TB in a Patient Receiving Immunosuppression Including a TNF Alpha Blocker

March 2006

Patient History

A 55-year old female emigrated from El Salvador in the mid 1980's. She had been employed by a poultry processing plant for 15 years (high risk environment associated with TB transmission). Medical history included a diagnosis of rheumatoid arthritis which was treated with prednisone 20 mgs twice daily, methotrexate and Humira (adalimumab-a tumor necrosis factor alpha blocking agent (TNFα)). Six months later she was evaluated for GI upset, cough, shortness of breath, fatigue, chills, headaches, persistent fever, and a 16 pound weight loss. No diagnosis was made. The patient stopped her Humira and left the state to visit family in Virginia. Two months later she was hospitalized with generalized weakness, cough and shortness of breath. A tuberculin skin test (TST) was negative. Chest X-ray and CT scan revealed interstitial infiltrates throughout both lungs primarily affecting the upper lobes. An ultrasound guided lung biopsy revealed a positive AFB culture of Mycobacterium tuberculosis. She was placed on Rifampicin, Isoniazid (INH), Ethambutol, Pyrazinamide and Zithromax. Sensitivity results showed resistance to INH, Streptomycin (SM) and p-amino salicylic acid (PAS).

Medical Issues

TNFα blocking agents used for the treatment of rheumatoid arthritis, Chrohn's disease and psoriasis have been associated with reactivation of tuberculosis. The three TNFα blockers, Infliximub, Etanercept and Adalimumab, work by blocking TNFα, an inflammatory cytokine expressed by activation of T cells and other immune cells. This process plays a crucial role in the host defense against M. tuberculosis and other intercellular pathogens. Before initiation of therapy, patients should be evaluated for active or latent TB infection (LTBI) by a TST. The patient should also be screened for additional risk factors for TB (i.e. foreign-born, congregate setting, place of employment, etc). If LTBI is diagnosed, treatment should be given for at least three to six months prior to starting the TNFα blocker.

Teaching Points

Heartland National TB Center
2303 SE Military Drive
San Antonio, Texas 78223
Phone: 1 (800) TEX-LUNG
Fax: (210) 531-4590