P781 Prevalence of antinuclear antibodies in inflammatory bowel disease and seroconversion after biological therapy
Abstract Background Higher levels of antinuclear antibodies (ANA) are detected in healthy populations with a prevalence of 6%. In autoimmune disorders it reaches 50–80%. In patients under TNF, the prevalence of positive ANA observed was 40% and occasionally may induce lupus like syndrome (LLS). However, there is a lack of evidence about the global prevalence in inflammatory bowel disease (IBD) and insufficient data about seroconversion of ANA after the beginning of biological therapy. Methods A unicentric transversal study of 879 IBD patients was designed. ANA determination was performed by immunofluorescence assay. IBD patients were classified according to the biological therapy. Presence and of ANA and titres were collected previously to the beginning of anti-TNF therapy. LLS symptoms were collected in a retrospective way. Results A valid result of ANA was obtained in 862 patients. Patients with any autoimmune disease which involve positive ANA were excluded. Positive ANA was reported in 13.62% of IBD patients. The prevalence of ANA was 28.67% in those patients under biological therapy (p < 0.001), especially if the biological treatment was anti-TNF. No significative difference was observed in those patients receiving ustekinumab or vedolizumab therapy. Positive ANA was observed in 4.67% for combined treatment with immunomodulator and biological therapy. In contrast, if the patient received only biological therapy, positive ANA was collected in 24 % (p < 0.001). A reduction in albumin levels and higher levels of IgG and IgM were related to positive ANA. It is important to highlight that a percentage of 53.45% positive ANA had never received biological therapy in the previous 5 years; that means, a 7.28% prevalence in the global cohort. A 48.15% of the patients had ANAs previous to the beginning of biological therapy. ANAs seroconversion was observed in 73.08% of the patients after the treatment. Conclusion IBD patients have a 13.62% prevalence of positive ANA; higher than prevalence in healthy population. The presence of ANA is frequently associated in patients under anti-TNF treatment and decreases with immunomodulator therapy associated to anti-TNF. It is unknown if positive ANA in IBD patients could be conditioned to the future development of other autoimmune disorders. Prospective studies are necessary to clarify these aspects.
