T Lymphocytes and Aging

Globerson, Amiela

doi:10.1159/000237091

Cited by 67 publications

(21 citation statements)

References 28 publications

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“…An agerelated decline in T cell function has been described in a variety of clinical settings [55][56][57][58][59] and as part of the normal ageing process. [60][61][62] This decline in T cell function has been linked to the involution of the thymus that begins as early as 1 year of age and continues throughout life. [63][64][65] Although several hypotheses have been put forward to explain age-related thymic involution (reviewed in George and Ritter 63 ), the exact mechanism remains unclear.…”

Section: Discussionmentioning

confidence: 99%

Factors affecting reconstitution of the T cell compartment in allogeneic haematopoietic cell transplant recipients

Fallen

McGreavey

Madrigal

et al. 2003

Bone Marrow Transplant

106

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Summary:The factors affecting T cell reconstitution post haematopoietic cell transplantation (HCT) are not well characterised. We carried out a longitudinal analysis of T cell reconstitution in 32 HCT recipients during the first 12 months post transplant. We analysed reconstitution of naı¨ve, memory and effector T cells, their diversity and monitored thymic output using TCR rearrangement excision circles (TRECs). Thymic-independent pathways were responsible for the rapid reconstitution of memory and effector T cells less than 6 months post HCT. Thymic-dependent pathways were activated between 6 and 12 months in the majority of patients with naı¨ve T cell numbers increasing in parallel with TREC levels. Increasing patient age, chronic GVHD and T cell depletion (with or without pretransplant Campath-1H) predicted low TREC levels and slow naı¨ve T cell recovery. Furthermore, increasing patient age also predicted high memory and effector T cell numbers. The effects of post HCT immunosuppression, total body irradiation, donor leucocyte infusions, T cell dose and post HCT infections on T cell recovery were also analysed. However, no effects of these single variables across a variety of different age, GVHD and T cell depletion groups were apparent. This study suggests that future analysis of the factors affecting T cell reconstitution and studies aimed at reactivating the thymus through therapeutic intervention should be analysed in age-, GVHD-and TCD-matched patient groups. While each of these parameters may have mutually exclusive effects on the outcome of the transplant, it is the combination of all of these parameters that will determine the ultimate success of the transplant. Furthermore, the effects of each of these parameters on immune reconstitution post HCT are unclear.The immediate post transplant period is followed by a severe and often prolonged immune deficiency that results in prolonged susceptibility to infection. 8,17,[19][20][21][22] Although infections that occur in the first month after engraftment probably result from deficiencies in both granulocytes and other mononuclear cell subsets, the more prolonged immune deficiency arises from deficiencies in effective CD4 þ T cell and B cell reconstitution and immunosuppressive therapy. 23,[27][28][29] It was then suggested that the reconstitution and maintenance of effective T cell immunity after HCT was dependent on education of T cell precursors in the thymus. [30][31][32] Furthermore, these observations generated considerable interest in the factors affecting the reconstitution of T cell immunity through thymic-dependent pathways. 33,34 Using phenotypic markers of T cell naivety (primarily the CD45RA antigen), initial studies demonstrated that increasing patient age had an adverse effect on the regeneration of naı¨ve CD4 þ T cells, presumably due to age-related thymic involution, 31 observations that were confirmed using the TCR rearrangement excision circle (TREC) assay to measure thymic output. 35,36 In addition, the thymus has been demonstrated to be...

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Section: Discussionmentioning

confidence: 99%

Factors affecting reconstitution of the T cell compartment in allogeneic haematopoietic cell transplant recipients

Fallen

McGreavey

Madrigal

et al. 2003

Bone Marrow Transplant

106

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“…The thymus disappears by early middle age and adults depend on T lymphocyte response in the secondary tissue [33]. The number of naïve T cells decreases in the elderly, increasing the dependency on memory T cells.…”

Section: Lymphocytesmentioning

confidence: 99%

Hematological Differences in Newborn and Aging: A Review Study

Jacob¹

2016

HTIJ

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The aim of this study was to highlight the possible cause of hematological differences in newborn and aging for appropriate hematological reference values to be used for treatment at all developmental stages. The neonate (newborn infant) older child and adult exhibit profound hematologic differences from one another because children mature at different rates, quantitative and qualitative differences are present as a reflection of the developmental changes during fetal hematopoiesis which correlate with gestational age. At birth, hematological of term newborns are significantly higher than those of older children and adults and in preterm neonates the differences are even more pronounced. It is inappropriate to use adult reference ranges for the assessment of pediatric blood values. Geriatric medicine is a rapidly growing branch of medicine, care of the elderly has become a growing trend as the life expectancy of the population continues to increase. Hematological changes are obvious in both the neonates and the elderly persons and at such; different hematological variables must be implemented in various developmental stages of the neonates as well as the different classes of aged elderly individuals. Also among the elderly, certain hematological disorders are more common which need urgent attention of their physicians. This review highlighted some major factors that responsible for hematological differences in newborn and aging.

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“…The decline of immunity occurs mainly in the T cell-dependent immune functions (Hirokawa et al, 1994;Globerson, 1995;Pawelec, 1995). The most dramatic change with age is reported to occur within the T-cell compartment where there is a declined function of both the CD4 + and CD8 + cells.…”

Section: Hemohim Recovers the Declined Nk Cell Activity In Aged Micementioning

confidence: 99%

“…Declined T cell function is believed to be the central defect in immune senescence (Globerson, 1995;Pawelec, 1995). Impaired T cell function has been well documented from numerous animal and human studies (Miller, 2000;Linton and Dorshkind, 2004).…”

Section: Introductionmentioning

confidence: 99%

Restoration of the immune functions in aged mice by supplementation with a new herbal composition, HemoHIM

Park¹,

Jo²,

Jung³

et al. 2007

Phytotherapy Research

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The effect of a new herbal composition, HemoHIM, on immune functions was examined in aged mice, in which various immune responses had been impaired. The composition HemoHIM was prepared by adding the ethanol-insoluble fraction to the total water extract of a mixture of three edible herbs, Angelica Radix, Cnidium Rhizoma and Paeonia Radix. Supplementation to the aged mice with HemoHIM restored the proliferative response and cytokine production of splenocytes with a response to ConA. Also, HemoHIM recovered the NK cell activity which had been impaired in the aged mice. Meanwhile aging is known to reduce the Th1-like function, but not the Th2-like function, resulting in a Th1/Th2 imbalance. HemoHIM restored the Th1/Th2 balance in the aged mice through enhanced IFN-γ γ γ γ γ and IgG2a production, and conversely a reduced IL-4 and IgG1 production. It was found that one factor for the Th1/Th2 imbalance in the aged mice was a lower production of IL-12p70. However, HemoHIM restored the IL-12p70 production in the aged mice. These results suggested that HemoHIM was effective for the restoration of impaired immune functions of the aged mice and therefore could be a good recommendation for immune restoration in elderly humans.

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T Lymphocytes and Aging

Cited by 67 publications

References 28 publications

Factors affecting reconstitution of the T cell compartment in allogeneic haematopoietic cell transplant recipients

Factors affecting reconstitution of the T cell compartment in allogeneic haematopoietic cell transplant recipients

Hematological Differences in Newborn and Aging: A Review Study

Restoration of the immune functions in aged mice by supplementation with a new herbal composition, HemoHIM

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