ABH incompatible bone marrow transplantation: removal of erythrocytes by starch sedimentation

T-Cell Replete Myeloablative Haploidentical Bone Marrow Transplantation Is an Effective Option for Pediatric and Young Adult Patients With High-Risk Hematologic Malignancies

Twenty-one pediatric and young adult patients (1.1-24.7 years) with hematologic malignancies underwent myeloablative T-cell replete haploidentical bone marrow transplant (haplo-BMT) between October 2015 to December 2019. Fifty-seven percent of the patients were ethnic or racial minorities. Thirteen patients had B-cell precursor acute lymphoblastic leukemia (B-ALL) with 10 receiving 1,200 cGy fractionated total body irradiation with fludarabine while the remaining 11 patients had targeted dose-busulfan, fludarabine, melphalan conditioning. Graft-vs.-host disease (GvHD) prophylaxis consisted of post-transplant cyclophosphamide (15 patients) or cyclophosphamide and bendamustine (six patients), with all patients receiving tacrolimus and mycophenolate mofetil. Twelve patients were in first or second remission at time of transplant with five in >2nd remission and four with measurable disease. Three patients had failed prior transplants and three CAR-T cell therapies. Only one patient developed primary graft failure but engrafted promptly after a second conditioned T-replete peripheral blood stem cell transplant from the same donor. An absolute neutrophil count of 0.5 × 109/L was achieved at a median time of 16 days post-BMT while platelet engraftment occurred at a median of 30 days. The cumulative incidence of grades III to IV acute GvHD and chronic GvHD was 15.2 and 18.1%, respectively. With a median follow-up of 25.1 months the relapse rate is 17.6% with an overall survival of 84.0% and a progression-free survival of 74.3%. The chronic graft-vs.-host-free relapse-free survival (CRFS) is 58.5% while acute and chronic graft-vs.-host-free relapse-free survival (GRFS) is 50.1%. Myeloablative conditioned T-replete haploidentical BMT is a viable alternative to matched unrelated transplantation for children and young adults with high-risk hematologic malignancies.

Progressive substitution of posttransplant cyclophosphamide with bendamustine: A phase I study in haploidentical bone marrow transplantation

We have initiated a single center phase I study in patients with hematologic malignancies progressively substituting day +4 posttransplant cyclophosphamide (PT‐CY) with bendamustine (PT‐BEN) following myeloablative conditioning (MAC) and T‐cell replete haploidentical bone marrow transplantation (haplo‐BMT). We report herein our interim analysis of our first three cohorts PT‐CY (mg/kg)/PT‐BEN (mg/m²): 40/20, 20/60, and 0/90. All patients have tolerated PT‐CY/BEN well with no dose limiting toxicities. Compared to contemporaneous controls undergoing haplo‐BMT with the same MAC regimens but only PT‐CY, we have observed earlier trilineage engraftment (P = .002 neutrophils, P = .014 platelets) and a lower incidence of cytomegalovirus reactivation (P = .016) in the PT‐CY/BEN cohorts. After substituting day +4 PT‐CY with PT‐BEN, the registered trial (www.clinicaltrials.gov;NCT02996773) is proceeding to replace day +3 PT‐CY with PT‐BEN with a view to identifying further evidence on the potential advantages of PT‐BEN.

Haploidentical Bone Marrow Transplantation with Post-Transplant Cyclophosphamide/Bendamustine in Pediatric and Young Adult Patients with Hematologic Malignancies

More than half of patients undergoing hematopoietic cell transplantation at our institution are ethnic or racial minorities, making the search for matched unrelated donors more challenging. Since the introduction of haploidentical bone marrow transplant (haplo-BMT) into our pediatric BMT program in 2015, 69.2% of recipients have been minorities. Herein, we describe our experience with the first 13 pediatric and young adult patients with hematologic malignancies who have undergone T cell-replete haplo-BMT after myeloablative conditioning (MAC) at our institution. We have previously documented that in experimental haplo-BMT, post-transplant bendamustine (PT-BEN) is at least as effective as post-transplant cyclophosphamide (PT-CY) against graft-versus-host disease (GVHD) and elicits superior graft-versus-leukemia (GVL) effects. We report on, for the first time in humans, 4 patients treated with PT-CY and PT-BEN after haplo-BMT as part of our ongoing institutional phase I/II study (NCT02996773). The remaining 9 patients reviewed in this report received PT-CY. Our findings indicate that MAC haplo-BMT is well tolerated by children and young adults with advanced hematologic malignancies with no observed nonrelapse mortality or grades III to IV GVHD. All patients who underwent haplo-BMT remain alive and disease-free with a median follow-up of 15.6 months (range, 1.5 to 31.2). Preliminary findings from our ongoing clinical trial demonstrate that partial substitution of PT-BEN for PT-CY is feasible and safe after haplo-BMT as an immune modulatory strategy to alleviate GVHD and potentially more effectively preserve GVL.

Concentration of Human Hematopoietic Stem Cells in Bone Marrow Transplantation: Results of a Multicenter Study Using Baxter CS 3000 plus Cell Separator

Preliminary BM processing to produce an enriched MNC fraction from large BM volumes improves subsequent pharmacological and/or immunological “ex vivo” treatment and cryopreservation. We detail on a multicenter study (6 Transplant Centers) performed to establish an effective and reliable protocol using a CS 3000 continuous flow separator on a large series of BM processed for autologous (96) and allogeneic (12) transplantation. The reduction in volume was 78.6+7.2% while 28.9+12.4% of the original nucleated cells were found in the final product. A mean of 84.3+13.2% of the starting MNC was yielded in a fraction containing over 81% MNC. Cloning efficiency indicated than the final graft was highly enriched in progenitor cells committed to the granulocyte/macrophage pathway (> 100%) as assessed in vitro (CFU-GM). Removal of RBC and PLT was 98.3+1.1 and 37.7+14.6%, respectively. The mean dose of MNC and CFU-GM was 0.6+0.37 x 108 and 0.96+1 x 108 recipient weight. The entire process was accomplished in 87.5+20 min. We concluded that this automated device is a simple and reproducible method for BM processing suitable as first step for further “ex vivo” automated negative and/or positive cell selections.

