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Endogenous factor VIII synthesis from the intron 22–inverted F8 locus may modulate the immunogenicity of replacement therapy for hemophilia A

2013; Nature Portfolio; Volume: 19; Issue: 10 Linguagem: Inglês

10.1038/nm.3270

1546-170X

Gouri Shankar Pandey, Chen Yanover, Lisa M. Miller-Jenkins, Susan H. Garfield, Shelley A. Cole, Joanne E. Curran, Eric K. Moses, Natalia Rydz, Vijaya L. Simhadri, Chava Kimchi‐Sarfaty, David Lillicrap, Kevin R. Viel, Teresa M. Przytycka, Glenn F. Pierce, Tom E. Howard, Zuben E. Sauna, Jeanne M. Lusher, Meera Chitlur, Afshin Ameri, Kavita Natarajan, Rathi V. Iyer, Alexis A. Thompson, Raymond G. Watts, Christine L. Kempton, Craig M. Kessler, John C. Barrett, Erica J. Martin, Nigel S. Key, Rebecca Kruse‐Jarres, Cindy Lessinger, Kathleen P. Pratt, Neil C. Josephson, Kevin McRedmond, Janice S. Withycombe, Christopher A. Walsh, Dana C. Matthews, Johnny Mahlangu, Amanda Krause, Rosemary Schwyzer, Rajendra Thejpal, Nadine Rapiti, Yasmin Goga, Marius Coetzee, David Stones, Kenneth G. Mann, Saulius Butenas, Laura Almasy, John Blangero, Melanie A. Carless, Raja Rajalingam, Elaine F. Reed,

Cancer-related gene regulation

Patients with hemophilia lacking functional coagulation factor VIII (FVIII) are treated with replacement FVIII proteins. The development of neutralizing antibodies to the replacement FVIII, a major clinical problem, depends on the nature of the mutation in the gene encoding FVIII. The authors find that a prevalent inversion allele can unexpectedly produce FVIII protein, explaining why individuals with this allele do not frequently develop neutralizing antibodies. Neutralizing antibodies (inhibitors) to replacement factor VIII (FVIII, either plasma derived or recombinant) impair the effective management of hemophilia A1. Individuals with hemophilia A due to major deletions of the FVIII gene (F8) lack antigenically cross-reactive material in their plasma (“CRM-negative”), and the prevalence of inhibitors in these individuals may be as high as 90%. Conversely, individuals with hemophilia A caused by F8 missense mutations are CRM-positive, and their overall prevalence of inhibitors is <10% (ref. 2). Individuals with the F8 intron 22 inversion (found in ∼50% of individuals with severe hemophilia A) have been grouped with the former on the basis of their genetic defect and CRM-negative status. However, only ∼20% of these individuals develop inhibitors3. Here we demonstrate that the levels of F8 mRNA and intracellular FVIII protein in B lymphoblastoid cells and liver biopsies from individuals with the intron 22 inversion are comparable to those in healthy controls. These results support the hypothesis that most individuals with the intron 22 inversion are tolerized to FVIII and thus do not develop inhibitors. Furthermore, we developed a new pharmacogenetic algorithm that permits the stratification of inhibitor risk for individuals and subpopulations by predicting the immunogenicity of replacement FVIII using, as input, the number of putative T cell epitopes in the infused protein and the competence of major histocompatibility complex class II molecules to present such epitopes. This algorithm showed statistically significant accuracy in predicting the presence of inhibitors in 25 unrelated individuals with the intron 22 inversion.