Idiopathic Thrombocytopenia Purpura (ITP) is an autoimmune disorder. It is characterized by antibodies directed against which of the following?

Idiopathic Thrombocytopenia Purpura (ITP) is an autoimmune disorder. It is characterized by antibodies directed against which of the following?

• A. Platelets
• B. Megakaryocytes
• C. Both platelets and megakaryocytes
• D. Fibrinogen

Answer: (C)

Autoimmune ITP involves antibodies that bind to platelet surface glycoproteins, marking platelets for destruction by splenic macrophages and shortening their lifespan, which directly causes low platelet counts. In many cases, these antibodies also affect megakaryocytes in the bone marrow, impairing platelet production and contributing further to thrombocytopenia. Fibrinogen is unrelated to the autoimmune platelet destruction seen in ITP, so it isn’t targeted. Therefore, antibodies directed against both platelets and megakaryocytes best explain the finding.

Autoimmune ITP involves antibodies that bind to platelet surface glycoproteins, marking platelets for destruction by splenic macrophages and shortening their lifespan, which directly causes low platelet counts. In many cases, these antibodies also affect megakaryocytes in the bone marrow, impairing platelet production and contributing further to thrombocytopenia. Fibrinogen is unrelated to the autoimmune platelet destruction seen in ITP, so it isn’t targeted. Therefore, antibodies directed against both platelets and megakaryocytes best explain the finding.