Do TNF-blockers reduce or induce uveitis?

Do TNF-blockers reduce or induce uveitis? SIR, Uveitis is a well-known manifestation of SpAs that may lead to functional impairment. TNF-blockers are effective for treating SpA-related uveitis flares [1], but recent retrospective studies support the possibility of differential TNF-blockers effectiveness, with infliximab or adalimumab showing a higher efficacy than etanercept in the treatment of uveitis [2–4]. In addition, Lim et al. [5] have recently published the finding that etanercept may induce new uveitis flares. During the last 2 years, we have conducted a study with the objective of investigating the impact of TNF-blockers on the appearance of new flares of uveitis in patients with SpAs who exhibit uveitis flares before beginning therapy for the rheumatic disease. All clinical records of patients with SpAs with a previous acute anterior uveitis who received treatment with TNF-blockers in our department after January 1999 were reviewed. After the study began in October 2005, all data from new uveitis flares in patients with SpAs treated with TNF-blockers were registered prospectively in our database. Flares data were calculated by exposure time and compared both before and after the commencement of therapy by a repeated measurements analysis of variance. The quantitative and qualitative variables were compared between groups with the Mann–Whitney U-test and Fisher's exact test, respectively. Out of 150 patients with SpAs on TNF-blockers therapy, 19 (12.7%) had uveitis flares prior to starting the treatment. Of these, 11 (58%) were women, 18 (94.7%) had HLA-B27, 10 were on etanercept and nine patients were on infliximab. One patient was switched from etanercept to infliximab because of the recurrence of uveitis and was analysed in both groups. The types of SpAs were: 15 AS, two undifferentiated SpAs and two PsA. The patterns of uveitis were: 13 recurrent acute unilateral, five recurrent acute bilateral and one chronic bilateral. The mean age at the first flare of uveitis and at the diagnosis of the SpA was 38.15 AE 10.43 and 35.20 AE 11.5 yrs, respectively. The mean age at the onset of TNF-blockers therapy was 48.25 AE 11.1 yrs and the mean duration of the SpA at this time was 13.22 AE 10.18 yrs. The mean duration of the TNF-blockers treatment was 2.98 AE 1.7 yrs. The demographic characteristics of the different groups of treatment were comparable (data not shown). The number of uveitis flares per patient in the exposure time before starting TNF-blockers was 0.61 AE 0.3 and 0.52 …