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

Abstract

Purpose: To investigate the concentrations of Fc epsilon receptor I (FcϵRI)-bindable immunoglobulin E (IgE) in the tear fluid and the proportion of IgE-saturated cells among FcϵRI-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 FcϵRI-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 FcϵRI-positive cells, we used two distinct monoclonal antibodies for FcϵRI for the immunohistochemistry. One antibody recognizes all FcϵRI regardless of whether it is with or without receptor-bound IgE. The other does not recognize IgE-bound FcϵRI. Results: The quantitative difference between FcϵRI-bindable IgE and total IgE were detected in the tear fluid of VKC patients. FcϵRI-positive cells were significantly increased in the giant papillae of VKC compared with normal conjunctivae. The proportion of IgE-saturated cells among FcϵRI-positive cells in giant papillae was higher than that in normal conjunctivae. Conclusion: These results suggest that FcϵRI-bindable IgE may be a critical factor to estimate the severity of VKC.