BACKGROUND Hematopoietic stem cells (HSCs) are routinely obtained from marrow, mobilized peripheral blood, and umbilical cord blood. Mesenchymal stem cells (MSCs) are traditionally isolated from marrow. Bone marrow–derived MSCs (BM-MSCs) have previously demonstrated their ability to act as a feeder layer in support of ex vivo cord blood expansion. However, the use of BM-MSCs to support the growth, differentiation, and engraftment of cord blood may not be ideal for transplant purposes. Therefore, the potential of MSCs from a novel source, the Wharton’s jelly of umbilical cords, to act as stromal support for the long-term culture of cord blood HSC was evaluated. STUDY DESIGN AND METHODS Umbilical cord–derived MSCs (UC-MSCs) were cultured from the Wharton’s jelly of umbilical cord segments. The UC-MSCs were then profiled for expression of 12 cell surface receptors and tested for their ability to support cord blood HSCs in a long-term culture-initiating cell (LTC-IC) assay. RESULTS Upon culture, UC-MSCs express a defined set of cell surface markers (CD29, CD44, CD73, CD90, CD105, CD166, and HLA-A) and lack other markers (CD45, CD34, CD38, CD117, and HLA-DR) similar to BM-MSCs. Like BM-MSCs, UC-MSCs effectively support the growth of CD34+ cord blood cells in LTC-IC assays. CONCLUSION These data suggest the potential therapeutic application of Wharton’s jelly–derived UC-MSCs to provide stromal support structure for the long-term culture of cord blood HSCs as well as the possibility of cotransplantation of genetically identical, HLA-matched, or unmatched cord blood HSCs and UC-MSCs in the setting of HSC transplantation.

Given the tremendous need for and potential of umbilical cord blood (CB) to be utilized as a donor source for hematopoietic stem cell (HSC) transplantation in adults, there is a strong push to overcome the constraints created by the limited volumes and subsequent limited HSC and hematopoietic progenitor cell (HPC) numbers available for HSC transplantation from a single collection. We have previously described the use of CD26 inhibitor treatment of donor cells as a method to increase the transplant efficiency of mouse HSCs and HPCs into a mouse recipient. To study the use of CD26 inhibitors as a method of improving the transplantation of human CB HSCs and HPCs, we utilized the nonobese diabetic/severe combined immunodeficient/beta 2 microglobulin null (NOD/SCID/B2m(null)) immunodeficient mouse model of HSC transplantation. We report here significant improvements in the engraftment of long-term repopulating cells following the treatment of either CD34(+) or lineage negative (lin()) donor CB with the CD26 inhibitor, Diprotin A, prior to transplant. These results establish a basis on which to propose the use of CD26 inhibitor treatment of donor CB units prior to transplantation for the purpose of improving transplant efficiency and subsequently patient outcome.

Early treatment of CLL/SLL does not impact survival-reflecting limitations in detecting progression early and identifying asymptomatic patients likely to benefit from early treatment. Improved understanding of CLL/SLL biology would identify better prognostic/predictive markers. This study attempts to address these issues by determining the relationship between cytokine aberrations and poor clinical outcomes in CLL/SLL in the context of a genetic-based prognostic model. Fifty-nine serum cytokines/chemokines were measured in 28 untreated CLL/SLL patients. Patients were stratified as GR or int/PR using cytogenetics. Comparison of CLL/SLL with 28 HCs revealed increased expression of Th2 cytokines (IL-10, IL-5, sIL-2Rα; P≤0.01) and decreased levels of Th1 cytokines (IL-17, IL-23, IFN-γ; P≤0.003). In a multivariate analysis of GR versus int/PR groups, differential expression of sIL-2Rα maintained significance with increased expression in int/PR CLL/SLL. With median follow-up of 54.3 months after diagnosis, four patients incurred disease progression, with an IL-17/sIL-2Rα model predicting need for treatment in all cases. In summary, specific cytokine signatures are associated with genetically defined aggressive disease and predict need for therapy. This suggests utility in detecting disease progression early, identifying those likely to incur a survival advantage with early treatment, and directing future therapy.

Objective We previously reported that inhibition or loss of CD26 (DPPIV/dipeptidylpeptidase IV) results in a defect in normal mobilization of hematopoietic stem and progenitor cells induced by granulocyte-colony stimulating factor (G-CSF). This suggests that CD26 is a necessary component of the mobilization pathway. Our goal in this study was to determine whether mobilization can be induced by the CXCR4 antagonist AMD3100 in mice lacking CD26 (CD26-/-). Materials and Methods Ten week old CD26-/- and C57BL/6 mice received a subcutaneous injection of AMD3100. One hour post-injection the mice were euthanized and peripheral blood and bone marrow were collected and evaluated. Results AMD3100 mobilizes hematopoietic progenitors into the peripheral blood of CD26-/- and mice. Conclusions Our finding that AMD3100 rapidly mobilizes hematopoietic progenitor cells from the bone marrow into the periphery in CD26 deficient transgenic mice that otherwise exhibit a mobilization defect in response to G-CSF suggests that: (1) CD26 is downstream of G-CSF but upstream of the CXCL12-CXCR4 axis and (2) AMD3100 can be used as a single agent to mobilize hematopoietic stem and progenitor cells in normal donors or patients that have an intrinsic defect in their response to G-CSF treatment. Stem cell transplants are often the only curative treatment in some cancer patients. The ability to perform the transplant and its success is dependent on the ability to mobilize adequate numbers of hematopoietic progenitor cells. The use of AMD3100 as a single agent would give patients or donors an additional option for a successful stem cell transplant.