Immunological reconstitution and correlation of circulating serum inflammatory mediators/cytokines with the incidence of acute graft-versus-host disease during the first 100 days following unrelated umbilical cord blood transplantation

Leukemia Cells and the Cytokine Network: Therapeutic Prospects

The network and balance of cytokines is of major importance in maintaining proper homeostasis of hematopoiesis. Abnormalities in this network may result in a variety of blood disorders; however, the role of this network is not clear in leukemia. The use of antineoplastic agents has improved the survival rate of some types of leukemia, and adjunctive therapy with cytokines may be helpful. Chemotherapeutic approaches are no longer the best choice because cytotoxicity may affect normal and leukemic cells, and leukemic cells may develop resistance to the chemotherapeutic agent. Induction of differentiation to a mature phenotype and the control of apoptotic-gene expression have provided other possible alternative therapies. Combined effects of cytokines and vitamin derivatives such as retinoic acid (RA) and 1, 25 dihydroxyvitamin D3 (VD3) were found more beneficial than any of these agents individually. These agents exhibit cooperative effects, potentiate each other's effects, or both. Therefore, understanding the hematopoietic actions of these agents, their interactions with their receptors, and their differentiation signaling pathways may result In the design of new therapies. However, the role of cytokines in apoptosis is controversial because in some cases they were found to increase tumor cell resistance to apoptosis-inducing agents. Recent studies in the molecular biology of gene regulation, transcription factors, and repressors have led to new possible approaches such as differentiation therapy for the treatment of leukemia. In addition, the development of drugs that act on the molecular level such as imatinib is just the beginning of a new era in molecular targeted therapy in which the drug acts specifically on the leukemic cell. There are many possible combinations of cytokines, retinoids, and VD3, and perhaps the best therapeutic combination is yet to be described. This minireview is an update on the role of cytokines and the therapeutic potential of combinations with agents such as RA, VD3, and other chemotherapeutic agents.

Cord blood unit bankability can be predicted by prenatal sonographic parameters

OBJECTIVE

To identify possible sonographic prenatal parameters and postnatal parameters in order to obtain more bankable cord blood units (CBUs) containing a high number of primitive progenitor cells, allowing CBUs to be used as a source of haematopoietic progenitors for clinical transplantation.

STUDY DESIGN

Prospective study undertaken in the Department of Gynaecology, Obstetrics and Reproductive Science, Second University of Naples, Italy. In total, 219 unrelated CBU donors were enrolled. Ultrasound parameters (biparietal diameter, head circumference, abdominal circumference, femur length, estimation of fetal weight, umbilical artery pulsatility index), collected at hospital admission, together with birth weight and placental weight, were correlated with bankable CBU parameters (CBU volume, total nucleated cell count, CD34+ cell count).

RESULTS

Femur length and abdominal circumference correlated positively with bankable CBUs. Receiver operating curve analysis showed that these parameters can identify bankable CBUs.

CONCLUSIONS

This is the first prospective study to show the relationship between ultrasonographic fetal parameters at term and the possibility of obtaining high-quality CBUs. As such, cord blood banking could be improved worldwide by performing low-cost ultrasonographic scans.

Kinetics of IL-7 and IL-15 levels after allogeneic peripheral blood stem cell transplantation following nonmyeloablative conditioning

BACKGROUND

We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning.

METHODS

EDTA-anticoagulated plasma and serum samples were obtained before conditioning and about once per week after transplantation until day 100. Samples were aliquoted and stored at -80°C within 3 hours after collection until measurement of cytokines. IL-7 and IL-15 levels were measured by ELISAs.

RESULTS

Median IL-7 plasma levels remained below 6 pg/L throughout the first 100 days, although IL-7 plasma levels were significantly higher on days 7 (5.1 pg/mL, P=0.002), 14 (5.2 pg/mL, P<0.001), and 28 (5.1 pg/mL, P=0.03) (but not thereafter) than before transplantation (median value of 3.8 pg/mL). Median IL-15 serum levels were significantly higher on days 7 (12.5 pg/mL, P<0.001), 14 (10.5 pg/mL, P<0.001), and 28 (6.2 pg/mL, P<0.001) than before transplantation (median value of 2.4 pg/mL). Importantly, IL-7 and IL-15 levels on days 7 or 14 after transplantation did not predict grade II-IV acute GVHD.

