| 1. |
- Elgbratt, Kristina, 1969-, et al.
(författare)
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A quantitative study of the mechanisms behind thymic atrophy in G alpha i2-deficient mice during colitis development
- 2012
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Ingår i: PLOS ONE. - San Francisco, USA : Public Library of Science. - 1932-6203. ; 7:5
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Tidskriftsartikel (refereegranskat)abstract
- Mice deficient for the G protein subunit G alpha i2 spontaneously develop colitis, a chronic inflammatory disease associated with dysregulated T cell responses. We and others have previously demonstrated a thymic involution in these mice and an aberrant thymocyte dynamics. The G alpha i2(-/-) mice have a dramatically reduced fraction of double positive thymocytes and an increased fraction of single positive (SP) thymocytes. In this study, we quantify a number of critical parameters in order to narrow down the underlying mechanisms that cause the dynamical changes of the thymocyte development in the G alpha i2(-/-) mice. Our data suggest that the increased fraction of SP thymocytes results only from a decreased number of DP thymocytes, since the number of SP thymocytes in the Gai2(-/-) mice is comparable to the control littermates. By measuring the frequency of T cell receptor excision circles (TRECs) in the thymocytes, we demonstrate that the number of cell divisions the G alpha i2(-/-) SP thymocytes undergo is comparable to SP thymocytes from control littermates. In addition, our data show that the mature SP CD4(+) and CD8(+) thymocytes divide to the same extent before they egress from the thymus. By estimating the number of peripheral TREC+ T lymphocytes and their death rate, we could calculate the daily egression of thymocytes. G alpha i2(-/-) mice with no/mild and moderate colitis were found to have a slower export rate in comparison to the control littermates. The quantitative measurements in this study suggest a number of dynamical changes in the thymocyte development during the progression of colitis.
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| 2. |
- Elgbratt, Kristina, et al.
(författare)
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Rapid migration of thymic emigrants to the colonic mucosa in ulcerative colitis patients
- 2010
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Ingår i: Clinical and Experimental Immunology. - Malden, USA : Wiley-Blackwell Publishing Inc.. - 0009-9104 .- 1365-2249. ; 162:2, s. 325-336
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Tidskriftsartikel (refereegranskat)abstract
- P>Inflammatory bowel disease (IBD) is associated with imbalances of the local intestinal immune responses, with dysregulated CD4+ T cells contributing to the chronic inflammation. Having demonstrated altered T cell maturation in the thymus in two different mouse models of colitis, we set out to investigate whether abnormalities in T cell maturation is present in patients with ulcerative colitis (UC) or Crohn's disease (CD). Specimens were obtained from peripheral blood (CD; n = 14, UC; n = 22), colon and small intestinal specimens (CD; n = 6, UC; n = 13). As controls, peripheral blood specimens were obtained from healthy volunteers, patients with adenocarcinomas (n = 18) and colonic specimens from patients with adenocarcinomas (n = 14). Recent thymic emigrants were estimated by analysis of the normalized ratio of T cell receptor excision circles (TRECs) by real-time polymerase chain reaction (PCR). The frequency of naive- and proliferating T lymphocytes and markers of extrathymic T cell maturation in the mucosa was analyzed by flow cytometry and real time-PCR. TREC levels in peripheral blood T lymphocytes were similar between IBD patients and controls. In contrast, UC patients demonstrated significantly increased levels of TRECs both in intraepithelial and lamina propria lymphocytes from the colonic mucosa compared to patients with adenocarcinomas and CD. However, markers for extrathymic T cell maturation in the mucosa were not different between controls and IBD patients. The increased TREC levels in mucosal but not peripheral blood lymphocytes in UC patients in the absence of increased extrathymic maturation in situ in the mucosa together demonstrate that recent thymic emigrants are recruited rapidly to the inflamed mucosa of these patients.
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| 4. |
- Kumawat, Ashok Kumar, et al.
(författare)
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Microscopic colitis patients have increased frequencies of Ki67+proliferating and CD45RO+ active/memory CD8+ and CD4+8+ mucosal T cells
- 2013
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Ingår i: Journal of Crohn's & Colitis. - Oxford, United Kingdom : Oxford University Press. - 1873-9946 .- 1876-4479. ; 7:9, s. 694-705
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Tidskriftsartikel (refereegranskat)abstract
- Background: Collagenous colitis (CC) and lymphocytic colitis (LC) are chronic inflammatory bowel disorders of unknown etiology. This study investigated phenotypic characteristics of the mucosal lymphocytes in CC and LC.Methods: Lamina propria and intraepithelial lymphocytes (LPLs, IELs) isolated from mucosal biopsies from CC (n = 7), LC (n = 6), as well as LC or CC patients in histopathological remission, (LC-HR) (n = 6) and CC-HR (n = 4) and non-inflamed controls (n = 10) were phenotypically characterized by four-color flow cytometry.Results: The proportions of CD8+ IELs were increased in CC and LC (p < 0.01) compared to controls. Increased proportions of CD45RO+CD8+ IELs and LPLs were observed in LC and even more in CC patients (p < 0.01). Both CC (p < 0.05) and LC patients had elevated proportions of CD4+8+ IELs and LPLs compared to controls. The proportions of CD45RO+ cells were increased in CD4+8+ IELs and LPLs (p < 0.05) in CC and LC patients compared to controls. Both CC (p < 0.05) and LC patients had higher proportions of Ki67+CD8+ IELs and LPLs compared to controls.In contrast, decreased proportions of CD4+ LPLs were observed in CC and LC as well as CD4+ IELs in LC compared to controls. Increased proportions of Ki67+CD4+ IELs and LPLs (p < 0.05) were observed in CC and LC patients. CC-HR but not LC-HR patients demonstrated normalized proportions of both IELs and LPLs compared to CC and LC patients respectively.Conclusion: LC and CC patients have differences in mucosal lymphocyte subsets, with increased proportions of Ki67+ and CD45RO+ CD8+ and CD4+8+ mucosal T cells.
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| 5. |
- Kumawat, Ashok Kumar, 1982-, et al.
(författare)
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Reduced T cell receptor excision circle levels in the colonic mucosa of microscopic colitis patients indicate local proliferation rather than homing of peripheral lymphocytes to the inflamed mucosa
- 2013
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Ingår i: BioMed Research International. - New York, USA : Hindawi Publishing Corporation. - 2314-6133 .- 2314-6141.
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Tidskriftsartikel (refereegranskat)abstract
- Dysregulated T cell responses in the intestine may lead to chronic bowel inflammation such as collagenous colitis (CC) and lymphocytic colitis (LC), together known as microscopic colitis (MC). Having demonstrated increased local T cell responses in the intestinal mucosa of MC patients, we investigated the recent thymic emigrants by measuring T cell receptor excision circle (TREC) levels in the colonic biopsies from CC (n = 8), LC (n = 5), and CC or LC patients in histopathological remission (CC-HR, n = 3) (LC-HR, n = 6), non-inflamed diarrhoea patients (n = 17), and controls (n = 10) by real-time PCR. We observed lower median TREC levels in both CC and LC patients as well as in LC-HR patients compared to controls. In contrast to MC patients, non-inflamed diarrhoea patients presented with enhanced TREC levels compared to controls. None of the recorded differences did, however, reach statistical significance. A trend towards increased relative expression of CD3 was noted in all MC subgroups examined and reached statistical significance in LC patients compared to controls. In conclusion, reduced TRECs level in the colonic mucosa, together with our previously demonstrated enhanced expression of Ki67(+) T cells, suggests local expansion of resident T lymphocytes in the inflamed mucosa of MC patients.
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