101
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Abstract
Combination anti-retroviral therapy for HIV disease has profoundly altered the nature of the AIDS epidemic. Mitigating the impact of an uncontrollable decline in immune function is no longer the focal point for AIDS therapy, but has evolved to an emphasis on maximizing the potential for immune regeneration. Improved control of HIV replication has diminished, albeit unevenly, the frequency of AIDS-related malignancies and has altered the focus of hematologic and oncologic interventions in HIV disease. Now, with adoptive cellular therapies and the genetic engineering of cells in the clinical arena, the potential for cellular therapeutics in enhancing immune restoration is being tested. These approaches are based on better understanding of the immunobiology of HIV and its impact on hematopoietic tissues.
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Affiliation(s)
- D T Scadden
- Massachusetts General Hospital, Dana-Farber/Partners Cancer Care, Harvard Medical School, Boston 02129, USA.
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102
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Flores KG, Li J, Sempowski GD, Haynes BF, Hale LP. Analysis of the human thymic perivascular space during aging. J Clin Invest 1999; 104:1031-9. [PMID: 10525041 PMCID: PMC408578 DOI: 10.1172/jci7558] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The perivascular space (PVS) of human thymus increases in volume during aging as thymopoiesis declines. Understanding the composition of the PVS is therefore vital to understanding mechanisms of thymic atrophy. We have analyzed 87 normal and 31 myasthenia gravis (MG) thymus tissues from patients ranging in age from newborn to 78 years, using immunohistologic and molecular assays. We confirmed that although thymic epithelial space (TES) volume decreases progressively with age, thymopoiesis with active T-cell receptor gene rearrangement continued normally within the TES into late life. Hematopoietic cells present in the adult PVS include T cells, B cells, and monocytes. Eosinophils are prominent in PVS of infants 2 years of age or younger. In the normal adult and the MG thymus, the PVS includes mature single-positive (CD1a(-) and CD4(+) or CD8(+)) T lymphocytes that express CD45RO, and contains clusters of T cells expressing the TIA-1 cytotoxic granule antigen, suggesting a peripheral origin. PBMCs bind in vitro to MECA-79(+) high endothelial venules present in the PVS, suggesting a mechanism for the recruitment of peripheral cells to thymic PVS. Therefore, in both normal subjects and MG patients, thymic PVS may be a compartment of the peripheral immune system that is not directly involved in thymopoiesis.
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Affiliation(s)
- K G Flores
- Department of Pathology, Department of Medicine, and Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA
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103
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Zhang L, Lewin SR, Markowitz M, Lin HH, Skulsky E, Karanicolas R, He Y, Jin X, Tuttleton S, Vesanen M, Spiegel H, Kost R, van Lunzen J, Stellbrink HJ, Wolinsky S, Borkowsky W, Palumbo P, Kostrikis LG, Ho DD. Measuring recent thymic emigrants in blood of normal and HIV-1-infected individuals before and after effective therapy. J Exp Med 1999; 190:725-32. [PMID: 10477556 PMCID: PMC2195623 DOI: 10.1084/jem.190.5.725] [Citation(s) in RCA: 283] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/1999] [Accepted: 07/06/1999] [Indexed: 11/21/2022] Open
Abstract
The role of the thymus in HIV-1 pathogenesis remains unclear. We developed an assay to quantify the number of recent thymic emigrants in blood based on the detection of a major excisional DNA byproduct (termed alpha1 circle) of T cell receptor rearrangement. By studying 532 normal individuals, we found that alpha1 circle numbers in blood remain high for the first 10-15 yr of life, a sharp drop is seen in the late teen years, and a gradual decline occurs thereafter. Compared with age-matched uninfected control individuals, alpha1 circle numbers in HIV-1-infected adults were significantly reduced; however, there were many individuals with normal alpha1 circle numbers. In 74 individuals receiving highly active antiretroviral therapy, we found no appreciable effect on alpha1 circle numbers in those whose baseline values were already within the normal range, but significant increases were observed in those with a preexisting impairment. The increases in alpha1 circle numbers were, however, numerically insufficient to account for the rise in levels of naive T lymphocytes. Overall, it is difficult to invoke thymic regenerative failure as a generalized mechanism for CD4 lymphocyte depletion in HIV-1 infection, as alpha1 circle numbers are normal in a substantial subset of HIV-1-infected individuals.
