Studies on murine thyroiditis: new insights from organ flow cytometry

The pathogenesis of autoimmune diseases is frequently studied in murine models, in which disease outcome is traditionally assessed by light microscopy. To determine whether digital imaging improves reliability of the histopathologic assessment, and whether flow cytometry is applicable directly on the murine thyroid, we studied 395 CBA/J mice 3 weeks after thyroglobulin immunization, and 192 nonimmunized CBA/J mice. Digital imaging significantly improved reliability of the histopathological assessment (r = 0.988, 95% confidence interval: 0.980-0.992, p < 0.0001), and flow cytometry on the murine thyroid could be performed successfully. We also found that normal thyroids contained a higher than expected number of hematopoietic cells in the interstitium. We suggest that digital imaging offers a better means of estimating disease outcome, and that flow cytometry performed at the target organ levels reflects the autoimmune pathogenesis more closely than when performed on peripheral lymphoid organs. These methods should also be applicable to other organ systems targeted by autoimmune attack, such as heart, exocrine, and other endocrine glands.