Lymphocyte collection for donor leucocyte infusion from normal donors: estimation of the minimum processed blood volume and safety of the procedure

High Graft CD8 Cell Dose Predicts Improved Survival and Enables Better Donor Selection in Allogeneic Stem-Cell Transplantation With Reduced-Intensity Conditioning

PURPOSE

To characterize the impact of graft T-cell composition on outcomes of reduced-intensity conditioned (RIC) allogeneic hematopoietic stem-cell transplantation (alloHSCT) in adults with hematologic malignancies.

PATIENTS AND METHODS

We evaluated associations between graft T-cell doses and outcomes in 200 patients who underwent RIC alloHSCT with a peripheral blood stem-cell graft. We then studied 21 alloHSCT donors to identify predictors of optimal graft T-cell content.

RESULTS

Higher CD8 cell doses were associated with a lower risk for relapse (adjusted hazard ratio [aHR], 0.43; P = .009) and improved relapse-free survival (aHR, 0.50; P = .006) and overall survival (aHR, 0.57; P = .04) without a significant increase in graft-versus-host disease or nonrelapse mortality. A cutoff level of 0.72 × 10(8) CD8 cells per kilogram optimally segregated patients receiving CD8(hi) and CD8(lo) grafts with differing overall survival (P = .007). Donor age inversely correlated with graft CD8 dose. Consequently, older donors were unlikely to provide a CD8(hi) graft, whereas approximately half of younger donors provided CD8(hi) grafts. Compared with recipients of older sibling donor grafts (consistently containing CD8(lo) doses), survival was significantly better for recipients of younger unrelated donor grafts with CD8(hi) doses (P = .03), but not for recipients of younger unrelated donor CD8(lo) grafts (P = .28). In addition, graft CD8 content could be predicted by measuring the proportion of CD8 cells in a screening blood sample from stem-cell donors.

CONCLUSION

Higher graft CD8 dose, which was restricted to young donors, predicted better survival in patients undergoing RIC alloHSCT.

Dysregulation in microRNA expression in peripheral blood mononuclear cells of sepsis patients is associated with immunopathology

Sepsis is a major cause of death worldwide. It triggers systemic inflammation, the role of which remains unclear. In the current study, we investigated the induction of microRNA (miRNA) during sepsis and their role in the regulation of inflammation. Patients, on days 1 and 5 following sepsis diagnosis, had reduced T cells but elevated monocytes. Plasma levels of IL-6, IL-8, IL-10 and MCP-1 dramatically increased in sepsis patients on day 1. T cells from sepsis patients differentiated primarily into Th2 cells, whereas regulatory T cells decreased. Analysis of 1163 miRNAs from PBMCs revealed that miR-182, miR-143, miR-145, miR-146a, miR-150, and miR-155 were dysregulated in sepsis patients. miR-146a downregulation correlated with increased IL-6 expression and monocyte proliferation. Bioinformatics analysis uncovered the immunological associations of dysregulated miRNAs with clinical disease. The current study demonstrates that miRNA dysregulation correlates with clinical manifestations and inflammation, and therefore remains a potential therapeutic target against sepsis.

Improved strategy for mononuclear cell collection for donor lymphocyte infusions

BACKGROUND

To improve donor management for donor lymphocyte collections, a protocol was established to tailor the amount of whole blood processed during leukapheresis to achieve the requested cellular dose.

STUDY DESIGN AND METHODS

A retrospective review of donor and product records of all donors who provided donor lymphocytes during the period October 27, 1999, to March 2, 2005, was performed (25 donors, 54 collections). Data on product total CD3+ T cells collected and total blood volume (TBV) processed were used to establish a correlation between the two variables. The resultant correlation from the reference group (8 donors, 13 collections) was then used to prospectively determine the TBV to be processed in a subsequent series of collections ("prospective group": 18 donors, 41 collections). Donor charts were also reviewed to determine leukapheresis-associated adverse events.

RESULTS

The application of the correlation data between TBV processed and CD3+ T-cell yields from the initial reference group to the prospective group yielded 92 percent successful collections; in 3 of the 4 inadequate collections, the predefined maximum of three times their TBV was processed. Compared to the reference group, the TBV processed in the prospective group was decreased from 12,598+/-4007 to 7942+/-5079 mL; the length of procedure was decreased from 208+/-53 to 146+/-79 minutes. Adverse event data were reviewed for 51 collections; the percentage of procedures without adverse events increased from 23 percent in the reference group to 37 percent in the prospective group.

