Tst Not Appropriate Ltbi Test Prior to Chemotherapy For Ra Posted: 10-20-05 01:58am
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.
