Search Results

Abstract

Case Description—A 12-year-old castrated male mixed-breed dog was evaluated because of blepharospasm and blindness affecting both eyes.

Clinical Findings—During examination and diagnostic testing of the dog, fine-needle aspirates of splenic nodules were examined microscopically and stage Vb multicentric large-cell lymphosarcoma was identified. Aqueocentesis was performed, and sample analysis revealed intraocular lymphosarcoma; B-cell neoplasia was confirmed by use of a PCR assay for antigen receptor rearrangement (PARR) performed on samples of aqueous humor. Secondary uveitis and glaucoma were detected bilaterally in addition to chronic superficial corneal ulcerations in the left eye.

Treatment and Outcome—Treatment for abdominal and intraocular lymphosarcoma involving administration of vincristine, l-asparaginase, cyclophosphamide, doxorubicin, and prednisone was initiated. Secondary uveitis and glaucoma were controlled with topical treatment; however, the corneal ulceration did not resolve. Seven weeks following diagnosis, the dog died as a result of complications related to systemic neoplasia and chemotherapy.

Clinical Relevance—In the dog of this report, intraocular lymphosarcoma was diagnosed via PARR performed on samples of aqueous humor. Moreover, the immunophenotype of the neoplastic cells was determined by use of that diagnostic technique. Because secondary uveitis is a common finding in dogs and cats with systemic lymphosarcoma, intraocular lymphosarcoma should be considered as a differential diagnosis; furthermore, investigation (eg, PARR performed on aqueous humor samples) to identify the presence of intraocular lymphosarcoma is warranted, thereby allowing targeted interventions to be considered in management of those patients.

Abstract

Objective—To describe the immunopathologic characteristics of superficial stromal immune-mediated keratitis (IMMK) immunopathologically by characterizing cellular infiltrate in affected corneas of horses.

Animals—10 client-owned horses with IMMK.

Procedures—Immunohistochemical staining was performed on keratectomy samples with equine antibodies against the T-cell marker CD3 and B-cell marker CD79a (10 eyes) and the T-helper cytotoxic marker CD4 and T-cell cytotoxic marker CD8 (6 eyes). Percentage of positively stained cells was scored on a scale from 0 (no cells stained) to 4 (> 75% of cells stained). Equine IgG, IgM, and IgA antibodies were used to detect corneal immunoglobulin via direct immunofluorescence (10 eyes). Serum and aqueous humor (AH) samples from 3 horses with IMMK were used to detect circulating and intraocular IgG against corneal antigens via indirect immunofluorescence on unaffected equine cornea.

Results—Percentage scores (scale, 0 to 4) of cells expressing CD3 (median, 2.35 [range, 0.2 to 3.7]; mean ± SD, 2.36 ± 1.08) were significantly greater than scores of cells expressing CD79a (median, 0.55 [range, 0 to 1.5]; mean, 0.69 ± 0.72). All samples stained positively for CD4- and CD8-expressing cells, with no significant difference in scoring. All samples stained positively for IgG, IgM, and IgA. No serum or AH samples collected from horses with IMMK reacted with unaffected equine cornea.

Conclusions and Clinical Relevance—Pathogenesis of superficial stromal IMMK included cell-mediated inflammation governed by both cytotoxic and helper T cells. Local immunoglobulins were present in affected corneas; however, corneal-binding immunoglobulins were not detected in the serum or AH from horses with IMMK.