The importance of the number of transplanted cells with dipeptidyl peptidase-4 expression on the haematopoietic recovery and lymphocyte reconstitution in patients with multiple myeloma after autologous haematopoietic stem-cell transplantation

Gender and the length of time since autologous hematopoietic stem cell transplantation-What is their influence on the immune reconstitution in multiple myeloma patients?

INTRODUCTION

In the literature there is lack of information on the influence of gender and time since autologous hematopoietic stem cell transplantation (HSCT) on the immune reconstitution in multiple myeloma (MM) patients.

OBJECTIVE

The aim of this study was to assess the diversity of the immune reconstitution according to gender in MM patients after autologous HSCT on the day of the clinic discharge and on the 29th day after discharge, as well as to investigate the changes in the immune system in females and males after staying at home for 28 days.

METHOD

The studied population comprised 13 females and 13 males after autologous HSCT. On the day of the clinic discharge and on the 29th day after discharge blood samples were taken to analyse 22 immunological parameters. Statistical analysis was performed using STATISTICA 10 StatSoft Poland. For multiple comparisons, the Bonferroni correction was used.

RESULTS

No statistically significant differences were observed in the analysed immunological parameters between the studied females and males with MM on the day of the clinic discharge and on the 29th day after discharge. However, on the 29th day after the clinic discharge compared to the day of the clinic discharge, statistically significant differences were found in 8 immunological parameters among females and 6 immunological parameters among males.

CONCLUSION AND RECOMMENDATION

Our results indicate that the immune reconstitution is similar but not the same in patients of both genders. Statistically significant differences in the immune response in the studied females and males imply that gender may play a role in the immune reconstitution and that the results obtained in MM patients should be analysed separately in females and males. In order to explain the observed changes in the immune system according to gender, further research should be carried out on a larger population. This would most probably make it possible to find their clinical application.

Effect of transplanted cells with CD184 and CD26 expressions and reconstitution of CD3+ lymphocyte population on long-term survival after autologous hematopoietic stem cell transplantation for multiple myeloma

Autologous hematopoietic stem cell transplantation (auto-SCT) is the recommended treatment for responding patients with multiple myeloma (MM). However, we do not know the risk factors influencing long-term survival without progression after auto-SCT. Therefore, this prospective study aimed to investigate the influence of transplanted cells with cluster of differentiation (CD)184+ expression, CD26+ lymphocytes and monocytes, and reconstitution of CD3+ lymphocytes on overall survival (OS) and progression-free survival (PFS) after auto-SCT in MM. Forty-eight patients with MM underwent auto-SCT at our center from 2011 to 2013. The numbers of CD184+ cells, CD26+ lymphocytes, and CD26+ monocytes were measured in the harvested material. In addition, the number of lymphocyte subpopulations (CD3+ lymphocytes, helpers, suppressors, natural killer (NK), cytotoxic NK, and B lymphocytes) was measured in peripheral blood during regeneration after auto-SCT. Flow cytometry was performed in both cases. The median OS was 92 months. Our analysis revealed a statistically significant effect of the number of transplanted CD184+ cells on OS and a statistically significant correlation between PFS and the number of transplanted CD184+ cells and reconstitution of CD3+ lymphocytes. In conclusion, our study showed that the increasing numbers of transplanted CD184+ cells, CD26+ lymphocytes, and CD26+ monocytes augmented the risk of death.

Degranulation of human cytotoxic lymphocytes is a major source of proteolytically active soluble CD26/DPP4

