scholarly journals Thymectomy in Juvenile Myasthenia Gravis Is Safe Regarding Long Term Immunological Effects

2021 ◽  
Vol 12 ◽  
Author(s):  
Trine H. Popperud ◽  
Kiran A. Gul ◽  
Cathrine Brunborg ◽  
Richard W. Olaussen ◽  
Tore G. Abrahamsen ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Myasthenia Gravis ◽  
Lower Number ◽  
Premature Aging ◽  
T Cell Subsets ◽  
Helper T Cells ◽  
Juvenile Myasthenia Gravis

Thymectomy is an established treatment in adult MG and also recommended for the treatment of post-pubertal onset juvenile MG. Whether the youngest children should be thymectomized is still debated. Signs of premature aging of the immune system have been shown in studies on early perioperative thymectomy in children with congenital heart defect. In this retrospective cohort study the objective was to investigate the long-term effects of treatment related thymectomy on T cell subsets and T cell receptor rearrangement excision circles (TRECs) in peripheral blood of juvenile myasthenia gravis (MG) patients, as well as clinical occurrence of autoimmune disorders, malignancies and infectious diseases. Forty-seven patients with onset of myasthenia gravis before the age of 19 years were included; 32 (68.1%) had been thymectomized and 15 (31.8%) had not. They were studied at varying times after thymectomy (7–26 years). We found a significant lower number of naïve helper T cells (CD4+CD45RA+) with an increased proportion of memory helper T cells (CD4+CD45RO+), and a significant lower number of naïve cytotoxic T cells (CD8+CD27+CD28+) in the thymectomized patients. In addition they showed a significant reduction in the number of TRECs and proportion of recent thymic emigrants (RTE) compared to non-thymectomized patients. In none of them an increased frequency of malignancies or infections was found. Our findings indicate a premature aging of the immune system after thymectomy in juvenile MG, but associated clinical consequences could not be verified.

scholarly journals Venetoclax imparts distinct cell death sensitivity and adaptivity patterns in T cells

2021 ◽  
Vol 12 (11) ◽  
Author(s):  
Lindsey M. Ludwig ◽  
Katrina M. Hawley ◽  
David B. Banks ◽  
Anika T. Thomas-Toth ◽  
Bruce R. Blazar ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Immune System ◽  
T Cell ◽  
T Cell Subsets ◽  
Treatment Modalities ◽  
Short Term ◽  
Bh3 Mimetics ◽  
Post Transplant

AbstractBH3 mimetics are increasingly used as anti-cancer therapeutics either alone or in conjunction with other chemotherapies. However, mounting evidence has also demonstrated that BH3 mimetics modulate varied amounts of apoptotic signaling in healthy immune populations. In order to maximize their clinical potential, it will be essential to understand how BH3 mimetics affect discrete immune populations and to determine how BH3 mimetic pressure causes immune system adaptation. Here we focus on the BCL-2 specific inhibitor venetoclax (ABT-199) and its effects following short-term and long-term BCL-2 blockade on T cell subsets. Seven day “short-term” ex vivo and in vivo BCL-2 inhibition led to divergent cell death sensitivity patterns in CD8+ T cells, CD4+ T cells, and Tregs resulting in shifting of global T cell populations towards a more memory T cell state with increased expression of BCL-2, BCL-XL, and MCL-1. However, twenty-eight day “long-term” BCL-2 blockade following T cell-depleted bone marrow transplantation did not lead to changes in the global T cell landscape. Despite the lack of changes in T cell proportions, animals treated with venetoclax developed CD8+ and CD4+ T cells with high levels of BCL-2 and were more resistant to apoptotic stimuli following expansion post-transplant. Further, we demonstrate through RNA profiling that T cells adapt while under BCL-2 blockade post-transplant and develop a more activated genotype. Taken together, these data emphasize the importance of evaluating how BH3 mimetics affect the immune system in different treatment modalities and disease contexts and suggest that venetoclax should be further explored as an immunomodulatory compound.

scholarly journals Long-Term Depletion of Naive T Cells in Patients Treated for Hodgkin's Disease

Blood ◽  
1997 ◽  
Vol 90 (9) ◽  
pp. 3662-3672 ◽  
Author(s):  
Nobukazu Watanabe ◽  
Stephen C. De Rosa ◽  
Anthony Cmelak ◽  
Richard Hoppe ◽  
Leonore A. Herzenberg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Hodgkin's Disease ◽  
Hodgkin’S Disease ◽  
Cell Subset ◽  
T Cell Subsets ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Cell Counts

