Page 1188 - Veterinary Immunology, 10th Edition

VetBooks.ir Induction of Autoimmunity

Autoimmune diseases appear to develop spontaneously, and
predisposing causes are rarely obvious. Nevertheless, they fall into

two major categories: they can result from a normal immune
response to an unusual or abnormal antigen, or they can result from
an abnormal immune response to a normal antigen (Fig. 36.1). The
second category is probably the most common. In these cases, the
mechanisms that normally prevent the development of self-

responsive T and B cells fail. Many different environmental factors
and genes contribute to this failure, and the failure may not always
be complete. Autoimmune diseases may result from an aberrant

response to a single specific antigen; alternatively, they may be due
to a general defect in the regulation of B or T cell functions.

FIG. 36.1 A simplified scheme for the pathogenesis of
autoimmune diseases.

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