Combined Immunodeficiency
The classic combined immunodeficiency (CID) condition occurs in humans and Arabian horses. The horse defect has a frequency of greater than 2% and is inherited as an autosomal recessive trait.

Combined immunodeficiency is occasionally reported in dogs. The first report involved a family of long-haired Dachshunds in Australia. Affected dogs developed fatal Pneumocystis carinii pneumonia between 9 and 12 months of age. More recently a family of basset hounds has been described with a form of CID of sex-linked inheritance. Affected dogs are prone to infections especially of Mycobacterium (tuberculosis) and other bacterial and viral diseases. These dogs produce only IgM immunoglobulins, have low lymphocyte counts, and die at a young age.

Selective IgA Deficiency
Selective IgA deficiency was reported in a large breeding kennel of Beagles and is also commonly seen in the Chinese shar pei and German shepherd breeds. The beagles had chronic recurrent respiratory tract infections with Bordetella, parainfluenza virus, and parvovirus despite proper vaccination for these diseases. Chronic ear infections and dermatitis were also present, and occasionally animals developed seizures. Each of these clinical manifestations occurs with human IgA deficiency. Serum levels of IgA are undetectable or very low whereas other immunoglobulins and T-cell function are normal. Respiratory infections in these dogs are attributed to inadequate secretory IgA levels at mucosal surfaces.

As many as 80% of all Chinese shar peis have IgA deficiency. A survey of 278 dogs of 32 common breeds with suspected immunodeficiency found 56% of them to have selective IgA deficiency. Clinical signs were similar to those of the Beagles studied. These dogs also had recurrent staphylococcal dermatitis, demodectic mange, thyroid disease, otitis externa, flea allergy, cystitis, food intolerance, bronchitis, and atopy.

Growth Hormone And Immune Deficiency
This condition was described in a colony of inbred Weimaraners with congenital growth hormone deficiency, a small thymus, and depletion of T- lymphocytes. Affected dogs are immunodeficient dwarfs that exhibit a wasting disease, unthriftiness, recurrent infections, and retarded growth. A parallel syndrome is recognized in immunodeficient dwarf mice. When treated with bovine growth hormone or a thymus gland extract (thymosin), affected pups responded dramatically by growing and developing normal T- cell lymphocyte responses.

Lethal Acrodermatitis
An autosomal recessive condition of English bull terriers, acrodermatitis results from impaired absorption and metabolism of zinc. Affected pups are lighter in color at birth and develop diarrhea and recurrent respiratory tract and skin infections. The foot-pads become crusty and crack, nails are incompletely formed, and purulent dermatitis affects the feet and body orifices. Skin biopsies show characteristic changes of zinc deficiency. Impaired T-cell function occurs and serum zinc levels are usually low. Zinc supplementation does not appear to help and affected animals usually die by 15 months of age.

References: Halliwell and Gorman, Vet Clin Immun, Philadelphia, WB Saunders. 1989; Campbell, Canine Pract. 16(4):7-11, 1991; Vaden et al, JAAHA 27:633-640, 1991; Dodds. Vet Pract STAFF 4(5): 19-21,1992; Dodds, Clin Tech Sm An Pract, 17(1); 58-63, 2002.