Faculty Bibliography

OBJECTIVE: Recommendations for screening for latent Mycobacterium tuberculosis (MTB) infection have been proposed but are not well studied in patients with rheumatoid arthritis (RA). We estimated the prevalence of anergy in RA and evaluated different methods to detect MTB exposure. METHODS: This was a prospective pilot study of 61 patients with RA and 42 healthy controls. Tuberculin skin test (TST) antigen, Candida, and tetanus toxoid were injected intradermally using the Mantoux method. Subjects negative for TST returned for a second-step test. Whole-blood interferon-gamma (IFN-gamma) release to mycobacterial antigens was evaluated with the first-generation QuantiFeron test (QIFN). RESULTS: Cutaneous anergy in patients with RA was not significantly different than healthy controls (p = 0.154), and was not affected by disease modifying antirheumatic drugs (p = 0.270). In patients with RA, 16.4% had positive TST with 10 mm cutoff vs 11.9% of controls. Using a 5 mm cutoff, 21.3% of patients with RA were positive, and this increased to 29.5% with a second-step TST. QIFN detected MTB exposure in 18% of patients with RA and 19% of controls (p = 0.897). However, indeterminate QIFN tests were higher in RA patients (11.5%) compared to controls (2.4%), demonstrating a lower sensitivity to detect latent MTB. CONCLUSION: Cutaneous anergy may be less common than previously reported in patients with RA. patients. However, the single-step TST and 10 mm cutoff may fail to detect all cases of latent exposure in RA patients. High rates of indeterminate results in QIFN testing suggest that QIFN should not be employed as an alternative, single-screening test in patients with RA. These pilot results require confirmation in larger studies to determine the optimal screening strategy in RA

OBJECTIVES: Reactivation of Mycobacterium tuberculosis (TB) is a significant problem with all available tumor necrosis factor (TNF) antagonists when used to treat rheumatoid arthritis (RA), psoriatic arthritis, psoriasis and other inflammatory diseases. Concerns have been raised regarding the appropriate management of patients with latent TB (LTB) exposure (or active TB infection) before initiating TNF antagonists since the safety data of combined therapy with two potentially hepatotoxic medications, methotrexate (MTX) and isoniazid (INH), is lacking. The goal of this study was to investigate the toxicity of MTX and INH therapy in RA patients before initiating TNF antagonists. METHODS: To investigate the toxicity of MTX and INH therapy in RA patients we performed a retrospective chart review of patients seen at the Bellevue Hospital Arthritis Clinic in New York City between 2002-2006. Forty-four patients who were concomitantly treated with both drugs were included. The primary outcome investigated was increase in liver function tests (LFT). RESULTS: Transient increases in LFT were seen in 11% of patients, but in no case was this more than twice the upper limit of normal values. All abnormal LFT resolved spontaneously without intervention. In addition, no patient has developed signs or symptoms of TB reactivation. CONCLUSION: The use of INH for LTB was well tolerated in RA patients on a background regimen of MTX. While the risks and benefits of all therapy must always be considered, in our experience the additive risk of INH to MTX in terms of hepatotoxicity was low. Nonetheless it is prudent to follow LFT closely on patients taking this combination