Evaluation of a DLA-79 allele associated with multiple immune-mediated diseases in dogs

Large-Scale Polymorphism Analysis of Dog Leukocyte Antigen Class I and Class II Genes (DLA-88, DLA-12/88L and DLA-DRB1) and Comparison of the Haplotype Diversity between Breeds in Japan

Polymorphisms of canine leukocyte antigen (DLA) class I (DLA-88 and DLA-12/88L) and class II (DLA-DRB1) genes are important for disease susceptibility studies, but information on the genetic diversity among dog breeds is still lacking. To better elucidate the polymorphism and genetic diversity between breeds, we genotyped DLA-88, DLA-12/88L, and DLA-DRB1 loci using 829 dogs of 59 breeds in Japan. Genotyping by Sanger sequencing identified 89, 43, and 61 alleles in DLA-88, DLA-12/88L, and DLA-DRB1 loci, respectively, and a total of 131 DLA-88-DLA-12/88L-DLA-DRB1 haplotypes (88-12/88L-DRB1) were detected more than once. Of the 829 dogs, 198 were homozygotes for one of the 52 different 88-12/88L-DRB1 haplotypes (homozygosity rate: 23.8%). Statistical modeling suggests that 90% of the DLA homozygotes or heterozygotes with one or other of the 52 different 88-12/88L-DRB1 haplotypes within somatic stem cell lines would benefit graft outcome after 88-12/88L-DRB1-matched transplantation. As previously reported for DLA class II haplotypes, the diversity of 88-12/88L-DRB1 haplotypes varied remarkably between breeds but was relatively conserved within most breeds. Therefore, the genetic characteristics of high DLA homozygosity rate and poor DLA diversity within a breed are useful for transplantation therapy, but they may affect biological fitness as homozygosity progresses.

Genetics of canine diabetes mellitus part 2: Current understanding and future directions

Part 1 of this 2-part review outlined the importance of disease classification in diabetes genetic studies, as well as the ways in which genetic variants may contribute to risk of a complex disease within an individual, or within a particular group of individuals. Part 2, presented here, describes in more detail our current understanding of the genetics of canine diabetes mellitus compared to our knowledge of the human disease. Ongoing work to improve our knowledge, using new technologies, is also introduced.

Therapeutic Strategies for Treatment of Immune-Mediated Hemolytic Anemia

Immune-mediated hemolytic anemia is a common hematologic disorder in dogs. Disease management involves immunosuppression using glucocorticoids, potentially in combination with other medications such as azathioprine, cyclosporine, or mycophenolate mofetil. Therapeutic drug monitoring may enhance the utility and maximize the safety of cyclosporine and mycophenolate mofetil. The disease is proinflammatory and prothrombotic. Antithrombotic drug administration is therefore essential, and anticoagulant therapy should be initiated at the time of diagnosis. Additional therapies include red blood cell transfusion to support blood oxygen content. Future therapies may include therapeutic plasma exchange, anti-CD20 monoclonal antibodies, and complement inhibitors.

Evolution of major histocompatibility complex class I genes in the sable Martes zibellina (Carnivora, Mustelidae)

The molecules encoded by major histocompatibility complex (MHC) genes play an essential role in the adaptive immune response among vertebrates. We investigated the molecular evolution of MHC class I genes in the sable Martes zibellina. We isolated 26 MHC class I sequences, including 12 putatively functional sequences and 14 pseudogene sequences, from 24 individuals from two geographic areas of northeast China. The number of putatively functional sequences found in a single individual ranged from one to five, which might be at least 1-3 loci. We found that both balancing selection and recombination contribute to evolution of MHC class I genes in M. zibellina. In addition, we identified a candidate nonclassical MHC class I lineage in Carnivora, which may have preceded the divergence (about 52-57 Mya) of Caniformia and Feliformia. This may contribute to further understanding of the origin and evolution of nonclassical MHC class I genes. Our study provides important immune information of MHC for M. zibellina, as well as other carnivores.

The utility of diagnostic tests for immune-mediated hemolytic anemia

BACKGROUND

A definitive diagnosis of immune-mediated hemolytic anemia (IMHA) can be difficult to make. However, it is critical to differentiate IMHA from other causes of anemia due to the impact on prognosis and outcome for IMHA patients. Recently published American College of Veterinary Internal Medicine recommendations for the diagnosis of IMHA should be followed to concurrently confirm ongoing anemia, verify in vivo hemolysis, and detect anti-erythrocyte antibodies. The reliability of immunologic IMHA tests varies depending on which test is used and how it is performed.

