Behçet's disease: activated T lymphocytes in retinal perivasculitis.

A 38-year-old man who died from systemic Behcet's disease had previously suffered from severe, recurrent bilateral retinal vasculitis, and anterior uveitis for 10 years. Immunopathological examination of the eyes postmortem revealed marked hyaline thickening of the retinal and optic nerve vessels. The vessels had an intramural and perivascular infiltrate of T lymphocytes which stained positively for CD4 and IL2 receptor surface markers. Small numbers of cells in the optic nerve head, retinal vascular endothelium, and retinal pigment epithelium were HLA DR positive.