Abstract
Purpose:
To develop an automated approach for the quantification of inflammatory cell infiltration into the conjunctiva in the course of an allergic inflammatory event.
Methods:
The study examined allergen challenge responses in subjects with a history of sensitivity to dust mites using a double-masked, randomized, placebo-controlled protocol. Tears natural II and Prednisolone Phosphate were used as placebo and active test compounds. Entry criteria included both minimal response to allergen challenge and maximal response to a saline (sham) challenge. Test CAC was conducted following 5 days QID dosing of either placebo or active. Evaluation criteria included (1) the number of white cells within the vessel, (2) number of white cells on the vessel walls, and (3) the number of cells in the tissue surrounding the vessel per unit area, following a challenge. There were 13 subjects who completed the study. An algorithm developed using Image J software was used to quantify cells in images captured using an HRT II corneal module confocal microscope. Images were captured immediately pre- and post-challenge, and again at 16 hours post-challenge.
Results:
Counts of cells for all 3 areas of interest were elevated in placebo subjects compared to prednisolone-treated eyes; this difference was statistically significant for cells apparently adhered to the vessel walls at the 16 hour time point. Post-CAC time course of these measures showed that this difference develops for many hours following allergen challenge, demonstrating a chronic response which was prevented by the topical steroid.
Conclusions:
This study demonstrated that delayed time-points such as the 16 hour post-CAC measure may be critical to the use of automated methods going forward. Future efforts may employ time course measures in which inflammation can be tracked from imaging of white cells adhering to vessel walls to the process of diapedesis, and subsequent dispersal of cells into surrounding tissues.
Keywords: 475 conjunctivitis •
468 clinical research methodology •
555 immunomodulation/immunoregulation