@article{oai:rakuno.repo.nii.ac.jp:00002029,
 author = {Watabe, Ai and Fukumoto, Shinya and Komatsu, Takahiro and Endo, Yoshifumi and Kadosawa, Tsuyoshi},
 issue = {3-4},
 journal = {Veterinary Immunology and Immunopathology},
 month = {Aug},
 note = {Article, Changes in an individual's immune status are considered major contributing factors towards the morbidity of cancer and mortality of aging. To evaluate age-related changes in the immune status of dogs, the immunophenotypes (CD3, CD4, CD8 and CD21) of peripheral blood lymphocytes were measured in 160 healthy dogs aged from 1 to 17 years, and in 365 dogs with various tumors and at various stages. In healthy dogs, the absolute numbers of white blood cells, lymphocytes, and CD3^+, CD4^+ and CD21^+ lymphocytes decreased significantly with age. The relative percentages of lymphocytes and CD4^+ cells decreased significantly, while CD8^+ cells increased significantly with age. The CD4:CD8 ratio showed a significant age-related decrease. In contrast, dogs with tumors possessed significantly lower absolute numbers and relative percentages of all lymphocyte phenotypes, while the CD4:CD8 ratio was significantly higher than in age-matched controls. The relative percentages of CD3^+ and CD8^+ lymphocytes were significantly lower in dogs with distant metastases compared with dogs without metastases, and the CD4:CD8 ratio increased with advanced stage. These observations illustrate the significant changes in immune status with age and the presence of marked immunological defects in a large-scale study of dogs with advanced tumors.},
 pages = {189--200},
 title = {Alterations of lymphocyte subpopulations in healthy dogs with aging and in dogs with cancer},
 volume = {142},
 year = {2011}
}