Cyclic hematopoiesis

What is ... ?: 

 This disorder of the immune system occurs in gray collies. Puppies are usually smaller and weaker than their littermates and by 8 to 12 weeks of age they develop clinical signs such as fever, diarrhea or joint pain, or other signs associated with eye, respiratory, or skin infections.

The disorder is caused by an abnormality of the stem cells in the bone marrow, from which all blood cells develop. The result is a cyclic fluctuation in blood cell numbers. Every 10 to 12 days, the number of neutrophils drops dramatically, and then rebounds. There is increased susceptibility to infection corresponding to the dip in neutrophil numbers. As well, the normal activity of the neutrophils is impaired. These dogs are also prone to bleeding episodes due to the drop in platelet numbers.

How is ... inherited?: 

The mode of inheritance is autosomal recessive. Both parents must carry the abnormal gene for the offspring to be affected.

What does ... mean to your dog & you?: 

 This is a serious disorder. These dogs are subject to severe recurring bacterial infections, primarily of the respiratory or gastrointestinal tract. Even with the best of care, affected dogs rarely live beyond 2 or 3 years of age.

How is ... diagnosed?: 

 Affected dogs have a light silver gray, possibly mixed with light beige, hair coat and a characteristic light coloured nose. Pups usually experience clinical illness by 8 to 12 weeks of age and are brought to the veterinarian at that time, if the breeder does not recognize the defect before then.

The disorder is diagnosed based on the cyclic fluctuation in blood cell numbers, as well as the characteristic coat coloration.

How is ... treated?: 

 Other than bone marrow transplantation, which is impractical, there is no effective treatment. Without supportive care, pups usually die before 6 months of age. Even with the best of care, including very close monitoring and antibiotics to counteract the variety of infections, these dogs usually die before 2  or 3 years of age.

For the veterinarian: 

 Cyclic neutropenia occurs every 10 to 12 days, persists 2 to 4 days, and is followed by a rebound neutrophilia (during which infections resolve). Other hematologic abnormalities include non-regenerative anemia, and cyclic reticulocytosis, monocytosis, and thrombocytosis. Even with optimal care, affected animals usually die before 2 to 3 years of age due to hepatic or renal failure associated with amyloidosis.

Breeding advice: 

 Parents and littermates of affected dogs should not be used for breeding, to avoid perpetuating this lethal defect.


 Felsburg, P.J. 1992.  Primary immunodeficiencys. In   R.W. Kirk and J.D. Bonagura (eds), Current Veterinary Therapy XI Small Animal Practice, p.448-453.  WB Saunders Co., Toronto. This has information on primary immunodeficiencies, including general information on management of animals with immunodeficiency diseases

What breeds are affected by ... ?