Gelatinase B in vernal keratoconjunctivitis.

OBJECTIVES To investigate the expression of gelatinase B in the conjunctiva of patients with vernal keratoconjunctivitis (VKC) and the cellular source of this enzyme. METHODS Conjunctival biopsy specimens from 12 patients with active VKC and 12 control subjects were studied using immunohistochemical techniques and a monoclonal antibody against gelatinase B. The phenotype of gelatinase B(+) inflammatory cells was examined using double immunohistochemical analysis and monoclonal antibodies against eosinophil peroxidase or macrophage CD68. Quantitative zymography was used to compare the activity of gelatinase B in conjunctival biopsy specimens from 10 patients with active VKC and 7 control subjects. RESULTS Gelatinase B was detected in a few polymorphonuclear cells in 8 control specimens. All VKC specimens showed gelatinase B immunoreactivity in the epithelial and stromal inflammatory infiltrate. Compared with control specimens, VKC specimens showed significantly more gelatinase B-positive cells (mean +/- SD, 40.8 +/- 29.9 vs 10.3 +/- 2.4; P<.02). Most gelatinase B-positive cells were eosinophils (90.2% +/- 3.6%). Zymography revealed that gelatinase B levels in VKC specimens were significantly higher than the levels found in normal conjunctiva (3780.3 +/- 3541.0 vs 610.1 +/- 397.1 scanning units; P<.03). CONCLUSIONS These findings suggest overexpression of gelatinase B by eosinophils in VKC specimens and participation of gelatinase B in the pathologic changes in VKC. CLINICAL RELEVANCE Control of the release and/or activation of gelatinase B in eosinophils may provide a new therapeutic strategy for treating VKC.