OBJECTIVES

Our aims were to determine which tests are currently used in veterinary medicine to diagnose IMHA and review the utility of assays that have historically been used to diagnose IMHA.

METHODS

A short survey was designed to see which diagnostic tests for IMHA were currently being used by veterinary practices. The survey was distributed via list-serves to veterinarians and veterinary technologists. A literature review was performed to report the utility of diagnostic tests for the diagnosis of IMHA.

RESULTS

Survey respondents indicated a variability in test protocols used to diagnose IMHA. Most respondents perform saline agglutination or Coombs' tests to detect anti-erythrocyte antibodies. Additional tests that can be used to support a diagnosis of IMHA are discussed in this review.

CONCLUSIONS

A standardized diagnostic approach should be followed to differentiate IMHA from other causes of anemia. Test methodology can vary from one laboratory to another, and clinicians should be familiar with the procedures used by their laboratory.

Primary immune-mediated haemolytic anaemia: a retrospective long-term study in 61 dogs

OBJECTIVES

The objective of this study is to describe the course of disease of dogs with primary immune-mediated haemolytic anaemia (pIMHA) with an observation period longer than 90 days in regard to clinical signs, laboratory results and treatment response.

MATERIAL AND METHODS

Clinical records between January 2003 and December 2011 were reviewed. Diagnosis of pIMHA was based on the presence of haemolytic anaemia with a packed cell volume of <0.35 L/L, a positive Coombs' test and/or erythrocyte agglutination, spherocytosis and exclusion of an underlying disease. Included were dogs which could be monitored for more than 90 days after initial presentation.

RESULTS

Sixty-one dogs with pIMHA were included. The initial packed cell volume ranged from 0.08 to 0.30 L/L (median 0.16). Immunosuppressive treatment included prednisolone in all the cases; 32 dogs successively received cyclosporine (28), cyclophosphamide (5), leflunomide (2) or human intravenous immunoglobulins (2) in addition. In 33/61 dogs, the drugs were discontinued 67-3372 days (median 334) after beginning of therapy; in 28 dogs, the drug dosage was reduced, but not discontinued until the end of the study. Three dogs developed immune-mediated thrombocytopenia (days 132, 156 and 680). The observation period ranged from 96 to 4147 days (median 628). A total of 22.9% (14/61) of the dogs developed a relapse after 94-3972 days (median 517). Five dogs were euthanased due to a relapse after 96-1188 days (median 628).

CLINICAL SIGNIFICANCE

Long-term prognosis in dogs with pIMHA is favourable. However, a relapse can occur after many years. Relapse was the most common cause of death in dogs with pIMHA that survive more than 90 days.

Urban environment: a risk factor for canine immune-mediated disease?

OBJECTIVES

To investigate whether dogs living in urban areas are more likely to develop immune-mediated disease than those in rural areas.

MATERIALS AND METHODS

A case-control study comparing the prevalence of urban home location between dogs with immune-mediated disease and matched controls. Dogs diagnosed with immune-mediated haemolytic anaemia, immune-mediated thrombocytopenia, immune-mediated polyarthritis or meningoencephalomyelitis of unknown origin were identified by case record searches. Breed-matched dogs presenting to the same hospital during the same year as cases were randomly selected as controls. Home locations were classified as rural or urban using the population density of the relevant census tract and conditional logistic regression was used to examine association between home location and immune-mediated disease.

RESULTS

In the 137 cases and 137 breed-matched controls, the odds ratio for any immune-mediated disease for dogs living in urban (versus rural) areas was 0·94 (95% confidence interval 0·58 to 1·55, P=0·80). Odds ratios for development of immune-mediated haematological diseases, immune-mediated polyarthritis or meningoencephalomyelitis of unknown origin were also not significantly different from the null value. Multivariable analysis including age, gender and season of presentation did not suggest confounding of effect of home location by these additional variables.

CLINICAL SIGNIFICANCE

This study does not support an association between urban environment and immune-mediated disease in dogs.