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.