Successful treatment of a patient with Takayasu's arteritis complicated with Crohn's disease with ustekinumab: A case report.

A 17-year-old woman was referred to our department with fever, general malaise, and weight loss. She was diagnosed with Takayasu arteritis (TAK) and Crohn's disease (CD) following positron emission tomography-computed tomography (PET-CT) and colonoscopy, respectively. Serological human leukocyte antigen (HLA) typing revealed HLA-B52 positivity. Initial treatment with prednisolone (PSL) (0.5 mg/kg) was insufficient; therefore, ustekinumab and 5-aminosalicylic acid were added. This treatment achieved PSL-free remission for both diseases, as confirmed by PET-CT and colonoscopy. Although treatment guidelines for TAK and CD have been previously established, treatment of patients with TAK with coexisting CD is controversial. Our case suggests that ustekinumab has the ability to achieve TAK remission in addition to its therapeutic effect on CD.