ABSTRACT
HIV-1 infection afflicts more than 35 million people worldwide, according to 2014 estimates from the World Health Organization. For those individuals who have access to antiretroviral therapy, these drugs can effectively suppress, but not cure, HIV-1 infection. Indeed, the only documented case for an HIV/AIDS cure was a patient with HIV-1 and acute myeloid leukemia who received allogeneic hematopoietic cell transplantation (HCT) from a graft that carried the HIV-resistant CCR5-∆32/∆32 mutation. Other attempts to establish a cure for HIV/AIDS using HCT in patients with HIV-1 and malignancy have yielded mixed results, as encouraging evidence for virus eradication in a few cases has been offset by poor clinical outcomes due to the underlying cancer or other complications. Such clinical strategies have relied on HIV-resistant hematopoietic stem and progenitor cells that harbor the natural CCR5-∆32/∆32 mutation or that have been genetically modified for HIV-resistance. Nevertheless, HCT with HIV-resistant cord blood remains a promising option, particularly with inventories of CCR5-∆32/∆32 units or with genetically modified, human leukocyte antigen-matched cord blood.
ABSTRACT
BACKGROUND: Umbilical cord blood (UCB) products have traditionally been thawed using a washing method intended to stabilize the cells, reduce dimethyl sulfoxide (DMSO) toxicity, and remove potentially ABO-incompatible red blood cell (RBC) stroma and plasma. Concerns with this approach include loss of total nucleated cells (TNCs), bag breakage during centrifugation, and poor reproducibility by transplant centers unfamiliar with this technique. We rationalized that a simple 1:1 dilution without centrifugation would stabilize the product and reduce the DMSO concentration by 50%, allowing for a controlled thaw in the laboratory without the risks of cell loss. STUDY DESIGN AND METHODS: We compared the traditional wash method with albumin reconstitution (dilution) and thaw only (no dilution or wash), assessing measurements of viability, TNC, CD34, and colony-forming cell (CFC) recovery post-thaw. Ten cryopreserved UCB products were thawed, split equally into three parts, and treated using each method. Product stability was measured at multiple time intervals up to 48hours post-thaw. RESULTS: Throughout the entire evaluation, traditional wash and dilution methods performed equally well with no significant differences observed in 7-aminoactinomycin viability, TNC, CD34, or CFC recovery. For 163 patients in which diluted products were administered, there were no serious adverse effects at infusion and similar time to engraftment was observed when compared to historical experiences with traditional wash and direct infusion. CONCLUSION: We conclude that removing DMSO, RBC stroma, and plasma post-thaw using a wash method is not necessary when UCB products are RBC and plasma reduced before cryopreservation.
