Martin Stern

Risk Score for Outcome After Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Analysis

It was investigated whether the European Group for Blood and Marrow Transplantation risk score, previously established for chronic myeloid leukemia, could be used to predict outcome after allogeneic hematopoietic stem cell transplantation (HSCT) for hematological disease in general.

Survival after T cell–depleted haploidentical stem cell transplantation is improved using the mother as donor

We hypothesized that transplacental leukocyte trafficking during pregnancy, which induces long-term, stable, reciprocal microchimerism in mother and child, might influence outcome of patients with acute leukemia given parental donor haploidentical hematopoietic stem cell transplantation (HSCT). We analyzed the outcome of 118 patients who received transplants for acute leukemia in 2 centers. Patients received highly T cell-depleted haploidentical grafts after myelo-ablative conditioning. Five-year event-free survival was better in patients who received transplants from the mother than from the father (50.6% +/- 7.6% vs 11.1% +/- 4.2%; P < .001). Better survival was the result of both reduced incidence of relapse and transplantation-related mortality. The protective effect was seen in both female and male recipients, in both lymphoid and myeloid diseases; it was more evident in patients receiving transplants in remission than in chemotherapy-resistant relapse. Incidences of rejection and acute graft-versus-host disease were not significantly influenced. Multivariate analysis confirmed donor sex in parental donor transplantation as an independent prognostic factor for survival (hazard ratio, father vs mother = 2.36; P = .003). In contrast, in a control cohort of patients who received transplants from haploidentical siblings, donor sex had no influence on outcome. Although obtained in a retrospective analysis, these data suggest that the mother of the patient should be preferred as donor for haploidentical HSCT.

Pre-emptive immunotherapy with purified natural killer cells after haploidentical SCT: a prospective phase II study in two centers

Adoptive immunotherapy with allogeneic purified natural killer (NK) cell products might exert graft-versus-tumor alloreactivity with little risk of GVHD. In a prospective phase II study in two centers, we administered purified NK cell products to high-risk patients treated with haploidentical T-cell-depleted SCT. Sixteen patients received a total of 29 NK cell infusions on days +3, +40 and +100 after transplantation. Median doses (and ranges) of infused NK- and T-cells per product were 1.21 (0.3–3.8) × 107/kg and 0.03 (0.004–0.72) × 105/kg, respectively. With a median follow-up of 5.8 years 4/16 patients are alive. Cause of death was relapse in five, GVHD in three, graft failure in three, and transplant related neurotoxicity in one patient. Four patients developed acute GVHD⩾grade II, all receiving a total of ⩾0.5 × 105 T cells/kg. Compared with historical controls, NK cell infusions had no apparent effect on the rates of graft failure or relapse. Adoptive transfer of allogeneic NK cells is safe and feasible, but further studies are needed to determine the optimal dose and timing of NK cell therapy. Moreover, NK cell activation/expansion may be required to attain clinical benefit, while careful consideration must be given to the number of T cells infused.

Use of natural killer cells in hematopoetic stem cell transplantation

Summary: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 107/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.

Human leukocyte antigens A23, A24, and A32 but not A25 are ligands for KIR3DL1.

Inhibitory killer cell immunoglobulin receptors (KIR) bind to major histocompatibility complex antigens. Concise knowledge of KIR ligands allows prediction of natural killer (NK)-cell alloreactivity after hematopoietic stem cell transplantation. KIR3DL1 binds to the Bw4 epitope on HLA-B antigens. Although the same epitope is also found on 4 HLA-A antigens (HLA-A23/24/25/32), these are not currently regarded as KIR3DL1 ligands. We show that expression of HLA A*2301, A*2402, or A*3201 but not HLA A*2501 protects target cells from lysis by KIR3DL1(+) NK cells. KIR3DL1(+) NK cells from donors expressing the Bw4 epitope on an HLA-A antigen only are fully functional and capable of lysing Bw4(-) target cells. HLA A25 differs at amino acid 90, close to the serologic Bw4 epitope, from A23/24/32 and from Bw4(+) HLA-B antigens. These data suggest that HLA-A antigens should be taken into consideration when assessing the potential for NK alloreactivity after hematopoietic stem cell transplantation.

Influence of donor/recipient sex matching on outcome of allogeneic hematopoietic stem cell transplantation for aplastic anemia

Background. Increased risk of transplant related mortality in male recipients of female hematopoietic stem cell grafts and in vitro reactivity of lymphocytes against H-Y encoded gene products in females with rejected male grafts have been documented. An increased rejection of male grafts in female recipients is not reported for solid organ or stem cell transplants and the role of H-Y as transplantation antigen has been controversial. Methods. Data from 1481 patients with a hematopoietic stem cell transplant for aplastic anemia reported from 154 centers in 28 countries were analyzed. Outcome was compared between patients with donors of the same or opposite sex. Results. Survival at 5 years was significantly better in patients with donors from the same sex: 68% vs. 60% (P=0.001). Male patients with female donors had a decreased survival (relative risk of death 1.52, P<0.001) and an increased risk of severe graft-versus-host disease (relative risk 1.33, P=0.03) compared to recipients of sex-matched grafts. Female patients with male donors had a decreased survival (relative risk of death 1.44, P=0.01) and an increased risk of rejection (relative risk 2.20, P=0.01) compared to recipients of sex-matched grafts. In a subgroup analysis, the negative effects of donor/recipient sex-mismatching appeared confined to patients receiving conditioning regimens not containing antithymocyte globulin. Conclusions. These data confirm H-Y as a clinically relevant transplantation antigen, in both the graft-versus-host and the host-versus-graft direction. Wherever possible, donor-recipient sex-matching should be integrated into donor selection algorithms.

