FRI0083 IS A HIGH LEVEL OF IGA PREDICTIVE OF THE EFFICACY AND TOLERANCE OF RITUXIMAB DURING RHEUMATOID ARTHRITIS NAIVE OF PRIOR BIOLOGICAL TREATMENTS?
Authors: nada cherkaoui, Imane El Bouchti
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> The elevation of immunoglobulin A levels during rheumatoid arthritis is not an exceptional situation although not as commonly found in spondyloarthritis. Hypothetically, this elevation should translate into multiple clinical as well as biological significance. <h3>Objectives:</h3> The objective of the study is to identify whether or not a high level of IgA would have an effect on the tolerance and response of rheumatoid arthritis treated with Rituximab. <h3>Methods:</h3> This is a retrospective study within which a total number of 33 patients with rheumatoid arthritis treated with Rituximab has been collected, whose peculiarity is the naivety to biological treatment (anti-TNF as it happens). We used regression models of Cox with univariate and multivariate analysis. The main criteria of judgment for efficiency were the EULAR response at 6 months treatment and the recourse to another cycle of rituximab. As regards tolerance, the existence of at least one adverse effect of an infectious, paradoxical or other nature constituted the eligibility argument <h3>Results:</h3> 33 patients were included, the average age was 47.46 years. 87.9% of patients were of female gender to 12.1% of male gender. All the patients had structural articular damage. The average initial DAS28 was 6.08. The average DAS28 at 6 months of treatment was 2.98. 13 patients had to go under the use of another cycle of rituximab and an average period of 16.8 months was observed between the 1st and 2nd courses of treatment. 75.8% of the patients achieved a good EULAR response at 6 months. The average serum levels of IgA were 3.86 g/L (1.20-7.29). 33.3% of the patients showed at least one adverse effect. High IgA levels were significantly correlated with recourse to Rituximab retreatment (p &lt;0.005), to prior tuberculosis infection and also to the increase of Alpha 2 globulins on the electrophoresis of blood proteins. We could not prove a relationship between high levels of IgA and the occurrence of side effects. <h3>Conclusion:</h3> Polyclonal elevation of IgA during rheumatoid arthritis is possible, although rare. Theoretically, several clinical eventualities should be sought in similar situations. Such as, the existence of a positive rheumatoid factor IgA Isotype, a chronic infection, Spondyloarthropathy, or associated celiac disease. More rarely, a lupus or a Sjogren syndrom. In our series, the existence of high levels of IgA was significantly correlated with recourse to rituximab retreatment, suggesting that there is an underlying entity or a particular etiopathogenic leading to incomplete anti CD20 response. At the same time, a history of tuberculosis and high levels of alpha-2-globulin also correlated with high IgA levels suggesting the existence of an infection with inflammatory reaction of chronic type. <h3>References:</h3> [1] Sellam J, Rouanet S, Hendel-Chavez H, et al. CCL19, a B cell chemokine, is related to the decrease of blood memory B cells and predicts the clinical response to rituximab in patients with rheumatoid arthritis. Arthritis Rheum 2013;65:2253–61. [2] -de Jong TD, Sellam J, Agca R, et al. A multi-parameter response prediction model for rituximab in rheumatoid arthritis. Joint Bone Spine 2018;85:219–26. [3] Stradner MH, Dejaco C, Brickmann K, Graninger WB, et al. A combination of cellular biomarkers predicts failure to respond to rituximab in rheumatoid arthritis: a 24-week observational study. Arthritis Res Ther 2016;18:190. [4] Vital EM, Dass S, Rawstron AC, et al. Management of nonresponse to rituximab in rheumatoid arthritis: predictors and outcome of re-treatment. Arthritis Rheum 2010;62:1273–9 [5] Jorgensen C, Anaya JM, Cognot C, Sany J. Rheumatoid arthritis associated with high levels of immunoglobulin A: clinical and biological characteristics. Clin Exp Rheumatol 199 I; 10:571-5 [6] Cowling E Ebringer P, Ebringer A. Association of inflammation with raised serum IgA in ankylosing spondylitis. Ann Rheum Dis 1980; 39:545-9 <h3>Disclosure of Interests:</h3> None declared