Haemolysis, pure red cell aplasia and red cell antibody formation associated with major and bidirectional ABO incompatible haematopoietic stem cell transplantation

BACKGROUND

Acute and delayed haemolysis, alloimmunisation and pure red cell aplasia (PRCA) are potential complications after ABO incompatible haematopoietic stem cell transplantation (HSCT). The aims of this study were to investigate acute and delayed red blood cell (RBC) antibody-associated complications, including haemolysis, PRCA and alloimmunisation in major and bidirectional ABO incompatible HSCT.

MATERIALS AND METHODS

We retrospectively examined the transplant courses of 36 recipients of bone marrow or peripheral blood stem cells from ABO incompatible donors and evaluated the current practice of performing plasmapheresis in patients with higher isoagglutinin titres. We investigated the role of ABO incompatibility in haematopoietic recovery, transfusion requirements, alloimmunisation and PRCA.

RESULTS

Laboratory signs of acute haemolysis were noted in five (14%) patients, one (3%) of whom had clinically overt haemolysis. Patients with haemolysis had IgM titres ≥1:8 and received >16 mL of RBC in the HSCT. In patients with higher titres, plasmapheresis performed prior to the transplant prevented acute haemolysis. Delayed haemolysis was not recorded in the follow up. Haematopoietic recovery and transfusion requirements did not differ notably between patients with and without haemolysis. De novo RBC antibodies were detected in two (5.5%) patients after HSCT, and PRCA was noted in one (3%) patient.

DISCUSSION

Carried out with adequate graft processing, plasmapheresis and blood component support, haemolysis is not a common complication after HSCT. Our results confirm that the occurrence of haemolysis depends on larger RBC volumes and higher isoagglutinin titres. Despite the reduction of patients' isoagglutinin titres by plasmapheresis, we still noted a critical combination for the development of laboratory signs of haemolysis (IgM titre ≥1:8 and RBC volume >16 mL). De novo immunisation to RBC antigens and PRCA are rare events following ABO incompatible HSCT.

Predictive value of the original content of CD34+ cells for enrichment of hematopoietic progenitor cells from bone marrow harvests by the apheresis procedure

We retrospectively investigated the feasibility of the apheresis procedure for red blood cell (RBC) reduction with a closed-bag system. We also sought to determine the optimal processing volume for the maximal recovery of hematopoietic progenitor cells (HPC). Twelve bone marrow (BM) harvests were processed for major ABO-incompatible allogeneic transplantation and one BM harvest was processed for autologous transplantation. The processing was performed through seven apheresis cycles with a two-bag system using COBE Spectra Version 6.1. The mean recovery rates were compared in the products after four cycles and seven cycles of BM processing. Mean cell recovery rates were 79.2% (67.6-97.5%) and 87.3% (68.9-111.9%) for the mononuclear cells (MNC) and 84.5% (69.4-109.5%) and 92.0% (79.0-107.7%) for the CD34(+) cells after four and seven cycles, respectively. A mean of 96.3% (93.0-98.1%) of the RBCs were finally removed. The yield of CD34(+) cells after seven cycles of processing (median: 10.35 x 10(7) cells) was 7.9% greater than that after four cycles of processing (median: 9.65 x 10(7) cells), exhibiting a less-than-significant enhancement in yield. The CD34(+) cell contents recovered in the concentrates up to four cycles (r = 0.989) and up to seven cycles (r = 0.993) were strongly correlated with the original content of the CD34(+) cells. Engraftment was obtained in all patients except one patient infused with purified CD34(+) cells. This latter result confirmed the hematopoietic potential of the cell populations recovered. Granulocyte recovery (defined as an absolute neutrophil cell count > or = 500/microL for a period of three consecutive days) ranged from 8 to 25 days (median: 16 days) post-transplantation. No hemolytic reaction was observed in any of the patients. Our results confirmed the efficacy of BM processing cycles with the COBE Spectra device. However, we could not conclude that the large-volume apheresis for BM processing significantly enhanced the yields of HPC. The final recovery of CD34(+) cells after processing could be predicted from the CD34(+) cell content of the original collected marrow.

ABO-histo blood group incompatibility in hematopoietic stem cell and solid organ transplantation

In contrast to solid organ transplantation (SOT), ABO-histo blood group incompatibility is of minor importance for hematopoietic stem cell transplantation (HSCT). Patients receiving ABO-incompatible HSCT are at an increased risk for immune-mediated hematological complications including immediate and delayed hemolysis, late red blood cell engraftment and pure red cell aplasia, but seem not to have a worse overall survival or increased transplant-related mortality. This review gives an overview of the immunological mechanisms leading to complications associated with ABO-incompatible HSCT and describes approaches to prevent them. The current organ shortage in SOT stimulates the exploration of new strategies to expand the donor pool including ABO-incompatible SOT and xenotransplantation. Here, we discuss the hypothesis that ABO-incompatible transplantation may be viewed as a human in vivo model for the humoral immune mechanisms of antigen-mismatched transplantation. ABO-incompatible HSCT and SOT provide excellent possibilities to analyze graft accommodation and transplantation tolerance. Understanding the underlying mechanisms of graft survival in ABO-incompatible transplantation may facilitate new strategies to overcome the immunological barriers in SOT and xenotransplantation.

Safety and impact of donor-type red blood cell transfusion before allogeneic peripheral blood progenitor cell transplantation with major ABO mismatch

BACKGROUND

Changes within the ABO system are regularly observed phenomena in allogeneic bone marrow transplantation (BMT) and peripheral blood progenitor cell transplantation (PBPCT). Major ABO mismatch can lead to different clinical problems including acute hemolysis after infusion of the allograft, delay of red blood cell (RBC) engraftment, or even manifestation of pure red cell aplasia (PRCA).

