دراسة تموضع الحواتم و تحت أصناف النمط الأسوي IgG لأضداد العامل الثامن لدى مرضى الناعور A

الملخص EN

Background& Objective: The development of inhibitors (Antibody against factor VIII ant-FVIII) is currently one of the major complications for the treatment of patients with hemophilia A, The only effective treatment available today when they appear is Immune Tolerance Induction ITI, There is no to the present any laboratory predictor of response to this worrying and expensive treatment.

This research aims to study the epitope mapping and identification of IgG sub-classes of factor FVIII inhibitors to study the immune response against factor VIII in patients with hemophilia A.

Materials & Methods: This research was conducted at the National Center for Scientific Research, Faculty of Medicine, University of Montpellier in France in 2010-2011, using the x-MAP technology and a BioPlex to analyze plasma samples taken from 26 hemophilia A patients with inhibitors: 73%, 27% had severe, moderate phenotype respectively.

Results: The median titer of inhibitors was: 4.8 Bethesda unit / ml, 0.9 Bethesda unit / ml respectively and the median age was: 20 years, 8 years, respectively.

57.7% of antibodies was directed against the heavy chain (HC) and 76% towards the light chain (LC) and targeted specifically to the C2 epitope in 61.5% and to A2 epitope in 53.8%.

Our data suggested the dominance of IgG1, IgG3 directed again HC, A2 while IgG2, IgG4 was dominant towards the region LC, C2 of factor VIII.

Conclusion: Study of the epitope mapping of inhibitors using x-MAP technology in hemophilia A patients can help to know the epitopes targeted and determine sub-classes of anti-FVIII which will have a significant role in predicting patient response to immune tolerance Induction and expected time required for the disappearance of inhibitors and thus will be an important sign of relapse , can also help in the development of preventive and treatment strategies for these patients and may avoid the need to use the very expensive treatment by passing agent and the rationalization of the application of immune tolerance Induction ITI.