Polymorphisms in the F8 gene and MHC-II variants as risk factors for the development of inhibitory anti-factor VIII antibodies during the treatment of hemophilia a: a computational assessment

PLoS Comput Biol. 2013;9(5):e1003066. doi: 10.1371/journal.pcbi.1003066. Epub 2013 May 16.

Abstract

The development of neutralizing anti-drug-antibodies to the Factor VIII protein-therapeutic is currently the most significant impediment to the effective management of hemophilia A. Common non-synonymous single nucleotide polymorphisms (ns-SNPs) in the F8 gene occur as six haplotypes in the human population (denoted H1 to H6) of which H3 and H4 have been associated with an increased risk of developing anti-drug antibodies. There is evidence that CD4+ T-cell response is essential for the development of anti-drug antibodies and such a response requires the presentation of the peptides by the MHC-class-II (MHC-II) molecules of the patient. We measured the binding and half-life of peptide-MHC-II complexes using synthetic peptides from regions of the Factor VIII protein where ns-SNPs occur and showed that these wild type peptides form stable complexes with six common MHC-II alleles, representing 46.5% of the North American population. Next, we compared the affinities computed by NetMHCIIpan, a neural network-based algorithm for MHC-II peptide binding prediction, to the experimentally measured values and concluded that these are in good agreement (area under the ROC-curve of 0.778 to 0.972 for the six MHC-II variants). Using a computational binding predictor, we were able to expand our analysis to (a) include all wild type peptides spanning each polymorphic position; and (b) consider more MHC-II variants, thus allowing for a better estimation of the risk for clinical manifestation of anti-drug antibodies in the entire population (or a specific sub-population). Analysis of these computational data confirmed that peptides which have the wild type sequence at positions where the polymorphisms associated with haplotypes H3, H4 and H5 occur bind MHC-II proteins significantly more than a negative control. Taken together, the experimental and computational results suggest that wild type peptides from polymorphic regions of FVIII constitute potential T-cell epitopes and thus could explain the increased incidence of anti-drug antibodies in hemophilia A patients with haplotypes H3 and H4.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Antibodies / chemistry
  • Antibodies / immunology
  • Antibodies / metabolism
  • Black People
  • Computational Biology / methods*
  • Factor VIII / chemistry
  • Factor VIII / genetics*
  • Factor VIII / immunology*
  • Factor VIII / metabolism
  • Haplotypes
  • Hemophilia A
  • Histocompatibility Antigens Class II / genetics*
  • Histocompatibility Antigens Class II / immunology
  • Histocompatibility Antigens Class II / metabolism*
  • Humans
  • Molecular Sequence Data
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / immunology
  • Peptide Fragments / metabolism
  • Polymorphism, Single Nucleotide
  • Protein Binding
  • Risk Factors

Substances

  • Antibodies
  • Histocompatibility Antigens Class II
  • Peptide Fragments
  • Factor VIII