STUDY DESIGN AND METHODS

This retrospective study demonstrates the safety and the impact of donor-type RBC transfusion before allogeneic PBPCT in major ABO settings as routinely performed at our transplantation unit. This study reports on transfusion of mismatched RBCs at the end of the conditioning period in 35 patients who underwent allogeneic PBPCT, which led to a decrease in isoagglutinin titers in most cases.

RESULTS

A decrease of isoagglutinin titer after donor-type RBC transfusion can significantly reduce the demand of RBC transfusion between transplantation and Day +30 (p = 0.003). Interestingly, patients who developed PRCA were not observed, a complication being regularly documented by other groups.

CONCLUSION

A decrease of isoagglutinin titers by in vivo immunoadsorption before allogeneic PBPCT does not only lack severe complication but also leads to a reduction in demand of RBC transfusion after engraftment and may reduce the incidence of PRCA in these patients.

Pre-transplant reduction of isohaemagglutinin titres by donor group plasma infusion does not reduce the incidence of pure red cell aplasia in major ABO-mismatched transplants

Major ABO incompatibility in stem cell transplant recipients has been associated with pure red cell aplasia (PRCA). Reduction of incompatible isohaemagglutinin titres pre-transplant by various methods has been thought to reduce the incidence of PRCA. Our data suggest that pre-transplant reduction of incompatible isohaemagglutinin titres by donor group plasma infusion does not reduce the incidence of PRCA. We also failed to find any relationship between pre-transplant ABO isohaemagglutinin titre and the risk of developing PRCA.

ABO-incompatible bone marrow transplantation: a GITMO survey of current practice in Italy and comparison with the literature

ABO incompatibility is not considered a contraindication for allogeneic haematopoietic stem cell transplantation (HSCT) despite its association with several immunohaematological complications. At present, there is no general agreement concerning the best methods to reduce these problems. To survey current practice related to ABO-incompatible HSCT in Italy, a questionnaire was sent to all GITMO centres. Specific questions were addressed for management in pretransplant, peritransplant and post transplant phases. A comparison was made with the experience reported in the literature. In all, 74% of GITMO centres answered the questionnaire. A high degree of heterogeneity concerning the pretransplant tests, methods to overcome infusion of ABO-incompatible marrow and post transplant transfusion policy and monitoring was evident. For many of these aspects the literature does not contain unanimous guidelines. The considerable degree of heterogeneity that reflects, at least partially, the lack of consensus in the literature demonstrates that ABO incompatibility is still an open issue in the setting of HSCT and that further studies are needed for a more rationale approach and for the production of evidence-based guidelines.

Inverted spin method for removing RBCs from BM buffy coat products

BACKGROUND

Inverted spin is a method of removing RBCs that historically has been part of blood banking practice. We investigated the feasibility of using this method for RBC depletion of BM buffy coat products in situations where recipient RBC Abs have been identified to donor RBC Ags.

METHODS

The BM buffy coat product was placed in a transfer pack, inverted, centrifuged at 600 g for 10 min, suspended and the RBCs removed slowly into another transfer pack. Nine patients treated between April 1998 and February 2001 received products prepared by our version of the inverted spin procedure.

RESULTS

We removed a median value of 81.2% of the RBCs, while still recovering a median of 94.3% of the mononuclear cells (median: 0.35 x 10(8)/kg; range: 0.17-0.9 x 10(8)/kg). The median volume of RBCs remaining in the product was 15.0 mL (range: 7.3-21.9 mL). The CD34(+) cell dose of the final product ranged from 1.0 x 10(6)/kg to 4.8 x 10(6) cells/kg (median: 1.9 x 10 6/kg). Granulocyte recovery (defined as ANC count >or=500/microL for a period of 3 consecutive days) ranged from 18-30 days post-infusion of the allograft (median: 24.0 days). One patient died shortly after his transplant from complications of his disease. No patient had any evidence of an acute hemolytic reaction.

DISCUSSION

Advantages of the inverted spin method include no need for additives (e.g. hydroxyethyl starch, HSA, or O negative RBC), and use of equipment readily available in most processing laboratories.

Hematopoietic stem cell transplantation between red cell incompatible donor-recipient pairs

Transplantation between red cell-disparate donor and recipient is feasible with minimal increase in the risk of transplantation if consideration is given to the immunohematological consequences of the transplant. The risks of immediate and delayed hemolysis must be managed. Some recipients will experience a delay in the recovery of red blood cells.

Transplantation of ABO-incompatible bone marrow and peripheral blood stem cell components

Hemolysis may occur during infusion of an ABO-incompatible HSC component if the recipient has isoagglutinins directed against donor red blood cells, or later as a result of the production by donor lymphocytes of isoagglutinins directed against recipient ABO-antigens. Peripheral blood stem cell (PBSC) components collected by apheresis contain few red cells but considerably greater numbers of lymphocytes than marrow. We reviewed the transplant courses of 158 recipients of marrow (n = 90) or PBSC (n = 68) from HLA-identical, ABO-incompatible sibling donors. No patient experienced immediate or delayed hemolysis attributable to the ABO incompatibility. Recipients of minor ABO-incompatible red cell-replete marrow required fewer red cell transfusions during the first week after transplantation than recipients of PBSC or marrows depleted of red cells; the red cell transfusion requirements for the following 3 weeks did not differ. The maximum level of bilirubin did not differ for patients classified by ABO incompatibility or source of HSC. The development of positive antiglobulin tests occurred for eight marrow recipients from a separate group of 22 patients (17 marrow, five PBSC) for whom this testing was performed. None of these patients developed overt hemolysis. These data indicate that hemolysis complicating ABO-incompatible transplantation is not common after either marrow or PBSC transplantation. Bone Marrow Transplantation (2000) 26, 749-757.

Hydroxyethylstarch sedimentation by gravity ex vivo for red cell reduction of granulocyte apheresis components

BACKGROUND

When selecting only leukocyte compatible donors, the requirement of ABO compatibility limits the investigation and application of granulocyte transfusion therapy by reducing the pool of potential donors. Ex vivo hetastarch (HES) sedimentation was evaluated as a method of red blood cell (RBC) reduction of granulocyte components. The objective was to determine if this procedure consistently resulted in reduction of component packed RBC (PRBC) volume to < 5 ml, the range acceptable for infusion of ABO incompatible blood components based on guidelines set forth by the American Association of Blood Banks (AABB).

