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Published on: May 6, 2016
Immunohistochemical investigation of canine episcleritis
Carrie B Breaux1, Lynne S Sandmeyer, Bruce H Grahn
1Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5B4, Canada.
Insights
Canine episcleritis and nodular granulomatous episclerokeratitis (NGE) require different treatment approaches. Biopsies reveal that a higher percentage of B lymphocytes in lesions needing ongoing therapy indicates a poorer prognosis for resolution.
Area of Science:
- Veterinary Ophthalmology
- Immunohistochemistry
- Canine Pathology
Background:
- Episcleritis and nodular granulomatous episclerokeratitis (NGE) are common ocular inflammatory conditions in dogs.
- Understanding the inflammatory cell infiltrate is crucial for predicting therapeutic outcomes.
Purpose of the Study:
- To identify macrophages, B cells, and T cells in canine episcleral biopsies.
- To correlate inflammatory cell presence with clinical presentation and treatment success.
Main Methods:
- Immunohistochemistry was used to label macrophages (CD18), B cells (CD79a), and T cells (CD3) in archived canine episcleral biopsies.
- Cell counts were performed, and clinical data including signalment, duration of illness, affected eyes, treatment, and outcome were reviewed.
- Dogs were grouped by clinical presentation: unilateral episcleritis, bilateral episcleritis, or NGE.
Main Results:
- Twenty-four cases (19 episcleritis, 5 NGE) were analyzed.
- Unilateral episcleritis cases had a better prognosis (50% resolution) compared to bilateral episcleritis and NGE, which often required long-term therapy.
- A significantly higher percentage of B lymphocytes was found in lesions requiring ongoing medical therapy for remission (P = 0.0471).
Conclusions:
- NGE and bilateral episcleritis have a poor prognosis for resolution without long-term medical management.
- The inflammatory cell profile, particularly the proportion of B lymphocytes, differs significantly between resolving and persistent episcleritis cases.
Objectives:
To identify macrophages, B cells and T cells in archived canine episcleral biopsies and to correlate these findings with the clinical presentation and therapeutic outcome.
Procedures:
Archived formalin-fixed biopsies were immunohistochemically labeled for CD18, CD79a, and CD3 to identify macrophages, B cells and T cells, respectively. Slides were digitally photographed and positive cells were manually counted. Signalment, duration of illness, affected eye(s), treatment, and therapeutic outcome were reviewed for each dog. Dogs were divided into groups based on clinical presentation (unilateral episcleritis, bilateral episcleritis or nodular granulomatous episclerokeratitis (NGE).
Results:
Twenty-four cases were evaluated. There were 19 episcleritis (13 unilateral, six bilateral) and five NGE cases. The mean age for clinical manifestations of unilateral episcleritis was 6.8 years, bilateral episcleritis was 8.7 years, and NGE was 3.8 years. The Cocker Spaniel was over-represented in the episcleritis groups. All NGE cases were Collies. Approximately 50% of the unilateral episcleritis cases resolved and did not require long-term therapy. Almost all cases of bilateral episcleritis and NGE required continuous medical therapy to maintain remission. There was a significantly higher percentage of B lymphocytes in biopsies from lesions that required ongoing medical therapy to maintain lesion remission than in the lesions that resolved, and for which medications were discontinued (P = 0.0471).
Conclusions:
The prognosis for resolution of NGE and bilateral episcleritis without long-term medical therapy is poor. There is a significant difference in the inflammatory cell population in episcleritis that resolved with medical therapy vs. episcleritis that required ongoing medical therapy.
