Publications by authors named "Stefanie Y Zimmermann"

3 Publications

  • Page 1 of 1

An alternative approach to establishing unbiased colorectal cancer risk estimation in Lynch syndrome.

Genet Med 2019 12 17;21(12):2706-2712. Epub 2019 Jun 17.

Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands.

Purpose: Biallelic pathogenic variants in the mismatch repair (MMR) genes cause a recessive childhood cancer predisposition syndrome known as constitutional mismatch repair deficiency (CMMRD). Family members with a heterozygous MMR variant have Lynch syndrome. We aimed at estimating cancer risk in these heterozygous carriers as a novel approach to avoid complicated statistical methods to correct for ascertainment bias.

Methods: Cumulative colorectal cancer incidence was estimated in a cohort of PMS2- and MSH6-associated families, ascertained by the CMMRD phenotype of the index, by using mutation probabilities based on kinship coefficients as analytical weights in a proportional hazard regression on the cause-specific hazards. Confidence intervals (CIs) were obtained by bootstrapping at the family level.

Results: The estimated cumulative colorectal cancer risk at age 70 years for heterozygous PMS2 variant carriers was 8.7% (95% CI 4.3-12.7%) for both sexes combined, and 9.9% (95% CI 4.9-15.3%) for men and 5.9% (95% CI 1.6-11.1%) for women separately. For heterozygous MSH6 variant carriers these estimates are 11.8% (95% CI 4.5-22.7%) for both sexes combined, 10.0% (95% CI 1.83-24.5%) for men and 11.7% (95% CI 2.10-26.5%) for women.

Conclusion: Our findings are consistent with previous reports that used more complex statistical methods to correct for ascertainment bias. These results underline the need for MMR gene-specific surveillance protocols for Lynch syndrome.
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December 2019

Age-matched lymphocyte subpopulation reference values in childhood and adolescence: application of exponential regression analysis.

Eur J Haematol 2008 Jun 12;80(6):532-9. Epub 2008 Feb 12.

Paediatric Haematology, Oncology and Haemostaseology, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany.

Background: Normal values of lymphocyte subpopulations for healthy children and adults have been published in defined age groups exclusively, which results in difficult data interpretation for patients close to the limit of contiguous age group ranges. In addition, normal values for a number of lymphocyte subpopulations have not been established to date.

Objective: The aim of this study was to develop a model which provides continuous age-dependent reference values. This model was applied for lymphocyte subpopulations such as naïve and memory T cells as well as their activation profile with diagnostic relevance in children and adults.

Study Design: A total of 100 blood samples, obtained from 80 healthy children and 20 adults were analysed by means of four colour-flow cytometry. Continuous age-dependent reference values were computed based on the residual values in an exponential regression model.

Results: We calculated a continuous age-related regression model for both, absolute cell counts and percentages of CD3(+)CD4(+) T helper (T(H)) cells, CD3(+)CD8(+) cytotoxic T cells, CD56(+)CD3(-) natural killer (NK) cells, CD56(+)CD3(+) T cells, CD3(+)CD4(+)CD45RA(+) naïve T(H) cells, CD3(+)CD4(+)CD45RO(+) memory T(H) cells, CD3(+)CD8(+)CD45RA(+)CD28(+) naïve cytotoxic T cells, CD3(+)CD8(+)CD45RO(+) memory cytotoxic T cells, CD3(+)CD8(+)CD69(+) early activated cytotoxic T cells and CD3(+)CD8(+)HLA-DR(+) late activated cytotoxic T cells, respectively, to obtain reference values.

Conclusion: Based on an exponential regression model, the obtained reference values reflect the continuous maturation of lymphocyte subsets during childhood.
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June 2008

Imbalance in distribution of functional autologous regulatory T cells in rheumatoid arthritis.

Ann Rheum Dis 2007 Sep 28;66(9):1151-6. Epub 2007 Mar 28.

pharmazentrum frankfurt, ZAFES Clinic of Goethe University, Frankfurt, Germany.

Objectives: Regulatory T cells (Tregs) exert their anti-inflammatory activity predominantly by cell contact-dependent mechanisms. A study was undertaken to investigate the regulatory capacity of autologous peripheral blood Tregs in contact with synovial tissue cell cultures, and to evaluate their presence in peripheral blood, synovial tissue and synovial fluid of patients with rheumatoid arthritis (RA).

Methods: 44 patients with RA and 5 with osteoarthritis were included in the study. The frequency of interferon (IFN)gamma-secreting cells was quantified in synovial tissue cell cultures, CD3-depleted synovial tissue cell cultures, synovial tissue cultures co-cultured with autologous CD4+ and with CD4+CD25+ peripheral blood T cells by ELISPOT. Total CD3+, Th1 polarised and Tregs were quantified by real-time PCR for CD3epsilon, T-bet and FoxP3 mRNA, and by immunohistochemistry for FoxP3 protein.

Results: RA synovial tissue cell cultures exhibited spontaneous expression of IFNgamma which was abrogated by depletion of CD3+ T cells and specifically reduced by co-culture with autologous peripheral blood Treg. The presence of Treg in RA synovitis was indicated by FoxP3 mRNA expression and confirmed by immunohistochemistry. The amount of FoxP3 transcripts, however, was lower in the synovial membrane than in peripheral blood or synovial fluid. The T-bet/FoxP3 ratio correlated with both a higher grade of synovial tissue lymphocyte infiltration and higher disease activity.

Conclusion: This study has shown, for the first time in human RA, the efficacy of autologous Tregs in reducing the inflammatory activity of synovial tissue cell cultures ex vivo, while in the synovium FoxP3+ Tregs of patients with RA are reduced compared with peripheral blood and synovial fluid. This local imbalance of Th1 and Treg may be responsible for repeated rheumatic flares and thus will be of interest as a target for future treatments.
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September 2007