Interplay of leucocyte–platelet complexes and clinical response to eltrombopag in immune thrombocytopenia patients

Summary Eltrombopag (ELT) is a thrombopoietin‐receptor agonist that stimulates platelet (PLT) production in patients with primary immune thrombocytopenia (ITP). One potential mechanism of ELT is modulating the inflammatory response by increasing PLTs binding to leucocytes. This study examined the effect of ELT on leucocyte–PLTs complexes in 38 ITP patients. Patients, predominantly females with a mean age of 59 years, underwent treatments like corticosteroids, intravenous immunoglobulin and splenectomy. Compared to healthy donors, ITP patients exhibited lower percentages of lymphocyte with bound PLTs, but similar monocyte‐ or neutrophil with bound PLTs. ELT treatment increased PLTs counts and all types of leucocyte with bound PLTs. Network analysis showed dynamic changes in leucocyte with bound PLTs relationships due to ELT. Machine learning indicated that higher percentages of monocytes with bound PLTs were linked to a better clinical response to ELT. A possible mechanism was an increased IL‐10 production in monocytes with bound PLTs from responder patients. This study provides insights into the immunological changes in ITP patients undergoing ELT and suggests potential predictive biomarkers for treatment response and disease monitoring.