Platelet Transfusion Refractoriness is one of the severe complications after multiple transfusions in patients with severe thrombopenia. Platelet Transfusion Refractoriness is characterized by inefficient transfusion and arise from allo-antibodies specific of platelets antigenes, mostly carried by HLA-I molecules.

A preliminary study has shown different isotypes of anti-HLA I in patients with Platelet Transfusion Refractoriness. Our hypothesis is that the type of anti-HLA I antibodies (recognised epitope, quantity, isotype) should establish predictive and diagnostic criteria for Platelet Transfusion Refractoriness.

Inclusion Criteria:

• Adult patient with Hematopoietic stem cells graft (autograft or allograft) or with acute leukemia with the indication of platelet transfusion.

Exclusion Criteria:

• Patient under guardianship
• Minor patient

Adult patient :

• with Hematopoietic stem cells graft (autograft or allograft)
• or with acute leukemia with the indication of platelet transfusion.