ABSTRACT
This chapter provides studies on the genetic predisposition to the antiphospholipid syndrome (APS) and to the production of the antiphospholipid antibodies (aPL). Many researchers involved in the field of immunogenetics have been trying to discover possible associations between APS or the various antibodies directed against negatively charged phospholipids and major histocompatibility complex (MHC) genes or their products. The human leukocyte antigen (HLA) class I and II molecules are polymorphic membrane glycoproteins found on the surface of nearly all cells. MHC class II molecules are normally expressed on the surface membrane of antigen presenting cells (APC), which are represented by macrophages, Langerhans cells, dendrytic cells, and B lymphocytes. In humans, the contribution of the genetic background to the development of aPL and APS has been addressed mainly by family studies and by population studies looking at the HLA region. Population studies suggest that HLA genes have a role in conferring susceptibility to develop primary APS.
