Pancreatic islet lesions of autoimmune origin, and ICA and ICSA.

CHBB male rats, 120-150 g in weight, were used both as animals to be sensitized and as donors of homologous islets as antigen. At no time did sensitized animals give a positive reaction for islet-cell antibodies or islet-cell surface bound antibodies at any of the dilutions tested. None of the frozen sections of the pancreas were positive for fluorescence specific for IgG or C3. Marked fibrosis and cell infiltration of pancreatic islets, a high degree of pyknosis of parenchymatous cells of islets, phagocytosis of fragmented islet cell nuclei by histiocytes, and a marked reduction in the number of beta cells were noted.