Immune profile and thyroid function in patients with rheumatoid arthritis

Thyroid autoantibodies and thyroid function were studied in 175 patients with rheumatoid arthritis (ARA criteria, 1987). The study included 149 women and 26 men aged (54.7 +/- 13.1) all treated in the Clinic of Rheumatology, Higher Medical Institute, Plovdiv. A control group comprising 72 healthy subjects (aged 51.2 +/- 3.2) was used. Rheumatoid factor (RF) (latex agglutination test and Waaler-Rose test), antithyroglobulin (TAT) and antimicrosomal antibodies (MAT), thyroid stimulating hormone (TSH) and the free fraction of thyroxine (FT4) were measured. 69.7% of all patients tested positive for RF by the latex test and 64.5% by the Waaler-Rose test. TAT was found in 55 (31.4%), MAT in 26 (14.8%) from all the examined, which is significantly greater in comparison with the controls (p < 0.05). The thyroid gland was in a euthyroid state in most of the RA patients although MAT and/or TAT were detected in them. The results suggest existence of two autoimmune diseases - rheumatoid arthritis and Hashimoto's thyroiditis and raise the question of whether they are not manifestations of a single autoimmune disease with different body organ localisation.