Purpose: To determine the pattern and distribution of mononuclear cells,
adhesion, and co-stimulatory molecules in the conjunctiva of patients
with Mooren ulcer.
Methods: Conjunctival biopsy specimens were obtained from 6 patients
with Mooren ulcer and 6 healthy individuals. Immunohistochemistry was
performed on frozen sections of the cryopreserved human conjunctivas
using monoclonal antibodies directed against CD1 alpha, CD3, CD4, CD8,
CD20, CD25, CD57, and CD68 cells; the adhesion molecules E-selectin,
vascular cell adhesion molecule-1 (VCAM-1), very late activation-4
(VLA-4), ICAM-1, and LFA-1; and the co-stimulatory molecules CD28, B7-1,
B7-2, and CTLA-4.
Results: Differences in expression on the conjunctival epithelium from
patients with Mooren ulcer and normal subjects were noted only for
VCAM-1, VLA-4, ICAM-1, and LFA-1. The ratio of CD4(+)/CD8(+) cells in
Mooren ulcer specimens was significantly higher (3.5-fold). However, in
the substantia propria, Mooren ulcer specimens revealed significantly
increased numbers of CD1 alpha(+), CD3(+), CD4(+), CD20(+), CD28(+),
B7-1(+), B7-2(+), and CD68(+) cells. The ratios of CD4(+)/CD8(+) cells
and B7-2(+)/antigen-presenting cells in Mooren ulcer specimens were
significantly higher (5-fold). All tested adhesion molecules showed
significant up-regulation in the patients’ conjunctivas. Mooren ulcer
vascular endothelial cells prominently expressed E-selectin, VCAM-1,
VLA-4, and ICAM-1 compared with normal conjunctiva.
Conclusion: The simultaneous presence of multiple types of inflammatory
cells, adhesion, and co-stimulatory molecules in Mooren ulcer
conjunctiva suggests that their interaction may contribute to a
sustained immune activation as at least part of the pathogenic mechanism
of this disorder.
(EN)