Abstract
Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by both reduced
platelet survival and suppression of megakaryocyte and platelet development. It can
either be primary or secondary to other autoimmune disorders, infections, vaccines,
lymphoproliferative disorders, and drugs. Antibodies reacting against platelet glycoproteins
are typical of ITP; these antibodies can mediate destruction of platelets by the monocyte–macrophage
system as well as suppress megakaryocyte proliferation and maturation. Abnormalities
of cell-mediated immunity are known to contribute to the pathologic process. Like
many other autoimmune diseases, ITP has a T helper cell type 1 bias and a reduced
activity of T-regulatory cells. Cytotoxic T cells may directly lyse platelets and
possibly suppress megakaryopoiesis. Recent studies suggest that mesenchymal stem cells
are dysfunctional in ITP and may contribute to an aberrant amplification of the autoimmune
response. Significant advances in the treatment of chronic ITP have been witnessed
in the past decade, first with the introduction of rituximab and more recently with
the thrombopoietin-receptor agonists. While splenectomy is still considered the gold
standard in this setting, effective medical therapy is now available for patients
in whom surgery is not an option.
Keywords
immune thrombocytopenia - platelet autoantibodies - B cells - T cells - corticosteroids
- splenectomy - thrombopoietin-receptor agonists
