic membrane, umbilical cord and placental decidua. Immunophenotype, differentiation ability, cell size, cell complexity, polarity index and growth kinetics of MSCs isolated from these four sources were analyzed. RESULTS: MSCs were successfully isolated from all four sources. Surface marker profile and differentiation ability were consistent with human MSCs. C-MSCs in suspension were the smallest cells, whereas UC-MSCs presented the greatest length and least width. A-MSCs had the lowest polarity index and UC-MSCs, as more elongated cells, the highest. C-MSCs, D-MSCs and UC-MSCs exhibited similar growth capacity until passage 8 (P8); C-MSCs presented better lifespan, whereas insignificant proliferation was observed in A-MSCs. DISCUSSION: Neonatal and maternal tissues can serve as sources of multipotent stem cells. Some characteristics of MSCs obtained from four neonatal tissues were compared and differences were observed. Amniotic membrane was the least useful source of MSCs, whereas chorionic membrane and umbilical cord were considered good options for future use in cell therapy because of the known advantages of immature cells.