THU0508 Evaluation of tissue specific autoantibodies in fibromyalgia patients with sicca and/or xerostomia
Authors: E. Applbaum, A. Lichtbroun
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> A significant proportion of patients with fibromyalgia complain of dry eyes and mouth. The 2010 preliminary criteria for fibromyalgia even includes dry eyes and mouth as part of the somatic symptoms severity complex used to diagnose this condition. A significant proportion of Sjögren's syndrome patients also complain of fibromyalgia symptoms, and there is literature that suggests that there is interplay between these two disorders. Recently, the presence of novel tissue specific autoantibodies (TSAs), SP-1, CA6, and PSP, has been observed in the early stages of Sjögren's syndrome (SS). These early markers present themselves before the classic autoantibodies, such as SSA/Ro, SSB/La, ANA, and RF. <h3>Objectives</h3> This study aims to examine the relationship between SS and fibromyalgia by testing patients with fibromyalgia, that also complain of xerostomia and sicca symptoms, for Sjögren's related biomarkers SSA/Ro, SSB/La, SP-1, CA6, and PSP. <h3>Methods</h3> Over the past 5 years, we identified a cohort of 310 patients that presented with symptoms of fibromyalgia and fulfilled both the 1990 and 2010 preliminary diagnostic criteria. These patients were further questioned about xerostomia and sicca symptoms. Patients that admitted to using artificial tears at least biweekly, drinking water excessively to relieve dry mouth, or have previously experienced a blocked tear duct, but did not meet the strict diagnostic criteria for SS and did not have elevated inflammatory markers ESR or CRP, were selected for this study. Serum from study patients was sent to a tertiary lab, Immco Diagnostics, for testing of the classic autoantibodies (SSA/Ro, SSB/La, ANA and RF) and Tissue Specific Autoantibodies (SP-1, CA6, PSP). Patients testing positive for the TSA markers were provided with literature on the disease and offered appropriate treatment options, such as hydroxychloroquine. <h3>Results</h3> As of November, 2017 310 patients were selected for this study and tested for the SS markers. 91.0% of the patients were female and 8.6% of the patients were male. The average patient age was 56.5 years. 271 of the study patients were tested for both the TSAs and classic autoantibodies, while 39 were tested for only TSAs. Of the patients that were evaluated for both the TSAs and classic Sjögren's autoantibodies, 29.8% (81) tested positive for SS. 22.8% (71) of the patients were positive for TSAs, 9.4%<sup>29</sup> were positive for the classic Sjögren's markers, and 2.3%<sup>7</sup> were positive for both the TSA and classic Sjögren's autoantibodies. Further analysis of all the patients that tested positive for the TSAs (n=71), found 74.5% (53) were positive for SP-1, 8.5%<sup>6</sup> were positive for CA6% and 44.7%<sup>32</sup> were positive for PSP. 68.1%<sup>48</sup> of these patients were positive for only one of the TSA and 23 (31.9%) were positive for more than one TSA. <h3>Conclusions</h3> In this cohort of 310 fibromyalgia patients, about 1/3 of patients that were tested for both the TSAs and classic Sjögren's markers tested positive for SS, with the majority of those patients being positive for one or more of the TSAs. This suggests that autoimmunity, specifically early- stage Sjögren's syndrome, may be a confounding variable in the pathophysiology of fibromyalgia. <h3>Reference</h3> [1] Shen L, et al. Clin Immunol2012;145:251–255. <h3>Disclosure of Interest</h3> None declared