[Antiplatelet antibodies in patients with acute myocardial infarct]

Seventy-seven patients with myocaridal infarction and ten normal individuals were studied in order to establish the presence of serous antibodies against platelets. With the complement fixation test antibodies were found in 6.4% of the patients and in none of the normal individuals. Leukoaglutinating and lymphocytotoxic antibodies were detected in 3.8% and 1.2% of the patients, respectively. No anti-platelet antibodies were found by immunoelectrophoresis or by double microimmunodiffusion neither in patients nor in normals. Rabbits immunized with human platelets had up to four antigen-antibody systems as shown by immunoelectrophoresis and double microimmunodiffusion. These rabbit sera were anticomplementary and thus they could not be tested by complement fixation test nor by lymphocytotoxicity. The data obtained suggest that circulating antiplatelets antibodies are rare and thus the possibility of their contributing further damage during myocardial infarction is also low. The alternatives to explain the low frequency of antiplatelet antibodies in patients with myocardial infarction are discussed.