Basal and reflex human tear analysis. II. Chemical analysis: lactoferrin and lysozyme.

Unstimulated basal tears and stimulated tears were collected from normal controls, keratoconjunctivitis sicca (KCS) patients, and contact lens (CL) wearers. Basal tear volume (Periopaper) and reflex tear volume (Schirmer Strip) were measured and tears eluted from their respective strip with a TMED-acetic acid buffer. Lactoferrin and lysozyme concentrations were measured in the eluates. Concentration of lysozyme in basal tears was: 65 +/- 43 mg% in normals; 44 +/- 26 mg% in KCS, and 81 +/- 50 mg% in CL wearers. Concentration of lysozyme in reflex tears was: 160 +/- 73 mg% in normals, 74 +/- 41 mg% in KCS, and 186 +/- 83 mg% in CL wearers. Concentration of lactoferrin in basal tears was 137 +/- 102 mg% in normals, 154 +/- 82 mg% in KCS, and 157 +/- 80 mg% in CL wearers. Concentrations of lactoferrin in reflex tears was: 327 +/- 187 mg% in normals; 171 +/- 69 mg% in KCS, and 302 +/- 160 mg% in CL wearers. The lactoferrin concentration in all tear samples was consistently higher (1.6-3.5 times) than lysozyme. In basal tears, lactoferrin concentrations were not significantly different in the three groups. In reflex tears, however, lactoferrin was significantly lower in KCS than normal or CL wearers. The concentration of lysozyme in both basal and reflex tears was significantly lower in the KCS when compared to normal or CL wearers. Lysozyme and lactoferrin concentrations in both basal and reflex tears were similar in CL wearers and normal controls. The sampling and elution of basal and reflex tears as described appears to be a feasible technique for analysis of lysozyme and lactoferrin concentrations by the electroimmunodiffusion technique and has potential diagnostic value.