Contribution of Anti-platelet Antibodies Identified With MAIPA Assay in the Demonstration of the Auto-immune Character of a Thrombocytopenia at Diagnosis

Official title

Contribution of Anti-platelet Antibodies Identified With" Monoclonal Antibody Immobilization of Platelet Antigens" Assay (MAIPA) in the Demonstration of the Auto-immune Character of a Thrombocytopenia at Diagnosis

Overview

Immune thrombocytopenia (ITP) is an autoimmune disease but, paradoxically, and unlike other autoimmune diseases, antiplatelet antibodies are not used either for the diagnosis of the disease or for its prognosis. ITP is a diagnosis of exclusion retained after elimination of other pathologies leading to a thrombocytopenia. No major study has prospectively evaluated the diagnostic value of the presence of anti-platelet antibodies in the etiological investigation of a thrombocytopenia, nor the impact of platelet antibodies on the course of ITP. The gold standard analysis for the determination of platelet antibodies, is the "monoclonal antibody immobilization of platelet antigens" assay (MAIPA), either direct to detect autoantibodies attached to platelets, or indirect to detect circulating antiplatelet antibodies. Therefore, this work aims to study the contribution of the presence of anti-platelet antibodies detected in MAIPA to determine the autoimmune nature of a thrombocytopenia at diagnosis.

Interventions

• Biological Blood samples
  * Thrombopoietin : 7 ml whole blood. * Anti-platelet antibodies free : 14 ml whole blood. * Anti-platelet antibodies bound : If the platelet count is ≥ 50 G / L : 14 ml whole blood for Peripheral blood mononuclear cell (PBMC) and monocytes isolation ; If the platelet count is \< 50 G / L and ≥ 20 G / L : 28 ml whole blood for Peripheral blood mononuclear cell (PBMC) and monocytes isolation ; If the platelet count is \< 20 G / L and ≥ 10 G / L: 42 ml whole blood for Peripheral blood mononuclear

Primary outcome measures

• Percentage of patients with a diagnosis of autoimmune thrombocytopenia among those in whom will be identified anti-platelet antibodies in direct and indirect MAIPA [Time frame: 12 months after baseline]

Secondary outcome measures (2)

• Percentage of patients with chronic ITP [Time frame: 12 months after baseline]
• serum Thrombopoietin concentration [Time frame: At baseline and 12 months after baseline]

Eligibility criteria

Inclusion criteria

• Patient over 18 years old;
• Patients with thrombocytopenia <100 G/L, checked twice, having ruled out false thrombocytopenia by platelet aggregation and acute leukemia by smear;
• No treatment started;
• Free, informed and written consent signed by the participant and the investigator (no later than the day of inclusion and prior to any review required by the research);
• Person affiliated or benefiting from a social security scheme.

Exclusion criteria

• Secondary ITP;
• False thrombocytopenia;
• Patients who have been transfused with platelets for less than 7 days with efficacy;
• Patient treated for thrombocytopenia (48 hours of corticosteroid therapy is tolerated and is not an exclusion criteria);
• Patient with acute leukemia;
• Pregnant or breastfeeding woman;
• False thrombocytopenia;
• Patient under guardianship, curatorship or any other legal protection regime.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Diagnostic

Study locations

France · 1 center

• CHU de Bordeaux - service de médecine interne — Pessac

Identifiers

NCT: NCT04800458 · CHUBX 2020/61

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