Thymic functions in uremic rats: evidence for thymosin alpha 1 deficiency.

Changes in the circulating lymphocyte populations and thymus glands were studied in rats with experimental chronic renal insufficiency (CRI). Compared to normal or sham-operated animals, rats with CRI had significant reduction in the percentages of circulating T and B lymphocytes. CRI was also associated with marked thymic atrophy and reduction in the numbers of small cortical and medullary thymic lymphocytes. Quantitative microfluorometry revealed a significant reduction in the intrathymic concentration of a potent immunomodulator, thymosin alpha 1 in all uremic animals. There was a significant positive correlation between the percentages of circulating T lymphocytes and the intrathymic concentrations of thymosin alpha 1.