Transforming growth factor-ß1 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-ß1 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.

The Latin American experience of allografting patients with severe aplastic anaemia: real-world data on the impact of stem cell source and ATG administration in HLA-identical sibling transplants.

We studied 298 patients with severe aplastic anaemia (SAA) allografted in four Latin American countries. The source of cells was bone marrow (BM) in 94 patients and PBSCs in 204 patients. Engraftment failed in 8.1% of recipients with no difference between BM and PBSCs (P=0.08). Incidence of acute GvHD (aGvHD) for BM and PBSCs was 30% vs 32% (P=0.18), and for grades III-IV was 2.6% vs 11.6% (P=0.01). Chronic GvHD (cGvHD) between BM and PBSCs was 37% vs 59% (P=0.002) and extensive 5% vs 23.6% (P=0.01). OS was 74% vs 76% for BM vs PBSCs (P=0.95). Event-free survival was superior in patients conditioned with anti-thymocyte globulin (ATG)-based regimens compared with other regimens (79% vs 61%, P=0.001) as excessive secondary graft failure was seen with other regimens (10% vs 26%, P=0.005) respectively. In multivariate analysis, aGvHD II-IV (hazard ratio (HR) 2.50, confidence interval (CI) 1.1-5.6, P=0.02) and aGvHD III-IV (HR 8.3 CI 3.4-20.2, P<0.001) proved to be independent negative predictors of survival. In conclusion, BM as a source of cells and ATG-based regimens should be standard because of higher GvHD incidence with PBSCs, although the latter combining with ATG in the conditioning regimen could be an option in selected high-risk patients.