AB0749 Is There Any Causal Relationship Between Infliximab Immunogenicity and Auto-Antibody Formation in Ankylosing Spondylitis Patients with Secondary Infliximab Treatment Failure

BackgroundIt has been mentioned, that continuous infliximab (Inf) therapy may be associated with increasing titers of antibodies (AB) to dsDNA and ANF, or emergence of neutralizing ABs, leading to loss in drug efficacy.ObjectivesTo study the correlation between anti-Inf ABs and increased levels of ANF and anti-dsDNA ABs in serum of patients with ankylosis spondylitis (AS) and loss of Inf efficacy.MethodsThe study included 26 AS (mNY criteria) patients (15 males and 11 females) with secondary Inf treatment failure after continuous (>1 year) effective therapy. Secondary failure was determined as loss of Inf efficacy within 4 weeks after two consecutive infusions. In all patients routinely were measured anti-dsDNA ABs (ELISA), ANF (indirect immunofluorescence) and anti-Inf ABs were quantified (ELISA with commercial Immunodiagnostik AG, Germany, kit).ResultsIn 18 (69%) patients anti-Inf ABs were detected, in 19 (73%) – maximal ANF titers of 1/1280, in 17 (54%) – anti-dsDNA ABs (maximal value – 260 IU/ml). In 9 (35%) patients anti-Inf ABs coexisted with ANF and anti-dsDNA ABs, in 4 (15%) patients – only with ANF, and in another one – only anti-dsDNA ABs. Only in 1 patient with anti-Inf ABs no autoantibodies were detected. In 5 out of 8 patients without anti-Inf ABs, nevertheless, ANF and anti-dsDNA auto-antibodies were present, and in remaining 3 – either ANF or anti-dsDNA ABs were found. No was no significant correlation between formation of auto-antibodies and anti-Inf ABs (Spearman rank test).ConclusionsInfliximab-neutralizing antibodies in AS patients with lost drug efficacy usually appear in parallel with autoantibodies, although no relationship between formation of these types of ABs has been established.Disclosure of InterestNone declared