Natural (antiphospholipid-PDH,-DNA) autoantibodies and their physiologic serum inhibitors

Antiphospholipid syndrome (APS) is an auto-immune condition where a combination of both clinical and laboratory findings coexists. The prominent laboratory finding in the syndrome is the presence of antiphospholipid antibodies (aPL), the most frequently detected of which is the anticardiolipin antibody. A study presented in this paper indicates that sera from any healthy individual contain a large variety of natural autoantibodies. The presence of anticardiolipin antibodies in normal human sera (NHS) is described, and this is expanded to the presence of antibodies directed against other phospholipids, PDH, and DNA in the IgG fractions purified from NHS. An additional finding is the presence of inhibitors in the NHS, which inhibit the binding of natural autoantibodies to their respective antigens. These inhibitors are factors present not only in human sera but in sera of many other species as well.