Background:  An autoimmune bleeding disease called immune thrombocytopenia (ITP) can lead to an exceedingly low count of platelets of no more than 100 × 109/L due to enhanced antibody-mediated platelet clearance and elimination by antigen-presenting cells mostly in the spleen. There are numerous forms of antiplatelet glycoprotein autoantibodies shown in ITP patients, including P-selectin, GP1B, GP 9, GP 2B and GP 3A. Objective: To assess the role of P-Selectin autoantibody in detecting response to treatment in patients with newly diagnosed primary ITP and patients with persistent primary ITP, and to evaluate association between P-Selectin autoantibody to GP IIbIIIa autoantibodies. Methodology: A cohort study was conducted on 90 adult patients suffering from immune thrombocytopenia. They were divided   according to type of thrombocytopenia into 45 adult patients with newly diagnosed primary ITP and receiving first-line corticosteroids treatment, and 45 adult patients with primary persistent ITP. Informed consent, detailed history, physical examination, and complete laboratory investigation, including measurements of platelet glycoprotein specific antibody and P-selectin autoantibody using enzyme-linked immunosorbent assay kits (ELISA) at the Hematology Unit of Ain Shams University hospital. Results: Regarding P-Selectin autoantibody levels, there was a lack of statistical significance between the research cohorts. In both groups, the full response rate was considerably greater within patients who were anti-P-selectin negative (27.60.0%) than those who were anti-P-selectin positive (18. 40.0%). In addition, a highly noteworthy positive correlation between GP IIb and IIIa (ng/ml) and P-Selectin (pg/ml) was discovered by the current analysis. Conclusion: detecting anti-P-selectin antibodies and GP IIbIIIa might be a useful technique for identifying individuals who are less receptive to medication.