Erythropoietic protoporphyria (EPP) is a rare and usually autosomal dominant disorder characterized by ferrochelatase deficiency and accumulation of protoporphyrin in red blood cells (RBCs), skin, and liver. A small minority of patients develop severe liver dysfunction for which optimum treatment is lacking. Therapeutic plasma exchange (TPE) and RBC exchange (RCE) have been anecdotally reported to benefit patients with EPP and liver failure. A 50-year-old female with EPP developed severe liver dysfunction after knee replacement surgery and high-dose acetaminophen use. Liver biopsy showed cholestatic liver injury without fibrosis. A total of 20 TPE procedures, six RCE procedures, and then 14 more TPE procedures were performed as adjunctive therapy with the purpose of preventing progression to end-stage liver failure. After initial TPE, the plasma and RBC protoporphyrin levels decreased from 834.9 to 180.4 μg/dL (normal, ≤1 μg/dL), and from 3,905 to 2,879 μg/dL (normal, ≤80 μg/dL), respectively, without liver function improvement. RCE decreased RBC protoporphyrin levels from 2,879 to 1,225 μg/dL but plasma protoporphyrin increased from 180.4 to 1,044.1 μg/dL, and liver function failed to improve. Additional TPE again stabilized plasma protoporphyrin and improved RBC protoporphyrin levels but the patient ultimately died owing to end-stage liver disease complications. This case illustrates that TPE and RCE may improve the plasma and RBC biochemical markers of EPP activity but liver function abnormalities may persist and patients may still progress to liver failure either because of irreversible liver injury or independent pathobiological factors unrelated to EPP-induced hepatotoxicity.

作者：Monica B, Pagano；William, Hobbs；Michael, Linenberger；Meghan, Delaney

来源：Journal of clinical apheresis 2012 年 27卷 6期