CONCLUSIONS

These data suggest that IL-7 and IL-15 levels remain relatively low after nonmyeloablative transplantation, and that IL-7 and IL-15 levels early after nonmyeloablative transplantation do not predict for acute GVHD.

Natural killer cell differentiation from hematopoietic stem cells: a comparative analysis of heparin- and stromal cell-supported methods

Natural killer (NK) cells differentiated from hematopoietic stem cells (HSCs) may have significant clinical benefits over NK cells from adult donors, including the ability to choose alloreactive donors and potentially more robust in vivo expansion. Stromal-based methods have been used to study the differentiation of NK cells from HSCs. Stroma and cytokines support NK cell differentiation, but may face considerable regulatory hurdles. A recently reported clinical-grade, heparin-based method could serve as an alternative. How the stromal-based and heparin-based approaches compare in terms of NK cell generating efficiency or function is unknown. We show that compared with heparin-based cultures, stroma significantly increases the yield of HSC-derived NK cells by differentiating less-committed progenitors into the NK lineage. NK cells generated by both approaches were similar for most NK-activating and -inhibiting receptors. Although both approaches resulted in a phenotype consistent with CD56(bright) stage IV NK cells, heparin-based cultures favored the development of CD56(+)CD16(+) cells, whereas stroma produced more NK cell immunoglobulin-like receptor-expressing NK cells, both of which are markers of terminal maturation. At day 21, stromal-based cultures demonstrated significantly more IL-22 production, and both methods yielded similar amounts of IFN-γ production and cytotoxicity by day 35. These findings suggest that heparin-based cultures are an effective replacement for stroma and may facilitate clinical trials testing HSC-derived NK cells.

NCI, NHLBI/PBMTC first international conference on late effects after pediatric hematopoietic cell transplantation: persistent immune deficiency in pediatric transplant survivors

Defective immune reconstitution is a major barrier to successful hematopoietic cell transplantation (HCT), and has important implications in the pediatric population. There are many factors that affect immune recovery, including stem cell source and graft-versus-host disease (GVHD). Complete assessment of immune recovery, including T and B lymphocyte evaluation, innate immunity, and response to neoantigens, may provide insight as to infection risk and optimal time for immunizations. The increasing use of cord blood grafts requires additional study regarding early reconstitution and impact upon survival. Immunization schedules may require modification based upon stem cell source and immune reconstitution, and this is of particular importance as many children have been incompletely immunized, or not at all, before school entry. Additional studies are needed in children post-HCT to evaluate the impact of differing stem cell sources upon immune reconstitution, infectious risks, and immunization responses.

Cytopenia and leukocyte recovery shape cytokine fluctuations after myeloablative allogeneic hematopoietic stem cell transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation is associated with profound changes in levels of various cytokines. Emphasis has been placed on conditioning-associated mucosal damage and neutropenia and associated bacterial translocation as the initiating conditions predisposing to acute graft-versus-host disease. The post-transplant period is, however, also associated with increases in certain homeostatic cytokines. It is unclear how much the homeostatic drive to lymphocyte recovery and the production of cytokines from the engrafting donor immune system determine cytokine fluctuations in the peri- and immediate post-transplant period. The aim of this study was to examine the contributions of the conditioning regimen, donor engraftment, infections, and graft-versus-host disease to fluctuations in cytokines involved in homeostasis and inflammation.

DESIGN AND METHODS

We examined the levels of 33 cytokines in relation to peri- and post-transplant events such as conditioning regimen, chimerism, and acute graft-versus-host disease in myeloablative, non-T cell-replete HLA-identical sibling donor stem cell transplantation for hematologic malignancies.

RESULTS

We identified two cytokine storms. The first occurred following conditioning and reached peak levels when all the leukocytes were at their lowest concentrations. The second cytokine storm occurred concurrently with hematopoietic reconstitution and subsided with the achievement of full donor lymphocyte chimerism.

CONCLUSIONS

Our results indicate that both recipient-related and donor-related factors contribute to the changes in cytokine levels in the recipient following allogeneic hematopoietic stem cell transplantation. The study reported here was performed using plasma samples drawn from patients enrolled in the ClinicalTrials.gov-registered trials NCT00467961 and NCT00378534.