STUDY DESIGN AND METHODS

HLA-matched, ABO-compatible sibling marrow donors were selected to donate granulocyte components, which were transfused into the allogeneic bone marrow transplant (BMT) recipient as prophylaxis against infection. Three granulocyte components were collected from each of 5 donors receiving G-CSF (daily x 5). Leukapheresis (LA) began 1 day after the first G-CSF dose (Day 1), and was repeated on Days 3 and 5. LA were performed using a continuous-flow blood cell separator, with 7L blood processed during each procedure. RBC sedimentation was facilitated by administration of a 6% HES solution to the donor line. The 5 granulocyte components collected on Day 1 were not manipulated after collection. The 10 components collected on Days 3 and 5 were manipulated by ex vivo gravity sedimentation for 60 minutes followed by transfer of the buffy coat (red cell poor [RCP] fraction) to a transfer bag with residual RBCs retained in the collection bag (red cell rich [RCR] fraction). The PRBC volume and cellular composition of the components and fractions were determined.

RESULTS

When data for the 10 manipulated components were combined, the fraction of the components with < 5 ml PRBC was 0.4 in the RCP and 0.1 in the RCR fractions. All unmanipulated components contained > 5 ml PRBC. The mean PRBC volume (ml) of the RCP and RCR fractions were 6.3 and 16.4, respectively (P = .06). The mean number of RBC (x10(11)) in the RCP and the RCR fractions were .41 and 1.73, respectively (P = .03). The average proportion of cells in the manipulated components lost to the RCR fraction was 19.2% of granulocytes and 18.6% of platelets.

CONCLUSION

Ex vivo HES sedimentation, as performed, significantly reduced the number of RBCs from granulocyte components, but did not consistently result in PRBC volumes in the RCP fraction within the range acceptable for infusion of ABO incompatible blood components based on the AABB guidelines. Moreover, significant numbers of granulocytes were lost to the RCR fraction.

Regeneration of erythropoiesis after related- and unrelated-donor BMT or peripheral blood HPC transplantation: a major ABO mismatch means problems

BACKGROUND

Blood group incompatibility in allogeneic BMT is common but does not appear to affect the outcome in terms of incidence of graft rejection or delayed engraftment. However, major ABO incompatibility may be associated with prolonged erythroid aplasia.

STUDY DESIGN AND METHODS

In a retrospective analysis of 286 allogeneic transplant recipients, the prevalence of prolonged erythroid aplasia, including pure RBC aplasia, was determined.

RESULTS

Patients receiving major ABO-incompatible grafts showed a significant delay in reticulocyte engraftment (median, 32 days; range, 12-347) from that in patients receiving ABO-identical (20; 10-152) or minor ABO-incompatible (21; 12-47) grafts. Pure RBC aplasia occurred in 7 (3%) of 240 evaluable recipients and was observed only in the major ABO-incompatible group (7/43, 16%). Treatment of pure RBC aplasia consisted of either plasma exchange, which resulted in a response within 16 to 68 days, or immunoadsorption, in which the response occurred between Days 119 and 204 after initiation of treatment.

CONCLUSION

Major ABO incompatibility may lead to delayed reticulocyte engraftment, resulting in prolonged transfusion dependency and increased risks of transmission of infection and iron overload. Therefore, therapeutic strategies should be taken into consideration to allow erythroid reconstitution in these patients.

Bone marrow processing using the fenwal CS-3000 plus blood cell separator: results of 99 procedures

BMT is used as an established therapy for patients with malignant and nonmalignant diseases. Many techniques for ex vivo treatment have been developed, but these techniques must be preceded by BM processing. We report our experience in processing 99 BM using the Fenwal CS-3000 Plus cell separator using the 1-special program. Ninety-nine procedures were performed in BM harvested from 73 patients and 26 healthy donors. The number of nucleated cells (NC), mononuclear cells (MNC), RBC, platelets, colony-forming units-granulocyte-macrophage (CFU-GM), CD34+ cells, relative purity of MNC and PMN, and volume were determined in the unprocessed BM and in the final product. BM processing resulted in NC, MNC, CFU-GM, and CD34+ cell recoveries of 31%, 82.2%, 117.6%, and 97.8%, respectively. RBC, PMN, platelets, and volume removal, respectively, were 96%, 92%, 37.2%, and 85.1%. In pediatric patients, the volume reduction was significantly lower than in adult patients (79.6% versus 88.8%). No other significant differences were found between pediatric and adult results. We conclude that BM processing with the Fenwal CS-3000 Plus cell separator provides a product that can undergo further ex vivo treatments or cryopreservation.

Processing of major ABO-incompatible bone marrow for transplantation by using dextran sedimentation

BACKGROUND

Various open and semi-closed methods are used for red cell (RBC) depletion and hematopoietic progenitor cell (HPC) enrichment of bone marrow (BM) in vitro, but with variable efficacy. A simple, efficient, and safe method using dextran 110k was developed.

STUDY DESIGN AND METHODS

An equal volume of 4.5-percent dextran was applied to major ABO-incompatible BM in transfer bags and sedimentation was allowed for 30 minutes. RBCs, nucleated cells (NCs), and mononuclear cells (MNCs) from BM allografts before and after dextran sedimentation (DS) were counted. Flow cytometry, short-term cultures, and long-term cultures were performed to assay the respective recovery of CD34+ cells, colony-forming units (CFUs), and long-term culture-initiating cells (LTC-ICs).

