Immunogenicity of Infliximab Among Patients With Behçet Syndrome: A Controlled Study.

Background: Immunogenicity of tumor necrosis factor alpha inhibitors (TNFis) has been recognized as an important problem that may cause loss of efficacy and adverse events such as infusion reactions. TNFis are being increasingly used among patients with Behçet syndrome (BS) and scarce data exist on this topic. Objective: We aimed to investigate the prevalence of anti-infliximab (IFX) antibodies in patients with Behçet syndrome together with suitable controls. Methods: We collected serum samples from 66 consecutive Behçet syndrome patients (51 M, 15 F, mean age 37 ± 9 years) who were treated with IFX. Additionally, similarly treated 27 rheumatoid arthritis, 53 ankylosing spondylitis, 25 Crohn's disease patients, and 31 healthy subjects were included as controls. Samples were collected just before an infusion, stored at -80°C until analysis, and serum IFX trough levels and anti-IFX antibodies were measured by ELISA. We used a cut-off value of 1 µg/ml for serum IFX trough level, extrapolating from rheumatoid arthritis studies. Results: Anti-IFX antibodies were detected in four (6%) Behçet syndrome, five (18.5%) rheumatoid arthritis, three (12%) Crohn's disease, and one (2%) ankylosing spondylitis patient. The median serum IFX trough level was significantly lower in patients with anti-IFX antibodies compared to those without antibodies [2.32 (IQR: 0.6-3.6) vs. 3.35 (IQR: 1.63-5.6); p = 0.019]. The serum IFX trough level was lower than the cut-off value in 6/13 (46%) patients with anti-IFX antibodies and in 25/158 (16%) patients without anti-IFX antibodies (p = 0.015). Among the four Behçet syndrome patients with anti-IFX antibodies, two experienced relapses and two had infusion reactions. Conclusions: Immunogenicity does not seem to be a frequent problem in Behçet syndrome patients treated with IFX, but may be associated with relapses and infusion reactions, when present.

The prevalence of Behçet's syndrome, familial Mediterranean fever, HLA-B51 and MEFV gene mutations among ethnic Armenians living in Istanbul, Turkey.

OBJECTIVES: We investigated the prevalence of Behçet's syndrome (BS) among the ethnic Armenians in Istanbul using Familial Mediterranean Fever (FMF) as a comparator disease. We also studied HLA-B51 and MEFV mutations among a group of healthy Armenians and a non-Armenian population. METHODS: The prevalence study was conducted in 2 parts in the Armenian primary schools in Istanbul, using the enrolled students as index cases to study the core family. In Part I, a questionnaire seeking only whether either parent had previously been diagnosed as having BS or FMF by a physician was distributed to a total of 1873 index students registered at 10 schools. A total of 1380 parents filled in the questionnaire, yielding a response rate of 37% (1380 / 3746). In Part II, eight schools participated with a response rate of 83 % (1183/1428). Also, genomic DNA samples of 108 healthy (14 M/94 F) Armenians and 97 (45 M/ 52 F) non-Armenians, were studied for HLAB51 and MEFV gene mutations. RESULTS: In Part I, none of the parents turned out to have been diagnosed as BS, whereas a total of 12 / 1380 (870/105) had been diagnosed as FMF. In the second part the estimated prevalence of BS was 90 /105 and that of FMF was 760/ 105. HLA-B51 carrier rate was found to be similar between the Armenian (27%, 29/108) and the non-Armenian participants (19%, 18/97), (p=0.158). Overall carrier rate of MEFV gene mutations was significantly higher in the Armenian group (36% vs. 20%, p=0.015). CONCLUSIONS: The genetic load for FMF is considerably higher among the Armenians when compared to the load for BS among the same ethnic group. On the other hand, the rather low frequency of BS among the Armenians when compared to the frequency among the general population living in the same environment is further evidence for a genetic predisposition to BS. HLA- B51 does not seem to play a dominant role in the said predisposition. Finally, as we have used an unorthodox epidemiological methodology in data collection our results might need to be further verified by more conventional methods.