Immunologic findings in tissue of thyroid carcinoma.

We studied the occurrence of DR-antigen (DR-Ag) positive thyroid epithelial cells (TEC), lymphocyte (Ly)-subsets, and antigen-presenting cells (APC) in thyroid carcinoma and the influence of thyroid-stimulating hormone (TSH) on immunologic behavior. Tissue slices from various thyroid carcinomas (n = 14) and endemic goiters (n = 12) were investigated by immunohistochemical methods (PAP/APAAP/FITC) using monoclonal antibodies (MoAbs) against DR-Ag, dendritic cells (APC), endothelial cells, CD-3 Ly, CD-4 Ly, and CD-8 Ly. Monolayers of TEC were cultured in the presence or absence of TSH (0.01 mU/ml) and/or PHA (0.1 mg/ml) over 24 h and screened for DR-Ag expression. Various ranges of DR-Ag expression were detectable in 13 thyroid carcinomas. One thyroid carcinoma and all endemic goiters were DR-Ag-. The amount of APC and local infiltrating Ly correlated very well with the presence and intensity of DR-Ag+ TEC. The lymphocytic CD-4/CD-8 ratio varied in a wide range. No prevalence of Ly-distribution for any type of carcinoma was found. PHA induced DR-Ag expression in all thyroid carcinomas and endemic goiters. This effect was enhanced significantly by TSH. DR-Ag expression on thyroid carcinoma cells may be considered as an immune activating factor. These "neoantigens" may be induced by lymphokines released by the local immune competent cells. The distribution of Ly and DR-Ag+ TEC in thyroid carcinoma seems to represent the individual immunologic response against the tumor. Whether TSH acts as an immune modulator directly or indirectly, as described elsewhere, cannot be concluded from these results.