Tear fluid concentration of mmp-8 is elevated in non-allergic eosinophilic conjunctivitis and correlates with conjunctival inflammatory cell infiltration.
BACKGROUND
To investigate tear fluid concentration of matrix metalloproteinase 8 (MMP-8) and its relation to conjunctival inflammatory cell infiltration in persistent non-allergic eosinophilic conjunctivitis (NAEC).


METHODS
Two groups were included: 26 consecutive adult patients with NAEC (conjunctival eosinophils at least 1+ [1-10 eosinophils/slide], skin prick test [SPT] to common allergens negative), and 26 asymptomatic adult persons (no conjunctival eosinophils, SPT negative). MMP-8 tear fluid concentrations were determined by immunofluorometric assay, and conjunctival brush cytology samples from NAEC patients were used for MMP-8 immunocytochemistry. Gelatin zymography was used to illustrate proteolytic activity within the tear fluid samples.


RESULTS
The mean MMP-8 concentration was significantly higher among NAEC patients (214.3 +/- 327.7 microg/l) than among healthy persons (50.4 +/- 62.3 microg/l, P < 0.0001). In the NAEC patients, tear fluid MMP-8 correlated with the numbers of conjunctival neutrophils (r = 0.66, P = 0.0002) as well as with goblet cells and columnar epithelial cells (r = 0.54 for both, P = 0.045), but not with the lymphocyte numbers (r = -0.36, P = 0.0741). By immunocytology, MMP-8 protein could also be detected in vivo in the inflammatory cell population within the conjunctiva. Zymography revealed that proteolysis was significantly higher in the NAEC group, and activated enzymes were practically found only in the NAEC group.


CONCLUSIONS
The results showed that NAEC is an inflammatory condition characterized by increased tear fluid MMP-8 levels, probably derived from both inflammatory and structural conjunctival cells. The increased proteolytic activity in NAEC patients may indicate risk of conjunctival structural changes (remodeling).
Kari
Osmo
O
Division of Allergology, HUCH Skin and Allergy Hospital, Nyyrikintie 20, 02100, Espoo, Helsinki, Finland. osmo.kari@optokari.fi
Määttä
Marko
M
Tervahartiala
Taina
T
Peltonen
Sirje
S
Kari
Marjatta
M
Hagström
Jaana
J
Sorsa
Timo
T
Saari
Matti
M
Haahtela
Tari
T
D000328:Adult; D003231:Conjunctivitis / Q000201:enzymology* / Q000473:pathology; D004802:Eosinophilia / Q000201:enzymology* / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D015200:Fluoroimmunoassay; D020397:Goblet Cells / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism*; D008875:Middle Aged; D009504:Neutrophils / Q000473:pathology*; D013666:Tears / Q000201:enzymology*
D005136:Eye Proteins; C042434:tear proteins; C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8