Involvement of the immune system in iodine deficient goiter.

: Iodine deficient goiters were studied by immunohistochemistry and showed extensive presence and typical arrangement of dendritic cells, known to have excellent antigen presenting capacity. These cells were positive for all MHC-class II epitopes and for ICAM-1. Epithelial follicle lining cells were also seen to be class II positive but lacked ICAM-1. Thyroglobulin seemed not to be iodinated at the C-terminal hormogenic site, as shown by reactions with monoclonal antibodies. Iodine therapy, as well as thyroxine therapy were effective in reducing thyroid size. Both forms of therapy were found to decrease the pretreatment levels of circulating thyroid growth stimulating immunoglobulins (TGI).