Inherited 7S immunoglobulin deficiency of chickens is associated with bursal degeneration anomalies

Partially inbred line UCD 140 chickens develop an age dependent inherited 7S immunoglobulin deficiency with features similar to acquired human agammaglobulinemia. Serial and developmental observations in line UCD 140 and control lines 440 and 444 reveal a significant progressive premature involution of the bursa of Fabricius. These bursal changes are characterized by epithelial and medullary degeneration, reduced follicular bursacyte mitosis, and decreased follicular plasma cells. These abnormalities have not been previously described in other avian systems and suggest that this immune deficiency is due to a primary bursal disease.