Changes in the Human Thymus During Aging

Steinmann, Gerhard

doi:10.1007/978-3-642-82480-7_2

Cited by 292 publications

(205 citation statements)

References 165 publications

(100 reference statements)

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“…The cellularity of the normal PVS increases up to approximately age 25 as the cellularity of the normal TES decreases. After age 25, the cellularity of both the normal PVS and TES decreases (37). The true thymus neither fills up with adipose tissue during aging nor fills up with inflammatory cells during MG. Rather, in aging and in MG, cellular infiltrates and adipose tissue fill the PVS around the true thymus lobules, with collapse of the medullary epithelial component of the thymus and loss of cortical epithelium (37).…”

Section: A Unifying Hypothesis and Future Studiesmentioning

confidence: 99%

“…Confusion on this point arose because early investigators did not appreciate the presence of the PVS in addition to the TES in human thymus. Steinmann and colleagues have clarified this point, and in 1986 summarized their work and the work of others (36,37). It is now appreciated that the true TES begins to involute beginning at the first year of life, whereas the PVS involutes at a different pace, increasing in size from the age of 1 yr until young adulthood, and then decreasing in size thereafter.…”

Section: The Thymus In Agingmentioning

confidence: 99%

“…To appreciate the changes that occur in thymus morphology in aging, MG, and in HIV infection, it is important to understand the (31)(32)(33)(34)(35)(36)(37). As will be discussed below, the latter two postulates are the most likely to be the case, depending on the age of the thymus and the clinical setting.…”

Section: The True Thymic Epithelial Space and The Thymic Perivascularmentioning

confidence: 99%

“…It is now appreciated that the true TES begins to involute beginning at the first year of life, whereas the PVS involutes at a different pace, increasing in size from the age of 1 yr until young adulthood, and then decreasing in size thereafter. Thus, the human TES reaches its maximum size at age 1, whereas the lymphoid volume of the PVS is only a potential space at birth, peaks in volume between ages 10 and 25, and decreases in volume thereafter (36)(37)(38). It is also important to note that the human thymus, in contrast to the mouse thymus, does not lose its volume during aging (36).…”

Section: The Thymus In Agingmentioning

confidence: 99%

“…During aging, the volume and size of HB decrease by over 60%, likely representing slowing down in TE cell maturation and function (37).…”

Section: (Fig 5) (36-38)mentioning

confidence: 99%

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The human thymus

Haynes

Hale

1998

Immunol Res

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The human thymus is a lymphoepithelial organ in which T cells develop during fetal life. After maturation and selection in the fetal thymic microenvironment, T cells emigrate to peripheral lymphoid tissues such as the spleen, gut, and lymph nodes, and establish the peripheral T cell repertoire. Although the thymus has enormous regenerative capacity during fetal development, the regenerative capacity of the human postnatal thymus decreases over time. With the advent of intensive chemotherapy regimens for a variety of cancer syndromes, and the discovery that infection with the Human Immunodeficiency Virus (HIV) leads to severe loss of CD4 + T cells, has come the need to understand the role of the human thymus in reconstitution of the immune system in adults. During a recent study of the thymus in HIV infection, we observed many CD8 + T cells in AIDS thymuses that had markers consistent with those of mature effector cytotoxic T cells usually found in peripheral immune tissues, and noted these CD8 + effector T cells were predominately located in a thymic zone termed the thymic perivascular space. This article reviews our own work on the thymus in HIV-1 infection, and discusses the work of others that, taken together, suggest that the thymus contains peripheral immune cell components not only in the setting of HIV infection, but also in myasthenia gravis, as well as throughout normal life during the process of thymus involution. Thus, the human thymus can be thought of as a chimeric organ comprised of both central and peripheral lymphoid tissues. These observations have led us to postulate that the thymic epithelial atrophy and decrease in thymopoiesis that occurs in myasthenia gravis, HIV-I infection, and thymic involution may in part derive from cytokines or other factors produced by peripheral immune cells within the thymic perivascular space.

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Section: A Unifying Hypothesis and Future Studiesmentioning

confidence: 99%

Section: The Thymus In Agingmentioning

confidence: 99%

Section: The True Thymic Epithelial Space and The Thymic Perivascularmentioning

confidence: 99%

Section: The Thymus In Agingmentioning

confidence: 99%

“…During aging, the volume and size of HB decrease by over 60%, likely representing slowing down in TE cell maturation and function (37).…”

Section: (Fig 5) (36-38)mentioning

confidence: 99%

See 3 more Smart Citations

The human thymus

Haynes

Hale

1998

Immunol Res

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Ectopic Cervical Thymus

Scott¹,

Schroeder²,

Greinwald³

2002

Arch Otolaryngol Head Neck Surg

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Ectopic cervical thymic tissue is an uncommon cause of neck masses in children, with fewer than 100 cases reported in children who presented with primary neck masses. To illustrate the unique characteristics of these tumors, we report the case of a 13-month-old boy with ectopic thymic tissue presenting with asymptomatic, bilateral, and solid cervical masses. This case report highlights several unique findings: (1) the rare nature of solid thymic tumors compared with cystic lesions, (2) the utility of magnetic resonance imaging scanning with and without fat suppression for diagnosis, and (3) the risks of surgical removal of thymic tissue in children. Despite its infrequent occurrence and often asymptomatic presentation, ectopic cervical thymus masses should be included as a rare cause of cervical masses in the pediatric population. Awareness of this diagnosis will allow for appropriate preoperative diagnostic studies, which may preclude the need for biopsy.

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Function of the Thymus in HIV-Infected Adults

Poulin

Sékaly²

1999

JAMA

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Changes in the Human Thymus During Aging

Cited by 292 publications

References 165 publications

The human thymus

The human thymus

Ectopic Cervical Thymus

Function of the Thymus in HIV-Infected Adults

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