Autoantibodies against cell nuclei

The detection of anti-nuclear antibodies (ANA) is an important diagnostic indicator in many autoimmune diseases. ANA are directed against various cell nuclear components. These encompass nucleic acids, cell nuclear proteins and ribonucleoproteins.

Autoimmune diseases such as systemic lupus erythematosus (SLE) and lupus-associated diseases are also found in dogs. Clinical symptoms of SLE in dogs include non-erosive polyarthritis, skin lesions, fever of unknown origin, glomerulonephritis, haemolytic anaemia, thrombocytopenia, polymyositis and neurological manifestations.

ANA occur in almost all (97 % to 100 %) dogs with SLE, often at high titers. Healthy animals and dogs with infections (e.g. Bartonella vinsonii, Ehrlichia canis or Leishmania infantum) or other diseases can exhibit low titers of ANA. In mild courses of discoid or cutaneous lupus erythematosus (skin symptoms without systemic manifestation) the detection of ANA is negative in most cases. In dogs, as in humans, positive ANA results and/or reversible SLE symptoms may occur after treatment with some drugs such as anticonvulsants (e.g. phenytoin), antiarrhythmics (e.g. procainamide), antihypertensives (e.g. hydralazine), the antimycotic agent griseofulvin and some antibiotics (e.g. tetracyclines).

Some dog breeds seem to be predisposed to develop SLE and lupus-associated diseases. In several studies, German shepherds were overrepresented (32 % to 47.6 %), as were e.g. Nova Scotia Duck Tolling Retrievers. These breeds frequently suffer from immune-mediated rheumatic disease (IMRD) and steroid responsive meningitis arteritis (SRMA).

Indirect immunofluorescence using HEp-2 cells is currently the method of choice for the detection of ANA in dogs. HEp-2 cells are even superior to canine cell lines or organ sections. A granular fluorescence pattern with negative chromosomal region in mitotic cells occurs most frequently (75 %) and is seen most often in dogs with diseases of the musculoskeletal system, lethargy and/or fever. The homogeneous fluorescence pattern, which is characterised by mitotic cells with a fluorescing chromosomal region, is found more rarely (25 %). This pattern is characteristic of animals with systemic manifestations and symptoms such as anaemia, diseases of the musculoskeletal system, fever, skin lesions and polyuria. In both cases the interphase nuclei can show a granular or spotted pattern.

• HEp-2 IIFT Dog (IgG)

¹ The test can also be used for cats by exchanging the conjugate for anti-cat IgG.