Sustained Platelet Improvement Temporally Associated with Dupilumab in Chronic Immune Thrombocytopenia: A Case Study

Introduction: Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by reduced platelet counts. Dupilumab, an IL-4 receptor antagonist, is effective in allergic and auto-inflammatory diseases; however, use in ITP remains unexplored. Case Presentation: A 78-year-old male with chronic ITP, maintained on a thrombopoietin receptor agonist (TPO-RA) with an average platelet count of around 78,000/μL, demonstrated a sustained rise in platelet counts (> 100,000/μL) shortly following initiation of dupilumab for an unrelated chronic obstructive pulmonary disease. This improvement enabled a stepwise reduction in TPO-RA to < 20% of his base dosage while maintaining adequate platelet levels for three years since. Despite detailed patient interviews and chart review, we were unable to identify any clinical factors besides commencement of dupilumab as a potential explanation. If indeed causative, we speculate that a TPO-RA-sparing effect of dupilumab might occur via disruption of IL-4 signaling, leading to inhibited Th9 cell activation and subsequent IL-21 production to restore Treg/Th17 balance, thus contributing to decreased platelet destruction. Conclusions: This case supports a potential role for dupilumab in the treatment of chronic ITP. To our knowledge, it is the first report suggesting a therapeutic benefit of IL-4 blockade in this disease. Identification of predictive immunologic biomarkers, such as cytokine profiles or T-cell subset signatures, might help identify patients most likely to benefit from IL-4 pathway modulation. Further controlled studies are warranted to clarify the immunologic mechanisms underlying this response and to assess the therapeutic potential of targeting the IL-4 axis in ITP.