Risk of infections associated with biological treatment in inflammatory bowel disease

Table 1 Testing to undertake prior to initiation of tumor necrosis factor-α inhibitor treatment

Infection	Tests	Consequences
TB	Latent TB infection should be tested by a combination of patient history, chest X-ray, tuberculin skin test and interferon-gamma release assays (Quantiferon test) according to local prevalence and national recommendations. The Quantiferon test is preferred in patients receiving immunosuppressive therapy and in BCG immunized patients	Patients diagnosed with latent TB infection prior to TNF-α inhibitor exposure should be treated with a complete therapeutic regimen for latent TB. TNF-α inhibitor treatment should not be initiated prior to one month after the introduction of anti-TB treatment When active TB is diagnosed, anti TB-therapy must be started, and TNF-α inhibitor therapy must be stopped but can be resumed after two months if needed
HBV	Blood test for HBsAg, anti- HBsAb and HBcAb to determine HBV status. In patients with positive HBsAg, viremia (HBV-DNA) should also be quantified	Patients with acute HBV infection (HBsAg positive) should be treated with antiviral drugs and treatment with TNF-α inhibitors should not be initiated before a test of HBV DNA is negative
		In case of evidence of quiescent HBV infection patients should be regularly monitored for evidence of HBV replication during treatment with TNF-α inhibitors
HIV	Blood test for HIV serology	In patients with uncontrolled HIV infection, treatment with TNF-α inhibitors is contra-indicated
VZV	In case of a negative history of chicken pox/herpes zoster infection VZV serology should be tested	Patients with negative serology for VZV should be vaccinated and treatment with TNF-α inhibitor should be awaited three weeks

TB: Tuberculosis mycobacterium; TNF-α: Tumor necrosis factor-α; HBV: Hepatitis B virus; HBsAg: Hepatitis B surface antigen; HBsAb: Hepatitis surface antibody; HBcAb: Hepatitis B core antibody; HIV: Human immunodeficiency virus; VZV: Varicella zoster virus.