Flowchart: Preparation: Zap70
 
 
 
 

 D-G

 

 BC

 

  A

 
                    

                      

Text Box: Cd45

                                                                                     

                                     

 Leukemia                                                                    

                   

Text Box: Zap70

           

                             

                                                                          

Text Box: Chronic lymphocyte leukemia
 


                             

 

 

 

 

J Clin Oncol. 2006 Feb 20;24(6):969-75. Epub 2006 Jan 17.

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Additional genetic high-risk features such as 11q deletion, 17p deletion, and V3-21 usage characterize discordance of ZAP-70 and VH mutation status in chronic lymphocytic leukemia.

Krober A, Bloehdorn J, Hafner S, Buhler A, Seiler T, Kienle D, Winkler D, Bangerter M, Schlenk RF, Benner A, Lichter P, Dohner H, Stilgenbauer S.

Department of Internal Medicine, University of Ulm, Ulm, Germany.

PURPOSE: Immunoglobulin heavy chain variable-region (VH) gene mutation status and zeta-associated protein 70 (ZAP-70) expression are correlated in chronic lymphocytic leukemia (CLL), but their concordance is variable. The goal of this study was to elucidate additional factors potentially characterizing their discordance. PATIENTS AND METHODS: We evaluated ZAP-70 expression by flow cytometry, VH status by DNA sequencing, and genomic aberrations by fluorescence in situ hybridization in 148 CLL patients. The parameters were analyzed for their associations and their individual prognostic impact. RESULTS: ZAP-70 expression and VH mutation status were strongly associated in CLL without additional genetic high-risk-features as defined by the absence of 11q or 17p deletion and V3-21 usage (concordance 84%). In contrast, the proportion of discordant cases was significantly higher (39%), if such additional genetic high-risk features were present. Discordant cases with V3-21 usage were almost exclusively ZAP-70 positive and VH mutated (89%), whereas all but one of the discordant cases with high-risk aberrations were ZAP-70 negative and VH unmutated (92%). By multivariate regression analysis, two models were developed, which both include high-risk genomic aberrations and, alternatively, VH mutation status and V3-21 usage or ZAP-70 expression as independent outcome predictors. CONCLUSION: There were characteristic modes of discordance between ZAP-70 and VH mutation status depending on the presence or absence of additional genetic high-risk features such as 11q and 17p deletion or V3-21 usage. Although the biologic background for these findings is yet to be determined, these data have biologic and clinical implications regarding ZAP-70 as a pathogenic factor and outcome predictor, respectively.

PMID: 16418492 [PubMed - indexed for MEDLINE]

J Immunol. 2006 Jan 15;176(2):931-8.

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The 77C->G mutation in the human CD45 (PTPRC) gene leads to increased intensity of TCR signaling in T cell lines from healthy individuals and patients with multiple sclerosis.

Do HT, Baars W, Borns K, Windhagen A, Schwinzer R.

Transplantationslabor, Klinik fur Viszeral-und Transplantationschirurgie, Hannover, Germany.

The 77C-->G mutation in exon A of the human CD45 gene occurs with low frequency in healthy individuals. An enhanced frequency of 77C-->G individuals has been reported in cohorts of patients suffering from multiple sclerosis, systemic sclerosis, autoimmune hepatitis, and HIV-1. To investigate the mechanisms by which the variant allele may contribute to disease susceptibility, we compared T cell reactivity in heterozygous carriers of the mutation (healthy individuals and multiple sclerosis patients) and wild-type controls. In vitro-generated T cell lines and freshly isolated CD4+CD45R0+ primed/memory T cells from 77C-->G individuals aberrantly expressed CD45RA isoforms and showed enhanced proliferation and IL-2 production when stimulated with anti-TCR/CD3 mAb or Ag. Mutant T cell lines contained a more active pool of p56lck tyrosine kinase and responded with increased phosphorylation of Zap70 and TCR-zeta and an enhanced Ca2+ flux to TCR/CD3 stimulation. These data suggest that 77C-->G may act as a risk factor for certain diseases by increasing the intensity of TCR signaling.

PMID: 16393978 [PubMed - indexed for MEDLINE]