Role for Regulatory T Cells in Thyroiditis
May be involved in progression from hyperthyroidism to thyroiditis, study in mice suggests
FRIDAY, Dec. 7 (HealthDay News) -- Regulatory T cells (Treg) may be involved in the progression of hyperthyroidism in Graves' disease and Hashimoto's thyroiditis, according to the results of a study in mice published in the December issue of Endocrinology.
Sandra M. McLachlan, Ph.D., from Cedars-Sinai Medical Center in Los Angeles, and colleagues depleted Treg in mice engineered to express the human thyrotropin receptor A-subunit targeted to the thyroid gland, then injected them with an adenovirus producing the receptor to try to break immune tolerance.
The researchers found that mice expressing high levels of the receptor did not develop thyrotropin receptor antibodies or hyperthyroidism after adenovirus injection, regardless of Treg depletion. Mice expressing low levels of the receptor developed low antibody levels but not hyperthyroidism, regardless of Treg depletion. However, Treg depletion in low-expressing mice with hypothyroidism led to thyroid lymphocytic infiltration that was associated with the spread of the antibody response to other "self" thyroid antigens.
"These data suggest a role for Treg in the natural progression of hyperthyroid Graves' disease to Hashimoto's thyroiditis and hypothyroidism in humans," McLachlan and colleagues conclude.