RESTRICTED USAGE OF T-CELL RECEPTOR V-ALPHA-V-BETA GENES IN INFILTRATING CELLS IN THE AORTIC TISSUE OF A PATIENT WITH ATHEROSCLEROTIC AORTIC-ANEURYSM

We report a rare case of an atherosclerotic aortic aneurysm with lymph ocyte infiltration in which T-cell receptor (TCR) V alpha as well as V Chi gene usage was restricted. Immunohistochemical studies showed tha t the infiltrating cells mainly consisted of macrophages, natural kill er (NK) cells, cytotoxic T lymphocytes (CTLs) and T-helper (Th) cells, and that there were almost no infiltrating delta T lymphocytes, and h uman leukocyte antigen (HLA) class I and 65-kD heat-shock protein (HSP -65) was not strongly expressed in the aortic tissue. Although the imm unohistochemical data were consistent with an ordinary atherosclerotic aortic aneurysm, in which TCR V alpha-V beta gene usage is known to b e polyclonal, the restricted TCR gene usage suggests that a certain au toimmune mechanism was involved in the pathogenesis of this case simil ar to Takayasu's arteritis, in which massive infiltration of delta T l ymphocytes and strong expression of HSP-65 in the aortic tissue are ch aracteristic.