Factor VIII Ise (R2159C) in a patient with mild hemophilia A, an abnormal factor VIII with retention of function but modification of C2 epitopes

Thromb Haemost. 1997 May;77(5):862-7.


We found a patient with mild hemophilia A who had no detectable factor VIII antigen (FVIII:Ag), as shown by two-site ELISA using inhibitor alloantibodies (TK). We then analyzed A2, A2/B, and C2 antigen of the patient's DDAVP-induced FVIII using several anti-FVIII monoclonal antibodies. Factor VIII activity (FVIII:C) was increased from 12 to 42 U/dl by the administration of DDAVP. The DDAVP-induced increases in the A2 and A2/B antigens were 40 and 36 U/dl, respectively. However, the increase in the C2 antigen was only 7.5 U/dl. SSCP analysis and subsequent sequencing demonstrated an Arg to Cys transition at codon 2159. The anti-FVIII:C titer of monoclonal antibody, NMC-VIII/5 which recognized the C2 domain, against normal plasma was 450 Bethesda U/mg of IgG. However, the titer against DDAVP-treated patient's plasma was only 15 Bethesda U/mg. We also tested DDAVP-induced increase in the FVIII:Ag in another mild hemophilia A patient with the same mutation at Arg2159. Increase in his C2 antigen levels was only 19% of those in the A2 and A2/B antigen. We designate this abnormal FVIII as FVIII Ise. Our results show that a missense mutation at Arg2159 to Cys modifies the antigenicity of the C2 domain.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Amino Acid Sequence
  • Antibodies, Monoclonal
  • Arginine
  • Base Sequence
  • Cysteine
  • DNA Primers
  • Deamino Arginine Vasopressin
  • Enzyme-Linked Immunosorbent Assay
  • Epitopes / analysis
  • Epitopes / chemistry
  • Exons
  • Factor VIII / biosynthesis
  • Factor VIII / chemistry
  • Factor VIII / genetics*
  • Hemophilia A / blood
  • Hemophilia A / genetics*
  • Humans
  • Isoantibodies
  • Male
  • Point Mutation*
  • Polymerase Chain Reaction
  • Polymorphism, Single-Stranded Conformational
  • von Willebrand Factor / biosynthesis


  • Antibodies, Monoclonal
  • DNA Primers
  • Epitopes
  • Isoantibodies
  • factor VIII Ise
  • von Willebrand Factor
  • Factor VIII
  • Arginine
  • Deamino Arginine Vasopressin
  • Cysteine