The relations between tear fluid concentrations of lysozyme, tear-specific prealbumin and lactoferrin.

A degeneration of the tear gland leads to reduced lysozyme concentrations in the tear fluid. Tear lysozyme concentrations are generally determined by enzymatic methods. Lysozyme determination by radial immunodiffusion has some advantages above the enzymatic assays, and laboratory facilities are not required. The enzymatic properties of lysozyme that favoured its choice as a parameter for tear gland function, influenced to some extent the results of the radial immunodiffusion assay. Therefore we looked among the proteins originating from the lacrimal gland for alternative parameters of tear gland function. In 94 tear samples obtained from a heterogeneous group, ranging from persons with normal lacrimal gland function to severe kerato-conjunctivitis sicca patients, a high degree of correlation was found between lysozyme concentration and that of lactoferrin as well as tear-specific prealbumin. This indicates that the latter two proteins can be used as alternatives for lysozyme in tear gland function tests.