[A chronological study of thymic crystalline inclusions and autoimmune disorders in Swan and NZB mice (author's transl)].

Swan and NZB mice represent good animal model for human systemic erythematosus with autoimmune phenomena (antinuclear antibodies, deposits of immunoglobulins in kidney and skin). The level of circulating thymic factor, responsible for T lymphocyte differenciation, falls during the first month of life in NZB mice, during the third month in Swan mice, during the sixth month in control mice (Swiss). In Swan mice, cytoplasmic crystalline inclusions have been found within the epithelial cells which are said to have a thymosine-like activity. The time-sequence of the appearance of the crystalline inclusions has been studied in relation to the development of autoimmune disorders (antinuclear antibodies, immunoglobulins in tissues). In each group of mice, the drop in circulating thymic factor appears before the appearance of crystalline inclusions and of autoimmunisation. Therefore, these crystals appear to represent a store of circulating thymosine-like factor or of a precursor in an ageing thymus.