Pathophysiological Mechanisms Leading to Low Platelet Count in Immune Thrombocytopenia

Abstract

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by the decrease in peripheral blood platelet count below 100 x 10 9 /L, and an increased bleeding risk when thrombocytopenia drops below 30 x 10 9 /L. The mechanisms leading to ITP in adults, although not completely elucidated, involves an imbalance between effector and regulatory cells that results in a breakdown of the immune tolerance. Autoantibodies are considered the main responsible for thrombocytopenia, although direct T-cell cytotoxic effect and lysis by Complement attachment and activation could also contribute to platelet elimination from circulation. In addition to increased peripheral clearance, abnormalities in platelet production also favors platelet count reduction. This review is intended to describe some specific knowledge about peripheral and bone marrow mechanisms leading to thrombocytopenia in adult ITP.

Immune Thrombocytopenic Purpura as a Hemorrhagic Versus Thrombotic Disease: An Updated Insight into Pathophysiological Mechanisms

“…ITP is associated with thrombocytopenia that has as clinical expression bleeding and hemorrhages in mucosa or skin [3,4]. ITP is a heterogeneous disease where clinical outcome and response to treatment display varied biologic behavior with a better outcome in the case of children and a worse outcome in adult cases [5,6].…”

Megakaryocytic Characteristics in Diagnosis of Patients with Thrombocytopenia

“…Similarly, not many cases of myelodysplastic syndrome, myelofibrosis, megaloblastic anaemia, and mixed nutritional anaemia along with idiopathic thrombocytopenia were included in this analysis for comparison. There were 5 MDS cases, all of which displayed a normal number of megakaryocytes in the bone marrow 18,24,25 . Discovery of emperipolesis among anaemia was observed in Tavassoli study 19 .…”

“…It is the source of bleeding that is most common. Thrombocytopenia arises from only four mechanisms, considering the amount and variety of disorders that are etiologically related: artifactual thrombocytopenia, low development of platelets, rapid degradation of platelets and an unequal distribution or platelet pooling inside the body 3 . Changes in the morphology of megakaryocytes in immune thrombocytopenic purpura, e.g., wide spread vacuolization of cytoplasm, hypogranularity and smoothing of the cell membrane, were previously identified by Frank in 1915and further verified by other researchers.…”

Treatment outcomes and adherence to treatment in patients with immune thrombocytopenia in two Ethiopian teaching hospitals: a retrospective cohort study

“…It is described as a transient or persistent reduction in platelet count < 100 × 10 9 /L and an increased risk of bleeding that depends on the degree of thrombocytopenia 2,3 . Autoantibodies are considered the main cause of thrombocytopenia, and binding of antiplatelet autoantibodies to their antigenic glycoprotein leads to elimination/phagocytosis of platelets in the reticuloendothelial system by monocytes/macrophages, primarily in the spleen 4,5 .…”