High level of Fc epsilon receptor I-bindable immunoglobulin E in the tear fluid and increased immunoglobulin E-saturated cells in the giant papillae of vernal keratoconjunctivitis patients.

PURPOSE To investigate the concentrations of Fc epsilon receptor I (Fc epsilon RI)-bindable immunoglobulin E (IgE) in the tear fluid and the proportion of IgE-saturated cells among Fc epsilon RI-positive cells in giant papillae from vernal keratoconjunctivitis (VKC) patients. METHODS The tear fluids and giant papillae were obtained from 8 VKC patients with their informed consent. To detect the quantitative difference between Fc epsilon RI-bindable IgE and total IgE in the tear fluid, we used a new enzyme-linked immunosorbent assay system we have developed. Next, to estimate the proportion of IgE-saturated cells among Fc epsilon RI-positive cells, we used two distinct monoclonal antibodies for Fc epsilon RI for the immunohistochemistry. One antibody recognizes all Fc epsilon RI regardless of whether it is with or without receptor-bound IgE. The other does not recognize IgE-bound Fc epsilon RI. RESULTS The quantitative difference between Fc epsilon RI-bindable IgE and total IgE were detected in the tear fluid of VKC patients. Fc epsilon RI-positive cells were significantly increased in the giant papillae of VKC compared with normal conjunctivae. The proportion of IgE-saturated cells among Fc epsilon RI-positive cells in giant papillae was higher than that in normal conjunctivae. CONCLUSION These results suggest that F epsilon RI-bindable IgE may be a critical factor to estimate the severity of VKC.