Variable impact of graft CD3+ cell content on graft versus host disease in hematopoietic stem cell transplant recipients: Is the role of donor CD3+ cells overestimated?

Graft cellular composition is considered as a significant determinant of transplant outcome. Donor CD3+ cells were shown to have a significant association with the development of graft vs host disease (GvHD). The aim of this study was to investigate the impact of graft CD3+ cell content on transplant outcome, particularly in terms of GvHD and relapse. We retrospectively analysed the records of 515 allo-HCT recipients [median age: 37(15-71) years; male/female: 323/192]. The optimal threshold of infused CD3+ cell count for acute GvHD development was estimated to be 197.5 × 106/kg (AUC: 0.572; 95 % CI: 0.513-0.631; p = 0.018) and 198.5 × 106/kg (AUC: 0.6; 95 % CI: 0.520-0.679; p = 0.019) for the general population and reduced-intensity conditioning (RIC) subgroup, respectively. Acute GvHD was more frequent in low-CD3+ group in the whole study population, particularly in RIC transplants. The incidence of cytomegalovirus reactivation was higher in low-CD3+ group and neutrophil engraftment occured earlier in the same group of patients. Overall survival and non-relapse mortality were comparable between high and low-CD3+ groups. Age, ECOG performance status, hypogammaglobulinemia, chronic GvHD and post-transplant relapse were found to predict prognosis in multivariate analysis. By focusing mainly on donor T cells, the potential role of host immune cells in the early post-transplant milieu may have been underestimated. Drawing a more detailed profile of graft and host immune cells in the joint microenvironment may elucidate our way to a better understanding of GvHD pathogenesis. By this way a comprehensive pre-transplant risk assessment could be improved to generate more personalized approaches.

The Impact of Pre-transplant Cell-free DNA Levels on Leukemia Relapse and Transplant-related Complications in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Background: Cell-free DNA, which may be considered as "liquid" biopsy, may serve as a diagnostic and prognostic marker not only in hematological malignancies but in solid tumors as well. Aims: To investigate the prognostic role of pre-transplant cell-free DNA levels in allogeneic hematopoietic stem cell transplant recipients. Study Design: Retrospective cohort study. Methods: A total of 177 allogeneic hematopoietic stem cell transplant recipients [median age: 36 (16-66) years; male/female: 111/66] with an initial diagnosis of acute leukemia were included in the study. Cell-free DNA was extracted from pre-transplant serum samples by using the MagNA Pure Compact Nucleic Acid Isolation Kit I with the MagNA Pure Compact instrument (Roche Diagnostics, Penzberg, Germany). Results: A positive correlation was demonstrated between cell-free DNA and age (p=0.018; r=0.177). Pre-transplant cell-free DNA levels were lower in bcr-abl (+) patients (p=0.001), while an adverse correlation was indicated between cell-free DNA and bcr-abl levels (p=0.001; r=−0.531). Acute lymphoblastic leukemia patients with bcr-abl positivity (p=0.001) or abnormal cytogenetics (p=0.038) represented significantly lower pre-transplant cell-free DNA levels. Cell-free DNA levels were lower in patients who developed sinusoidal obstruction syndrome (p=0.035). In terms of long-term complications, acute myeloid leukemia patients who experienced post-transplant relapse had significantly lower pre-transplant cell-free DNA levels (p=0.024). Overall survival was not statistically different between high- and low- cell-free DNA groups (45.2% vs 22.5; p=0.821). Conclusion: In general, low serum levels of pre-transplant çell-free DNA seem to be associated with transplant-related morbidities and may be considered an adverse prognostic factor for allogeneic hematopoietic stem cell transplant recipients.

Factors affecting hematopoietic stem cell mobilization and apheresis in allogeneic donors: The role of iron status.

Infused CD34 cell count has a significant impact on transplant outcome. In this retrospective study, we aimed to analyze the impact of donor iron parameters on peripheral blood stem cell (PBSC) collection. A total of 303 related donors were included in the study. The mobilization regimen, recombinant G-CSF, was given for four consecutive days. A CD34+ cell count below 2×106/kg was defined as mobilization failure which was demonstrated in 23 donors (7.6%). Mobilization failure was more frequent in female donors than male donors (13.7% vs 3.4%). Body mass index, mean corpuscular volume, hemoglobin and ferritin levels were found to be lower in donors with mobilization failure. Body mass index was significantly correlated with PBSC count on the 4th day of G-CSF. Body mass index, male gender, mean corpuscular volume and ferritin levels had significant impact on PBSC count. Although PBSC count was found to be similar between female and male donors, female gender was shown to have an adverse impact on PBSC collection, which may be attributed to lower body weight and concurrent iron deficiency.

Inflammatory markers, oxidative stress, and antioxidant capacity in healthy allo-HSCT donors during hematopoietic stem cell mobilization.

The aim of this study is to investigate the impact of mobilization with granulocyte colony stimulating factor (G-CSF) and apheresis procedure on inflammatory and oxidative stress markers, and antioxidant capacity in healthy allo-HSCT donors. The study was conducted in the Stem Cell Transplantation Unit of Gazi University Hospital between October 2010 and March 2011, and 25 consecutive allo-HSCT donors were included. The alteration in the serum levels of iron, iron binding capacity, albumin, ferritin, IL-6, hs-CRP, TAC, MDA, and AOPP were determined at five different time points. (1) Prior to the first dose of G-CSF (T0), (2) preapheresis (on the fourth day of G-CSF before the apeheresis procedure) (T1), (3) immediately postapheresis (T2), (4) 24 h postapheresis (T3), and (5) a week after apheresis (T4). Serum ferritin levels increased steadily after administration of G-CSF and remained high up toT4. Both serum IL-6 and hs-CRP levels began to increase in the T1 sampling and reached to a maximum level at T3 and decreased even below the basal levels at T4. Serum AOPP levels decreased at preapheresis and postapheresis time points, while they increased at T3 and T4 samples. Serum MDA levels decreased at T1, T2, T3, and T4 samples. Serum TAC increased significantly and steadily at all time points post G-CSF. In conclusion; mobilization with G-CSF and apheresis caused a transient inflammatory reaction and a protein limited oxidative stress in healthy allo-HCT donors.