Allergy and infections: long-term improvement of vernal keratoconjunctivitis following viral conjunctivitis.

PURPOSE Vernal keratoconjunctivitis (VKC) is a severe, chronic allergic inflammatory disease of the ocular surface poorly responsive to antiallergic treatments and possibly leading to permanent visual impairment. VKC, because of mast cell, eosinophil, and Th2-type inflammation, polyclonal IgE activation, and tissue remodeling, is considered to be a typical Th2- driven disease. Viral infection stimulates a Th1 type immune response, potentially attenuating allergen-induced inflammation. The purpose of this report is to describe the effect of viral keratoconjunctivitis in a patient with VKC. METHODS The authors report on a patient with a severe form of VKC, poorly responsive to antiallergic treatments, who developed a viral keratoconjunctivitis. Signs, symptoms, and cytologic findings were recorded during the 5-year follow-up period. RESULTS The authors observed a prompt and permanent improvement of signs and symptoms of the allergic condition after the viral infection. Conjunctival scraping confirms that the inhibition of the eosinophilic inflammation lasts at least for 5 years. CONCLUSIONS In this case, the viral infection seemed to induce a clinical recovery of allergic disease, suggesting that an immune deviation induced by Th1-polarizing agents may revert an ongoing Th2 inflammation.