Immune cells in the human choroid

Aim: To characterise the leucocytes in human macular choroid with and without drusen, and in eyes with advanced age-related macular degeneration (AMD) with fibrovascular scarring (FVS). Methods: Ten eyes from nine donors (range 55-91 years of age) were obtained from an eye bank within 38 h post mortem. Fixed macular biopsies were sectioned, stained immunochemically and examined for the presence of leucocyte antigens CD45, CD4, CD8, CD14 and CD83. Results: Four eyes without drusen, four eyes with drusen and two eyes with FVS contained 23.9 (SD 6.2)%, 27.5 (7.2)%, and 19.3 (11.3)% CD45-positive cells, respectively. The corresponding percentages for CD4-positive cells were 5.4 (4.3), 8.9 (3.0) and 7.5 (8.1); for CD8-positive cells, 3.8 (0.7), 6.8 (2.2) and 6.3 (2.1); and for CD14-positive cells, 3.7 (3.7), 3.6 (1.6) and 2.6 (3.6), respectively. The authors found CD83-positive cells solely in one of the two FVS eyes examined that had the more severe form of scarring. Conclusion: Human choroid contains similar amounts of CD4-positive cells and monocytes irrespective of the presence of drusen, but CD8-positive cells are more abundant in macular choroid with drusen. The presence of haematopoietic cells in the macular choroid provides further evidence for the possible participation of inflammatory cells in pathogenesis of AMD.