Correlation of Serum Thyroid Hormones Autoantibodies with Self-Reported Exposure to Thyroid Disruptors in a Group of Nonsegmental Vitiligo Patients

Vitiligo is a pigmentary disorder strongly associated with autoimmune thyroid disorders (ATD). Thyroid hormones antibodies (THAb) directed toward thyroxine (T3) and triiodothyronine (T4) (T3- and T4-Ab) are rare in the general population but are increased in individuals wit ATD and extrathyroid autoimmune disorders. Because it is known that alcohol, smoke, iodine, and some thyroid disruptors can elicit the appearance of ATD, the aim of our study was to evaluate possible correlation between T3- and T4-Ab expression and past toxic exposures in vitiligo patients. Seventy vitiligo patients were examined and self-reported exposure to thyroid disruptors (4,4'-isopropylidenediphenol, perchlorates, polychlorinated biphenyls (PCBs), hexachlorobenzene, resorcinol, dichlorodiphenyltrichloroethane, alachlor/amitriole, nitrate, thiocyanate, soy isoflavones), iodine intake, smoke, and alcohol consumption were investigated through standardized questionnaires. Immunoglobulin (Ig)M-T3-Ab, IgG-T3-Ab, IgM-T4-Ab,and IgG-T4-Ab were dosed by a radioimmunoprecipitation technique. Seventy-seven (95.7 %) patients had at least one type of THAb. Most of them had contemporarily both T3- and T4-Ab (50/70). We found a significant association between PCBs and T4-IgG-Ab (P = 0.039) and between food intake containing nitrate, thiocyanate, and soy isoflavones with (IgM + IgG)-T3-Ab (P = 0.041). Our study underlines a possible influence of diet and environment in vitiligo patients in eliciting THAb. Therefore, in the event of a positive exposure to thyroid disruptors, an evaluation of thyroid function might be useful to early detect possible associated thyroid autoantibodies such as THAb.