No 7, 2012

Publication of the Month

 

July 07/12: 

Usefulness of additional markers for APS

  

Key message:

  • The low sensitivity of prothrombin IgG/IgM antibodies limits their usefulness in APS diagnosis.
  • Anti-β2GPI IgA is an independent risk factor for death in hemodialysis patients.

  

Background: In addition to anticardiolipin (aCL) IgG/IgM and/ anti-β2glycoprotein I (anti-β2GPI) IgG/IgM, several other autoantibodies are discussed as potential markers for the diagnosis of antiphospholipid syndrome (APS) and disease subsets, but their clinical significance is still questioned. Anti-prothrombin (aPT) IgG/IgM and anti-β2GPI IgA belong to these candidates.

 

 

Hoxha A, Ruffatti A, Pittoni M, Bontadi A, Tonello M, Salvan E, Plebani M, Punzi L
The clinical significance of autoantibodies directed against prothrombin in primary antiphospholipid syndrome
Clin Chim Acta 2012;413:911-913  

 

Summary: The evaluations show that anti-prothrombin (aPT) IgG/IgM are significantly associated with primary APS (PAPS) with high specificity, but low sensitivity. aPT IgG are significantly associated with thrombosis and pregnancy morbidity. aPT IgG were significantly associated with aCL IgG, anti-β2GPI IgG and lupus anticoagulant. aPT IgM was associated with anti-β2GPI IgM and lupus anticoagulantbut not with aCL IgM.  

 

Conclusions: The study confirms that aPT IgG/IgM are significantly associated with PAPS and indicate that aPT IgG are associated with clinical subsets of the disease. For the time being, however, the lower sensitivity of IgG/IgM antibodies with respect to conventional phosholipid antibodies precludes their inclusion in the recommendations for the diagnosis of PAPS.    

 

 

Serrano A, Garcia F, Serrano M, Ramirez E, Alfaro FJ, Lora D, de la Camara AG, Paz-Artal E, Praga M, Morales JM
IgA antibodies against beta2 glycoprotein I in hemodialysis patients are an independent risk factor for mortality
Kidney Int 2012;81:1239-1244  

 

Summary: End-stage renal disease patients on hemodialysis were followed up to evaluate the prevalence of aCL and anti-β2GPI and their influence on clinical outcomes. Patients positive for anti-β2GPI IgA showed higher mortality, had more thrombotic events, more thrombosis on vascular access and a higher incidence of atherosclerosis-related vascular events.  

 

Conclusions: anti-β2GPI IgA are associated with mortality and incidence of thrombotic processes. Testing anti-β2GPI IgA in dialysis patients may be important to identify risk patients of thrombosis and vascular disease and to establish a better and quick management.  

 

Comment: Although both markers show association to specific disease subsets, only anti-β2GPI IgA adds clinical value to the conventional APS markers. Currently, several publications examine the developments in APS diagnosis. Two studies were chosen as examples. Those underline the current attempt to improve the diagnosis and management of antiphospholipid syndrome.

 

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As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.