Unrelated donor cord blood (CB) is one of the three sources of hematopoietic stem cell transplantation (HSCT) that are capable of curing ~80–160 standard hematologic and certain non-hematologic indications. Despite its many advantages, the principal drawback for CB in HSCT is its limited cell dose. Our group has focused on developing minimally manipulated technologies and strategies to maximize stem, progenitor, and nucleated cell doses to overcome this limitation. The term “MaxCell” is used in this chapter to denote two proprietary CB volume reduction processing technologies that yield virtually 100% recovery of all cell lineages in the manufactured CB products, including what the authors designate as “second generation” (2nd Gen) or plasma depletion/reduction (PDR) and “third generation” (3rd Gen) MaxCB or MaxCord CB processing technologies. In our proposed nomenclature system, the traditional red cell reduction (RCR) processing techniques are designated as “first generation” methods. The properties of various popular 1st Gen techniques are compared to the MaxCell CB processing technologies. Parallel processing with the traditional hetastarch (HES) RCR technique and the patented MaxCell CB processing technology were used to compare recovery of the various stem, progenitor, nucleated, and red cell lineages. MaxCell processing technology achieved virtually 100% recovery of all stem, progenitor, and nucleated cells tested after processing, with high cell viability upon thawing. The higher cell recovery produced MaxCell inventory with higher average stem, progenitor and nucleated cell doses, allowing patients to receive CB products with higher cell doses. Clinical outcome of HSCT using MaxCell CB products was compared to the outcome of HSCT with RCR CB products published in the literature from transplant data registries or CB banks. To allow for more rigorous comparisons, two matched-pair analysis (MP) were performed using a logistic regression model to find pairs of pediatric patients with hematologic malignancies and thalassemia transplanted with RCR CB or MaxCell CB, and patients receiving MaxCell CB showed superior engraftment, survival, and transplant-related mortality, confirming pre-match observations.
Since the first cord blood transplantation (CBT), many indications have been proven for this stem cell therapy. Besides the standard hematological indications, such as leukemia, lymphomas, and aplastic anemia, CBT has also been a proven curative therapy for non-hematological indications such as Krabbe’s disease, and osteopetrosis. As transplant-related mortality (TRM), overall survival (OS) and disease-free survival (DFS) for CBT continue to improve with larger inventories, double CBT, higher cell dose CB products, optimal conditioning, GvHD, HLA matching, and infection prophylaxis and treatment, the utility of this stem cell source will expand to certain indications which in the past, rarely used CBT. For patients and physicians to accept CBT for indications such as thalassemia, autoimmune diseases or HIV, the benefit-risk ratio has to be significantly improved so that patients will take a chance on a risky procedure in order to improve their lifespan or quality of life. We review here some of the efforts to improve clinical outcome of CBT for thalassemia through increasing cell dosage using a combination strategy – (1) Chow’s MaxCell second and third generation technologies that maximize CB cell dosage, (2) double CBT, (3) no-wash thaw direct infusion advocated by Chow et al., and (4) optimal product selection.