Immune-mediated thrombocytopaenia (ITP) occurs due to an autoimmune response directed against circulating platelets or megakaryocytes in the bone marrow. The destruction of cells is mediated by antibodies, making ITP a form of '''[[Type II Hypersensitivity|type II hypersensitivity]]'''. The antibodies bind to cells and act as a foundation for the assembly of serum complement components or as opsonins, promoting the uptake and destruction of platelets by cells of the monocyte-phagocyte system (MPS). The destruction of platelets usually results in severe [[Platelet Abnormalities|thrombocytopaenia]] and, if the blood level of platelets fall below approximately 50x10^9/l, the affected animal is at risk of mucosal haemorrhages. | Immune-mediated thrombocytopaenia (ITP) occurs due to an autoimmune response directed against circulating platelets or megakaryocytes in the bone marrow. The destruction of cells is mediated by antibodies, making ITP a form of '''[[Type II Hypersensitivity|type II hypersensitivity]]'''. The antibodies bind to cells and act as a foundation for the assembly of serum complement components or as opsonins, promoting the uptake and destruction of platelets by cells of the monocyte-phagocyte system (MPS). The destruction of platelets usually results in severe [[Platelet Abnormalities|thrombocytopaenia]] and, if the blood level of platelets fall below approximately 50x10^9/l, the affected animal is at risk of mucosal haemorrhages. |