CONCLUSION

Application of correlation data between TBV processed and CD3+ T-cell yield was useful to predict efficient and successful donor lymphocyte collections.

Leukapheresis for the extraction of monocytes and various lymphocyte subpopulations from peripheral blood: product quality and prediction of the yield using different harvest procedures

BACKGROUND AND OBJECTIVES

Leukapheresis of non-mobilized healthy donors is performed to harvest monocytes and lymphocyte subpopulations for use in various therapeutic regimens. In this methodological study, we compared two different leukapheresis programs, using equivalent volumes of processed blood over similar processing periods, to determine the influence of the procedures on the donor peripheral blood count and to establish the procedure that yields the highest quality product.

MATERIALS AND METHODS

The target variables obtained in 41 healthy blood donors who underwent short-term leukapheresis (80-105 min) were retrospectively compared. Twenty-one volunteers were processed on a COBE Spectra machine at the MNC setting and 20 volunteers were processed at the AutoPBSC setting. Data were collected on pre- and postleukapheresis samples and on the product.

RESULTS

AutoPBSC and MNC procedures resulted in a decrease of haemoglobin (5-7%), platelets (17-20%), monocytes (22%) and lymphocytes (23-27%), but not of granulocytes in peripheral blood. Both procedures produced nearly identical leucocyte and lymphocyte yields. AutoPBSC products contained a greater number of granulocytes, monocytes and red cells, but fewer platelets. The preleukapheresis values correlated with the yields for monocytes, T-helper and T-suppressor cells, B-lymphocytes and natural killer cells, but not for granulocytes or platelets.

CONCLUSIONS

Leukapheresis is a safe and efficient procedure for collecting large numbers of peripheral blood monocytes and different lymphocyte populations from non-mobilized donors. The two programs yield comparable leucocyte harvests. Based on our results, yields can be predicted from the peripheral cell counts.

Use of natural killer cells in hematopoetic stem cell transplantation

Adoptive immunotherapy using natural killer (NK) cells may prove useful, especially in situations where infusion of T cells is impractical such as in recipients of haploidentical stem cell transplantation (HSCT) from haploidentical donors. NK cells may induce potent antileukemic and possibly antirejection activity and may even mitigate graft versus host disease (GvHD). Whether such effects are clinically important and whether they are mediated mainly or exclusively by KIR-HLA class I interactions remains to be determined. Recent advances in graft engineering provide for methods to isolate large numbers of purified NK cells. Several groups have shown that clinical grade NK cells up to a dose of 10(7)/kg may be collected and purified for the purpose of infusion to patients. Early results, in a limited number of patients, show that these cell doses may be administered without adverse events and without inducing GvHD. Whether such infusions will be useful in preventing graft rejection, or exerting graft versus leukemia effects and hastening immune recovery requires further study.

Purified donor NK-lymphocyte infusion to consolidate engraftment after haploidentical stem cell transplantation

This pilot study tested feasibility of natural killer cell purification and infusion (NK-DLI) in patients after haploidentical hematopoietic stem cell transplantation (HSCT). The aim was to obtain >or=1.0 x 10(7)/kg CD56+/CD3- NK cells and <1.0 x 10(5)/kg CD3+ T cells. Mononuclear cells were collected by 10 l leukapheresis. A two-step ex vivo procedure was used to purify NK cells, using an immunomagnetic T-cell depletion, followed by NK-cell enrichment. Five patients with high-risk myeloid malignancies were included, presenting 3-12 months after a haploidentical HSCT with mixed chimerism (3), impending graft failure (1) or early relapse (1). The purified product contained a median of 1.61 x 10(7)/kg (range 0.21-2.2) NK cells and 0.29 x 10(5)/kg (0.11-1.1) T cells. A purity of NK cells of 97% (78-99), a recovery of 35.5% (13-75), and a T-cell depletion of 3.55 log (2.9-4.5) was achieved. Infusions were well tolerated and none of the patients developed graft-versus-host disease. We observed an increase in donor chimerism in 2/5, stable mixed chimerism, decreasing chimerism and relapse of AML in one patient each. Selection of NK-DLI is technically feasible. NK cells are well tolerated when used as adoptive immunotherapy in recipients of haploidentical HSCT.

