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Immunodeficiency Syndromes, Dog 531

Immunodeficiency Syndromes, Dog
VetBooks.ir Clinical Presentation Diseases and Disorders

BASIC INFORMATION
HISTORY, CHIEF COMPLAINT able to synthesize IgM, but IgG concentra-
tions are significantly reduced, and IgA is
Definition • Recurrent infections seen at a young age not detectable.
Primary immunodeficiency syndrome: an that may or may not respond to appropriate • Complement deficiency: autosomal recessive
inherited defect involving the humoral (B-cell) therapy. mode of inheritance; dogs that are homo-
or cell-mediated (T-cell) immune system, a • Type of infection may vary with defect in zygous for the trait have no detectable C3,
combination of the two, or the phagocytic the immune system. which is required for opsonization of bacteria.
system Affected individuals suffer recurrent sepsis,
PHYSICAL EXAM FINDINGS bronchopneumonia, pyometra, or wound
Epidemiology • Humoral (B-cell) immunodeficiency disorder: infections.
SPECIES, AGE, SEX physical exam findings are remarkable only • Functional phagocytic immunodeficiency:
• Signs often first manifest about 8-12 weeks of for signs associated with chronic/recurring affected animals have an increased risk
age, when the protective effects of maternal infections; increased incidence of chronic of systemic or superficial infections with
antibody are lost. respiratory, skin, and intestinal infections pyogenic microorganisms.
• No sex predisposition except for sex-linked • Cell-mediated (T-cell) immunodeficiency ○ Weimaraner immunodeficiency syndrome:
severe combined immunodeficiency syn- disorder: absence of palpable lymph nodes; inherited, exact mechanism unknown but
drome (X-SCID) in males tonsils are not visible. Affected dogs typi- there is neutrophil dysfunction at the site
• More syndromes are described for dogs versus cally have signs of growth retardation and of lesions, and there appears to be a failure
cats. unthriftiness compared with the other to produce IgA and IgG.
puppies in the litter. ○ CLAD: deficiency of leukocyte surface
GENETICS, BREED PREDISPOSITION • Combined (B-cell and T-cell) immuno- glycoprotein (beta 2 integrin) associated
• Humoral (B-cell) immunodeficiency disorders deficiency disorder: similar findings as for with leukocyte adherence and egress into
○ Selective immunoglobulin A (IgA) defi- humoral and cell-mediated immunodefi- affected tissues; failure to express the beta 2
ciency: German shepherd dog, Shar-pei, ciency disorder integrin CD18
and beagle • Functional phagocytic immunodeficiency ○ TNS: retention of neutrophils in the
○ IgG deficiency: Cavalier King Charles disorder: fever, generalized lymphadenopathy, bone marrow leads to neutropenia and
spaniel dermatitis, pododermatitis, gingivitis, secondary infections
○ IgM-IgA-IgG deficiency: some lines of osteomyelitis; striking absence of exudate
miniature dachshunds formation (CLAD), and poor wound healing DIAGNOSIS
• Complement deficiency: Brittany spaniel
• Cell-mediated (T-cell) immunodeficiency Etiology and Pathophysiology Diagnostic Overview
disorder • Humoral (B-cell) immunodeficiency: decreased Affected puppies present with various, often
○ Thymic hypoplasia: dwarf Weimaraner concentrations or absence of certain immu- nonspecific clinical signs and commonly with
• Combined (B-cell and T-cell) immunodefi- noglobulins, with increased susceptibility to recurrent infections. It is the recurrence of the
ciency disorder bacterial infections infections and the poor response to therapy
○ SCID: Jack Russell terrier, Frisian water ○ IgA deficiency: mode of inheritance is that warrant further investigation of a primary
dog unknown. Epidemiologic studies show immunodeficiency syndrome. Multiple animals
○ X-SCID: basset hound, Cardigan Welsh that puppies born to dams with IgA in a litter may be affected.
corgi deficiency are at increased risk for infec-
• Functional phagocytic immunodeficiency tions related to mucosal surfaces such as Differential Diagnosis
disorder upper respiratory infections, recurrent • Humoral immunodeficiency: varies, based
○ Canine leukocyte adhesion disorder bronchopneumonia, pyoderma, otitis, on presenting complaint
(CLAD): Irish setter demodicosis, and enteritis. ○ Upper respiratory infection: Bordetella
○ Weimaraner immunodeficiency syndrome: • Cell-mediated (T-cell) immunodeficiency: bronchiseptica
Weimaraner affected animals have low numbers of or ○ Primary ciliary dyskinesia
• Cyclical neutropenia: border collies, collie nonfunctional T cells. Findings include a ○ Otitis
(gray) small thymus and lack of lymph nodes, ○ Stomatitis
• Trapped neutrophil syndrome (TNS): Border tonsils, and Peyer’s patches on postmortem ○ Staphylococcal dermatitis
collies exam. Affected animals are at increased risk ○ Atopic dermatitis
for infections with intracellular bacterial, • Cell-mediated immunodeficiency
CONTAGION AND ZOONOSIS fungal, protozoal, and viral organisms. ○ Fungal (cryptococcosis, aspergillosis,
Most opportunistic infections that affect • Combined (B-cell and T-cell) immunodefi- blastomycosis, dermatophytosis)
immunocompromised individuals are over- ciency ○ Protozoal (toxoplasmosis, giardiasis)
growths or infections with organisms that ○ SCID: autosomal recessive: affected ○ Viral infections can be seen after vaccina-
otherwise are not pathogenic to immunocom- individuals are unable to mount an appro- tion with modified live virus vaccine.
petent hosts. However, immunocompromised priate antigen-specific immune response ○ Intracellular bacteria (mycobacterial
animals are more susceptible than normal because of a lack of DNA protein kinase infections)
individuals to infection with organisms that are (DNA-PK) activity; DNA-PK is required • Combined immunodeficiency: affected
potentially zoonotic (e.g., dermatophytosis) or for lymphocyte precursors to mature. animals are susceptible to bacterial, viral,
contagious to other dogs (e.g., respiratory tract ○ X-SCID: sex-linked mutation in the fungal, and protozoal agents.
pathogens). gamma chain of the interleukin 2 (IL-2) • Functional phagocytic immunodeficiency
receptor required for normal B-cell and ○ Sepsis
T-cell function. Affected male puppies are ○ Bacteremia

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