Prevalence and clinical significance of nonorgan specific antibodies in patients with autoimmune thyroiditis as predictor markers for rheumatic diseases

Abstract

Autoimmune diseases are considered the 3rd leading cause of morbidity and mortality in the industrialized countries. Autoimmune thyroid diseases (ATDs) are associated with high prevalence of nonorgan-specific autoantibodies, such as antinuclear antibodies (ANA), antidouble-stranded deoxyribonucleic acid (anti-dsDNA), antiextractable-nuclear antigens (anti-ENAs), rheumatoid factor (RF), and anticyclic-citrullinated peptides (anti-CCP) whose clinical significance is unknown.We aimed to assess the prevalence of various nonorgan-specific autoantibodies in patients with ATD, and to investigate the possible association between these autoantibodies and occurrence of rheumatic diseases and, if these autoantibodies could be considered as predictor markers for autoimmune rheumatic diseases in the future.This study had 2 phases: phase 1; in which 61 ATD patients free from rheumatic manifestations were assessed for the presence of these nonorgan-specific autoantibodies against healthy 61 control group, followed by 2nd phase longitudinal clinical follow-up in which cases are monitored systematically to establish occurrence and progression of any rheumatic disease in association to these autoantibodies with its influences and prognosis.Regarding ATD patients, ANA, anti-dsDNA, Anti-ENA, and RF were present in a percentage of (50.8%), (18%), (21.3%), and (34.4%), respectively, with statistically significance difference (P < 0.5) rather than controls. Nearly one third of the studied group (32.8%) developed the rheumatic diseases, over 2 years follow-up. It was obvious that those with positive anti-dsDNA had higher risk (2.45 times) to develop rheumatic diseases than those without. There was a statistically significant positive linear relationship between occurrence of disease in months and (age, anti-dsDNA, anti-CCP, RF, and duration of thyroiditis). Anti-dsDNA and RF are the most significant predictors (P < 0.0001).ATD is more associated with rheumatic diseases than previously thought. Anti-dsDNA, RF, and anti-CCP antibodies may be used as predictive screening markers of systemic lupus erythematosus and RA, with early referral to rheumatologists for close follow-up and early diagnoses for appropriate disease management of the disease, as early disease control will allow better quality of life.

Rheumatic Disease Autoantibodies in Patients with Autoimmune Thyroid Diseases

“…However, this was a study with a different design from the present study, as these authors did not exclude patients with prior diagnosis of rheumatic disease from their sample. In contrast to our findings, Elnady et al [13] followed HT patients with non-organ specific autoantibodies for 2 years and found that almost 1/3 developed rheumatic disease; anti-dsDNA and RF were the most significant predictors of disease occurrence. Differences in the ethnic background of the studied sample may explain some of these discrepancies as both ATD and rheumatic diseases are influenced by genes such as MHC class 2, CTLA4, and PTPN22 [16].…”

“…On the contrary, in the other half of ANA-positive patients the pattern was fine or coarse speckled and about 15% of them were positive for anti-Ro/SS-A. Morita et al [11] did not find anti-Ro/SS-A in their 50 patients with autoimmune thyroid disease, but Tektonidou et al [12] found a prevalence of 10% of anti-Ro/SS-A positivity, and Elnady et al [13], a positivity of 14.8% in their sample. Finding of anti-Ro/SS-A positivity in a disease with female predominance is very important, as this autoantibody may cross the placenta barrier in pregnant women and cause neonatal lupus with a risk of congenital heart block, independently of the diagnosis of a background disease [14].…”

The impact of thyroid autoimmunity (TPOAb) on bone density and fracture risk in postmenopausal women

“…These could form a link between AITD and rheumatoid arthritis and the impact of these two autoimmune diseases on bone quality. 30 Accumulating evidence suggests that osteoclasts, originating from the monocyte lineage and immune cells share a number of regulatory molecules including cytokines, receptors, signaling molecules and transcription factors, thereby mutually influencing each other. Furthermore, immune cells are derived from bone marrow and thus develop in the same microenvironment as osteoclasts.…”

Undifferentiated connective tissue diseases and adverse pregnancy outcomes. An undervalued association?

“…Some of the adverse effects of ARDs on pregnancy outcomes can be mediated by their association with thyroid autoimmunity. In particular, subjects with ARDs have an increased prevalence of antithyroid antibodies in both pregnant and non‐pregnant states . In addition, the detection of isolated antithyroid antibodies is a risk factor for the subsequent development of a rheumatic disorder .…”