[Glanzmann thrombasthenia, PLA1 antigen and anti-Glanzmann antibody]

Six cases of Glanzmann's thrombasthenia were studied using a platelet indirect radioactive Coombs (PIRC). In serum of two among six patients, an antibody was found, which reacted positively with all platelets except those of thrombasthenic patients. Such "anti-public" antibody which shortens the life of transfused platelets is a very serious complication of Glanzmann's thrombasthenia. Attempts to define the PLA group of the six Glanzmann patients, with human allo antisera recognizing PLA1 antigen, gave negative results. Three hypothesis were discussed: (1) Interference in the test of the aggregation defect of thrombasthenic platelets. However, anti-HLA antibodies were normally fixed in the PIRC test. (2) PLA2 gene and Glanzmann gene have a strong gametic association and all Glanzmann's patients are PLA1 negative. (3) Glanzmann gene is coding for the PLA gene substrate. In such case, thrombasthenic patients might be genetically PLA1 positive and phenotypically PLA1 negative. Moreover they would also be PLA2 negative, this could not be tested due to the lack of anti-PLA2 antiserum.