AIM: To assess tumor necrosis factor-alpha (TNF-alpha), infliximab (IFX) concentrations,
and antibodies against IFX molecules in patients with inflammatory bowel disease (IBD)
who develop loss of response, side effects, or allergic reaction during anti TNF-alpha
therapy. METHODS: Blood samples of 36 patients with response loss, side effects, or
hypersensitivity to IFX therapy (Group I) and 31 patients in complete clinical remission
(Group II) selected as a control group were collected to measure trough serum TNF-alpha
level, IFX, and anti-IFX antibody (ATI) concentration. We examined the correlation
between loss of response, the development of side effects or hypersensitivity, and
serum TNF-alpha, IFX trough levels, and ATI concentrations. RESULTS: The serum TNF-alpha
level was shown to be correlated with the presence of ATI; ATI positivity was significantly
correlated with low trough levels of IFX. ATIs were detected in 25% of IBD patients
with loss of response, side effects, or hypersensitivity, however no association was
revealed between these patients and antibody positivity or lower serum IFX levels.
Previous use of IFX correlated with the development of ATI, although concomitant immunosuppression
did not have any impact on them. CONCLUSION: On the basis of the present study, we
suggest that the simultaneous measurement of serum TNF-alpha level, serum anti TNF-alpha
concentration, and antibodies against anti TNF-alpha may further help to optimize
the therapy in critical situations.
