A global expression profile of peripheral blood from patients with immune thrombocytopenic purpura (ITP) was performed that identified an ITP-specific signature, which also included interferon (IFN)-induced genes. Several genes correlated with ITP have been shown to be associated with expression signatures in systemic lupus erythematosis and rheumatoid arthritis, indicating an overlap with other autoimmune disorders. Pathway analysis demonstrated that IFN signalling, death receptor and protein ubiquitination pathways were associated with ITP. These results provide the first glimpse of the genes and pathways consistently aberrant in ITP, identifying new targets for investigations of pathogenesis and treatment of ITP.