Abstract We investigated the representation of T cells in patients who had been treated for Hodgkin's disease (HD). We found a marked depletion in both CD4 and CD8 naive T-cell counts that persists up to 30 years after completion of treatment. In contrast, CD4 and CD8 memory T-cell subsets recovered to normal or above normal levels by 5 years posttreatment. Thus, the previously-reported long-term deficit in total CD4 T-cell counts after treatment for HD is due to specific depletion of naive T cells. Similarly, total CD8 T-cell counts return to normal by 5 years only because CD8 memory T cells expand to higher than normal levels. These findings suggest that the treatment (mediastinal irradiation) results in a longterm dysregulation of T-cell subset homeostasis. The profound depletion of naive T cells may explain the altered T-cell function in treated patients, including the poor response to immunization after treatment for HD. Further, in some individuals, we identified expansions of unusual subsets expressing low levels of CD8. Eight-color fluorescence-activated cell sorting analyses showed that these cells largely express CD8αα homodimers and CD57, consistent with the phenotype of potentially extrathymically derived T cells. In addition, these cells, both CD4+ and CD4−, are probably cytotoxic lymphocytes, as they express high levels of intracellular perforin. In adults treated for HD, an increased activity of extrathymic T-cell differentiation may partially compensate for the loss of thymic-derived T cells.

6 Murine T cell subsets and interleukins: Relationships between cytotoxic T cells, helper T cells and accessory cells

1982 ◽  
Vol 11 (3) ◽  
pp. 607-630
Author(s):  
Hermann Wagner ◽  
Martin Kronke ◽  
Werner Solbach ◽  
Peter Scheurich ◽  
Martin Röllinghoff ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
T Cell Subsets ◽  
Helper T Cells ◽  
Accessory Cells

scholarly journals The impact of body mass index on adaptive immune cells in the human bone marrow

2020 ◽  
Author(s):  
Luca Pangrazzi ◽  
Erin Naismith ◽  
Carina Miggitsch ◽  
Jose’ Antonio Carmona Arana ◽  
Michael Keller ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Bone Marrow ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Immune Cells ◽  
Memory T Cells ◽  
T Cell Subsets ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

Abstract Background. Obesity has been associated with chronic inflammation and oxidative stress. Both conditions play a determinant role in the pathogenesis of age-related diseases, such as immunosenescence. Adipose tissue can modulate the function of the immune system with the secretion of molecules influencing the phenotype of immune cells. The importance of the bone marrow (BM) in the maintenance of antigen-experienced adaptive immune cells has been documented in mice. Recently, some groups have investigated the survival of effector/memory T cells in the human BM. Despite this, whether high body mass index (BMI) may affect immune cells in the BM and the production of molecules supporting the maintenance of these cells it is unknown.Methods. Using flow cytometry, the frequency and the phenotype of immune cell populations were measured in paired BM and PB samples obtained from persons with different BMI. Furthermore, the expression of BM cytokines was assessed. The influence of cytomegalovirus (CMV) on T cell subsets was additionally considered, dividing the donors into the CMV- and CMV+ groups.Results. Our study suggests that increased BMI may affect both the maintenance and the phenotype of adaptive immune cells in the BM. While the BM levels of IL-15 and IL-6, supporting the survival of highly differentiated T cells, and oxygen radicals increased in overweight persons, the production of IFNγ and TNF by CD8+ T cells was reduced. In addition, the frequency of B cells and CD4+ T cells positively correlated with BMI in the BM of CMV- persons. Finally, the frequency of several T cell subsets, and the expression of senescence/exhaustion markers within these subpopulations, were affected by BMI. In particular, the levels of bona fide memory T cells may be reduced in overweight persons.Conclusion. Our work suggests that, in addition to aging and CMV, obesity may represent an additional risk factor for immunosenescence in adaptive immune cells. Metabolic interventions may help in improving the fitness of the immune system in the elderly.

