banks meeting FACT/Netcord standards. All transplant centers followed COBLT protocols and reported transplant outcomes according to COBLT protocols. The increase in the number of transplant centers and access to additional units facilitated the completion of the COBLT study. In addition, cord blood units were made available to patients who did not meet specific transplant criteria for the COBLT study strata through a separate protocol called the Expanded Access Protocol. Transplant centers using COBLT units in the Expanded Access Protocol were required to report the transplant outcome data to the COBLT medical coordinating center. The study allowed the use of these external transplant data, as long a COBLT laboratory performed the HLA typing and the transplant center complete the forms required for participation in the COBLT protocol. These requirements were developed to ensure that all outcomes data for the patients with cord blood transplants analyzed in the COBLT study were consistent with those from the centers already participating in the study.

The study made a concerted effort to increase the ethnic and racial diversity of their cord blood inventory, which by extension would increase the diversity of the HLA types with different ethnic and racial populations. The collection centers were specifically tasked to retrieve specified proportions of cord blood specimens from targeted minority populations to ensure that potential minority recipients had a similar chance of locating a unit to any other group. The target distribution of the sources of the cord blood specimens in the bank was 43 percent Caucasian, 30 percent African American, 17 percent Hispanic, and 10 percent Asian American (COBLT, 2000b). As of 2003, the distribution of the blood specimens in the COBLT cord blood banks by ethnicity and race were 42 percent Caucasian, 15 percent African American, 22 percent Hispanic, 9 percent Asian, 11 percent mixed, and 1 percent other (Baxter-Lowe et al., 2003). The study team came to the conclusion that it was possible to provide at least one unit matched at four of six HLAs (minimum cell dose, 1 × 107 total nucleated cells) to 94 percent of patients who were searching for a cord blood unit for transplantation (Baxter-Lowe et al., 2003).

Although the study results are still being evaluated, a definite relationship between the volume of cord blood collected and the nucleated cell counts and CD34+ levels was observed. The study has reported that cord blood samples from African-American women generally have lower nucleated cell and CD34+-cell counts per milliliter of cord blood (Kurtzberg et al., 2004) than samples from Caucasian women. The study also reported that birth weight, gender, gestational age, and type of delivery (vaginal versus cesarean) affect the size and the quality of the cord blood units. It has found that these factors are significant in the selection of units and are important in the development of plans to recruit donors (Cairo et al., 2004).



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