The impact of granulocyte colony stimulating factor at content of donor lymphocytes collected for cellular immunotherapy

BACKGROUND AND OBJECTIVES

Donor lymphocyte infusions (DLI) have become widely used for prevention or treatment of relapse after allogeneic hematopoietic stem cell transplantation. Increasing use of reduced intensity conditioning regimens (RICR) and subsequent application of DLI forced the hemapheresis centers to collect donor lymphocytes in certain quantity and quality. The place of growth factors especially granulocyte colony stimulating factor (rhG-CSF, filgrastim) in allogeneic hemapoietic stem cell (HSC) collection is established, but there is no consensus about the role of rhG-CSF. We aimed to clarify the dose effect of rhG-CSF on lymphocyte subpopulations (CD3+, CD3+4+, CD3+8+, CD19+, CD3-16+56+) cells and CD34+ HSC.

DONORS AND METHODS

Major indications for DLI (mean volume: 180+/-52 ml) were for relapse or transplants using RICR mainly in patients with acute leukemia (n=20) or chronic myeloid leukemia (n=15). In four years we performed 40 lymphocyte apheresis (LA) on 30 healthy (med. age 28, M/F 21/9) donors using continuous flow cell separators by processing 2-2.5 times of their total blood volume (TBV). The apheresis data is divided into three groups according to rhG-CSF dose used for priming. Donors in Group I (n=18), Group II (n=9) and Group III (n=13) received no rhG-CSF (steady state), rhG-CSF 5 microg/kg/dsc x 5 days and rhG-CSF 10 microg/kg/dsc x 5 days, respectively. There was no difference within groups concerning TBV processed and recipient body weight.

RESULTS

A total of 11,565 ml (+/-3700) of blood was processed in 216 min (+/-36.5) at an inlet of 56.8 ml/min (+/-10.6) using 999 ml (+/-307) ACD. The CD34+ HSC increased with increasing rhG-CSF dose as expected. Median CD3+ lymphocyte yield per recipient body weight in Group I, II and III were 0.9 x 10e8/kg (range: 0.1-2.1), 2.9 x 10e8/kg (range: 1.6-4.3) and 2.1 x 10e8/kg (range: 0.6-6.9), respectively. The primed donors T lymphocyte yield was 2-3-fold more in comparison to Group I. This gain was most significant between Group I and III in terms of mean CD3+ (1.09 x 10e8/kg vs 2.41 x 10e8/kg, p=0.02), CD3+4+ (0.64 x 10e8/kg vs 1.44 x 10e8/kg, p=0.02) and CD3+8+ (0.42 x 10e8/kg vs 0.89 x 10e8/kg, p=0.03) cells, respectively.

CONCLUSION

Though the yield of lymphocyte subsets in G-CSF primed donors exceeds the non-primed donors, the target range of 1 x 10e7-1 x 10e8/kg CD3+ lymphocytes could be achieved in the majority of the apheresis procedures without rhG-CSF priming. The yield of T and B lymphocyte subsets are increased by G-CSF stimulation but not on a logarithmic scale, which did not correlate into a clinical relevance.

Monitoring and isolation of blood dendritic cells from apheresis products in healthy individuals: a platform for cancer immunotherapy

The fundamental role of dendritic cells (DC) in initiating and directing the primary immune response is well established. Furthermore, it is now accepted that DC may be useful in new vaccination strategies for preventing certain malignant and infectious diseases. As blood DC (BDC) physiology differs from that of the DC homologues generated in vitro from monocyte precursors, it is becoming more relevant to consider BDC for therapeutic interventions. Until recently, protocols for the isolation of BDC were laborious and inefficient; therefore, their use for investigative cancer immunotherapy is not widespread. In this study, we carefully documented BDC counts, yields and subsets during apheresis (Cobe Spectra), the initial and essential procedure in creating a BDC isolation platform for cancer immunotherapy. We established that an automated software package (Version 6.0 AutoPBPC) provides an operator-independent reliable source of mononuclear cells (MNC) for BDC preparation. Further, we observed that BDC might be recovered in high yields, often greater than 100% relative to the number of circulating BDC predicted by blood volume. An average of 66 million (range, 17-179) BDC per 10-l procedure were obtained, largely satisfying the needs for immunization. Higher yields were possible on total processed blood volumes of 15 l. BDC were not activated by the isolation procedure and, more importantly, both BDC subsets (CD11c(+)CD123(low) and CD11c(-)CD123(high)) were equally represented. Finally, we established that the apheresis product could be used for antibody-based BDC immunoselection and demonstrated that fully functional BDC can be obtained by this procedure.