The level of tryptase in human tears. An indicator of activation of conjunctival mast cells.

Tryptase, a neutral endoprotease, is secreted by activated mast cells in human tissues. Tryptase levels in various body fluids have been used as an indicator of mast cell activation. The authors determined tryptase levels in unstimulated tears collected from the following groups of patients: (1) normal control, (2) nonallergic ocular inflammation, (3) asymptomatic seasonal allergic conjunctivitis, (4) symptomatic seasonal allergic conjunctivitis, (5) vernal conjunctivitis, and (6) contact lens-associated giant papillary conjunctivitis. They also assessed the release of tryptase into the tear fluid after provoking the conjunctiva with (7) allergens, (8) compound 48/80, and (9) rubbing. Tryptase levels were elevated in tears of patients with active ocular allergy and also increased after provoking the conjunctiva with allergens in atopic subjects and with compound 48/80 and rubbing in nonatopic subjects. Tryptase levels in tear fluid may prove useful as a clinical indicator of mast cell involvement in ocular allergic disorders. In provocation experiments, tryptase levels may be used to evaluate and compare different mast cell stabilizing agents.