The laboratory identification of serum antinuclear antibody in the dog.

An indirect immunofluorescence test with sections of rat liver as a substrate, proved useful in detecting antinuclear antibodies (ANA) in the dog. A specific anti-canine IgG reagent conjugated with fluorescein isothiocyanate was used. A proportion of normal dogs gave positive reactions at low titres. The presence of ANA was one of the criteria used to diagnose canine systemic lupus erythematosus. Some dogs within a general hospital population were also positive for the auto-antibody. The indirect immunofluorescence test with Trypanosoma brucei as a substrate was insensitive. The LE-cell test was laborious and insensitive. A commercial latex slide agglutination test used for detecting ANA in man gave false positive and false negative results in the dog. A commercial radioimmunoassay used in man gave many false positive results. A similar assay with synthetic DNA gave encouraging results and is worthy of further study.