A novel association between relaxin receptor polymorphism and hematopoietic stem cell yield after mobilization

Getting blood out of a stone: Identification and management of patients with poor hematopoietic cell mobilization

Hematopoietic cell transplantation (HCT) has become a primary treatment for many cancers. Nowadays, the primary source of hematopoietic cells is by leukapheresis collection of these cells from peripheral blood, after a forced egress of hematopoietic cells from marrow into blood circulation, a process known as "mobilization". In this process, mobilizing agents disrupt binding interactions between hematopoietic cells and marrow microenvironment to facilitate collection. As the first essential step of HCT, poor mobilization, i.e. failure to obtain a desired or required number of hematopoietic cell, is one of the major factors affecting engraftment or even precluding transplantation. This review summarizes the available mobilization regimens using granulocyte-colony stimulating factor (G-CSF) and plerixafor, as well as the current understanding of the factors that are associated with poor mobilization. Strategies to mobilize patients or healthy donors who failed previous mobilization are discussed. Multiple novel agents are under investigation and some of them have shown the potential to enhance the mobilization response to G-CSF and/or plerixafor. Further investigation of the risk factors including genetic factors will offer an opportunity to better understand the molecular mechanism of mobilization and help develop new therapeutic strategies for successful mobilizations.

Salvage treatment with plerixafor in poor mobilizing allogeneic stem cell donors: results of a prospective phase II-trial

We conducted a prospective clinical trial to investigate the safety and efficacy of plerixafor (P) in allogeneic peripheral blood stem cells (PBSC) donors with poor mobilization response to standard-dose granulocyte colony-stimulating factor (G-CSF), defined by <2 × 10⁶ CD34 + cells/kg recipient body-weight (CD34+/kg RBW) after 1st apheresis. A single dose of 240 µg/kg P was injected subcutaneously at 10 p.m. on the day of the 1st apheresis. Thirty-seven allogeneic PBSC donors underwent study treatment. The median CD34+ count in peripheral blood was 15/µl on Day 1 after G-CSF alone, versus 44/µl on Day 2 after G-CSF plus P (p < 0.001). The median yield of CD34+ cells was 1.1 × 10⁸ on Day 1 and 2.8 × 10⁸ on Day 2. In contrast to a median yield of only 1.31 × 10⁶ CD CD34+/kg RBW on Day 1, triggering study inclusion, a median of 3.74 × 10⁶ CD CD34+/kg RBW were collected with G-CSF plus P on Day 2. Of 37 donors, 21 reached the target cell count of >4.5 × 10⁶ CD34+/kg RBW (57%, 95%CI 40-73%). No donor experienced a severe adverse event requiring treatment. In conclusion, P might be considered on a case-by-case basis for healthy allogeneic donors with very poor stem cell mobilization success after G-CSF.

Impact of CD44 gene single nucleotide polymorphism (rs 13347) in mobilization of autologous HSCT

MOBILIZATION: of stem cells into peripheral blood is a crucial step in the procedure of autologous stem cell transplantation. Mobilization can be affected by many variables;underlying diseases, prior treatment and age. Many genetic polymorphisms mainly in adhesion molecules are thought to affect mobilization success. The CD44 is a cell adhesion molecule which is highly heterogeneous structurally. Polymorphisms in this molecule may impair HSC lodgment in the bone marrow.

THE AIM OF THE WORK

was to assess the impact of CD44 single nucleotide polymorphism (rs13347) on the efficacy of mobilization of CD34+ hematopoietic progenitor cells in a cohort of Egyptian patients treated for lymphoma and multiple myeloma and scheduled for autologous stem cell transplantation.

PATIENTS AND METHODS

the study was conducted on 92 patients scheduled for autologous HSC mobilization and transplantation. SNP genotyping was done by 5 ꞌ nuclease assay on rotor gene.

RESULTS

A statistical significant difference was detected between the patients with genotypes (CT + CC) and patients with (TT) genotype regarding the number of apheresis sessions required to gather the target CD34 count (p = 0.006).T allele is implicated in poorer mobilization.

CONCLUSIONS

CD44 SNPs analysis may be helpful for predicting the poor mobilizers. These patients may benefit from newer modalities like adhesion molecules inhibitors.

The Biological and Clinical Relevance of G Protein-Coupled Receptors to the Outcomes of Hematopoietic Stem Cell Transplantation: A Systematized Review

Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment for several malignant and non-malignant diseases at the cost of serious treatment-related toxicities (TRTs). Recent research on extending the benefits of HSCT to more patients and indications has focused on limiting TRTs and improving immunological effects following proper mobilization and engraftment. Increasing numbers of studies report associations between HSCT outcomes and the expression or the manipulation of G protein-coupled receptors (GPCRs). This large family of cell surface receptors is involved in various human diseases. With ever-better knowledge of their crystal structures and signaling dynamics, GPCRs are already the targets for one third of the current therapeutic arsenal. The present paper assesses the current status of animal and human research on GPCRs in the context of selected HSCT outcomes via a systematized survey and analysis of the literature.