High prevalence of antithyroid antibodies in anti-glomerular basement membrane antibody-mediated disease.

Anti-glomerular basement membrane antibody (anti-GBM Ab)-mediated disease and autoimmune thyroiditis are characterized by the presence of organ-specific antibodies. The diagnosis of autoimmune thyroiditis is usually based on the presence of serum antithyroid antibodies. Few studies have addressed the relationship between anti GBM-Ab mediated disease and autoimmune thyroid pathology. Given that this disorder is often asymptomatic, associations of the two pathologies may be under-diagnosed. This study investigated the prevalence of serum antithyroid antibodies (antithyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO)) in patients with anti-GBM Ab-mediated disease. Antithyroid antibodies presence was investigated in sera from 35 patients in whom anti-GBM Ab-mediated disease had been diagnosed. Anti-glomerular basement membrane antibodies and anti-thyroid antibodies (anti-TG and anti-TPO) were assayed using an enzyme-linked immunosorbent assay. Forty-five percent of patients with anti-GBM Ab-mediated disease (16/35) had positive antithyroid antibody titers. Eighteen percent (3/16) suffered from subclinical hypothyroidism. In conclusion, the high prevalence of antithyroid antibodies in these patients suggests a possible pathogenic link between autoimmune thyroiditis and anti GBM Ab-mediated disease.