RESULTS

Sixteen BM collections were processed. The mean volume was 666 mL (range, 189-1355 mL). The mean +/-1 SD post-DS NC, MNC, CD34+ cell, and CFU counts per kg of the recipient's body weight were 4.11 +/-1.74 x 10(8), 8.98 +/- 3.68 x 10(7), 2.90 +/- 1.95 x 10(6), and 2.03 +/- 2.01 x 10(5), respectively, with the corresponding post-DS recovery being 90.6 percent, 90 percent, 92.4 percent, and 100.8 percent. The numbers of LTC-ICs in cultures (up to 12 weeks) of pre-DS and post-DS samples of five BM allografts were comparable (p = 0.91). Residual RBCs were 5.1 +/- 4.6 (0.1-14) mL with depletion of 96.5 +/- 3.2 percent. There was no significant difference in the mean absolute RBC count in post-DS BM allografts and in four ficoll-treated BM allografts (8.09 x 10(10) vs. 4.9 x 10(9); p = 0.206) and in eight major ABO-incompatible peripheral blood HPC collections (8.09 x 10(10) vs. 9.81 x 10(10); p = 0.87). No posttransplant hemolysis was encountered. Engraftment occurred at 22 +/- 7 days, which is similar to that of four transplants with ficoll-treated BM allografts (22 +/- 9; p = 0.611) and 54 unprocessed BM allografts (19 +/- 6; p = 0.129).

CONCLUSION

DS is an efficient method of depleting RBCs in major ABO-incompatible BM allografts without significant loss of HPCs.

Bone marrow processing for transplantation using the COBE spectra cell separator

BM processing, volume reduction, and granulocyte and erythrocyte depletion are important considerations for minimizing the side effects of graft administration and bypassing ABO incompatibility in allogeneic BMT. We used the COBE Spectra cell separator for BM processing in 33 patients suffering from hematologic malignancy and solid tumor (median age 39 years). We processed 42 BM harvests with the aim of maximizing recovery of mononuclear cells (MNC). BM was collected from the posterior iliac crest under general anesthesia. The mean volume of collected BM before filtration was 1,303 ml, and the mean number of collected total nucleated cells (TNC) was 2.61 x 10(8)/kg. The BM processing resulted in a mean recovery of 35.8% (10.1%-78.3%) TNC, 22.3% (1.1%-75.7%) of granulocytes, 78.8% (34.3%-135.2%) of MNC, 77.2% (8.3%-260.0%) of CD34+ cells, and 153.3% (32.9%-464.0%) of colony-forming units (CFU-GM) in the final product. A mean of 98.2% (94.5%-99.5%) of RBC was removed, with a mean of 13.3 ml (5.1-26.2 ml) of RBC in the final product. BM processing using the COBE Spectra cell separator proved to be fast, safe, and effective. However, the reasons for the very wide range of recovery of harvested CD34+ cells and CFU-GM need to be further investigated.

Umbilical cord blood: an alternative to the transplantation of bone marrow stem cells

Recent in vitro analyses of human UCB have demonstrated the potential of UCB as a source for haematopoietic stem and progenitor cell harvest. Clinical data have further indicated that UCB can be given in vivo to fully and partially HLA-matched siblings or non-familial recipients for marrow reconstitution in genetic disorders as well as malignancies. In comparison to adult peripheral blood, UCB displayed decreased immune responses to alloantigens and was enriched in the numbers of CD34+ progenitor cells with high proliferative and long-term marrow reconstituting potential. Cord blood banks now store large transplantable resources of UCB that are analysed with respect to immunological parameters. Cryopreserved UCB cells may fill the gap in finding a stem-cell transplant for patients who lack a matched related or unrelated donor when a bone marrow transplant is needed.

Autologous bone marrow transplantation

Autologous bone marrow transplantation has become a very popular and successful treatment for many patients with lymphomas and other malignancies. The current indications, pretreatment regimes, and laboratory manipulations are discussed as well as the application of gene transfer to eliminate selected genetic diseases and detect disease relapse.

Hyperfractionated total lymphoid irradiation and cyclophosphamide for preparation of previously transfused patients undergoing HLA-identical marrow transplantation for severe aplastic anemia

PURPOSE

To assess the immunosuppressive capacity of hyperfractionated total lymphoid irradiation and cyclophosphamide for transplantation of unmodified allogeneic marrow in sensitized aplastic anemia patients.

METHODS AND MATERIALS

From February 1983 to September 1990, 23 multiply transfused aplastic anemia patients underwent unmodified bone marrow transplantation from HLA genotypically identical sibling donors following preparation with 6 Gy hyperfractionated total lymphoid irradiation and 160 mg/kg cyclophosphamide. Graft-versus-host disease prophylaxis included steroids in one patient, methotrexate in four, cyclosporine in seven, and methotrexate/cyclosporine in 12. There were 17 males and 6 females with a median age of 13 (range: 2.5-32).

RESULTS

One patient died early before engraftment of bacterial sepsis. Twenty-two patients were evaluable for engraftment. Three experienced graft failure including one primary, and two late graft failures associated with cyclosporine withdrawal. Acute graft-versus-host disease occurred in 7/22 (> or = grade II in 6), and chronic graft-versus-host disease in 3/17 patients. Except for a patient who received total body irradiation for a second transplant, no patient in this series developed interstitial pneumonia. Fifteen patients are alive with follow-up of 38-125 months (median 68). The overall actuarial survival at 5 years is 69%, at 8 years it is 60%, with one late death. The survival of adult patients was similar to that of younger patients (> or = 16 years old: 63%, < 16 years old: 55%). The development of acute graft-versus-host disease adversely influenced survival (88% with Grade 0-I, 17% with grade II-IV; p = 0.002). No hypothyroidism or secondary malignancies have been documented in this series.

CONCLUSION

Pretransplant immunosuppression with 6 Gy of hyperfractionated total lymphoid irradiation and 160 mg/kg CY reduces but does not eliminate the incidence of graft failure in sensitized aplastic anemia patients. The dose and the mode of administration of total lymphoid irradiation in this trial may be associated with a lower incidence of late side effects. Survival is comparable to that obtained using preparative regimens without radiation.