Body mass index affects adaptive immune cells in the human bone marrow

2020 ◽  
Author(s):  
Luca Pangrazzi ◽  
Erin Naismith ◽  
Carina Miggitsch ◽  
Jose’ Antonio Carmona Arana ◽  
Michael Keller ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Bone Marrow ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Body Mass ◽  
Immune Cells ◽  
T Cell Subsets ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

Abstract Background. Obesity has been associated with chronic inflammation and oxidative stress. Both conditions play a determinant role in the pathogenesis of age-related diseases, such as immunosenescence. Adipose tissue can modulate the function of the immune system with the secretion of molecules influencing the phenotype of immune cells. Recently, the importance of the bone marrow (BM) in the maintenance of antigen-experienced adaptive immune cells has been documented. Despite this, whether high body mass index (BMI) may affect immune cells in the BM and the production of molecules supporting the maintenance of these cells it is unknown. Methods. Using flow cytometry, the frequency and the phenotype of immune cell populations were measured in paired BM and PB samples obtained from persons with different BMI. Furthermore, the expression of BM cytokines was assessed. The influence of cytomegalovirus (CMV) on T cell subsets was additionally considered, dividing the donors into the CMV - and CMV + groups. Results. Our study suggests that increased BMI may affect both the maintenance and the phenotype of adaptive immune cells in the BM. While the BM levels of IL-15 and IL-6, supporting the survival of highly differentiated T cells, and oxygen radicals increased in overweight persons, the production of IFNγ and TNF by CD8 + T cells was reduced. In addition, the frequency of B cells and CD4 + T cells positively correlated with BMI in the BM of CMV - persons. Finally, the frequency of several T cell subsets, and the expression of senescence/exhaustion markers within these subpopulations, were affected by BMI. In particular, the levels of bona fide memory T cells may be reduced in overweight persons. Conclusion. Our work suggests that obesity may represent an independent risk factor supporting immunosenescence, in addition to aging and CMV. Metabolic interventions may help in improving the fitness of the immune system in the elderly.

The Role of Bone Marrow T Cells in Regulating Hematopoietic Stem Cell Function.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2349-2349
Author(s):  
Claudia Brandao ◽  
Alexander M. de Bruin ◽  
Martijn A. Nolte
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Cd8 T Cells ◽  
Feedback Mechanism ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Self Renewal ◽  
Hematopoietic Stem

Abstract Abstract 2349 After immune activation, effector/memory T cells, including virus-specific CD8 T cells, are known to migrate to the bone marrow (BM), where they can be maintained by the production of IL-15 by the stroma; however, it is not yet known whether these T cells also have a function at this site. Since depletion of T cells from allogenic BM grafts compromises HSC engraftment, we hypothesize that T cells can directly influence the balance between differentiation and self-renewal of hematopoietic stem cells (HSCs). To test the ability of T cells to affect hematopoiesis, we performed co-cultures of HSCs and T cells isolated from murine BM. We found that T cells localized in the BM are able to enhance HSC differentiation as well as their self-renewal capacity. This feature is specific for BM central memory (CM) CD8 T cells, since other T cell subsets are not able to affect HSCs to the same extent. Moreover, depletion of CM CD8 T cells from the total BM T cell pool abrogates the impact on HSC differentiation and self-renewal, indicating that this particular T cell population is both sufficient and required for the observed effects. BM CM CD8 T cells do not affect quiescence of HSCs, but do enhance their proliferative capacity, and we found that supernatant from CM CD8 T cells is sufficient for this effect. Interestingly, competitive transplantation assays showed that HSCs cultured with CM CD8 T cells-derived supernatant contribute much better to leukocyte formation than medium-treated HSCs. This effect is seen in both the myeloid and lymphoid compartment, indicating that CM CD8 T cells are able to release soluble factors that support and enhance the multilineage reconstitution capacity of HSCs. Functional studies with blocking antibodies or knock-out mice showed that the supernatant-mediated effect is not caused by the hematopoietic cytokines IL3, IL6, IL21, GM-CSF, RANTES, TNFα or IFNγ. Preliminary data indicate that this feedback mechanism of the immune system on the hematopoietic process in the bone marrow is also present in the human situation, since autologous BM T cells increase the numbers of human HSCs, as well as their differentiation capacity. Overall, these findings demonstrate that T cells have an important function in the BM and that especially CD8 TCM cells can directly influence HSC homeostasis. We postulate that this feedback mechanism of the immune system on the hematopoietic process in the BM is particularly relevant during viral infection, as the efficient migration of virus-specific CD8 T cells to the BM could well benefit the replenishment of the HSC/progenitor cell compartment and restoration of blood cell numbers that got lost upon infection. Disclosures: No relevant conflicts of interest to declare.

