Page 1313 - Veterinary Immunology, 10th Edition

sire results in approximately half the males in each litter being
VetBooks.ir affected and all the females being phenotypically normal.

These dogs are lymphopenic (~1000/µL). Their CD4/CD8 ratio is,
however, approximately 15 : 1, compared with normal dogs that
+
have a ratio of 1.7 : 1, indicating a major drop in CD8 cell numbers.
Their absolute number of T cells is less than 20% of normal. The
dogs have normal numbers of B cells. The few lymphocytes in the
blood are unresponsive to mitogens. The puppies have normal IgM

levels but very low, or no, IgG and IgA. These dogs do not make
antibodies against antigens such as tetanus toxoid.
On necropsy the thymus of affected dogs is approximately 10% of
the normal weight and lacks a defined cortex (Fig. 39.10). Their

lymph nodes and tonsils are very small and dysplastic and may be
very difficult to find. When present, the nodes are disorganized and
contain few small lymphocytes. Their spleens contain large
periarteriolar lymphoid nodules with occasional small lymphocytes

and few plasma cells. The bone marrow in these dogs appears
normal.

FIG. 39.10 Photomicrograph of the thymus of a Basset Hound with

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