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Affiliation(s)
- Linqi Zhang
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Sharon R. Lewin
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Martin Markowitz
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Hsi-Hsun Lin
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Eva Skulsky
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Rose Karanicolas
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Yuxian He
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Xia Jin
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Sarah Tuttleton
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Mika Vesanen
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Hans Spiegel
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - Rhonda Kost
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | | | | | - Steven Wolinsky
- Department of Medicine, Northwestern University School of Medicine, Chicago, Illinois 60611
| | - William Borkowsky
- Department of Pediatrics, New York University Medical Center, New York, New York 10016
| | - Paul Palumbo
- Department of Pediatrics, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103
| | - Leondios G. Kostrikis
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
| | - David D. Ho
- From the Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016
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104
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Wolthers KC, Noest AJ, Otto SA, Miedema F, De Boer RJ. Normal telomere lengths in naive and memory CD4+ T cells in HIV type 1 infection: a mathematical interpretation. AIDS Res Hum Retroviruses 1999; 15:1053-62. [PMID: 10461825 DOI: 10.1089/088922299310340] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To study CD4+ T cell productivity during HIV-1 infection, CD4+ T cell telomere lengths were measured. Cross-sectional and longitudinal analysis of HIV-1-infected individuals with CD4+ T cells counts >300 cells/mm3 showed normal average telomeric restriction fragment (TRF) length and normal shortening rates of CD45RA+ naive and CD45RO+ memory CD4+ T cells. These TRF data were interpreted in terms of CD4+ T cell production by means of a mathematical model. This model resolves previous criticisms arguing that the normal TRF length of CD4+ T cells in HIV-1 clinical latency is due to the killing of dividing CD4+ T cells by the virus. Only an increased priming rate of naive CD4+ T cells to become memory cells may elongate the average TRF length of memory CD4+ T cells, and may therefore mask the shortening effect of increased turnover in the CD4+ memory T cell compartment. The data are more compatible with the notion that during HIV-1 clinical latency the turnover of CD4+ T cells is not markedly increased, however, and that HIV-related interference with renewal from progenitors plays a role in CD4+ T cell depletion. In such a "limited renewal" scenario disease progression is no longer a consequence of markedly increased CD4+ T cell production.
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Affiliation(s)
- K C Wolthers
- Department of Clinical Viro-Immunology, Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, University of Amsterdam, The Netherlands
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105
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Haynes BF. HIV infection and the dynamic interplay between the thymus and the peripheral T cell pool. Clin Immunol 1999; 92:3-5. [PMID: 10413647 DOI: 10.1006/clim.1999.4738] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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106
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Kaushal S, Landay AL, Lederman MM, Connick E, Spritzler J, Kuritzkes DR, Kessler H, Levine BL, St Louis DC, June CH. Increases in T cell telomere length in HIV infection after antiretroviral combination therapy for HIV-1 infection implicate distinct population dynamics in CD4+ and CD8+ T cells. Clin Immunol 1999; 92:14-24. [PMID: 10413649 DOI: 10.1006/clim.1999.4726] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Changes in mean telomeric terminal restriction fragment (TRF) length were examined as a marker for cellular replicative history in HIV-1-infected individuals after institution of anti-retroviral therapy (ART). Increases in mean T cell TRF lengths were observed in most patients following therapy; however, the contribution of individual T cell subsets was complex. An elongation of CD8+ T cell TRF was nearly uniformly observed while changes in mean TRF length in CD4+ T cells were heterogeneous as, despite potent suppression of viral replication, CD4 cell telomeres recovered in some patients, yet continued to decline in others. Increases in CD8 cell TRF correlated with decreased memory cells, suggesting a negative selection in the periphery for CD8 cells with extensive replicative history. In contrast, increases in CD4+ T cell TRF length correlated with increases in naive cell subsets, suggesting that the CD4+ T cell TRF increase may reflect a thymic contribution in some patients. These are the first increases in somatic cell telomere length in a population of cells observed in vivo, and the findings are compatible with therapy-induced reconstitution of the lymphoid compartment with cells having a more extensive replicative potential. These findings further distinguish lymphocytes from other somatic cell populations where only decreases in TRF over time have been noted. Thus, institution of ART in persons with moderately advanced HIV-1 disease reveals distinct population dynamics of CD4 and CD8 T cell subsets and also shows that the lymphocyte replicative history is dynamic.
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Affiliation(s)
- S Kaushal
- Henry M. Jackson Foundation for the Advancement of Military Medicine, U.S. Military HIV Research Program, Bethesda, Maryland 20889, USA
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107
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Jamieson BD, Douek DC, Killian S, Hultin LE, Scripture-Adams DD, Giorgi JV, Marelli D, Koup RA, Zack JA. Generation of functional thymocytes in the human adult. Immunity 1999; 10:569-75. [PMID: 10367902 DOI: 10.1016/s1074-7613(00)80056-4] [Citation(s) in RCA: 258] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Reconstituting the immune response will be critical for the survival of HIV-infected individuals once viral load is brought under control. While the adult thymus was previously thought to be relatively inactive, new data suggest it may play a role in T cell reconstitution. We examined thymopoiesis in adults up to 56 years of age and found active T cell receptor (TCR) rearrangement, generating a diverse TCR Vbeta repertoire. The resulting thymocytes are functional and are capable of responding to costimulatory signals. These data demonstrate that the adult thymus remains active late in life and contributes functional T cells to the peripheral lymphoid pool.
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Affiliation(s)
- B D Jamieson
- Department of Medicine, UCLA School of Medicine and Jonsson Comprehensive Cancer Center, Los Angeles, California 90095-1678, USA.
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108
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Haynes BF, Hale LP. The human thymus. A chimeric organ comprised of central and peripheral lymphoid components. Immunol Res 1999; 18:175-92. [PMID: 9951649 DOI: 10.1007/bf02788778] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
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 predominantly 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-1 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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Affiliation(s)
- B F Haynes
- Department of Medicine, Duke University School of Medicine, Duke Medical Center, Durham, NC, USA.
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109
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Haynes BF, Hale LP. The human thymus. A chimeric organ comprised of central and peripheral lymphoid components. Immunol Res 1998; 18:61-78. [PMID: 9844826 DOI: 10.1007/bf02788750] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
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-1 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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Affiliation(s)
- B F Haynes
- Department of Medicine, Duke University School of Medicine, Duke Medical Center, Durham, NC, USA.
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