Autoantibody Explosion In Antiphospholipid Syndrome - ד"ר אוריאל כץ, יהודה שונפלד, גלעד טויג, יניב שרר

Thrombosis or blood clot formation inside a blood vessel and frequent pregnancy loss characterize antiphospholipid syndrome (APS), which shows the presence of high levels of classical, antiphospholipid antibodies (aPL) and some ‘non-classical’ aPL, and other antibodies too. Some most common examples of antiphospholipid antibodies are anticardiolipin, lupus anticoagulant and anti-beta2-glycoprotein I. Autoantibodies against platelets, various coagulation factors, glycoproteins, mitochondrial antigens, lamins, and cell surface markers also feature in APS. The disease Systemic lupus erythematosus (SLE) is frequently associated with APS. More than 100 autoantibodies are linked with SLE and this phenomenon is termed as autoantibody explosion in SLE which can now be exyended to APS as well. In 75% of APS patients, lupus anticoagulants like beta2-glycoprotein I and prothrombin are found. Also, lupus anticoagulants are frequently found in healthy persons too making their corelation with APS diagnosis difficult which use phospholipid-dependent screening tests. Along with these, anticardiolipin autoantibodies are found in 84-90% of APS patients. Antiphosphatidylserine, which participates in clot formation, is there in almost 60% patients while 95% patients are positive for antiphosphatidylethanolamine, against phosphatidylethanolamine, a component of cell membrane. Anti-plasmin/plasminogen, anti-tissue tPA (plasminogen activator), Antineutrophil cytoplasmic antibodies (ANCA), anti-mitochondrial, anti-thyroid, anti-lamin, anti-heat shock protein, anti-CD40, and antinuclear antibodies etc. too play an additive role in promoting the pro-thrombotic tendency of the syndrome and can be used for early diagnosis of the syndrome. Anticardiolipin antibodies are positive in APS, syphilis, malaria, hepatitis A, HIV, and in a number of drug-induced disease conditions too. A combination of lupus anticoagulants and anticardiolipin antibodies show good diagnosis of APS. The routine testing for the presence of other antiphospholipid antibodies is expensive and does not improve the diagnosis of APS significantly, even when these antiphospholipid antibodies like antiphosphatidylserine, antiphosphatidylethanolamine, antiphosphatidylglycerol, antiphosphatidic acid and antiphosphatidylinositol etc. are more specific for APS. A similar approach can be used in cancer where phospholipid metabolites can be used as indicators of cancer cell functions.