Tst Not Appropriate Ltbi Test Prior to Chemotherapy For Ra

Rheumatoid arthritis therapy and tuberculin skin test (tst)

previous scientific and clinical studies have identified that drugs commonly used to treat patients with rheumatoid arthritis can lead to the activation of latent tuberculosis infections (ltbi). This potentially life-threatening complication of therapy has resulted in the usa food and drug administration recommending that all rheumatoid arthritis patients are evaluated for ltbi prior to commencing therapy.

A recent publication arising from a study conducted at the hospital nacional guillermo almenara irigoyen in peru has identified that patients undergoing drug therapy for rheumatoid arthritis, have a significantly lower tst reactivity (29%) compared to a control group of healthy test subjects (74%). It should be noted that while tuberculosis infection in peru is prevalent, bacille calmette-guérin (bcg) vaccination rates are very high (up to 90%), and consequently the use of the tst leads to significant rates of false positive responses.

The study, which was published in the september issue of the annals of rheumatic diseases by Dr. Ponce de león and colleagues, clearly demonstrates that the tst is not an appropriate test to identify ltbi prior to chemotherapy for rheumatoid arthritis. The use of a ltbi diagnostic such as the quantiferon®-tb gold test would prove invaluable in this clinical setting as it is not influenced by bcg vaccination status or individuals with mild to moderate immunosuppression.

Ponce de león d., acevedo-vasquez e., sanchez-torres a., cucho m., alfaro j., perich r., pastor c., harrison j. And sanchez-schwartz c. (2005) “attenuated response to purified protein derivative in patients with rheumatoid arthritis: study in a population with a high prevalence of tuberculosis.” ann. Rheum. Dis. 64, 1360-1361.