Allogeneic Hematopoietic cell Transplantation Using Alemtuzumab in Asian Patients with Inborn Errors of Immunity

• DOI: 10.1007/s10875-024-01734-5
• Publication Date: 2024-05-22T03:38:20Z
• Authors: Satoshi Miyamoto; Daiki Niizato; Dan Tomomasa; Akira Nishimura; Akihiro Hoshino; Takahiro Kamiya; Takeshi Isoda; Masatoshi Takagi; Michiko Kajiwara; Shohei Azumi; Shinsuke Hirabayashi; Kenichi Sakamoto; Kenji Kishimoto; Takako Miyamura; Katsutsugu Umeda; Ayana Hirose; Dai Keino; Masakatsu Yanagim...; Kaori Kanda; Yuta Sakai; Yasuhiro Ikawa; Kenichiro Watanabe; Keisuke Tanaka; Takehiko Mori; Tatsuo Ichinohe; Hirotoshi Sakaguchi; Tomohiro Morio; Hirokazu Kanegane
• Keywords: Male; Transplantation Conditioning; Adolescent; Hematopoietic Stem Cell Transplantation; Infant; Graft vs Host Disease; Treatment Outcome; Asian People; Japan; Immune System Diseases; Child, Preschool; Humans; Transplantation, Homologous; Female; Child; Alemtuzumab; Retrospective Studies

Alemtuzumab is used with reduced-toxicity conditioning (RTC) in allogeneic hematopoietic cell transplantation (HCT), demonstrating efficacy and feasibility for patients with inborn errors of immunity (IEI) in Western countries; however, the clinical experience in Asian patients with IEI is limited. We retrospectively analyzed patients with IEI who underwent the first allogeneic HCT with alemtuzumab combined with RTC regimens in Japan. A total of 19 patients were included and followed up for a median of 18 months. The donors were haploidentical parents (n = 10), matched siblings (n = 2), and unrelated bone marrow donors (n = 7). Most patients received RTC regimens containing fludarabine and busulfan and were treated with 0.8 mg/kg alemtuzumab with intermediate timing. Eighteen patients survived and achieved stable engraftment, and no grade 3-4 acute graft-versus-host disease was observed. Viral infections were observed in 11 patients (58%) and 6 of them presented symptomatic. The median CD4+ T cell count was low at 6 months (241/µL) but improved at 1 year (577/µL) after HCT. Whole blood cells continued to exhibit > 80% donor type in most cases; however, 3/10 patients exhibited poor donor chimerism only among T cells and also showed undetectable levels of T-cell receptor recombination excision circles (TRECs) at 1 year post-HCT. This study demonstrated the efficacy and safety of alemtuzumab; however, patients frequently developed viral infections and slow reconstitution or low donor chimerism in T cells, emphasizing the importance of monitoring viral status and T-cell-specific chimerism. (238 < 250 words).