Autoimmune-Mediated Hypertriglyceridemia in a Young Male with Refractory Immune Thrombocytopenia: A Case Report.

Severe hypertriglyceridemia (HTG), defined as triglyceride levels >500 mg/dL can cause acute pancreatitis and other metabolic complications. While primary forms are typically genetic, autoimmune-mediated HTG is rare. We report a 24-year-old male with refractory immune thrombocytopenia (ITP) who developed severe HTG due to anti-GPIHBP1 autoantibodies. Conventional therapies, including plasmapheresis and immunosuppressive agents, were insufficient. Compassionate use of plozasiran, an RNA interference agent targeting APOC3, achieved an 80% reduction in triglyceride levels. This case highlights the importance of considering autoimmune dyslipidemia in young patients with severe HTG and autoimmune disorders and suggests that targeted therapies may be effective even when the underlying mechanism differs from classical genetic variants.