Background 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 (Sjö) patients also complain of fibromyalgia symptoms and there is literature that questions the interplay of these two disorders. Recently, novel autoantibodies, SP-1, CA6, and PSP, have been described in early Sjögren's syndrome (SS). These early markers present themselves before the classic autoantibodies, such as Ro, La, ANA, and RF. A recent paper found that 76% of patients with idiopathic xerostomia and exophthalmia for less than 2 years were positive for the early markers, while only 31% had antibodies to Ro and La. The authors concluded that SP-1, CA6, and PSP may be useful markers for identifying patients with SS at an early stage of the disease.
Objectives 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 Sjö markers Ro, La, SP-1, CA6, and PSP.
Methods Beginning in April 2013, a cohort of patients was identified that presented with symptoms of fibromyalgia, meeting both the 1990 and 2010 preliminary criteria. These patients were further questioned about xerostomia and sicca symptoms. Patients that admitted to using artificial tears at least biweekly, drinking water excessively, 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 (Ro, La) and early Sjö (SP-1, CA6, PSP) markers. Patients testing positive for the Sjö markers were provided with literature on the disease and offered appropriate treatment options, such as hydroxychloroquine.
Results As of January 2016, 210 patients were selected for this study and tested for the Sjö markers. 91.0% of the patients were female and 8.6% of the patients were male. The average patient age was 56.5. 171 of the study patients were tested for both the early and classic markers, while 39 were tested for only the early markers. Of the patients that were evaluated for both the early and classic Sjö markers, 29.8% (51) tested positive for SS. 39 (22.8%) of the patients were positive for the early Sjö markers, 9.4% (16) were positive for the classic Sjö markers, and 2.3% (4) were positive for both the early and late Sjö markers. Further analysis of all the patients that tested positive for the early Sjö markers (n=47), found 74.5% (35) were positive for SP-1, 8.5% (4) were positive for CA6 and 44.7% (21) were positive for PSP. 68.1% (32) of these patients were positive for only one of the early markers and 15 (31.9%) were positive for more than one early marker.
Conclusions In this cohort of fibromyalgia patients, about 1/3 of patients that were tested for both the early and classic Sjö markers tested positive for SS, with the majority of those patients being positive for one or more of the early Sjö markers. This suggests that autoimmunity, specifically early Sjögren's syndrome, may be a confounding variable in the pathophysiology of fibromyalgia.
Shen, L, et al. Clin Immunol (2012) 145, 251–255
Disclosure of Interest None declared