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

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.

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.

Granulocyte-colony-stimulating factor after allogeneic and autologous bone marrow transplantation in children

We evaluated the use of granulocyte CSF (G-CSF) after both allogeneic BMT (allo-BMT) and autologous BMT (ABMT) in children. After allo-BMT, G-CSF was used in 15 children who were compared with 20 historical controls. The ABMT patients were two sequential groups: the G-CSF group of 13 children and 11 historical controls. The patients were conditioned with different high-dose chemotherapy regimens with or without total body irradiation. G-CSF was administered at 5 micrograms/kg/day s.c. and was continued until an absolute neutrophil count (ANC) of 1,000 x 10(6)/l was reached. Following allo-BMT, G-CSF accelerated myeloid engraftment with a difference of 5 days at the ANC level of 500 x 10(6)/l (P<0.02) and 9 days at 1,000 x 10(6)/l (P<0.001). In the ABMT patients, G-CSF also accelerated myeloid engraftment. The difference between the G-CSF group and the control group was 6 days at ANC 200 (P<0.05), 11 days at ANC 500 (P<0.02) and 17 days at ANC 1,000 (P<0.005). In the ABMT patients, benefit by G-CSF was also observed in a smaller number of days with fever and days on antibiotics. We conclude that G-CSG significantly accelerated myeloid engraftment, after both allogeneic and autologous BMT in children, and also decreased the duration of febrile illness in the ABMT patients.

Allogeneic bone marrow transplantation in children: single institution experience from 1974 to 1992

At the Children's Hospital, University of Helsinki, Finland, bone marrow transplantations have been performed since 1974. Between 1974 and 1992, 62 children received allogeneic bone marrow grafts. Median patient age was 9.3 years. Thirty-two patients had ALL, 13 AML and 11 had severe aplastic anemia (SAA). Graft failure occurred in 4 of the 62 patients. The overall long-term survival rate was 47%. Relapse of leukemia was the most common cause of death, especially in patients with ALL transplanted in second or later remission. Deaths during the first 2 months after transplant have decreased with time. In a small country such as Finland, it is important to centralize the experience of allogeneic BMTs, particularly for pediatric patients.

Reemphasis on leukocyte transfusions: induction of myeloid marrow recovery in critically ill neutropenic children with cancer

Neutropenia is the major factor predisposing to sepsis in cancer patients, and its duration is important for survival. We administered leukocyte transfusions (LT) to 10 children suffering from documented life-threatening infections during profound, prolonged neutropenia. Nine had acute leukemia, and one had aplastic anemia; three were bone marrow transplant recipients. These 10 were the only patients in our unit who received LT during the past 7 years. The median leukocyte dose was 0.6 x 10(9)/kg in total. Instead of leukapheresis products, we used pooled buffy coats from random donors, with a high relative content of lymphocytes and especially T lymphocytes. The leukocyte concentrates were irradiated with 15 Gy. In all 10 patients, we observed prompt and sustained myeloid marrow recovery following LT. Such an effect of LT has never been described before. We hypothesize that in the internal milieu of these aplastic patients the transfused leukocytes were stimulated to secrete cytokines, the result being a cascade-like phenomenon and stimulation and proliferation of the patient's own bone marrow cells. The bone marrow-stimulating effect of LT merits further study.

A simple technique for red blood cell removal in major ABO-incompatible bone marrow transplantation

A simple technique for red blood cell (RBC) removal in major ABO-incompatible bone marrow transplantation is reported requiring two centrifugation steps, special blood bags and a mechanical device to separate the buffy coat from RBCs within the bag. In 42 transplantations an average of 84% of nucleated cells was recovered with an average contamination of 7.5 ml packed RBCs. The preparations were well tolerated in all patients whose isoagglutinin titers had not been reduced. Bone marrow engraftment was not significantly different from control groups.

Inadequate red cell depletion of large-volume marrow harvests processed on the Fenwal CS-3000 Plus

In this report we describe a procedure for the depletion of erythrocytes in bone marrow harvests using the Fenwal CS-3000 Plus cell separator. In a study of 15 consecutive harvests, adequate red cell depletion could not be achieved with large-volume marrows with > 500 ml erythrocytes.