P32 Should we continue to test for latent tuberculosis infection in patients treated with biologics?

Abstract

Abstract Background Timely diagnosis of tuberculosis (TB) infection is important in patients receiving biologics. Current BSR guidelines on biologic safety in inflammatory arthritis (2018) advise to screen all patients for TB before starting treatment. Due to limitations of tuberculin skin test (TST), IFN-γ release assay (IGRA) is frequently used in addition to clinical examination, risk assessment and chest x-ray (CXR). There are no clear guidelines whether IGRA should be part of follow up assessments. The Royal College of Nursing suggest patients on biologics should have repeat CXR in 3 months after starting biologics and then annually. The American College of Rheumatology suggest an annual TST or IGRA for high-risk individuals receiving biologics. Centers for disease control and prevention guidelines allows to use TST and IGRA for surveillance in selected population. Methods We present two cases in which patients developed TB after starting biologics. Both patients had negative IGRA, normal CXR and low risk of developing TB on prebiologic screening. Results First patient was a 64-year-old female with rheumatoid arthritis diagnosed in 2001. She failed multiple conventional DMARDs and was started on Certolizumab in 2014. Prebiologic screen showed a negative IGRA (T Spot) and CXR was clear. She was a smoker and her mother had pulmonary TB when she was a child. After 4 years she presented with weight loss and cough. CXR showed 1.4 cm round opacity in right upper lobe. She underwent surgical resection and histology showed acid fast bacilli on ZN stain with superimposed aspergilloma. She was started on quadruple therapy and we switched Certolizumab to Etanercept due to its shorter half-life. Second patient was a 27-year-old man with ankylosing spondylitis diagnosed in 2015. He was a smoker and had no past medical history. He was started on Adalimumab in 2016. T Spot was negative and CXR was clear. There were no risk factors for TB. Two years later he presented with multiple tender subcutaneous nodules over thighs and lower abdomen. Skin biopsy after dermatology assessment showed superficial and deep perivascular inflammation with lymphocytes and small number of eosinophils. Differential were granulomatous infection or panniculitis due to injection site reaction. TB cultures came back negative but repeat T Spot was positive. He was treated as latent TB infection for 3 months and Adalimumab was restarted without any problems. Conclusion Current BSR guidelines advise to monitor patient clinically for any signs of TB while receiving biologics. We suggest that there is a need to review whether TST or IGRA should be done annually on high risk patients along with CXR. Disclosures A.A. Sidhu None. A. Nandagudi None.