A variety of rheumatic manifestations (RM) has been described in association with autoimmune thyroiditis (AIT). In the past, most of these manifestations were attributed to the underlying thyroid dysfunction, in particular hypothyroidism. AIT is often associated with non-organ specific autoimmunity. Increased prevalence of non-organ specific autoantibodies in patients with AIT without any evidence of rhemautic manifestations is clinically unclear. Aim of this study was to find out the frequency of apperance of non-organ specific antibodies in serum in patients with AIT and prevalence of RM (arthralgia/arthitis).
The group consisted of 80 patients with diagnosis AIT. The diagnosis of AIT was made according to established criteria. This diagnosis was primarily based on laboratory markers including thyroid hormone levels (TSH, fT4, fT3), the detection of antithyroid antibodies (anti-TPO, anti-TG, anti-RTSH antibodies) and on ultrasound examination (imaging signs of thyroid autoimmunity) of thyroidal gland. None of the above patients had a history of systemic autoimmune disorders. In the group of patients with AIT we evaluated the prevalence of non-organ specific antibodies (ANA/Hep 2, ENA scr., SSA, SSB, nRNP, dsDNA, DNP, RF, ACLA scr., ANCA/MPO, ANCA/PR3) and presence of RM (arthritis/arthralgia). The control group consisted of 34 patients with no overt history of AIT or systemic autoimmune disorders.
In the group of patients with AIT ANA positivity was found in 36/80 (45%) patients compared with 5/34 (14.7%) in healthy controls (p < 0.05). The prevalence of ANA autoantibodies was significantly higher in patients with AIT than in healthy controls. Other levels of non-organ specific antibodies (ENA scr., SSA, SSB, nRNP, dsDNA, DNP, RF, ACLA scr., ANCA/MPO, ANCA/PR3) were not significantly different among patients with AIT and healthy controls. 40/80 (50%) of patients with AIT had artralgia compared with 7/34 (20.6%) in healthy controls (p < 0.05) and 19/80 (23.75%) of patients with AIT had arthritis compared with 1/34 (2.9%) in healthy controls (p < 0.05). The prevalence of RM (arthralgia and arthritis) in group of patients with AIT was significantly higher than in healthy controls.
The prevalence ofANA autoantibodies and RM (arthralgia/arthritis - both) was significantly higher in patients with AIT than in healthy controls.