Status of antithyroid antibodies in Bangladesh

To study autoimmunity among thyroid diseases, 397 thyroid patients (age 30 (13) years; M/F 75/322) from two referral centres in Bangladesh and 94 heal thy controls (age 30 (13) years; M/F 24/70) were studied for antimicrosomal and antithyroglobulin antibodies. Thyroid patients were clinically grouped as suspected autoimmune thyroid disease (AITD), non-autoimmune, or indeter minate groups (where no decision could be reached). Antimicrosomal antibody was strongly positive in 19.4% and weakly positive in 7.3% of patients but only 4.3% and 2.1% respectively in the controls (chi(2) = 17.852; p = 0.00 0) whereas strong and weak positivity were 27.2% and 6.8% in patients compa red with 8.5% and 4.3% respectively in the controls (chi(2) = 16.916; p = 0 .000) for antithyroglobulin antibody. Antibodies were positive in 63.0% wit h Hashimoto's thyroiditis, 36.4% with Graves' disease, and 44.7% with atrop hic thyroiditis among the autoimmune group. In the non-autoimmune group ant ibodies were positive in 100% with multinodular hypothyroidism, 46.7% with subacute thyroiditis, 40.0% with suspected iodine deficiency goitre, 31.3% with toxic multinodular goitre, 30.8% with nontoxic solitary nodules, and 1 9.4% with simple diffuse goitre. None was positive for antimicrosomal antib ody without being positive for antithyroglobulin antibody. The two antibodi es strongly correlated in both patients (r = 0.977, p = 0.000) and controls (r = 0.986, p = 0.000). About 9% (36/397) of patients were mismatched with the final diagnosis on antibody measurement; most of them had Hashimoto's thyroiditis (33/36). Prevalence of AITD among thyroid patients was 48.36%. Specificity of antimicrosomal and antithyroglobulin antibodies were 93% and 87%. It was concluded that AITD is not uncommon in Bangladesh; antimicroso mal antibody is a useful marker for AITD and unless antibodies are checked, an appreciable number of patients with AITDs will remain undetected.