Bone marrow fractionation by the haemonetics system: reduction of red cell mass before marrow freezing, with special reference to pediatric marrow volumes

For purposes of freezing autologous marrow or transplants of allogeneic marrow with major ABO blood group incompatibility, 54 freshly harvested bone marrows from children of 7-65 kg of weight were depleted of their red cells with the Haemonetics V50 system. The marrow volumes ranged from 230 to 1,145 ml, with 17 small (200-399 ml), 18 intermediate (400-799 ml) and 19 large (800-1,200 ml) volumes. After processing, the median recoveries were: volume 24%, red cell mass 18%, and nucleated cells 75%. In the small marrow volume group, a good nucleated cell recovery was achieved at the expense of red cell depletion. The colony-forming units, granulocytes-macrophages (CFU-GM) were normal after thawing of processed, cryopreserved marrows, and good engraftment of both allogeneic and autologous marrows were achieved. We conclude that marrow processing with the Haemonetics V50 system results in adequate red cell depletion and good nucleated cell recovery without open-air contact of marrow or excessive time consumption. For small marrow volumes, however, the red cell depletion was suboptimal, and a bowl size smaller than 125 ml is desirable for pediatric use.

Isoagglutinins following ABO-incompatible bone marrow transplantation

Isoagglutinins were investigated following ABO-incompatible bone marrow transplantation. In major incompatibility anti-A tends to require more time to disappear than anti-B. Correspondingly, A erythrocytes require more time to become demonstrable. There is no such difference in major plus minor incompatibility. In minor incompatibility, isoagglutinins against the recipient blood group may be produced early after bone marrow transplantation, which then give way to a possibly lifelong tolerance for the recipient's old blood group.

Case report: isoimmune inhibition of erythropoiesis following ABO-incompatible bone marrow transplantation

A 26-year-old ABO-O positive patient with aplastic anemia received a bone marrow transplant from his genotypically HLA identical, but ABO-A positive, brother. Engraftment of myeloid and megakaryocytic lineages occurred within 4 weeks but pure red cell aplasia and transfusion dependent anemia persisted for 160 days. The authors postulated that the failure of erythropoiesis was due to a high titer of anti-A isohemagglutinins. They tested this hypothesis with clonal cell cultures and flow cytometric analysis of ABO antigen expression by colony forming cells in vitro. During the period of prolonged red cell aplasia, the patient had normal numbers (85 +/- 12 per 10(6) cells) of circulating donor derived, burst forming units-erythroid (BFU-E). Immunophenotypic analysis of erythroid burst colonies derived from culture of the patient's bone marrow cells showed that 91 +/- 5% of 274 nucleated red cells were A-antigen positive, confirming full donor engraftment. Autologous plasma and complement added on day 1 of culture did not affect the colony growth (82.5 +/- 15 per 10(6) cells). However, when the addition of complement was delayed until day 7 of culture, there was 90% inhibition of BFU-E (7.5 +/- 5 per 10(6) cells) compared to controls (p less than 0.0004). Based on this, the authors propose a model for expression of ABO antigens during erythropoiesis, in which BFU-E do not express ABO antigens but their progeny do. The data support the hypothesis that the mechanism of prolonged pure red cell aplasia after ABO-incompatible bone marrow transplantation is complement mediated immune destruction of erythroid progenitors past the stage of BFU-E in differentiation.

Marrow transplantation from human leukocyte antigen-identical or haploidentical donors for correction of Wiskott-Aldrich syndrome

Since 1979, a total of 17 patients with Wiskott-Aldrich syndrome have undergone allogeneic bone marrow transplantation at Memorial Sloan-Kettering Cancer Center. Eleven patients received marrow from either human leukocyte antigen (HLA) genotypically identical siblings (nine patients) or an HLA phenotypically identical parent (two patients). Six patients received marrow grafts from HLA-disparate parents. Cytoreduction was accomplished with busulfan and cyclophosphamide for the HLA-identical recipients and total-body irradiation followed by high-dose cytarabine therapy in the mismatched recipients. All 11 recipients of HLA-identical marrow had successful grafts, and 10 of 11 are alive and well 28 to 145 months after transplantation. One patient died 10 months after transplantation of chronic graft-versus-host disease and interstitial pneumonitis caused by cytomegalovirus. Only one of the six mismatched graft recipients survives, 52+ months after transplantation; the other patients have died of extensive chronic graft-versus-host disease (one patient), lymphoma (three patients), or progressive pancytopenia accompanying Candida sepsis (one patient). Thus bone marrow transplantation represents the treatment of choice in patients with Wiskott-Aldrich syndrome who have an HLA-identical donor. However, our approach for patients lacking a histocompatible family donor requires modifications to overcome allogeneic resistance and decrease the posttransplantation immunoincompetence in these patients.

Bone marrow processing for transplantation

As indications for BMT increase, so do variations in bone marrow processing and manipulation techniques. Many centers have their own unique methods of mononuclear cell purification, concentration and storage. This is particularly evident in the processing of bone marrow for autologous BMT to allow dose intensification as salvage therapy for malignant disease. Unique procedures have been developed to maximize yields, concentrate mononuclear cells necessary for engraftment, and reduce the likelihood of GVH disease. Graft rejection and disease relapse still remain a problem in some of these "manipulated" marrows. Newer procedures may allow titration of the optimum numbers of immune reconstituting cells; however, at this time, these techniques are not precise and the balance between preventing GVH disease at the expense of graft failure or relapse may still jeopardize disease-free survival. Innovative purging techniques that include pharmacologic and immunologic methods, continue to evolve, necessitating standards for bone marrow processing that are flexible yet practical. Quality control and viability assays are essential to verify the biologic proliferative potential of progenitor cells capable of marrow reconstitution. Although no standards are yet established, all centers should have criteria to monitor the quality of the processed marrow. Blood banks and transfusion services are well versed in regulations governing processing, labeling, storage, and quality control of blood components. Bone marrow is the ultimate blood component, and it stands to reason that methods outlined in this article be integrated into transfusion medicine.

