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Studies of human lymphocytes in the newborn and the aged
Insights
Newborns have higher T and B lymphocyte counts, while the elderly show reduced T cells and increased B cell proportions. These immune changes in the elderly may increase susceptibility to infections and cancers.
Area of Science:
- Immunology
- Gerontology
- Cell Biology
Background:
- Immune system function changes with age, impacting T and B lymphocyte populations.
- Infancy is characterized by relative lymphocytosis, while aging is associated with immune senescence.
Purpose of the Study:
- To compare T and B lymphocyte proportions and numbers in newborns and the elderly against adult controls.
- To investigate age-related changes in lymphocyte subsets and their potential correlation with autoantibody incidence.
Main Methods:
- Flow cytometry and sheep red blood cell rosette techniques were used to quantify T and B lymphocytes.
- Peripheral blood samples were analyzed from 30 newborns, 77 elderly individuals (60-95 years), and adult controls.
Main Results:
- Newborns exhibited elevated total T and B lymphocyte numbers compared to adults.
- Elderly individuals showed decreased total lymphocyte and T cell counts, with an increased proportion of B lymphocytes.
- Autoantibody incidence was higher in the elderly, but no direct correlation with lymphocyte subset changes was found.
Conclusions:
- Age-related alterations in T and B lymphocyte populations, particularly the decline in T cells in the elderly, may underlie increased vulnerability to infections and neoplasia.
- Immune profiling across different life stages is crucial for understanding age-related health risks.
Abstract:
Proportions and absolute numbers of T and B lymphocytes were determined among 30 newborn infants and group of 77 elderly patients 60 to 95 years of age. Total lymphocytes in the cord blood of the newborn showed a distinct elevation in total numbers of T and B lymphocytes (p less than 0.005) as compared to that in blood from normal adult controls, reflecting the relative lymphocytosis of infancy. Proportions of cord blood T lymphocytes as reflected by the sheep cell rosette technic were considerable lower than those in lymphocytes from normal adult controls, however, proportions of cord blood T lymphocytes as determined by indirect immunofluorescence were not significantly different from those in controls. Old people showed a significant reduction in total numbers of lymphocytes (p less than 0.005) when compared with those in normal adult controls 18 to 51 years of age. Moreover, there was a significant increase in the relative proportions of peripheral blood B lymphocytes in the elderly although the absolute numbers of B lymphocytes in the elderly although the absolute numbers of B cells did not differ from those in younger controls. A significant decrease in total numbers of T cells as measured both by sheep cell rosettes and indirect immunofluorescence was recorded among older patients (p less than 0.001). In addition, there was a broad increment in the incidence of various autoantibodies (anti-nuclear, andi-IgG, antismooth muscle, antimitochondrial and antiparietal cell) among the old people studies. No direct correlation could be determined between relative B-cell percentage increase or T-cell decrease and the presence of various autoantibodies in individual patients. Diminution in total lymphocyte counts as well as absolute numbers of T cells in the elderly may provide the cellular basis for an increased susceptibility to neoplasia and infection.