Absence of antinuclear antibodies in dogs infected with Ehrlichia canis
Kelly, P.J.; Carter, S.D.; Bobade, P.A.; Matthewman, L.A.; Bell, S.C.
Veterinary Record 134(15): 382
1994
ISSN/ISBN: 0042-4900 PMID: 8009803 Document Number: 431020
Serum samples from 40 dogs in Zimbabwe with serological evidence of E. canis infection (indirect fluorescent antibody test titres to E. canis antigen >1/20) were tested for antinuclear antibodies (ANA) using direct fluorescent antibody testing on frozen rat liver sections. A positive control serum obtained from a case of previously documented systemic lupus erythematosus (SLE) was also used in the test. The sera were initially screened at a 1/10 dilution in phosphate buffered saline (pH 7.3). Reactive sera were subsequently tested at doubling dilutions. A positive ANA titre of 1/80 with a diffuse homogeneous staining pattern was found on only one dog, a 3-year-old German Shepherd bitch. The dog showed no abnormalities on physical examination and had normal biochemistry values. Routine haematological tests were normal except for leucopenia (5.4 x 109/litre) as a result of neutropenia (3.3 x 109/litre).The dog was lost to follow-up. These results showed that there was a low prevalence of ANA in these dogs suggesting that ANA are not important in the pathogenesis of canine ehrlichiosis. Also, since many of the clinical signs associated with canine ehrlichiosis are similar to those of SLE, ANA testing may be helpful in the differentiation of the two conditions.