Immunohistochemical assessments of HLA-DR antigen expression in autoimmune thyroid diseases

40 thyroid specimens from Tru-cut needle biopsy and surgerywere analyzed by APAAP immunohistochemical technique.It was shown thatthe expression of HLA-DR antigen on thyroid follicular cells (TFC) wasinvolved in almost every patient.The degree of DR expression was signifi-cantly higher in autoimmune thyroiditis (AIT) than in Graves’ disease (GD)and in nontoxic goiter (NTG),The level of DR expression on TFC not onlycorrelated markedly with degree of MNC infiltration,but more so with degreeof DR expression on intrathyroidal infiltrates,suggesting that aberrant DR ex-pression in vivo may be related to the activation of intrathyroidal T cells.