Treatment of pure red-cell aplasia following major ABO-mismatched T-cell-depleted bone marrow transplantation. Two case reports with successful response to plasmapheresis

Major ABO-mismatched bone marrow transplantation (BMT) may be accompanied by red-cell haemolysis, but pure red-cell aplasia following BMT is a rare complication. Two cases of transient pure red-cell aplasia following T-lymphocyte-depleted BMT for a period of greater than 20 weeks are described, both of which responded to one cycle of plasmapheresis. The prompt response of the two patients described with red-cell aplasia with no evidence of haemolysis suggests that plasmapheresis may be considered in such clinical situations as a first treatment of choice before attempting more complex modes of therapy.

Hematopoietic stem cell processing and storage

The techniques to collect, process, and store HSC in anticipation of transplantation are now widely available. Important unresolved issues revolve around the as yet imperfect identification and classification of totipotential progenitors. However, much progress has been and will continue to be made despite this limitation. Research priorities of present and future stem cell processing laboratories should include: 1. Optimization of liquid (nonfrozen) storage techniques. This will permit more complex cell-specific manipulations, such as T-lymphocyte subset selection, isolation of CD34+ populations, treatment in vitro with growth factors, gene transfer experiments, and long-range transport of HSC, to be performed while preserving HSC integrity. 2. A better understanding of the regulation and kinetics of peripheral blood and umbilical cord HSC, to allow optimum collection procedures that do not require marrow harvesting. 3. An intensive study into the optimum conditions of collection, processing, and storage of megakaryocytic progenitors to decrease the long platelet-transfusion dependency of the myeloablated patient. 4. A search for a simple in vitro correlate of engraftment potential of a stem cell preparation. This will greatly improve the quality control functions of the laboratory as well as contribute to better patient selection for transplantation.

Separation of mononuclear bone marrow cells using the Cobe 2997 blood cell separator

In the present study, we report the results of our evaluation of the use of the continuous-flow cell separator Cobe 2997 to isolate from human bone marrow (BM) aspirates the mononuclear cell (MNC) fraction containing hematopoietic stem cells. This MNC concentrate is isolated in 15% of the original BM volume and contains 23% of the initial nucleated cells. It is enriched as concerns the BM MNC fraction (lymphocytes + monocytes recovery; 80%), whereas the contamination with granulocytes, red blood cells and platelets is reduced to 7.2, 1.5% and 41%, respectively, of the cells initially present in the BM suspensions. Furthermore, it is demonstrated that this MNC concentrate is highly enriched in granulocyte-macrophage-colony-forming cells (CFU-GM; recovery 83%). The method is simple, inexpensive, efficient and reproducible. It allows rapid processing of a large volume of BM without substantial loss of hematopoietic progenitor cells. It represents a valuable method of BM MNC concentration prior to further in vitro manipulations such as T cell or tumor cell depletion or cryopreservation.

Allogeneic bone marrow transplantation after hyperfractionated total-body irradiation and cyclophosphamide in children with acute leukemia

Ninety-seven children with either acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML) received HLA-identical bone marrow transplants from sibling donors, after preparation with 1320 cGy of hyperfractionated total-body irradiation and high-dose cyclophosphamide. Kaplan-Meier product-limit estimates (means +/- SE) of disease-free survival at five years among patients with ALL in second remission, third remission, and fourth remission or relapse were 64 +/- 9, 42 +/- 14, and 23 +/- 11 percent, respectively, with probabilities of relapse of 13 +/- 7, 25 +/- 13, and 64 +/- 16 percent. Among patients with AML in first remission, second remission, and third remission or relapse, five-year disease-free survival estimates were 66 +/- 10, 75 +/- 15, and 33 +/- 19 percent, with respective relapse probabilities of 0, 13 +/- 12, and 67 +/- 19 percent. The most frequent cause of death in patients in early remission (ALL in second or third remission or AML in first or second remission) was bacterial sepsis, fungal sepsis, or both, most often in the presence of acute or chronic graft-versus-host disease. Among patients with ALL who received transplants while in second remission, the duration of the initial remission had no effect on the probability of relapse after transplantation. The only pretransplantation factor that significantly affected outcome was the disease status at the time of transplantation; patients in early remission had better disease-free survival. We conclude that transplantation after preparation with hyperfractionated total-body irradiation and cyclophosphamide is an effective mode of therapy in children with refractory forms of acute leukemia.

Plasma exchange and plasma modification for the removal of anti-red cell antibodies prior to ABO-incompatible marrow transplant

Plasma exchange (PE) is performed only rarely to remove a specific, well defined antibody. ABO incompatibility in marrow transplantation has allowed us a unique opportunity to compare the effectiveness of three apheresis procedures for removing anti-red cell antibodies. We performed 140 marrow transplants in which a major ABO incompatibility between donor and recipient existed. To avoid a hemolytic transfusion reaction at the time of marrow infusion PE, plasma immunoadsorption (PIA) or whole-blood immunoadsorption (WBIA) was performed a total of 243 times. PE removed a mean of 87% of intravascular IgM and 86% of intravascular IgG directed against red cell antigens. PIA removed 75% and 73% of IgM and IgG, respectively (P less than .001 when compared to PE). Results for WBIA were 66% and 65%, respectively. Thus, PIA and WBIA were less efficient at removing antibody than PE. Furthermore, there were a few specific instances in which PIA or WBIA removed little or no antibody owing to differences in antibody specificity. PIA and WBIA resulted in less platelet consumption than PE. Although somewhat less effective that PE, PIA and WBIA have other advantages that can make them more desirable.

Preparation for blood group-incompatible bone marrow transplantation: comparison of two techniques

Two similar techniques of red cell depletion of blood group-incompatible marrow prior to bone marrow transplantation were compared in 8 patients. The first method involved a single sedimentation step and removed a mean of 91% of marrow red cells and 33% of marrow nucleated cells. The second method involved multiple sedimentation steps and removed a mean of 96% of red cells and 29% of nucleated cells. Both methods can be recommended to a transfusion service newly involved in a bone marrow transplantation program.

