The objective of this human study was to evaluate the association between the specificity of anti-platelet autoantibodies and response to IVIG treatment.

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder, in which platelet surface GPIIb/IIIa and GPIb/IX are the two most frequently targeted autoantigens. Our previous studies in animal models of ITP demonstrated that intravenous immunoglobulin G (IVIG) could protect against anti-GPIIb/IIIa-mediated thrombocytopenia but failed to ameliorate ITP induced by most anti-GPIb/IX antibodies. The objective of this human study was to evaluate the association between the specificity of anti-platelet autoantibodies and response to IVIG treatment.

Inclusion Criteria:

• (1) the diagnosis of ITP was based on the presence of isolated thrombocytopenia and the absence of any obvious initiating and/or underlying cause of the thrombocytopenia in accordance with the recently released international consensus guidelines,(2) a diagnosis was established during the 4 weeks prior to initiation of IVIG treatment, (3) age ≥ 18 years, (4) a platelet count of ≤ 20 × 109/L, and (5) a bleeding score ≥ 9 at the time of admission according to the clinical scoring system described by Khellaf et al. to assess the severity of hemorrhage.

Exclusion Criteria:

• a history of any ITP-specific treatment administered prior to or concomitantly with the IVIG

adult patients with severe ITP who underwent IVIG therapy and had platelet autoantibodies assayed