scholarly journals In Situ Activation of Helper T Cells in the Lung

2001 ◽  
Vol 69 (8) ◽  
pp. 4790-4798 ◽  
Author(s):  
Bindu Raju ◽  
Chung F. Tung ◽  
Debbie Cheng ◽  
Nora Yousefzadeh ◽  
Rany Condos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Subsets ◽  
Helper T Cells ◽  
Cell Marker ◽  
Color Flow ◽  
Purified Protein Derivative ◽  
Surface Molecules ◽  
In Situ Activation ◽  
Significant Difference

ABSTRACT To better understand the lung and systemic responses of helper T cells mediating memory immunity to Mycobacterium tuberculosis, we used three- and four-color flow cytometry to study the surface phenotype of CD4+ lymphocytes. Bronchoalveolar lavage (BAL) fluid and peripheral blood (PB) samples were obtained from a total of 25 subjects, including 10 tuberculosis (TB)-infected subjects, 8 purified-protein-derivative-negative subjects, and 7 purified-protein-derivative-positive subjects. In marked contrast to CD4+ lymphocytes from PB (9% ± 5% expressing CD45RA and CD29), the majority (55% ± 16%) of CD4+ lymphocytes in BAL (ALs) simultaneously expressed CD45RA, a naı̈ve T-cell marker, and CD29, members of the very late activation family. Further evaluation revealed that CD4+ ALs expressed both CD45RA and CD45RO, a memory T-cell marker. In addition, the proportion of CD4+ lymphocytes expressing CD69, an early activation marker, was drastically increased in BAL fluid (83% ± 9%) compared to PB (1% ± 1%), whereas no significant difference was seen in the expression of CD25, the low-affinity interleukin 2 receptor (34% ± 15% versus 40% ± 16%). More importantly, we identified a minor population of CD69bright CD25bright CD4+lymphocytes in BAL (10% ± 6%) that were consistently absent from PB (1% ± 1%). Thus, CD4+ lymphocytes in the lung paradoxically coexpress surface molecules characteristic of naı̈ve and memory helper T cells as well as surface molecules commonly associated with early and late stages of activation. No difference was observed for ALs obtained from TB-infected and uninfected lung segments in this regard. It remains to be determined if these surface molecules are induced by the alveolar environment or if CD4+ lymphocytes coexpressing this unusual combination of surface molecules are selectively recruited from the circulation. Our data suggest that ex vivo experiments on helper T-cell subsets that display distinctive phenotypes may be pivotal to studies on the human immune response to potential TB vaccines.

scholarly journals Early Thymectomy Is Associated With Long-Term Impairment of the Immune System: A Systematic Review

2021 ◽  
Vol 12 ◽  
Author(s):  
Nara Vasconcelos Cavalcanti ◽  
Patrícia Palmeira ◽  
Marcelo Biscegli Jatene ◽  
Mayra de Barros Dorna ◽  
Magda Carneiro-Sampaio
Keyword(s):  
Systematic Review ◽  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Heart Diseases ◽  
Subsequent Development ◽  
Treg Cells ◽  
Ki 67 ◽  
T Cell Subpopulations

Background and AimsCongenital heart diseases (CHDs) are diagnosed in approximately 9 in 1,000 newborns, and early cardiac corrective surgery often requires partial or complete thymectomy. As the long-term effect of early thymectomy on the subsequent development of the immune system in humans has not been completely elucidated, the present study aimed to evaluate the effects of thymus removal on the functional capacity of the immune system after different periods.MethodsA systematic review of the literature was performed using MEDLINE, EMBASE, LILACS and Scopus. The inclusion criteria were original studies that analyzed any component of the immune system in patients with CHD who had undergone thymectomy during cardiac surgery in the first years of life. The results were evaluated for the quality of evidence.ResultsTwenty-three studies were selected and showed that patients who underwent a thymectomy in the first years of life tended to exhibit important alterations in the T cell compartment, such as fewer total T cells, CD4+, CD8+, naïve and CD31+ T cells, lower TRECs, decreased diversity of the TCR repertoire and higher peripheral proliferation (increased Ki-67 expression) than controls. However, the numbers of memory T cells and Treg cells differed across the selected studies.ConclusionsEarly thymectomy, either partial or complete, may be associated with a reduction in many T cell subpopulations and TCR diversity, and these alterations may persist during long-term follow-up. Alternative solutions should be studied, either in the operative technique with partial preservation of the thymus or through the autograft of fragments of the gland.Systematic Review RegistrationProspero [157188].

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