Report on the evaluation of the prevalence of anti-neutrophilic cytoplasmic auto-antibodies (pANCA) in the population of Soft Coated Wheaten Terriers in the United Kingdom.
This study was supported by a grant from the Kennel Club Charitable Trust
Barbara Haesler, Amanda Craig, Barbara Wieland, Carolina Mancho-Alonso, Cathryn Mellersh and Karin Allenspach
Approximately 10% of the population of Soft Coated Wheaten Terriers (SCWT) in the USA and an unreported percentage in the UK develop either protein-losing enteropathies and/or protein-losing nephropathies at an average age of 4-6 years.
The detection of pANCA (perinuclear anti-neutrophilic cytoplasmic antibodies) is a serum test based on evaluation of antibodies which can be easily assessed from about 1ml of whole blood. This test has been
evaluated in a group of 22 SCWT in the USA which were tested for pANCA every 6 months.
The interesting fact is that the positive pANCA result was seen on average 2-3 years before the dogs showed any signs of illness. This means that the pANCA serum test could be
useful in identifying subclinical cases before they become ill. These dogs could then receive early treatment and their participation in a breeding program could be reviewed early in their life.
Our study aimed to estimate how many SCWT in the UK are pANCA positive by obtaining and testing blood samples from a random sample of approximately 200 dogs. Moreover, we
want to find out if pANCA can serve as an early test for the detection of subclinical cases of protein-losing diseases in SCWT and if heritability patterns in the breed can be detected.
In 2007, Dr. Karin Allenspach and her veterinary research team organised 5 blood sampling sessions with the great support of the Soft Coated Wheaten Terrier Club of Great Britain
and the Wheaten Health Initiative. All of these sessions were organized with the help of the Clinical Investigations center at the RVC. In addition, 9 blood samples could be taken
from dogs that were referred to the Queen Mother Hospital or were taken at the local vets and then sent to the Royal Veterinary College in Hawkshead, Hatfield.
In total, 189 dogs could be sampled and tested (Table 1).
Table 1 : Number of dogs sampled and tested for the pANCA study in 2007
Session |
Location |
no's of dogs |
3 June 2007 |
Weedon Bec, Northampton |
31 |
1 July 2007 |
St. Leonard's Church Hall, Oxon |
37 |
5 August 2007 |
Weedon Bec, Northampton |
46 |
23 September 2007 |
Hasland, Derbyshire |
36 |
11 November 2007 |
Highworth, Wiltshire |
30 |
Whole year |
Royal Veterinary College/Local Vet |
09 |
Total |
|
189 |
In the laboratory, samples were centrifuged within 1 hour and serum was harvested and dispensed into plastic vials. Serum aliquots were properly identified and stored frozen at -20ºC
until testing. The 189 samples were then tested for detection of perinuclear anti-neutrophilic cytoplasmic auto-antibodies (pANCA) using immunofluorescence, a method that allows to
label antibodies with fluorescent dyes. Additionally, serum concentration of albumin was measured to estimate the prevalence of occult protein-losing disease, as a decreased
serum albumin concentration is a sensitive indicator of possible protein-losing disease.
Of the 189 dogs tested:
150 were pANCA negative (79.4%) and 39 were pANCA positive, (20.6%).
Figure 1 shows the age distribution of the tested dogs: Among the negative dogs, 50 were < 4 years and 98 were ≥ 4 years (age of 2 dogs unknown); among the positive dogs,
11 were < 4 years and 27 were ≥ 4 years (age of 1 dog unknown).
Figure 1 : Number of pANCA negative and positive dogs with their age distribution
Serum albumin is produced in the liver and has important biological functions, such as blood volume regulation or transport of certain substances (e.g. fatty acids or hormones) in the blood.
It is important to measure serum albumin concentrations as if this parameter is decreased, then this may be an early indicator of protein losing diseases. However, serum
albumin concentrations above the reference range occur frequently in healthy dogs and could just be related to dehydration on the day of serum sampling.
The reference range for albumin in dogs in our laboratory is 28-39g/l. Among the tested dogs, 146 had normal albumin levels. Among the negative dogs, 5 (3.6%) were found to have
decreased and 21 (14.1%) to have increased albumin levels. Among the positive dogs, 1 2.6%) had decreased and 15 (38.5%) increased albumin levels (Table 2).
Table 2 : Albumin levels of pANCA negative and positive dogs. Reference range: 28-39g/l.
Albumin - dogs | < 28g/l
| 28-39g/l
| > 39g/l
| Total |
Negative |
5 (1) |
123 |
21 |
149(2) |
Positive |
1 |
23 |
15 |
39 |
Total |
6 |
146 |
36 |
188 |
1. Borderline albumin levels, i.e. between 27 and 28g/l.
2. One albumin result was missing
The pANCA results as well as the albumin levels have been communicated to the owners either by mail or email.
In a next step, we would like to follow up about 80 pANCA negative dogs longitudinally, i.e. we plan to test them in 6 months intervals over the next 1-2 years to see if they stay negative.
Additionally, we would like to re-test all positive dogs to confirm the positive results and to monitor the dogs’ disease status over time.
This will help us to asses if there is a link between pANCA results and the later development of protein-losing disease in SCWTs. The longitudinal study will require repeated testing of
the dogs (free of charge) either through attendance at a day testing session or through blood collection by private veterinarians and subsequent postage of the sample to the Royal Veterinary College.
Dr. Karin Allenspach and her research team are currently contacting the owners of both negative and positive SCWT by phone to recruit as many dogs as possible
for the follow-up study. The first follow-up testing session is envisaged to take place in May 2008.
Despite the unknown cause of protein-losing enteropathy and nephropathy, it is believed that there is a familial inheritance in the SCWT. Over the next months, we will examine the pedigrees
of affected dogs to check if there is a familiar pattern of genetic inheritance in the breed.
We would like to thank all participating owners and their dogs for their willingness to help us with our research as well as acknowledge the help of the Clinical Investigations centre at the RVC.
In addition, we would like to thank the Kennel Club Charitable Trust for supporting the study.
We would also like to thank the Soft Coated Wheaten Terrier Club of Great Britain and Wheaten Health Initiative, without their help this study would not have been possible.
We are determined to further investigate protein-losing diseases in the SCWT in order to eliminate these diseases in the future and are convinced that our preliminary investigations represent a first step towards this goal.
Royal Veterinary College, March 2008
Dr. Karin Allenspach, Med. Vet., PhD, DECVIM-CA
Lecturer in Internal Medicine