TEAR TRYPTASE LEVELS AND ALLERGIC CONJUNCTIVITIS

We measured tryptase, a neutral protease stored in the secretory granu les of mast cells, by solid-phase radioimmunoassay in tears of 12 subj ects with vernal keratoconjunctivitis (VKC) during remission phases, n ine subjects with seasonal or perennial allergic conjunctivitis, and e ight healthy controls. Mean values of tear tryptase levels were signif icantly (P < 0.02) increased in VKC patients (14.5 +/- 13 mu g/l) when compared to those measured in patients with seasonal or perennial all ergic conjunctivitis (0.6 +/- 0.1 mu g/l) and in controls (3.3 +/- 3.2 mu g/l). In subjects with allergic conjunctivitis, the levels of tryp tase, almost undetectable before allergen conjunctival challenge, show ed a significant increase in the challenged eye 20 min - but not 6 h - after provocation in 5/9 cases. Our results indicate that VKC, a seve re ocular disease characterized by an increased number and abnormal di stribution of mast cells in the conjunctiva, also shows elevated level s of tryptase in tears even during remission phases. Evidence of mast- cell activation, as revealed by a significant increase of tryptase lev els in tears, is documented during the early-phase reaction, but not d uring the late-phase reaction, of allergic conjunctivitis patients cha llenged topically by specific allergen.