Female-Versus-Male Alloreactivity as a Model for Minor Histocompatibility Antigens in Hematopoietic Stem Cell Transplantation

H‐Y encoded gene products were the first to be recognized as clinically relevant minor histocompatibility antigens. Compared to other gender combinations, female donor/male recipient (FDMR) transplants are associated with increased graft‐versus‐host disease (GvHD), increased transplant‐related mortality (TRM) and reduced risk of relapse. Still, their relative impact on transplant outcome remains controversial. We analyzed donor/recipient sex combination in 53u2003988 patients treated with allogeneic hematopoietic stem cell transplantation (HSCT) between 1980 and 2005. We found a strong increase in chronic GvHD and late TRM and decreased survival in FDMR transplants irrespective of underlying disease. Conversely, FDMR patients had lower relapse rates. The negative effect on survival decreased with advancing disease stage as relapse protection became more important. Effects of H‐Y alloreactivity were most pronounced in patients transplanted from HLA‐matched donors and in those receiving transplants from an adult donor. Adjustment for acute and chronic GvHD only partially corrected the effects of H‐Y alloreactivity. Analysis of the FDMR proportion over time indicated that the frequency of this gender combination has declined in unrelated transplants over the last 10 years. These data define the role of H‐Y mismatching in allogeneic HSCT and support the current practice of avoiding female donors for male patients, if possible.

Clinical Grade Purification and Expansion of NK Cell Products for an Optimized Manufacturing Protocol

Allogeneic natural killer (NK) cells are used for adoptive immunotherapy after stem cell transplantation. In order to overcome technical limitations in NK cell purification and activation, the following study investigates the impact of different variables on NK cell recovery, cytotoxicity, and T-cell depletion during good manufacturing practice (GMP)-grade NK cell selection. Forty NK cell products were derived from 54 unstimulated donor leukaphereses using immunomagnetic CD3 T-cell depletion, followed by a CD56 cell enrichment step. For T-cell depletion, either the depletion 2.1 program in single or double procedure (D2.11depl, nu2009=u200918; D2.12depl, nu2009=u200913) or the faster depletion 3.1 (D3.1, nu2009=u20099) was used on the CliniMACS instrument. Seventeen purified NK cell products were activated in vitro by IL-2 for 12u2009days. The whole process resulted in a median number of 7.59u2009×u2009108 CD56+CD3− cells with both purity and viability of 94%, respectively. The T-cell depletion was significantly better using D2.11depl/2depl compared to D3.1 (log 4.6/log 4.9 vs. log 3.7; pu2009<u20090.01) and double procedure in two stages led always to residual T cells below 0.1%. In contrast D3.1 was superior to D2.11depl/2depl with regard to recovery of CD56+CD3− NK cells (68% vs. 41%/38%). Concomitant monocytes and especially IL-2 activation led to increased NK cell activity against malignant target cells compared to unstimulated NK cells, which correlated with both up-regulation of natural cytotoxicity receptors and intracellular signaling. Overall, wide variations in the NK cell expansion rate and the distribution of NK cell subpopulations were found. In conclusion, our results indicate that GMP-grade purification of NK cells might be improved by a sequential processing of T-cell depletion program D2.1 and D3.1. In addition NK cell expansion protocols need to be further optimized.

Haploidentical hematopoietic transplantation from KIR ligand–mismatched donors with activating KIRs reduces nonrelapse mortality

Because activating killer cell immunoglobulinlike receptors (KIRs) are heterogeneously expressed in the population, we investigated the role of donor activating KIRs in haploidentical hematopoietic transplants for acute leukemia. Transplants were grouped according to presence vs absence of KIR-ligand mismatches in the graft-vs-host direction (ie, of donor-vs-recipient natural killer [NK]-cell alloreactivity). In the absence of donor-vs-recipient NK-cell alloreactivity, donor activating KIRs had no effects on outcomes. In the 69 transplant pairs with donor-vs-recipient NK-cell alloreactivity, transplantation from donors with KIR2DS1 and/or KIR3DS1 was associated with reduced risk of nonrelapse mortality, largely infection related (KIR2DS1 present vs absent: hazard ratio [HR], 0.25; P = .01; KIR3DS1 present vs absent: HR, 0.18; P = .006), and better event-free survival (KIR2DS1 present vs absent: HR, 0.31; P = .011; KIR3DS1 present vs absent: HR, 0.30; P = .008). Transplantation from donors with KIR2DS1 and/or KIR3DS1 was also associated with a 50% reduction in infection rate (P = .003). In vitro analyses showed that KIR2DS1 binding to its HLA-C2 ligand upregulated inflammatory cytokine production by alloreactive NK cells in response to infectious challenges. Because ∼40% of donors able to exert donor-vs-recipient NK-cell alloreactivity carry KIR2DS1 and/or KIR3DS1, searching for them may become a feasible, additional criterion in donor selection.

The value of routine ferritin measurement in blood donors

BACKGROUND: Iron store deficiency is a common side effect of whole blood donation. Early recognition and reversal of excessive iron loss may avoid symptomatic iron store depletion in blood donors and reduce volunteer loss due to iron deficiency (ID) anemia.