CTLA-4 (CD152) Expression in T Cells during the Acute Stage of Kawasaki Disease

The pathogenesis of coronary arterial inflammation in acute Kawasaki Disease (KD) is unclear. Immunophenotypic characterization of the inflammatory cells in the KD vascular lesion has been reported previously in only a single case, by Terai and colleagues. To test the hypothesis that the vascular lesion in KD is an activated T lymphocyte-dependent process, we performed immunohistochemical studies on coronary artery aneurysms from eight fatal acute KD cases using antibodies to CD45RO (activated/memory T lymphocyte), CD8 (cytotoxic/suppressor T lymphocyte), CD4 (helper T lymphocyte), HAM56 (macrophage), and CD20 (B lymphocyte). We found that acute KD coronary arteritis was characterized by transmural infiltration of CD45RO+ T lymphocytes, with four- to five-fold more CD8+ T lymphocytes compared with CD4+ T lymphocytes. Macrophages were present primarily in the adventitial layer, and CD20+ B lymphocytes were notably absent. These data lend support to the hypotheses that KD results from infection with an intracellular pathogen such as a virus whose antigens are presented by MHC class I molecules, and that CD8+ T lymphocytes and macrophages are important in the pathogenesis of KD coronary aneurysms.