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CANINE IgA DEFICIENCY

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Iga Deficiency
What is Selective Iga Deficiency

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IgA Deficiency

INHERITED IMMUNODEFICIENCY DISEASES IN DOGS AND CATS

This information is provided by Provet for educational purposes only.
You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.
Several inherited immunodeficiency diseases have been reported to occur in animals as well as in humans

The following congenital diseases cause immunodeficiency :
Canine Leucocyte Adhesion Deficiency / Canine Granulocytopathy Syndrome

Canine granulocytopathy syndrome (now called canine leucocyte adehesion deficiency) has been reported to be an inherited autosomal recessive trait in Irish Setters and the condition has been reviewed recently in a report (Trowald-Wigh G. et al Journal of Small Animal Practice (2000) Vol41 p211-217).

With this disorder neutrophils have impaired phagocytosis and have impaired ability to kill bacteria due to lack of adhesion proteins (integrins CD11b/CD18,  b2-integrins). Deficiency of these proteins prevents leucocytes from leaving blood vessels - so poor numbers are found in tissues even though large numbers are present in the blood - and renders them unable to phagocytose bacteria opsonised by fragment C3b.

The age of onset of problems is 2-4 months and clinical signs reported include :
Post-natal infection of the umbilicus (called omphalophlebitis)
Inappetance (anorexia)
Gingivitis
Lymph node enlargement
High white blood cell (neutrophil) count. Over 200,000mm3 has been reported.
Metaphyseal osteodystrophy - radius and ulna
Craniomandibular osteopathy
Osteomyelitis
Respiratory disease including interstitial pneumonia
Poorly healing skin wounds

These cases are difficult to treat and most animals are euthanased before they are 6 months of age.

Chediak-Higashi Syndrome
Chediak-Higashi Syndrome is caused by giant lysosomes forming in cells - including leucocytes. It has been reported to occur in blue Persian cats, Hereford cattle and other species.

Clinical signs include :
Dilution of hair colour
Albinism (coat and iris)
Photophobia
Haemorrhages - due to abnormal platelets.
Increased susceptibility to infection - due to impaired chemotaxis, and reduced hexose monophosphate activity.
In blue Persians the coat becomes lighter, the iris changes colour from copper or gold to yellow/light green and the retina loses pigment. Congenital cataracts may be present. 

Combined Immunodeficiency
Combined B-cell and T-cell immunodeficiency is extremely serious and life-threatening. Combined immunodeficiency has been reported in long-haired dachshunds and in basset hounds. Clinical signs

Severe respiratory tract infections
Premature death   

Complement (C3) Deficiency
Complement fragment C3b is an opsonin which coats bacteria surfaces rendering them susceptible to phagocytosis. C3 deficiency results in affected individuals being unable to opsonize bacteria, making affected individuals susceptible to severe bacteraemias. Complement C3 deficiency has been reported to be an autosomal recessive trait in Brittany Spaniels. C3 concentrations in heterozygotes are about 50% of the normal amount, but individuals do not show clinical signs. Homozygous individuals have C3 concentrations of only 0.003% normal and  show typical signs of immunodeficiency with bacterial infections, septicaemia, and death. Clostridia and gram-negative bacteria are usually involved. 

Cyclic Haematopoiesis of Grey Collies
This is a cyclic disorder of the bone marrow resulting in low neutrophil counts, and these neutrophils also have impaired bactericidal activity due to altered intracellular biochemical activity including reduced myeloperoxidase activity and impaired iodination of ingested protein . The precise mechanism that causes this disorder is not known but it is an autosomal recessive trait.

Clinical signs include :
Severe, recurrent bacterial infections
Haemorrhages - due to low platelet counts
Respiratory infections
Gastrointestinal infections
Infection of the umbilicus  
Death - neonatal or within 3 years.  
Affected animals can be successfully treated with a normal bone marrow transplant and lithium carbonate has been reported to be a successful treatment restoring cell counts to normal ....but it must be given continually.

Growth hormone deficiency
Immunodeficiency has been reported in a litter Weimaraners which were deficient in growth hormone and had low T-cell lymphocytes.

Clinical signs included :
Recurrent severe infections
Poor growth rate and condition
Treatment with bovine growth hormone was successful.

A line of German Shepherd Dogs have also been reported to have  this disorder and it is an autosomal recessive inherited defect.

IgA Deficiency
A genetic defect resulting in IgA deficiency has been reported to occur in Beagles, Shar Peis and German Shepherd Dogs..

