[A histochemical and immunohistochemical study of cornea and adjacent bulbar conjunctiva in Mooren's ulcer].

OBJECTIVE

To investigate immunopathologic changes of cornea and adjacent bulbar conjunctiva in Mooren's ulcer, and roles of macrophage, T lymphocyte, and VCAM-1 in the pathogeny of Mooren's ulcer.

METHODS

The specimens of the cornea lesions and their adjacent bulbar conjunctiva taken from 18 active Mooren's ulcer cases who received resection of conjunctiva and lamellar keratoplasty surgery were studied with histochemical and labelled streptavidin biotin (LSAB) immunohistochemical techniques to investigate the expressions of CD68, CD3, CD4, CD8, CD1a, VCAM-1, HSP70, and TNF in the affected cornea and adjacent conjunctiva.

RESULTS

Under the histochemical examination, infiltration of neutrophils, plasma cells, lymphocytes, and eosinophils were found in the affected cornea and conjunctiva. Degeneration and necrosis of corneal epithelium, Bowman's layer, collageneous fiber in stromal layer, and edema of conjunctiva were shown. Infiltration of a large number of macrophages and T lymphocytes in the affected cornea and adjacent conjunctiva were shown in LSAB immunohistochemical staining. The main infiltrating T lymphocytes were the CD4 positive cells. The CD4/CD8 ratio was significantly higher than that of normal contrals (P < 0.01). VCAM-1 was strongly expressed in the affected corneal and conjunctival epithelium. There were no significant differences for expressions of CD1a, HSP70, and TNF between the pathological specimens and normal contrals.

CONCLUSION

The large number of infiltrating macrophages are responsible for the immunopathological damage caused by T lymphocyte infiltration, aberrant production of cytokikens and aberrant expression of HLA-DR antigen of Mooren's ulcer. There is an aberrant expression of VCAM-1 in the affected corneal and conjunctival epithelium. The role of VCAM-1 in the immunopathogenesis of Mooren's ulcer needs to be studied.