1
|
Costa M, Cruz E, Barton JC, Thorstensen K, Morais S, da Silva BM, Pinto JP, Vieira CP, Vieira J, Acton RT, Porto G. Effects of highly conserved major histocompatibility complex (MHC) extended haplotypes on iron and low CD8+ T lymphocyte phenotypes in HFE C282Y homozygous hemochromatosis patients from three geographically distant areas. PLoS One 2013; 8:e79990. [PMID: 24282517 PMCID: PMC3839968 DOI: 10.1371/journal.pone.0079990] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 10/02/2013] [Indexed: 12/16/2022] Open
Abstract
Hereditary Hemochromatosis (HH) is a recessively inherited disorder of iron overload occurring commonly in subjects homozygous for the C282Y mutation in HFE gene localized on chromosome 6p21.3 in linkage disequilibrium with the human leukocyte antigen (HLA)-A locus. Although its genetic homogeneity, the phenotypic expression is variable suggesting the presence of modifying factors. One such genetic factor, a SNP microhaplotype named A-A-T, was recently found to be associated with a more severe phenotype and also with low CD8+T-lymphocyte numbers. The present study aimed to test whether the predictive value of the A-A-T microhaplotype remained in other population settings. In this study of 304 HH patients from 3 geographically distant populations (Porto, Portugal 65; Alabama, USA 57; Nord-Trøndelag, Norway 182), the extended haplotypes involving A-A-T were studied in 608 chromosomes and the CD8+ T-lymphocyte numbers were determined in all subjects. Patients from Porto had a more severe phenotype than those from other settings. Patients with A-A-T seemed on average to have greater iron stores (p = 0.021), but significant differences were not confirmed in the 3 separate populations. Low CD8+ T-lymphocytes were associated with HLA-A*03-A-A-T in Porto and Alabama patients but not in the greater series from Nord-Trøndelag. Although A-A-T may signal a more severe iron phenotype, this study was unable to prove such an association in all population settings, precluding its use as a universal predictive marker of iron overload in HH. Interestingly, the association between A-A-T and CD8+ T-lymphocytes, which was confirmed in Porto and Alabama patients, was not observed in Nord-Trøndelag patients, showing that common HLA haplotypes like A*01–B*08 or A*03–B*07 segregating with HFE/C282Y in the three populations may carry different messages. These findings further strengthen the relevance of HH as a good disease model to search for novel candidate loci associated with the genetic transmission of CD8+ T-lymphocyte numbers.
Collapse
Affiliation(s)
- Mónica Costa
- Basic and Clinical Research on Iron Biology (BCRIB), Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
| | - Eugénia Cruz
- Basic and Clinical Research on Iron Biology (BCRIB), Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
- Clinical Hematology, Santo António Hospital – Centro Hospitalar do Porto, Porto, Portugal
| | - James C. Barton
- Southern Iron Disorders Center and Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Ketil Thorstensen
- Department of Medical Biochemistry, St. Olav Hospital, Trondheim, Norway
| | - Sandra Morais
- Multidisciplinary Unit of Biomedical Investigation (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- Internal Medicine, Pedro Hispano Hospital, Matosinhos, Portugal
| | - Berta M. da Silva
- Multidisciplinary Unit of Biomedical Investigation (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Jorge P. Pinto
- Basic and Clinical Research on Iron Biology (BCRIB), Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
| | - Cristina P. Vieira
- Evolutionary Systems Biology, Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
| | - Jorge Vieira
- Molecular Evolution, Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
| | - Ronald T. Acton
- Southern Iron Disorders Center and Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Microbiology and Department of Epidemiology and International Health, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Graça Porto
- Basic and Clinical Research on Iron Biology (BCRIB), Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto, Portugal
- Clinical Hematology, Santo António Hospital – Centro Hospitalar do Porto, Porto, Portugal
- Molecular Pathology and Immunology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- * E-mail:
| |
Collapse
|
2
|
Abstract
In order to update the review published in Tissue Antigens in 1997, we present here a new overview on microsatellites in the HLA region, including additional information, with focus on the following points: * Description of 103 microsatellite characteristics in the HLA region, 50 markers having been newly described since 1996. * An integrated map of the HLA region, including microsatellites and some HLA genes, revealing an important microsatellite density in the MHC (Class I, Class II and Class III regions). * A synthesis of microsatellite analysis in disease studies, summarizing results of microsatellite approaches in 24 pathologies, including autoimmune diseases, HLA-associated or HLA-linked diseases and cancers. * Other applications of HLA region microsatellites in population or transplantation studies.
Collapse
Affiliation(s)
- A Foissac
- Département d'Epidémiologie, Economie de la Santé et Santé Communitaire, Faculté de Médecine, Toulouse, France
| | | |
Collapse
|