Clinical signs include :
Recurrent respiratory tract infections (eg Bordatella bronchiseptica)
Dermatitis (staphylococcal infections, demodex)
Parvovirus infection (despite vaccination)
Seizures
Bacterial overgrowth in the intestine of German Shepherd Dogs ?
The defect occurs because in affected individuals B-cell lymphocytes fail to develop into plasma cells which synthesise and secrete IgA. 

Lethal Acrodermatitis in Bull Terriers
In affected individuals impaired T-cell function results from an autosomal recessive trait for abnormal zinc absorption and metabolism.

The zinc deficiency and immunodeficiency causes a variety of signs :
Dilution of coat colour
Recurrent respiratory tract infections
Skin disease - footpad cracks, paronechia, dermatitis with crusting  of the feet and around mucocutaneous junctions.
This condition does not respond to zinc supplementation because the animal can not absorb or utilise it properly and affected puppies die by 15 months of age.

Pelger-Huet Anomaly
In this condition the neutrophils and eosinophils have round nuclei due to incomplete nuclear segmentation and they may be described as "juvenile" on laboratory examination.. The disorder is an autosomal dominant trait that has been reported to occur in foxhounds other dogs eg Basenji, and domestic short-haired cats.

Clinical signs include :
Neonatal deaths
Lower litter sizes surviving to weaning than normal dogs.     
Copyright (c) 1999 - 2007 Provet. All rights reserved. Email: info@provet.co.uk   
reprinted with kind permission from Mike Davies Provet Limited

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What is selective IgA deficiency?
Immunoglobulins are proteins that function as antibodies and thus, provide immune protection. Immunoglobulin A (IgA) is important in protecting body surfaces, which include the skin, and the respiratory, digestive and reproductive tracts.

Dogs with IgA deficiency are prone to recurrent infections and the development of allergies (eg. atopy or food allergies) or immune-mediated diseases.

How is selective IgA deficiency inherited?
unknown.

What breeds are affected by selective IgA deficiency?
Chinese shar-pei, beagle, German shepherd

For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.

What does selective IgA deficiency mean to your dog & you?
Dogs with IgA deficiency usually have problems from a young age. They may have recurring skin, respiratory, gastrointestinal or urinary tract infections. The typical signs you might see include pustules and scratching, sneezing or nasal discharge, prolonged or recurring diarrhea, frequent or painful urination (cystitis - bladder infection).

These dogs are also prone to develop allergies or immune-mediated disorders.

How is selective IgA deficiency diagnosed?
Your veterinarian may suspect an immune deficiency if your dog is having recurring or frequent infections, especially of the skin.  S/he will take a blood sample to measure your dog's immunoglobulin levels, which will show reduced or absent IgA.

For the veterinarian: Serum IgA levels are low in all puppies, but by 4 months have reached levels where normal and IgA deficient dogs can be differentiated. However serum IgA only reaches maximal levels at 15 to 18 months of age, so it is important to age match when comparing.

Low IgA levels may be found in clinically normal dogs (who likely have normal secretory levels but not serum levels). IgG and/or IgM may be elevated in a compensatory manner. IgA deficiency diagnosed in dogs less than a year of age may be transient.

How is selective IgA deficiency treated?
The various infections, allergies, or autoimmune disorders associated with IgA deficiency are treated as required. Different treatments to stimulate the immune system itself have been tried with varying success.

For the veterinarian: Staphylococcal phage lysate and Propionibacterium acnes vaccine are 2 immunomodulating agents which have been shown to enhance antibody production, and assist in the treatment of recurrent staphylococcal pyodermas in dogs.

Breeding advice
Affected animals should not be bred, and it is prudent to avoid breeding close relatives as well.
FOR MORE INFORMATION ABOUT THIS DISORDER, PLEASE SEE YOUR VETERINARIAN.

Copyright © 1998 Canine Inherited Disorders Database. All rights reserved.Revised: July 23, 2001.
This database is a joint initiative of the Sir James Dunn Animal Welfare Centre at the Atlantic Veterinary College, University of Prince Edward Island, and the Canadian Veterinary Medical Association.
reprinted with kind permission from:-
 Alice Crook, DVM,Coordinator, Sir James Dunn Animal Welfare Centre, Atlantic Veterinary College,University of Prince Edward Island, 550 University Ave.Charlottetown, PEI C1A 4P3
http://www.upei.ca/cidd

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The above information is simply informational. It's intent is not to replace the advice of a veterinarian nor to assist you in making a diagnosis of your pet. Please consult with your own veterinarian for confirmation of any diagnosis. Your pets life may depend on it.