Combined impact of HLA-allele matching and the CD34-positive cell dose on optimal unit selection for single-unit cord blood transplantation in adults

Toshio Yabea , Masahiro Satakeb* , Takeshi Odajimaab, Naoko Watanabe-Okochia , Fumihiro Azumaac, Koichi Kashiwasea, Kayoko Matsumotod, Takeshi Oriharae, Hiromasa Yabef, Shunichi Katof, Koji Katog, Shunro Kaih, Tetsuo Morii, Satoko Morishimaj, Minoko Takanashic, Kazunori Nakajimaak, Makoto MurataI & Yasuo Morishimagmon behalf of Japanese Cord Blood Transplantation Histocompatibility Research Groupa Kanto-Koshin-etsu Block Blood Center, Tokyo, Japanb Central Blood Institute, Japanese Red Cross Blood Service Headquarters, Tokyo, Japanc Japanese Red Cross Blood Service Headquarters, Tokyo, Japand Japanese Red Cross Kinki Cord Blood Bank, Osaka, Japane Japanese Red Cross Hokkaido Cord Blood Bank, Sapporo, Japanf Tokai University Cord Blood Bank, Isehara, Japang Central Japan Cord Blood Bank, Seto, Japanh Hyogo Cord Blood Bank, Kobe, Japani Japanese Red Cross Kyushu Cord Blood Bank, Chikushino, Japanj Division of Endocrinology, Diabetes and Metabolism, Hematology, Rheumatology (Second Department of Internal Medicine), Graduate School of Medicine, University of the Ryukyus, Nishihara, Japank Japanese Red Cross Kanto-Koshin-etsu Cord Blood Bank, Tokyo, JapanI Department of Hematology and Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japanm Department of Promotion for Blood and Marrow Transplantation, Aichi Medical University School of Medicine, Nagakute, JapanPresent address: †Central Japan Cord Blood Bank.‡Division of Cell Transplantation and Regenerative Medicine, Department of Innovative Medical Science, Tokai University School of Medicine, Isehara, Japan.Supplemental data for this article can be accessed here.CONTACT Masahiro Satake m-satake@jrc.or.jp Central Blood Institute, Japanese Red Cross Blood Service Headquarters, Tatsumi 2-1-67, Koto-ku 135-8521, Tokyo, Japan.AbstractThe combined effects of HLA-allele matching at six-loci (HLA-A, -B, -C, -DRB1, -DQB1, and -DPB1) and CD34+ cell dose on clinical outcomes were analyzed in 1,226 adult cases with single-unit unrelated cord blood transplantation. In the six-loci analysis, low HLA-allele matches did not significantly increase the overall mortality compared to higher matches, whereas in the five-loci analysis excluding HLA-DPB1, they caused a higher overall mortality (HR 1.42, p = .002), possibly due to the graft-versus-leukemia effect of HLA-DPB1 mismatches. A lower CD34+ cell dose (<.50 × 105/kg) resulted in higher mortality and lower engraftment; these inferior outcomes were offset by high HLA-allele matches (7-10/10 match), while the inferior outcomes of low HLA-allele matches were improved by increasing the CD34+ cell dose. Consideration of the combined effects of the CD34+ cell dose and HLA matching may expand the options for transplantable units when HLA matching or the CD34+ cell dose is inadequate.