A single apheresis procedure in the donor may be enough to complete an allograft using the "Mexican method" of non-ablative allografting

Abstract

Background: Since 1999, in Mexico we have been using a regimen to conduct allografts that involves non-myeloablative conditioning and peripheral blood stem cells (PBSC) and have introduced some changes with the main goal of decreasing the cost of the procedure.

Materials and methods: We analysed the salient apheresis features of a group of 175 allogeneic peripheral blood stem cell transplants conducted in two institutions in a 7-year period. The grafts were conducted using the "Mexican" non-myelo ablative conditioning regimen employing oral busulphan, i.v. cyclophosphamide and i.v. fludarabine. In all instances, the apheresis machine employed was the Baxter CS3000 Plus and donors were mobilised with filgrastim. The apheresis procedures were performed on days 0, +1 and +2, the end-point of collection being 5,000 mL of blood/m2 in each procedure. Three apheresis sessions were planned but the number was adjusted according to the cell yield.

Results: The final number of allografted CD34 cells ranged between 0.5 and 25.4 x 10(6)/Kg of the recipient's body weight (median, 5.2 x 10(6)/Kg). One to three apheresis procedures were needed to obtain a product containing more than 0.5 x 10(6) CD34 cells/Kg of the recipient, the median being two procedures; in 72 cases (41%) a single apheresis procedure was sufficient to obtain the target number of CD34 cells. The volumes of apheresis ranged between 50 and 600 mL (median, 400 mL).

Conclusions: Since the median cost of each apheresis procedure is 900 USD, the fact that two apheresis procedures was spared in 72 cases and one apheresis was spared in another 65 cases, led to a total saving of approximately 188,100 USD. It can be concluded that, in many cases, allogeneic transplants can be completed with a single apheresis session and that there are considerable financial benefits from this practice.

Keywords: allografts; apheresis; costs saving; transplantation.

Figure 1

Diagnosis of the patients who were allografted. ALL = acute lymphoblastic leukaemia; AML = acute myelogenous leukaemia; CML = chronic myelogenous leukaemia; NHL = non-Hodgkin’s lymphoma, MM = multiple myeloma; AA = severe aplastic anaemia; MDS = myelodysplastic syndrome, HD = Hodgkin’s disease. Others include pure red cell aplasia, Blackfan-Diamond syndrome, paroxysmal nocturnal haemoglobinuria, prolymphocytic leukaemia, chronic lymphocytic leukaemia, Sezary’s syndrome, Wiskott-Aldrich syndrome, mycosis fungoides, primary myelofibrosis, chronic myelomonocytic leukaemia, rhabdomyosarcoma and pulmonary carcinoma.

Figure 2

Number of apheresis procedures needed to collect more than 0.5 × 10⁶ viable CD34 cells/Kg of the recipient’s body weight. In many donors (41%) a single apheresis session was sufficient.