49-OR

Abstract

Aim Alloantibodies against MICA antigens are found in solid organ transplant recipients but MICA antibody test kits, available from different sources, produced markedly discrepant results. Therefore, a collaborative project was initiated in the 16 th International Histocompatibility and Immunogenetics Workshop. Methods Well characterized sera containing antibodies against MICA antigens were used in an effort to attain international agreement. Four shipments each consisting of four well documented sera were tested in 18 participating laboratories from 7 countries. Results From the beginning, positive/negative assignments were reported with essential agreement among the participating laboratories. There were considerable differences however, in the specificity of antibodies detected. These discrepancies appeared to be due mainly to the use of different MICA antibody kits manufactured by laboratories of four different suppliers. As a result of the reports provided, and modifications they stimulated, the comparison of results between laboratories improved in the second and third serum exchange. Finally, the results of the fourth serum exchange showed that a consensus has been almost reached among participating laboratories and the results obtained with MICA antibody testing kits produced by the four supplier laboratories became very similar. Conclusions International collaboration and the efforts of the participating laboratories contributed to the improvement in the detection of true MICA alloantibodies that was observed.