Immune thrombocytopenia is an acquired autoimmune disease, in which platelets are opsonized by auto-antibodies and destroyed by phagocytic cells .Genetic polymorphisms in the immune mediators have been suggested to play a pivotal role in the pathogenesis of many autoimmune disorders . Several genetic polymorphisms of the immune system genes have been described in ITP such as interleukins, tumor necrosis factors (TNF) alpha and beta, and interferon-gamma., These polymorphisms were found to be associated with an increased risk of ITP progression or exacerbation .CD40 is a co-stimulatory 4348 kDa glycoprotein molecule composed of 277 amino acid residues which belongs to the tumor necrosis family. It is encoded by a gene which is located at chromosome 20q11-13, expressed mainly on antigen presenting cells (APCs), some non-immune cells and tumors.Antinuclear antibodies (ANA) is a collective term for a large and heterogeneous group of circulating autoantibody. Reflecting their clinical importance, ANA are diagnostic, prognostic or classification criteria for many autoimmune diseases.

Inclusion Criteria:

• sign an informed written consent from the patients or their parents
• patient with newly diagnosed ITP
• patient age > 1 year and < 65 years and both sexes are included.

Exclusion Criteria:

• Refusal to sign an informed written consent
• patient with persistent ITP, patient with secondary immune thrombocytopenia
• patient age < 1 year or > 65 years.