Risk assessment in haematopoietic stem cell 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.

The influence of social support on hematopoietic stem cell transplantation survival: a systematic review of literature

BACKGROUND

Hematopoietic Stem cell Transplantation (HSCT) can negatively impact the psychosocial well-being of the patient. Social support is a complex term that has been variably used to encompass perceived and objective support, including caregiver presence. Social support has been associated with superior psychosocial outcomes; however the influence of social support on HSCT survival remains unclear. We sought to summarize the literature on the influence of social support on HSCT survival.

METHODS

MEDLINE, EMBASE, COCHRANE, CINAHL, AND PSYCINFO WERE SEARCHED USING THE FOLLOWING SEARCH CATEGORIES/CONCEPTS: 1) HSCT, 2) Social support, 3) Caregiver, 4) Survival, and 5) Treatment outcomes.

RESULTS

We identified 6 relevant studies: 4 publications, 1 dissertation, and 1 abstract. Three studies were retrospective and 3, prospective. Sample size ranged between 92-272 with a mean/median patient age between 30-55 yrs. The duration of follow-up ranged between 13.3-48 months. Social support was measured inconsistently: 2 by retrospective investigator assessment, 2 as patients' perceived support, 1 as caregiver presence, and 1 included caregiver presence and retrospective investigator assessment. The 4 published studies and 1 abstract demonstrate an association between better social support and survival. However, the unpublished dissertation, with the largest sample size found no association.

CONCLUSIONS

There is a paucity of evidence examining social support with HSCT survival. Available studies are older, with the most recent publication in 2005. A heterogeneous group of HSCT patients were studied with variable follow-up times. Further, covariates were variably considered in HSCT survival analyses and we suggest that there may be publication bias, given the negative unpublished study with the largest sample size. Prospective studies using validated scales are necessary to better assess the influence of social support on HSCT mortality. Given the potential for improved HSCT survival with better social support, HSCT centres should routinely provide HSCT recipients and their caregivers with enhanced psychosocial services.

The EBMT risk score

The European Group for Blood and Marrow Transplantation (EBMT) risk score provides a simple tool to assess instantly chances and risks of hematopoietic SCT(HSCT) for an individual patient pre-transplant. Five factors, age of the patient, stage of the disease, time from diagnosis, donor type and donor recipient gender combination augment risk for an individual patient with increasing score from 0 as best to 7 as worst in an additive way. The score holds for all acquired hematological disorders, for allogeneic and autologous HSCT (score 0-5), is independent of the HSCT technology and is valid for standard or reduced intensity conditioning. Survival is uniformly worse for older patients, transplanted in advanced disease stage after a long-time interval and with a mismatched donor than for younger patients, transplanted soon in early stage with a well matched donor. Additional risk factors such as performance score, CMV serostatus or cytokine polymorphisms improve prediction but to different extents for low or high-risk patients. Comparative assessment of disease risk and global pre-transplant risk should guide decisions for each patient with his/her specific disease between HSCT and a non-transplant approach and replace the traditional 'donor vs no donor' with such a risk-adapted individualized strategy.

The central role of the chemokine receptor, CXCR4, in haemopoietic stem cell transplantation: will CXCR4 antagonists contribute to the treatment of blood disorders?

Recent clinical trials have used CXCR4 antagonists for the rapid mobilization of CD34(+) haemopoietic stem/progenitor cells (HSC/HPC) from the bone marrow to the blood in patients refractory to granulocyte-colony-stimulating factor (G-CSF). These antagonists not only mobilize non-cycling cells with a higher proportion of repopulating cells, but also enhance CD34(+) cell mobilization when used in combination with G-CSF. Here, we review the importance of CXCR4 and its ligand CXCL12 in haemopoiesis, and the potential roles of CXCR4 antagonists in the clinical HSC transplant setting.