IMMUNOHISTOCHEMICAL ANALYSIS OF DENDRITIC LANGERHANS CELLS IN THYROIDCARCINOMAS/

Recent immunohistochemical investigations of thyroid carcinomas have r evealed that dense infiltration by dendritic cells (DCs) is correlated with a favorable prognosis. The present study was done to clarify the frequency and characteristics of DC infiltration in thyroid carcinoma s, and also cytokines associated with DC maturation and migration. Com pared with follicular carcinomas, papillary carcinomas contained signi ficantly higher numbers of DCs, interleukin (IL)-1 alpha- and tumor ne crosis factor (TNF)-alpha-positive cells, and cells positive for two T NF-alpha receptors (p60 and p80). The centers of cancer nodules had la rge numbers of CD1a- and CD1c-positive DCs suggesting that they were L angerhans cells, whereas the periphery of cancer nodules and inflamed surrounding thyroid tissues had numerous CD1b-, L-M2- and X-12-positiv e DCs suggesting that they were interdigitating cells, as well as many CD1a- and CD1c-positive DCs. Neoplastic cells of papillary carcinomas were more frequently reactive with antibodies against IL-1 alpha and TNF-alpha than those of follicular carcinomas, and a good correlation between their immunoreactivity and the frequency of DCs was found. The se data suggest that cytokines such as IL-1 alpha and TNF-alpha releas ed from carcinoma cells and cells in the cancer stroma may regulate th e infiltration and maturation of dendritic/Langerhans cells, and that this process may be better preserved in papillary than in follicular c arcinomas.