Immunobiology of inhibitor development in hemophilia A

Semin Thromb Hemost. 2003 Feb;29(1):61-8. doi: 10.1055/s-2003-37940.

Abstract

After treatment with factor (F) VIII concentrate a significant number of patients with hemophilia A develop inhibitory antibodies that neutralize FVIII. Epitope mapping revealed that antibodies bind to selected regions within the A2, A3, and C2 domains of FVIII. Anti-A2 and anti-A3 antibodies interfere with assembly of FVIIIa with FIXa, whereas anti-C2 antibodies impede the interaction of FVIII with phospholipids. The immunologic mechanisms underlying inhibitor development in hemophilia A have not been fully elucidated. FVIII is recognized by the immune system as a foreign antigenic substance that evokes the T cell-dependent formation of high-affinity antibodies. Clonal analysis of B cell responses in hemophilia A patients has given further insight into the epitope specificity and molecular characteristics of FVIII inhibitors. Costimulatory blockade of FVIII-reactive T cells in a mouse model for hemophilia A has suggested new approaches for treatment of inhibitor patients. In this article, recent studies on the immunobiology of FVIII inhibitors are summarized and discussed with reference to their potential impact on treatment and prevention of immune responses in patients with hemophilia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • B-Lymphocytes / immunology
  • Epitope Mapping
  • Factor VIII / chemistry*
  • Factor VIII / immunology
  • Hemophilia A / drug therapy*
  • Hemophilia A / immunology*
  • Humans
  • Models, Biological
  • Models, Molecular
  • Protein Structure, Tertiary
  • T-Lymphocytes / metabolism
  • Time Factors

Substances

  • Factor VIII