Page 1317 - Veterinary Immunology, 10th Edition

normal serum IgG and IgM levels but very little IgA (<5 mg/dL).
VetBooks.ir Phenotypically normal parent dogs had very low IgA levels. Four

affected dogs had circulating anti-IgA antibodies. Their T and B
lymphocyte numbers and lymphocyte responses to mitogens were

normal, as was their response to tetanus toxoid. They had a normal
number of plasma cells secreting IgG and IgM, but no plasma cells
secreting IgA. When two affected animals were mated, four out of
five pups in a litter were IgA deficient. The disease was not sex

linked.
A transient hypogammaglobulinemia has been seen in two
puppies from a litter of Spitz puppies that experienced recurrent
upper respiratory tract infections between 8 and 16 weeks of age.

These dogs had normal T cell numbers and mitogen responses.
They had low immunoglobulin levels and low antibody titers to
vaccine antigens at 16 weeks. The puppies responded very weakly
to tetanus toxoid when it was administered at 4 months. By 6

months, however, immunoglobulins had risen to normal levels, and
the puppies regained their health. It is believed that these puppies
experienced a delayed onset of immunoglobulin synthesis.
Symptomatic treatment is sufficient to support these animals until

their immune system becomes functional.
Cavalier King Charles Spaniels with Pneumocystis pneumonia
had IgG concentrations that were significantly lower in affected
dogs (median, 3.2 mg/mL) than in breed- and age-matched control

dogs (median, 8.5 mg/mL). IgM levels, in contrast, were
significantly higher in the affected dogs. IgA levels were within the
normal range. Lymphocyte counts in affected dogs were normal or
high. This may well be an IgG-deficiency syndrome.

Pneumocystis pneumonia has been observed repeatedly in
Miniature Dachshunds. The affected animals were usually less than
1 year old and appeared to be immunodeficient. Serum
electrophoresis showed a marked reduction in IgM, IgG, and IgA.

In addition, lymphocyte responses to both phytohemagglutinin and
pokeweed mitogens were severely depressed. There was a
reduction in B cell numbers. Although the Pneumocystis pneumonia
responded to aggressive therapy, these animals did not do well and
died young.

An inherited rhinitis/bronchopneumonia syndrome has been

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