title: α1-antitrypsin and C-reactive protein levels in tear fluid after continuous contact lens wear.
abstract: BACKGROUND
  Corneal inflammation has long been associated with contact lens wear and the use of extended-wear lenses enhances the risk of corneal injury. Elucidation of the molecular mediators of contact lens-associated inflammation has the potential to provide injury-identifying markers early in the inflammatory process, as well as determine potential therapeutic targets.
  
  
  METHODS
  This cross-over study investigated a potential correlation between overnight contact lens wear and the concentrations of two markers of inflammation, α1-antitrypsin and C-reactive protein, in tear fluid. To obtain baseline measurements, 17 subjects adapted to wearing silicone hydrogel contact lenses wore their prescribed eye glasses for one week, after which tears were collected and ocular health assessed by a licensed optometrist. Subjects then returned to wearing their prescribed silicone hydrogel lenses continuously for one week. A second tear sample was collected and ocular inflammation was again assessed. Enzyme-linked immunosorbent assays were performed on all tear samples for both α1-antitrypsin and C-reactive protein.
  
  
  RESULTS
  α1-antitrypsin was significantly (p = 0.01) elevated after continuous contact lens wear, with increases above baseline concentrations averaging 2.48-fold. Optometric assessment of inflammation loosely correlated with levels of this inflammatory marker. C-reactive protein was detected in the tears of subjects at both times and levels were also slightly elevated after extended lens wear, but not significantly (p > 0.5) and not consistently in all subjects.
  
  
  CONCLUSIONS
  The results of this study suggest that α1-antitrypsin in tear fluid may be useful as an early marker of contact lens-associated ocular irritation and inflammation. The presence of C-reactive protein in the tears of contact lens wearers is a novel finding which, while not correlative with either α1-antitrypsin concentrations or clinically observable inflammation, may warrant further study.
authors.affiliation: Medical Laboratory Sciences Department, Weber State University, Ogden, Utah, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Barrett
authors.forename: Derek
authors.initials: D
authors.lastname: Gnehm
authors.forename: Jordan
authors.initials: J
authors.lastname: Jones
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Trask
mesh_terms: D000210:Acute-Phase Reaction / Q000276:immunology / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D002097:C-Reactive Protein / Q000276:immunology / Q000378:metabolism*; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D007634:Keratitis / Q000209:etiology* / Q000276:immunology / Q000378:metabolism; D008297:Male; D012828:Silicones; D013666:Tears / Q000276:immunology / Q000378:metabolism*; D055815:Young Adult; D000515:alpha 1-Antitrypsin / Q000276:immunology / Q000378:metabolism*
chemical_list: D012828:Silicones; D000515:alpha 1-Antitrypsin; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D002097:C-Reactive Protein
keywords: acute phase proteins; contact lenses; continuous wear; inflammation; tears