title: Letter: Complications with Christmas factor (factor IX) concentrates.
mesh_terms: D000707:Anaphylaxis / Q000209:etiology; D005164:Factor IX / Q000009:adverse effects*; D005260:Female; D002836:Hemophilia B / Q000628:therapy; D006505:Hepatitis / Q000209:etiology*; D006801:Humans; D011247:Pregnancy; D013923:Thromboembolism / Q000209:etiology*
chemical_list: D005164:Factor IX