Mycobacterium kansasii Infection in a Patient Receiving Biologic Therapy-Not All Reactive Interferon Gamma Release Assays Are Tuberculosis.
Mycobacterium kansasii, a nontuberculous mycobacterium, can lead to lung disease similar to tuberculosis. Immunotherapeutic biologic agents predispose to infections with mycobacteria, including M kansasii. T-cell-mediated interferon gamma release assays like QuantiFERON-TB Gold Test (QFT) are widely used by clinicians for the diagnosis of infections with Mycobacterium tuberculosis; however, QFT may also show positive result with certain nontuberculous mycobacterial infections. We report a case of M kansasii pulmonary infection, with a positive QFT, in an immunocompromised patient receiving prednisone, leflunomide and tocilizumab, a humanized anti-interleukin-6 receptor monoclonal antibody. This case highlights the risk of mycobacterial infections with the use of various biologic agents and the need for caution when interpreting the results of interferon gamma release assays.
Infectious Diseases Section, Department of Internal Medicine, Presence Saint Joseph Hospital, Chicago, Illinois. Electronic address: nasirsaleemmd@gmail.com.
Nasir
N
Saleem
Infectious Diseases Section, Department of Internal Medicine, Presence Saint Joseph Hospital, Chicago, Illinois.
Raya
R
Saba
Infectious Diseases Section, Department of Internal Medicine, Presence Saint Joseph Hospital, Chicago, Illinois.
Srikanth
S
Maddika
Infectious Diseases Section, Department of Internal Medicine, Presence Saint Joseph Hospital, Chicago, Illinois.
Mitchell
M
Weinstein
D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000150:complications / Q000175:diagnosis* / Q000382:microbiology; D019909:Mycobacterium kansasii / Q000302:isolation & purification*
Biologic therapy; Mycobacterium kansasii; QuantiFERON-TB; Tocilizumab