Background: The detection of important immunocompetence-like features on endocrine steroid cells raises questions about direct intercellular communication between the adrenal and immune systems. This article summarizes our recent work and new data on immune-adrenal interactions.
Materials and methods: RT-PCR and immunohistochemistry were performed to examine MHC class II (HLA-DR) expression in adrenocortical tumours. Coculture systems of NCI-H295 adrenocortical carcinoma cells and HLA-matched lymphocytes were used to examine effects on steroid production and survival of lymphocytes.
Results: HLA-DR m-RNA is found in both benign and malignant adrenals, except the NCI-H295 cell line. Under direct coculture conditions with NCI-H295 cell line, spontaneous apoptosis of immune cells was reduced. Synthesis of cortisol and especially of dehydroepiandrosterone production of tumour cells was markedly increased. Differences by separating CD4- and CD8- T cells were not detected.
Conclusions: Direct cellular contact between lymphocytes and adrenocortical cells seems to be involved in the peripheral regulation of androgen synthesis in the adrenal. The molecular basis of this interaction is not known. With regard to normal adrenals, ligation of MHC class II antigens could be a potential mechanism for a peripheral regulation of androgen secretion.