An immunopathological study of deep pyoderma in the dog.

The numbers of T lymphocytes (expressing the CD3 marker) and B lymphocytes/plasma cells (expressing IgG, IgM or IgA) in normal canine skin and infiltrating the lesions of deep pyoderma in seven German shepherd dogs and four dogs of other breeds are compared. All dogs with deep pyoderma had similar numbers of IgG, IgM and IgA bearing B lymphocytes/plasma cells but there was a marked paucity of T lymphocytes within the affected skin of German shepherd dogs when compared with that of dogs from other breeds. This suggests a role for T cell dysfunction in the pathogenesis of deep pyoderma in the German shepherd dog.