Familial PLE and PLN in Soft- coated Wheaten Terriers

A unique clinical syndrome has been reported in Soft-coated Wheaten Terriers.⁵³ Affected dogs may present with signs of PLE, PLN, or both. A genetic basis is likely and, although the mode of inheritance is not yet clear, a common male ancestor has been identified.

Etiology and pathogenesis

The disease is probably immune-mediated, given the presence of inflammatory cell infiltration. Also, a potential role for food hypersensitivity has been suggested, since affected dogs have demonstrated adverse reactions during provocative food trials, and alterations in antigen-specific fecal IgE concentrations.^55,56 However, it can be speculated when considering the concur­rence of intestinal and renal pathology, that this disease is not a failure of tolerance to bacterial antigens, but either a genetic defect in, or an autoimmune reaction to, a common protein / antigen. The brush border membrane of renal tubular cells resembles that of the enterocytes and even digestive enzymes, including the disaccharidases such as sucrase, are expressed in the kidney. Thus this condition is unlikely to remain in the idiopathic IBD category as more research is undertaken.

Clinical signs

Signs of PLE tend to develop at a younger age than PLN, and the clinical signs include vomiting, diarrhea, weight loss, and / or pleural and peritoneal effusions. Affected dogs are also at risk of thromboembolic disease.⁵⁷

Diagnosis

Preliminary laboratory investigations, as in most dogs with PLE, demonstrate panhypoproteinemia and hypocholestero- lemia. In contrast, hypoalbuminemia, hypercholesterolemia, proteinuria, and ultimately azotemia are seen with PLN. On histopathological examination of intestinal biopsies, there is evidence of intestinal inflammation, villus blunting, epithelial erosions, dilated lymphatics, and lipogranulomatous lymphan­gitis.

Treatment and prognosis

Treatment is similar to that described for general IBD (see above) including dietary modification and immunosuppres­sion, but the prognosis is usually poor.

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