Tear lipocalin and lysozyme in Sjögren and non-Sjögren dry eye.
OBJECTIVE
To evaluate the concentration of tear lipocalin, lysozyme, and total protein in Sjögren's Syndrome (SS), non-Sjögren's keratoconjunctivitis sicca (KCS), and non-dry-eyed (NDE) individuals.


METHODS
Seventy-six subjects were recruited for this study: 25 SS subjects; 25 KCS subjects, and 26 NDE individuals. Symptoms were measured with a visual analogue scale. Tear flow was measured by the Schirmer I test without anesthesia. Tears were collected using an eye wash technique. Total tear protein was quantified using the DC Protein Assay Kit. Tear lipocalin and lysozyme were quantified via Western blotting performed on a Phast System.


RESULTS
By definition, the SS and KCS groups both had significantly lower mean Schirmer scores (5.12 +/- 5.96 mm and 7.84 +/- 7.35 mm) compared with the NDE group (23.83 +/- 7.85 mm; p < 0.0001). There was no difference in mean Schirmer scores between SS and KCS groups (p = 0.19). The tear film of the SS group was characterized by significantly reduced (p < 0.0001) total protein and lipocalin concentrations compared with both KCS and NDE groups. No difference between the KCS and NDE groups was found in total protein (p = 0.92) or lipocalin (p = 0.19) concentration. In contrast, the concentration of tear film lysozyme was found to be statistically similar in all three groups examined. No statistically significant correlation was found in any group between mean Schirmer values compared with total protein, lipocalin or lysozyme concentration.


CONCLUSIONS
Our data demonstrate a biochemical distinction between the Sjögren's group compared with both KCS and control groups, in that both tear lipocalin and total tear protein were significantly reduced. Although correlations were not found between protein measurements and tear flow, a combination of tests including Schirmer I and quantitation of tear film biomarkers may allow for the identification of SS patients without the need for invasive testing.
Caffery
Barbary
B
Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada. barbaracafferyeyes@yahoo.ca
Joyce
Elizabeth
E
Boone
Adrienne
A
Slomovic
Allan
A
Simpson
Trefford
T
Jones
Lyndon
L
Senchyna
Michelle
M
D015153:Blotting, Western; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007638:Keratoconjunctivitis Sicca / Q000378:metabolism; D054834:Lipocalins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009113:Muramidase / Q000378:metabolism*; D012859:Sjogren's Syndrome / Q000378:metabolism*; D013666:Tears / Q000378:metabolism*
D005136:Eye Proteins; D054834:Lipocalins; C042434:tear proteins; D009113:Muramidase