Drawbacks of the MAIPA technique in characterising human antiplatelet antibodies

Monoclonal Antibody-specific Immobilisation of Platelet Antigens (MAIPA) assays have been developed to allow the identification and characterisation of antibodies directed against platelets. A major disadvantage of the MAIPA test is the existence of false negative results. This is due to the competition between human and monoclonal antibodies (MoAb) for epitopes that are either identical or very close. In this report we used the MAIPA technique to test anti-HPA-1a alloantibodies and anti-Naka isoantibodies in conjunction with a panel of murine MoAbs directed against CD41/61 or CD36 respectively. Our data demonstrate that the choice of MoAbs used in MAIPA is very important for accurate diagnosis of clinical conditions and institution of specific therapy. Moreover, the results obtained are in favour of an heterogeneity for the recognition of the alloepitope HPA-1a and of distinguishable epitopes on GPIV.