Expression of apoptosis-related antigens, Fas, bcl-2, and p53, and Mib-1 proliferation index in the hypoplastic thymus of DiGeorge syndrome
Apoptosis, along with cellular proliferation, plays a major role in normal developmental processes and tissue homeostasis. We hypothesized that altered apoptosis-related pathways and/or reduced cell proliferation might play a role in the thymic hypoplasia or aplasia in DiGeorge syndrome (DG). We use...
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Published in | Pediatric and developmental pathology Vol. 5; no. 5; pp. 465 - 471 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.09.2002
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Subjects | |
Online Access | Get full text |
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Summary: | Apoptosis, along with cellular proliferation, plays a major role in normal developmental processes and tissue homeostasis. We hypothesized that altered apoptosis-related pathways and/or reduced cell proliferation might play a role in the thymic hypoplasia or aplasia in DiGeorge syndrome (DG). We used immunohistochemistry to evaluate the apoptosis-related antigens Fas (CD95), bcl-2, and p53, as well as Mib-1 proliferation index in the thymuses from six patients with DG. The results were compared with those from the thymuses from six patients with non-DG congenital heart disease. All DG patients (age 32 weeks GA to 4 months) had hypoplastic thymuses ranging from microscopic foci to 2.7 g in weight (expected for age, 4.7 +/- 3.6 g to 10 +/- 6 g). The thymic weights from the patients with non-DG congenital heart disease (age 37 weeks GA to 1 month) ranged from 3 to 5.6 g and were at the lower range of expected weight by age (expected for age, 8.4 +/- 5.6 g to 12 +/- 7 g). All thymuses showed histologic features of stress-induced involution. In both groups, a - 50% Mib-1 proliferation index was found in the cortical thymocytes, whereas <5% Mib-1 labeling was seen in the medullary thymocytes; Fas stained medullary epithelial cells (3+) and cortical epithelial cells (1+); bcl-2 stained medullary thymocytes (3+) and cortical thymocytes (1+); p53 stained less than 1% of nuclei in all sections. No significantly altered Mib-1 proliferation index or expression of Fas, bcl-2, and p53 was observed in the hypoplastic thymuses in DG, compared to these same measures in non-DG. These results suggest that thymic hypoplasia in DG may be mediated by mechanisms other than reduced cellular proliferation and/or altered Fas, bcl-2, and p53 apoptotic pathways. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1093-5266 1615-5742 |
DOI: | 10.1007/s10024-002-2004-7 |