An immunohistochemical study of topical cyclosporine in vernal keratoconjunctivitis

To determine the immunomodulating effects of topical cyclosporine on the immune cells in the conjunctival biopsy specimens obtained from patients with active vernal keratoconjunctivitis.

We studied six patients who had severe active vernal keratoconjunctivitis. Each patient was given topical cyclosporine 2% eyedrops four times daily. A 2 x 2-mm limbal conjunctival biopsy specimen was obtained from each patient before and three weeks after treatment. Using a panel of monoclonal and polyclonal antibodies and immunohistochemical techniques, we analyzed the conjunctival immune cells before and after cyclosporine treatment.

Three weeks after topical cyclosporine treatment, there was marked clinical improvement and a statistically significant reduction in the number of epithelial and stromal class II MHC+ cells, UCHL1+ T cells, and stromal IgA+ and IgG+ plasma cells. The mean number of cells before and after therapy, respectively, were: class II MHC+ (epithelium), 31.5 +/- 13.1 and 8.3 +/- 5.6 (P = .031); class II MHC+ (stroma), 77.0 +/- 28.7 and 24.7 +/- 17.5 (P = .031); UCHL1+ T cells (epithelium), 24.5 +/- 14.1 and 4.2 +/- 2.9 (P = .031); UCHL1+ T cells (stroma), 78.7 +/- 31.1 and 44.5 +/- 27.5 (P = .031); IgA+ plasma cells, 66.7 +/- 32.1 and 22.2 +/- 7.8 (P = .031); and IgG+ plasma cells, 37.3 +/- 30.0 and 9.0 +/- 6.4 (P = .031). There was a statistically insignificant decrease in the epithelial class II MHC+ dendritic Langerhans cells, epithelial and stromal KP1+ macrophages, stromal OPD4+ helper/inducer T cells, and stromal L26+ B cells. The numbers of IgE+ plasma cells and mast cells were unaltered.

The clinical improvement in vernal keratoconjunctivitis after topical cyclosporine therapy may result from its immunomodulating effect on the components of cell-mediated and humoral immune responses. In contrast, the drug has no immunomodulatory effect on mast cells and IgE-mediated allergic response.