Immunoadsorption for removal of anti-A and anti-B blood group antibodies in ABO-incompatible bone marrow transplantation

About 10-15 percent of all patients undergoing allogeneic bone marrow transplantation have a major ABO-incompatibility with their donors. The risk of acute hemolytic reactions due to the infusion of an incompatible donor marrow into the recipient can basically be prevented by recipient antibody depletion or by donor marrow red cell depletion. Nine patients were treated by immunoadsorption using a cartridge with chemically synthesized human blood group A and B antigen as immunoadsorbent for antibody depletion. Within a four-hour-procedure about 2-4 times the patient plasma volume could be processed, thus lowering the anti-A and -B hemagglutinins by 2 to 3 tubes. There was a tendency of better IgG removal when titers initially were high, showing a high antibody clearing capacity. There was no significant correlation between starting titer or amount of plasma volume processed and titer reduction. No decrease in titers were observed in one case. We propose repeated immunoadsorption procedures over 2-3 consecutive days before BMT. The procedure is largely safe and without serious side effects. A major advantage is the avoidance of nonautologous human blood products compared to the conventional plasma exchange. All 8 patients surviving long enough had prompt and stable engraftment of all three cell lines post BMT. No late serological complications occurred when patients were regularly monitored and in vivo adsorption was used when titers increased.

Bone marrow transplantation in two multiply transfused patients with thalassaemia major

Bone marrow transplantation has generally been unsuccessful when applied to patients with thalassaemia major over the age of 6 years. We report here two successful transplants for this disorder in a 7 1/2-year-old boy and an 11-year-old girl following a pre-transplant cytoreductive/immunosuppressive regimen of total body irradiation and cyclophosphamide. Complete durable engraftment of donor haematopoietic and lymphoid populations was documented through several approaches, including cytogenetic analysis, haemoglobin electrophoresis, globin chain synthetic ratios, red cell typing and DNA restriction enzyme analysis. Both patients are surviving in good health, 28 and 9 months from transplantation. The successful outcome in these patients demonstrates the feasibility of marrow transplantation for the treatment of thalassaemia in multiply transfused and, presumably, highly sensitized patients.

Bone marrow transplantation in the management of childhood cancer

Bone marrow transplantation has become a curative therapy for selected children with leukemia and offers promise as a treatment for certain childhood solid tumors. Complications such as graft-versus-host disease, interstitial pneumonia, and recurrent malignancy continue to affect many patients. As these are overcome, and as methods for T-cell depletion and marrow purging are developed that extend the scope of bone marrow transplantation, it will become an even more significant therapy for childhood malignancy.

Treatment of acute leukemia in adults with chemoradiotherapy and bone marrow transplantation

The use of supralethal chemoradiotherapy followed by marrow transplantation has progressed from being an experimental approach applied only to a limited number of end-stage patients to an important therapeutic option appropriate for many adults with a variety of hematologic malignancies. With the use of transplantation, 10% to 30% of patients with relapsed leukemia and approximately 50% of patients with acute nonlymphoblastic leukemia in first remission can be cured. Cures have also been seen in a variety of other hematologic malignancies, including chronic granulocytic leukemia, preleukemia, hairy cell leukemia, and malignant lymphoma. Transplantation is currently limited by the need for a suitable marrow donor; by the complications of the transplant procedure, including infection, graft-versus-host disease, and the toxicities of intensive chemoradiotherapy; and by the risk of recurrent disease. Some of these limitations will likely be overcome as a result of current research. The use of partially matched family members and matched unrelated donors will make transplantation available to more patients. Some forms of posttransplant infection, including those associated with herpes simplex and cytomegalovirus, can now be prevented or treated. Improved methods of controlling graft-versus-host disease including T-cell depletion of marrow and the use of more effective immunosuppressive agents, as well as a better understanding of the toxicities of the preparative regimens, are making the transplant procedure safer and more tolerable. Finally, the development of better preparative regimens and transplantation earlier in the patient's disease course will likely allow for a larger percentage of patients to be cured.

Transplantation of major ABO-incompatible bone marrow depleted of red cells by hydroxyethyl starch

23 bone marrow transplant recipients whose donors where major ABO-incompatible received marrow depleted of red cells prior to infusion utilizing gravity sedimentation in hydroxyethyl starch. The in vitro red cell-depletion procedure effectively removed 97.8% (mean) of the red cells from the harvested marrows and preserved 86.8% of the nucleated cells and 98.2% of the CFU-C activity in 25.4% of the original volume. All recipients had a significant quantity of isohemagglutinins of both IgM and IgG classes demonstrable in their serum at the time of the marrow infusion. Patients were premedicated and well-hydrated prior to the infusion and tolerated the infusion well. These patients demonstrated bone marrow engraftment at the same rate as did those patients whose marrow donors were either ABO-identical or minor ABO-incompatible. There was no difference in the incidence of or time to development of graft versus host disease, the incidence of graft rejection, or patient survival among the groups. Recipients of red cell-depleted major ABO-incompatible bone marrow transplants demonstrated production of donor-type red cells somewhat later and required slightly more red cell transfusion support that did the other groups of recipients. This red cell-depletion technique is safe and effective in the management of major ABO-incompatible bone marrow transplantation.

A and B blood group antigen expression on mixed colony cells and erythroid precursors: relevance for human allogeneic bone marrow transplantation

Using anti-A and anti-B blood group monoclonal antibodies and fluorescent activated cell sorting of human bone marrow, A (or B) blood group antigen was shown to be on 5.2 +/- 5.9 (mean +/- SD) % of CFU-GEMM and 12.5 +/- 19.6% of the erythroid burst forming cells (designated BFU-GEMM) as defined by the mixed colony assay, and 49.5 +/- 20% of the BFU-E and 83.5 +/- 9.9% of the CFU-E as defined by the erythroid colony assay. This antigen expression on the BFU-GEMM is consistent with the concept that erythroid bursts stimulated by leucocyte conditioned medium are less mature, and are closer in development to the pluripotent stem cell than the BFU-E. These results help to explain the delayed erythropoiesis, and perhaps impaired engraftment of all cell lineages, that may occur in some recipients of ABO incompatible bone marrow transplants with persistent and high anti-A titres.