Focal lymphocytic infiltration in the adrenal cortex of the elderly: immunohistological analysis of infiltrating lymphocytes.

The incidence of mononuclear cell infiltration in the adrenal cortex was examined in autopsy cases of young and old subjects, and the infiltrating mononuclear cells were immunohistologically characterized by monoclonal antibodies. Histologically, 110 of 174 autopsy cases of persons greater than 60 years (63.2%) were shown to have mononuclear cell infiltration of varying degree within the adrenal cortex, whereas such a lesion was observed in lesser incidence (7.4%) in the 54 younger, control subjects aged less than 49 years. In addition, severely infiltrating lesions in the adrenal cortex were found frequently in the elderly greater than 70 years. Immunohistochemical study revealed that the infiltrating mononuclear cells were mainly composed of CD3+ T cells. The major proportion of CD3+ T cells expressed CD4, whereas CD8+ T cells were less in number. Moreover, a considerable proportion of CD4+ T cells was activated as judged by interleukin 2 receptor expression. These findings indicate that T lymphocytes infiltration in aged human adrenal cortex may represent a pre-clinical manifestation of organ-specific autoimmune adrenalitis which is based on autoimmunity associated with ageing process.