TNFalpha plays a pivotal role not only in the inflammatory process but also in 
the normal response against pathogens and therefore, interfering with this 
cytokine may increase the risk of infection. TNFalpha antagonists are commonly 
used in daily clinical practice for the treatment of inflammatory rheumatic 
diseases including rheumatoid arthritis, ankylosing spondylitis, psoriatic 
arthritis and juvenile idiopathic arthritis since the beginning of 2000. The 
spectrum of pathogens giving infectious disease in patients under anti-TNFalpha 
therapies ranges from common bacteria to more opportunistic organisms such as 
Mycobacterium tuberculosis. The infections which were described with TNFalpha 
inhibitors may have a benign course or may be a serious, life threatening 
disease, and may be localized or disseminated. These TNFalpha inhibitors related 
infections were described in the randomized clinical trials, and were then 
declared to post-marketing surveillance systems and special registries. 
Tuberculosis (TB) is the most frequent opportunistic infection which has been 
reported with TNFalpha antagonists and the highest risk appears to be associated 
with infliximab, and at a lesser extent with etanercept. Currently available 
data and recent patents on the risk of TB with adalimumab are not sufficient to 
conclude, but TB cases were also reported with this agent. The description of TB 
infections with TNFalpha inhibitors led to the establishment of new guidelines 
for screening patients at high risk of developing TB. These data highlight the 
importance of post-marketing surveillance and special registries for accurately 
evaluating the safety profile and particularly the infectious risk of this very 
effective class of drug in inflammatory rheumatic diseases.