Immunological characteristics of patients with vernal keratoconjunctivitis

Purpose: Previously, we have reported that local excision and immunosuppressive treatment are useful in treating patients with very severe vernal keratoconjunctivitis (VKC). Methods: We measured serum levels of immunoglobulins, cytokines, and interleukin-2 receptors (IL-2R) and the concentration of IL-4 in tears of 10 patients with severe VKC, and made a comparison with data from 10 healthy controls. Brush cytology specimens were examined to determine the number of inflammatory cells and the human lymphocyte antigen (HLA)-DR expression in conjunctiva. Results: The mean serum level of total immunoglobulin (Ig)E, but not IgG, was higher in severe VKC patients compared with healthy controls. Specific IgE positivity to housedust, dust mites, and cat antigens was observed in 60-80% of patients. The level of IL-4 and IL-2R in serum and IL-4 in tears before treatment was higher in patients with VKC compared with controls. Serum levels of IL-2 and interferon-γ did not increase. Brush cytology specimens from patients expressed HLA-DR. Conclusions: These results suggest that VKC could be a combination of type I allergic disease and an inflammatory cell disease including activated T cells, especially Th2 cells. Therefore, the surgical removal of inflammatory cells combined with immunosuppressive therapy could be advocated as a method of treatment.