Abstract
Purpose: :
To compare the intracellular expression of ICAM-1 in the conjunctival epithelial cells of atopic individuals in an asymptomatic baseline state and 24 hours after an allergen challenge.
Methods: :
Nine volunteers with history of ocular allergy were recruited through advertisement. Informed consent was obtained. A complete eye examination including slit lamp and funduscopy were conducted to exclude individuals with any other ocular disease. Clinical manifestations of allergy were documented and the minimum dose required to elicit an inflammatory response was established. A week later, an impression cytology sample was collected when the subjects were asymptomatic and had normal clinical examination. A porous filter paper was used to scrape the bulbar conjunctiva . Cytospin slides were made from the specimen. Slides were stained using Fluorescein isothiocyanate (FITC) conjugated anti-ICAM-1 monoclonal antibody. Propidium Iodide was used as the counter stain. Digital images of the slides were obtained utilizing an Upright Epifluorescence Microscope equipped with a Nikon DXM1200 color CCD camera. A semi-quantitative visual scoring scale was utilized. Immediately following the baseline sample collection, patients were challenged with the previously established allergen dose. Twenty-four hours later another impression cytology sample was obtained and stained and studied in the same manner. Staining intensity was compared in the two samples.
Results: :
ICAM-1 was present in the baseline impression cytology specimen as measured by semi-quantitative analysis of the digital images. There was a marked increase in the staining intensity at the 24 hour post allergen challenge specimen. ICAM-1 expression was increased at 24 hours compared to baseline by a magnitude of three fold by semi-quantitative visual score.
Keywords: conjunctivitis • cell adhesions/cell junctions • inflammation