AE, adverse event; AIP, acute intermittent porphyria; ALF, acute liver failure; GGT, gamma-glutamyl transferase; HBV, hepatitis B virus; HCV, hepatitis C virus; IFN, interferon; NIH, National Institutes of Health; PCT, porphyria cutanea tarda; SLE, systemic lupus erythematosus; SR, systematic review.