Humoral immune response and expression of spontaneous postnatal amelanosis in DAM line chickens.

The delayed amelanotic (DAM) chicken line has been developed as a model of human vitiligo. Vitiligo in humans and chickens is characterized symptomatically by spontaneous loss of integumentary pigmentation and is often associated with uveitis. In humans, vitiligo is also associated with increased frequencies of several autoantibodies, suggesting a state of immune hyperreactivity. An adult DAM chicken population was tested for levels of circulating antibody after challenge with sheep red blood cells or Brucella abortus. There was a significantly higher mean titer level to both antigens in the amelanotic birds than in normally pigmented birds. The severity of feather amelanosis and visual defects was associated with increased antibody levels. This suggests that amelanosis and blindness in DAM chickens may be associated with elevated antibody responses to foreign antigens and perhaps with a generalized state of hyperimmunity.