[An immunological study of changes in the thymus with aging].
Immunological changes of the thymus with aging were studied in human thymic lymphocytes that were obtained from 48 patients undergoing open heart surgery at the 2nd Department of Surgery, Tottori University Hospital. Flow cytometric analysis indicated significant reductions in the ratios of CD8, CD4, and CD1 positive thymic lymphocytes with aging significant increases in the ratios of HLA-DR and CD20 positive cells, and no significant change in the ratio of CD3 positive cells. Immunohistological staining indicated a predominance of CD8, CD4, and CD1 positive cells in the cortex of the thymus, while a predominance of CD3, HLA-DR, and CD20 positive cells was indicated in the medulla of the thymus. The mitogen responses of thymic lymphocytes to PHA, Con A, and PWM were enhanced with aging. Quantitative analysis of the subsets of thymic lymphocytes, their distribution in the thymus, and the measurement of the mitogen responsiveness of those lymphocytes are indispensable for obtaining basic data indicating immunological changes of the thymus with aging, as well as for clarifying the age-related characteristics of thymic lymphocytes in cases of autoimmune diseases such as myasthenia gravis.
Fukuta
M
M
Second Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D008875:Middle Aged; D013950:Thymus Gland / Q000276:immunology*