Case Report: Rare factor V inhibitor found in a patient with ulcerative colitis during latent tuberculosis infection.

Acquired factor V deficiency (AFVD) is a rare disease characterized by a relative deficiency of coagulation factor V (FV) due to the presence of internal FV inhibitors. Patients may exhibit a range of symptoms from asymptomatic to severe bleeding. The heterogeneity of AFVD among clinical conditions makes its diagnosis challenging. Infection is a common secondary cause of FV inhibitors. This article reported a case of a patient with ulcerative colitis (UC) in the latent tuberculosis infection (LTBI) stage, who had abnormal initial screening of coagulation function. Traditional treatment strategies targeting the primary disease and empirical anti-infection therapy did not improve the patient's condition. It was not until the laboratory reported high-titer FV inhibitors followed by the clinical team providing immunomodulatory treatment with intravenous immunoglobulin and preventive anti-tuberculosis therapy, which successfully led to the elimination of FV inhibitors and significant improvement in the bleeding and infection symptoms of the primary disease. This article reviews relevant literature to provide ideas for the clinical diagnosis and treatment of rare factor inhibitors. To our knowledge, this is the first report of FV inhibitor in patients with UC during LTBI, as well as the first observation of a benefit in using immunoglobulin regimen to clear cycle inhibitors.