Immune Thrombocytopenia: Immune Dysregulation and Genetic Perturbations Deciphering the Fate of Platelets

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder. It involves impaired production and excessive destruction of platelets. It is a complex and heterogeneous disorder with unknown pathophysiology. Both genetic and immunologic perturbations have been implicated in the disease pathogenesis. Immune dysregulations involve both the humoral and cellular immunity. Attack of anti-platelet autoantibodies has been found to be the fundamental cause of platelet destruction. Other mechanisms including T cell mediated platelet destruction, complement activation, apoptosis, and desialylation have also been found in the development of ITP. Genetic testing has revealed various predispositions including single nucleotide polymorphisms (SNPs), copy number variations (CNVs), and epigenetic changes in the immunoregulatory genes of ITP subjects. Varying methylation patterns have also been found in the immune-related genes. This review summarizes the dysregulated immune cells, immunologic cascades, altered signaling pathways, genetic mutations and epigenetic changes in ITP pathogenesis. These alterations induce autoimmune responses against the platelets resulting in complex bleeding manifestations and onset of ITP.