Association of functional polymorphisms of the transforming growth factor B1 gene with survival and graft-versus-host disease after unrelated donor hematopoietic stem cell transplantation

Investigation of TGFB1 -1347C>T variant as a biomarker after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative therapeutic option for malignant hematopoietic diseases. Cytokines including transforming growth factor β1 (TGFβ1) play a pivotal role in immune reconstruction, and the development of graft versus host disease (GvHD) or infections. The aim of this study was to investigate the role of TGFB1 gene -1347C>T variant in the outcome of HSCT in a cohort of 409 adult recipient-donor pairs. TGFB1 variant was analysed from genomic DNA with LightCycler hybridisation probe method. In case of myeloablative conditioning, donor TGFB1 genotype correlated with overall survival (60-month OS for CC: 62.1 ± 4.8%; CT: 46.8 ± 4.8%; TT: 35.6 ± 9.3%; p = 0.032), which was independent of age, donor type and GvHD prophylaxis in multivariate analysis (HR:2.35, 95%CI:1.35-4.10, p = 0.003). The cumulative incidence of acute GvHD grade III-IV [CC:10%; CT:17%; TT:24%], and non-relapse mortality was higher in TT-carriers (24-month NRM: CC:24%; CT:26%; TT:46%, p = 0.035). We did not find any association between recipient TGFB1 -1347C>T polymorphism and HSCT outcome. Our results suggest that donor TGFB1 -1347C>T may exert an adverse influence on the outcome of myeloablative conditioning transplantation.

Transforming growth factor-β1 functional polymorphisms in myeloablative sibling hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) with sibling donors (s.d.) is a life-saving intervention for patients with hematological malignancies. Numerous genetic factors have a role in transplant outcome. Several functional polymorphisms have been identified in TGF-β1 gene, such as single-nucleotide polymorphism (SNP) at +29C>T within exon 1. Two hundred and forty five patient/donor pairs who underwent a s.d. HSCT in our centers were genotyped for this SNP. In the myeloablative cohort, +29CC donors were associated with an increase in severe chronic GvHD (32% vs 16%, hazard ratio (HR) 9.0, P=0.02). Regarding survival outcomes, +29CC patients developed higher non relapse mortality (NRM) (1-5 years CC 28-32% vs TC/TT 7-10%; HR 5.1, P=0.01). Recipients of +29TT donors experienced a higher relapse rate (1-5 years TT 37-51% vs TC 19-25% vs CC 13%-19%; HR 2.4, P=0.01) with a decreased overall survival (OS) (1-5 years TT 69-50% vs TC/CC 77-69%; HR 1.9, P=0.05). Similar to previous myeloablative unrelated donors HSCT results, we confirmed that +29CC patients had higher NRM. In addition we found that +29TT donors might be associated with a higher relapse rate and lower OS. These results should be confirmed in larger series. Identification of these SNPs will allow personalizing transplant conditioning and immunosuppressant regimens, as well as assisting in the choice of the most appropriate donor.

Transforming growth factor-β1 polymorphisms and graft-versus-host disease risk: a meta-analysis

Some studies have demonstrated that transforming growth factor (TGF)-β polymorphisms may have an important role in the pathological process of graft-versus-host disease (GVHD). However, the results are not consistent. Thus, we performed a meta-analysis. Online databases were searched to obtain relevant articles published up until May 2015. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Donors (OR=0.56; 95%CI, 0.32-0.98; P=0.04) and recipients (OR=0.73; 95%CI, 0.63-0.85; P<0.0001) with TGF-β1 rs1800469 polymorphism showed decreased GVHD risk, respectively. Donors with TGF-β1 rs1800470 polymorphism were also observed to have lower GVHD risk (OR=0.65; 95%CI, 0.46-0.94; P=0.02). However, TGF-β1 rs1800470 polymorphism in recipients was not associated with GVHD risk (OR=1.28; 95%CI, 0.81-2.01; P=0.29). No significant heterogeneity was found in the meta-analysis. This meta-analysis suggests that donors or recipients with TGF-β1 rs1800469 polymorphism and donors with TGF-β1 rs1800470 polymorphism might be associated with reduced GVHD risk.

Polymorphism in TGFB1 is associated with worse non-relapse mortality and overall survival after stem cell transplantation with unrelated donors

Transforming growth factor β-1, encoded by the TGFB1 gene, is a cytokine that plays a central role in many physiological and pathogenic processes. We have sequenced TGFB1 regulatory region and assigned allelic genotypes in a large cohort of hematopoietic stem cell transplantation patients and donors. In this study, we analyzed 522 unrelated donor-patient pairs and examined the combined effect of all the common polymorphisms in this genomic region. In univariate analysis, we found that patients carrying a specific allele, 'p001', showed significantly reduced overall survival (5-year overall survival 30.7% for p001/p001 patients vs. 41.6% others; P=0.032) and increased non-relapse mortality (1-year non-relapse mortality: 39.0% vs. 25.4%; P=0.039) after transplantation. In multivariate analysis, the presence of a p001/p001 genotype in patients was confirmed as an independent factor for reduced overall survival [hazard ratio=1.53 (1.04-2.24); P=0.031], and increased non-relapse mortality [hazard ratio=1.73 (1.06-2.83); P=0.030]. In functional experiments we found a trend towards a higher percentage of surface transforming growth factor β-1-positive regulatory T cells after activation when the cells had a p001 allele (P=0.07). Higher or lower production of transforming growth factor β-1 in the inflammatory context of hematopoietic stem cell transplantation may influence the development of complications in these patients. Findings indicate that TGFB1 genotype could potentially be of use as a prognostic factor in hematopoietic stem cell transplantation risk assessment algorithms.

Concise review: workshop review: understanding and assessing the risks of stem cell-based therapies

The field of stem cell therapeutics is moving ever closer to widespread application in the clinic. However, despite the undoubted potential held by these therapies, the balance between risk and benefit remains difficult to predict. As in any new field, a lack of previous application in man and gaps in the underlying science mean that regulators and investigators continue to look for a balance between minimizing potential risk and ensuring therapies are not needlessly kept from patients. Here, we attempt to identify the important safety issues, assessing the current advances in scientific knowledge and how they may translate to clinical therapeutic strategies in the identification and management of these risks. We also investigate the tools and techniques currently available to researchers during preclinical and clinical development of stem cell products, their utility and limitations, and how these tools may be strategically used in the development of these therapies. We conclude that ensuring safety through cutting-edge science and robust assays, coupled with regular and open discussions between regulators and academic/industrial investigators, is likely to prove the most fruitful route to ensuring the safest possible development of new products.