Dipeptidyl peptidase 4 (DPP4, CD26) is a serine protease detected on several immune cells and on epithelial cells of various organs. Besides the membrane-bound enzyme, a catalytically active soluble form (sCD26/DPP4) is detected in several body fluids. Both variants cleave off dipeptides from the N-termini of various chemokines, neuropeptides, and hormones. CD26/DPP4 plays a fundamental role in the regulation of blood glucose levels by inactivating insulinotropic incretins and CD26/DPP4 inhibitors are thus routinely used in diabetes mellitus type 2 therapy to improve glucose tolerance. Such inhibitors might also prevent the CD26/DPP4-mediated inactivation of the T-cell chemoattractant CXCL10 released by certain tumors and thus improve anti-tumor immunity and immunotherapy. Despite its implication in the regulation of many (patho-)physiological processes and its consideration as a biomarker and therapeutic target, the cellular source of sCD26/DPP4 remains highly debated and mechanisms of its release are so far unknown. In line with recent reports that activated T lymphocytes could be a major source of sCD26/DPP4, we now demonstrate that CD26/DPP4 is stored in secretory granules of several major human cytotoxic lymphocyte populations and co-localizes with effector proteins such as granzymes, perforin, and granulysin. Upon stimulation, vesicular CD26/DPP4 is rapidly translocated to the cell surface in a Ca2+-dependent manner. Importantly, activation-induced degranulation leads to a massive release of proteolytically active sCD26/DPP4. Since activated effector lymphocytes serve as a major source of sCD26/DPP4, these results might explain the observed disease-associated alterations of sCD26/DPP4 serum levels and also indicate a so far unknown role of CD26/DPP4 in lymphocyte-mediated cytotoxicity.

Non-viral magnetic engineering of endothelial cells with microRNA and plasmid-DNA-An optimized targeting approach

Genetic modulation of angiogenesis is a powerful tool for the treatment of multiple disorders. Here, we describe a strategy to produce modified endothelial cells, which can be efficiently magnetically guided. First, we defined optimal transfection conditions with both plasmid and microRNA, using a polyethyleneimine/magnetic nanoparticle-based vector (PEI/MNP), previously designed in our group. Further, two approaches were assessed in vitro: direct vector guidance and magnetic targeting of transfected cells. Due to its higher efficiency, including simulated dynamic conditions, production of miR/PEI/MNP-modified magnetically responsive cells was selected for further detailed investigation. In particular, we have studied internalization of transfection complexes, functional capacities and intercellular communication of engineered cells and delivery of therapeutic miR. Moreover, we demonstrated that 10⁴ miRNA/PEI/MNP-modified magnetically responsive cells loaded with 0.37pg iron/cell are detectable with MRI. Taken together, our in vitro findings show that PEI/MNP is highly promising as a multifunctional tool for magnetically guided angiogenesis regulation.

Mobilization with cyclophosphamide reduces the number of lymphocyte subpopulations in the leukapheresis product and delays their reconstitution after autologous hematopoietic stem cell transplantation in patients with multiple myeloma

BACKGROUND

Autologous hematopoietic stem cell transplantation is considered the standard of care for younger patients with multiple myeloma. Several mobilization regimens are currently used, most commonly growth factors alone or in combination with chemotherapy. The aim of our study was to investigate the differences in lymphocyte subpopulation counts between three different mobilization regimens on collection day, in the leukapheresis product and on day 15 after autologous hematopoietic stem cell transplantation.

PATIENTS AND METHODS

In total 48 patients were prospectively enrolled in three different mobilization regimens; (i) filgrastim (20), (ii) pegfilgrastim (19) and (iii) cyclophosphamide + filgrastim (9). Lymphocytes, CD16+/56+ natural killer and CD4+/CD25^high T regulatory cells were determined by flow cytometry.

RESULTS

We found a statistically significant difference between the mobilization regimens. Cyclophosphamide reduced lymphocyte and natural killer (NK) cell counts on collection day (lymphocytes 1.08 × 10⁹/L; NK cells 0.07 × 10⁹/L) compared to filgrastim (lymphocytes 3.08 × 10⁹/L; NK cells 0.52 × 10⁹/L) and pegfilgrastim (lymphocytes 3 × 10⁹/L; NK cells 0.42 × 10⁹/L). As a consequence lymphocyte and NK cell counts were also lower in the leukapheresis products following cyclophosphamide mobilization regimen (lymphocytes 50.1 × 10⁹/L; NK cells 4.18 × 10⁹/L) compared to filgrastim (lymphocytes 112 × 10⁹/L; NK cells 17.5 × 10⁹/L) and pegfilgrastim (lymphocytes 112 × 10⁹/L; NK cells 14.3 × 10⁹/L). In all mobilization regimens T regulatory cells increased 2-fold on collection day, regarding the base line value before mobilization. There was no difference in T regulatory cell counts between the regimens.

CONCLUSIONS

Mobilization with cyclophophamide reduces the number of mobilized and collected lymphocytes and NK cells as compared to mobilization with growth factors only and results in their delayed reconstitution following autologous hematopoietic stem cell transplantation. We found no difference between filgrastim and pegfilgrastim mobilization.