Case Series and Literature Narrative Review of Immune-Mediated Thrombotic Thrombocytopenic Purpura in Children.

Background/Objectives: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare but life-threatening thrombotic microangiopathy in children. Secondary forms, occurring in association with immune dysregulation, autoimmune disease, or other triggers, are particularly challenging to diagnose and manage, and pediatric-specific data remain limited. This study aimed to describe the clinical characteristics, diagnostic pathways, and management of pediatric iTTP and to contextualize these findings within the recent literature. Methods: We conducted a retrospective case series of pediatric patients diagnosed with iTTP at a tertiary referral center, between November 2021 and January 2026. Clinical presentation, laboratory findings, including ADAMTS13 activity and ADAMTS13 inhibitors, associated conditions, treatment strategies, and outcomes were reviewed. In parallel, a narrative literature review was performed focusing on pediatric immune-mediated secondary TTP published over the past five years. Results: Four pediatric patients (three females, one male; median age 14 years) met inclusion criteria. All presented with severe thrombocytopenia and microangiopathic hemolytic anemia, accompanied by prominent neurologic manifestations in three cases. Severe ADAMTS13 activity deficiency (≤10%) with positive inhibitors was documented in all patients. Secondary iTTP occurred in association with evolving systemic autoimmunity, systemic lupus erythematosus, common variable immunodeficiency, or without an identifiable trigger at presentation. High clinical probability scores facilitated early diagnosis. Management required plasma exchange, corticosteroids, and targeted and immunomodulatory therapy. Conclusions: Pediatric secondary iTTP is a heterogeneous condition that frequently presents with diagnostic ambiguity and severe neurologic involvement. Early recognition, prompt initiation of TTP-directed therapy, and comprehensive immunologic evaluation are critical for favorable outcomes. Case series combined with narrative reviews remain valuable for advancing understanding and optimizing individualized care in this rare pediatric disorder.