Avidity of antiphospholipid antibodies - our current knowledge

Antiphospholipid antibodies (APL), which represent serum markers of the antiphospholipid syndrome, comprise an extremely heterogeneous group of autoantibodies directed against various phospholipids and protein cofactors. The heterogeneity of APL includes not only their antigen-binding site specificity but also their avidity. The aim of this study was to summarize the current knowledge about commonly-used procedures for the avidity determination with a special interest in the antiphospholipid antibodies and to evaluate the clinical significance of APL avidity determination. The common techniques in clinical laboratories for avidity determination utilize the ELISAs in the presence of various chaotropic agents. The findings of clinical studies suggest that the high avidity APL are associated with thrombosis and antiphospholipid syndrom (APS). The determination of APL avidity might be a complementary laboratory marker applicable in the classification of APS.