Acquired aplastic anemia (AA) is caused by autoreactive T cell–mediated destruction of early hematopoietic cells. Somatic loss of human leukocyte antigen (HLA) class I alleles was identified as a mechanism of immune escape in surviving hematopoietic cells of some patients with AA. However, pathogenicity, structural characteristics, and clinical impact of specific HLA alleles in AA remain poorly understood. Here, we evaluated somatic HLA loss in 505 patients with AA from 2 multi-institutional cohorts. Using a combination of HLA mutation frequencies, peptide-binding structures, and association with AA in an independent cohort of 6,323 patients from the National Marrow Donor Program, we identified 19 AA risk alleles and 12 non-risk alleles and established a potentially novel AA HLA pathogenicity stratification. Our results define pathogenicity for the majority of common HLA-A/B alleles across diverse populations. Our study demonstrates that HLA alleles confer different risks of developing AA, but once AA develops, specific alleles are not associated with response to immunosuppression or transplant outcomes. However, higher pathogenicity alleles, particularly HLA-B*14:02, are associated with higher rates of clonal evolution in adult patients with AA. Our study provides insights into the immune pathogenesis of AA, opening the door to future autoantigen identification and improved understanding of clonal evolution in AA.
Timothy S. Olson, Benjamin F. Frost, Jamie L. Duke, Marian Dribus, Hongbo M. Xie, Zachary D. Prudowsky, Elissa Furutani, Jonas Gudera, Yash B. Shah, Deborah Ferriola, Amalia Dinou, Ioanna Pagkrati, Soyoung Kim, Yixi Xu, Meilun He, Shannon Zheng, Sally Nijim, Ping Lin, Chong Xu, Taizo A. Nakano, Joseph H. Oved, Beatriz M. Carreno, Yung-Tsi Bolon, Shahinaz M. Gadalla, Steven G.E. Marsh, Sophie Paczesny, Stephanie J. Lee, Dimitrios S. Monos, Akiko Shimamura, Alison A. Bertuch, Loren Gragert, Stephen R. Spellman, Daria V. Babushok
This file is in Adobe Acrobat (PDF) format. If you have not installed and configured the Adobe Acrobat Reader on your system.
PDFs are designed to be printed out and read, but if you prefer to read them online, you may find it easier if you increase the view size to 125%.
Many versions of the free Acrobat Reader do not allow Save. You must instead save the PDF from the JCI Online page you downloaded it from. PC users: Right-click on the Download link and choose the option that says something like "Save Link As...". Mac users should hold the mouse button down on the link to get these same options.