Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet counts with or without mucocutaneous bleeding (McMillan, 2007). Like the majority of autoimmune diseases, ITP is an organ-specific disease, and abnormalities in the regulation of the immune system have been shown to play an important role in the initiation and/or perpetuation of the disease (McKenzie et al.,2013).

Still, immune thrombocytopenia (ITP) is a significant clinical problem due to chronicity, treatment cost, occurrence mainly in, young, and relatively poorer quality of life

In recent years the critical role of miRNAs has been established in many diseases, including autoimmune disorders. Immune thrombocytopenic purpura (ITP) is a predominant autoimmune disease, in which aberrant expression of miRNAs has been observed, suggesting that miRNAs are involved in its development (Jafarzadeh et al., 2021). Studies have also shown that cell-free miRNAs in circulation are stable and that such miRNAs may be exploited as novel disease markers (Etheridge et al.,2011) and ( van Rooij et al., 2008).

MicroRNAs (miRNAs) are endogenous small RNAs, usually 18-25 nucleotides in length. These non-coding RNAs regulate gene expression by several mechanisms, such as repressing protein translation and altering mRNA stability (Ambros, 2008. Bartel,2004). In humans, >2,000 miRNAs have been discovered. The functional significance of the majority of the identified miRNAs has yet to be fully elucidated. Studies have shown that miRNAs play important roles in hematopoietic differentiation, e. g. megakaryocytopoiesis. (Garzon et al., 2008) and erythropoiesis ( Masaki et al., 2007 )and (Bruchovaetal., 2007), and in hematological malignancies (Rossi et al.,2010) and (Visone et al.,2009). More recently, miRNAs have also been implicated in cellular immune responses that contribute to ITP (Jernas et al., 2013) and (McKenzie etal., 2013). It was found that 23 differentially expressed miRNAs in ITP (14 up-regulated and 9 down-regulated) Altered miRNA expression may occur in specific diseases and at specific disease stages (Martin et al., 2012) Also, Recent studies have demonstrated that Th17, which is characterized for its production of IL-17, is elevated in ITP patients (Hu et al., 2012) and (Huber et al., 2007). IL-17 belongs to the IL-17 cytokine family. Increased IL-17 expression has been observed in various autoimmune diseases, such as rheumatoid arthritis (RA) ( Roeleveld et al., 2013) and systemic lupus erythematosus (SLE) (Ballantine et al., 2014). This evidence suggests that IL-17 may be associated with autoimmune diseases.

Inclusion Criteria:

• ITP patients

Exclusion Criteria:

• 1- Secondary causes of ITP as systemic lupus erythematosus (SLE), viral infections (HIV, hepatitis B or C infections) 2- Other underlying medical diseases that may cause thrombocytopenia as:
• malignancy
• megaloblastic anemia
• aplastic anemia
• lymphoproliferative disorders
• liver disease
• renal impairment
• pregnancy 3-Organomegally and/or lymphadenopathy. 4-Recent history of vaccination. 5-Recent evidence of bacterial infection.

This is a cross-sectional study. Patients will be recruited from the internal department- hematology unit outpatient clinic of El Minia University Hospital in collaboration with the clinical pathology department El Minia University Hospital and the biochemistry department of Minia and Sohag University. Research Ethics Medical Review Board of El-Minia University has approved the protocol.