Spontaneous familial systemic lupus erythematosus in a canine breeding colony

A colony of German shepherd dogs was studied in which a high proportion of antinuclear antibody (ANAb) carriers and dogs with systemic lupus erythematosus (SLE)-like signs were found. The titre of serum thymulin and the percentage of circulating T lymphocytes were both low. The incidence of disease decreased down the generations through the introduction of outside sires, thus suggesting a genetic origin for the disease.