Takayasu's arteritis: a pathogenetic role for cytotoxic T lymphocytes?

Takayasu's arteritis is an inflammatory panarteritis of unknown aetiology affecting large elastic arteries. We examined a segment of abnormal common carotid artery removed at by-pass surgery from a 23-year-old man with typical angiographic features of Takayasu's arteritis. Using monoclonal antibodies we were able to demonstrate marked infiltration of the arterial wall with OKT8 positive lymphocytes (suppressor/cytotoxic cells) but not with OKT4 positive lymphocytes (helper cells). Studies of circulating lymphocytes showed increased numbers of "activated" cells and increased in vitro cytotoxicity against cultured human umbilical cord endothelial cells, compared to normal lymphocytes. Cellular immunological mechanisms may play an important role in the pathogenesis of Takayasu's arteritis, possibly through the direct action of cytotoxic T cells on large elastic arteries.