Evaluation of anti-tumor necrosis factor levels and anti-tumor necrosis factor antibodies in rheumatic diseases treated with infliximab and adalimumab; preliminary results from a local registry.

Resumen del trabajo presentado al "Annual Scientific Meeting of the American College of Rheumatology/Association of Rheumatology Health Professionals" celebrado en Chivago (US) del 4 al 9 de Noviembre de 2011.[Background/Purpose]: To analyse the clinical relevance of serum levels of infliximab (INF) and adalimumab (ADA) and the production of anti-INF (INF-Abs) or anti-ADA antibodies (ADA-Abs) from a local registry of patients with rheumatic diseases on treatment with INF or ADA. [Methods]: We included 55 consecutive patients receiving treatment for more than 6 months with INF (25 patients) and ADA (30 patients). Clinical characteristics, clinical activity index (DAS in 28 joints for rheumatoid arthritis -RA- and psoriatic arthritis -PsA-; BASFI, BASDAI for ankylosing spondylitis -AE-) were recorded. Serum levels of INF or ADA and INF-Abs or ADA-Abs (ELISA kit. Promonitor®-INF, ADA. Proteomika, Derio. Vizcaya. Spain) were evaluated. Cut-off level for serum Abs for INF was >15 U/mL, and for ADA >8 U/mL and cut-off level for serum level of INF and ADA were <0.04 mg/L and <0.002 mg/L respectively. Serum samples were collected at the time of infusion of INF or before injection of ADA, and stored frozen until analysis. Infusion reactions with INF were defined as any event appearing during infusion requiring either arrest of drug infusion or the administration of parenteral medication. Patients were considered responders if they had at the same time of extraction, DAS28-ESR<=3 in RA or PsA patients; BASDAI<=4 in AE patients. [Results]: We enrolled 55 patients, 36 were women; the mean age was 55±14 years. The diagnosis of patients was: RA (49%), AE (31%), PsA (15%) and others (5%). The average time of treatment for the whole population was 33.63 months and for INF and ADA was 41.5 months (range: 6–127) vs 25 months (range: 8–51) respectively. INF was the first anti-TNF received in 24 (96%) of the patients, and ADA was the first in 25 (83%) of the patients. Antibodies were detected in 9 patients (18%): 5/25 patients (20%) INF-Abs and 4/30 patients (13%) ADA-Abs. In the ADA-Abs patients: all of them had low level of ADA, with a range level of Abs between 132–717.824 U/mL. Table 1 showed the characteristics in responders and non-responders patients. In the INF-Abs patients, only one patient had normal level (1.3 mg/L), and the range level of Abs was between 20–121.840 U/mL. Three patients had infusion reaction with INF, 2 of them with high level of Abs (1.282, 121.849 U/mL), and one patient without Abs.Peer Reviewe