Instability of Foxp3 expression limits the ability of induced regulatory T cells to mitigate graft versus host disease

PURPOSE

Graft versus host disease (GVHD) is the major complication of allogeneic bone marrow transplantation (BMT) and limits the therapeutic efficacy of this modality. Although the role of natural T-regulatory cells (nTreg) in attenuating GVHD has been extensively examined, the ability of induced T-regulatory cells (iTreg) to mitigate GVHD is unknown. The purpose of this study was to examine the ability of in vitro and in vivo iTregs to abrogate GVHD.

EXPERIMENTAL DESIGN

We examined the ability of in vitro differentiated and in vivo iTregs to reduce the severity of GVHD in a clinically relevant mouse model of BMT. The effect of blockade of interleukin (IL) 6 signaling on the efficacy of these Treg populations was also studied.

RESULTS

In vitro differentiated iTregs fail to protect mice from lethal GVHD even when administered at high Treg:effector T-cell ratios. Lack of GVHD protection was associated with loss of Foxp3 expression and in vivo reversion of these cells to a proinflammatory phenotype characterized by secretion of IFN-γ. Phenotypic reversion could not be abrogated by blockade of IL-6 signaling or by in vitro exposure of iTregs to all-trans retinoic acid. In contrast, the in vivo induction of iTregs was significantly augmented by IL-6 blockade and this resulted in reduced GVHD.

CONCLUSION

Instability of Foxp3 expression limits the utility of adoptively transferred iTregs as a source of cellular therapy for the abrogation of GVHD. Blockade of IL-6 signaling augments the ability of in vivo iTregs to prevent GVHD but has no effect on in vitro differentiated iTregs.

Interleukin (IL)-15 in combination with IL-2, fms-like tyrosine kinase-3 ligand and anti-CD3 significantly enhances umbilical cord blood natural killer (NK) cell and NK-cell subset expansion and NK function

BACKGROUND AIMS

Interleukin (IL)-15 and fms-like tyrosine kinase-3 (FLT-3) are crucial factors for the development of human and murine natural killer (NK) cells. Previously, we have demonstrated significant ex vivo expansion and activation of unrelated cord blood (UCB) NK cells with an antibody/cytokine cocktail consisting of anti-CD3 + IL-2 + IL-12 + IL-7 and anti-CD3 + IL-2 + IL-12 + IL-18.

METHODS

In the current experiments, we investigated the effects of short-term culture with anti-CD3 + IL-2 + FLT-3 + IL-15 on cord blood (CB) NK cell and NK-cell subset expansion and function. CB mononuclear cells were cultured for 48 h in AIM-V media or AIM-V + IL-2 (5 ng/mL) + anti-CD3 (50 ng/mL) + FLT-3 (50 ng/mL) ± escalating doses of IL-15 (1, 10 or 100 ng/mL). Flow cytometric analysis was performed using various fluorescent-conjugated monoclonal antibodies. In vitro cytotoxicity was determined with a standard europium assay against K562 and Daudi cells.

RESULTS

There was a 4.8-fold significant increase in NK-cell population (CD3(-)/16(+)/56(+); P < 0.03), 21-fold significant increase in CD3(-)/56(+)/158a(+) (KIR2DL1/S1; P < 0.002), 46-fold significant increase in CD3(-)/56(+)/158b(+) (KIR2DL1/S2; P < 0.002) and 11.5-fold significant increase in CD3(-)/56(+)/NKB1(+) (KIR3DL1; P < 0.01). We also noted a significant increase in both NK and lymphokine-activated killer (LAK) cytotoxicity with IL-2 + anti-CD3 + FLT-3 + IL-15 (100 ng/mL) compared with IL-2 + anti-CD3 + FLT-3 and media alone against K562 (P < 0.01) and Daudi (P < 0.001), respectively.

CONCLUSIONS

We have demonstrated a significant increase in UCB NK cells and NK cells expressing a variety of killer immunoglobulin-like receptor (KIR) receptors after short-term culture with anti-CD3, IL-2, FLT-3 and IL-15. Furthermore, there was a significant increase in in vitro NK/LAK cell cytotoxicity.

High susceptibility to severe infectious complications at reinduction chemotherapy in patients who relapse after stem cell transplantation

Patients who relapse after stem cell transplantation (SCT) usually appear to be liable to severe infectious complications at reinduction chemotherapy compared to patients at the first induction therapy, though this is not statistically substantiated. The aim of this study was to analyze episodes of infectious complications during reinduction chemotherapy among patients who relapsed after SCT compared with those at the first induction chemotherapy. Between February 1988 and March 2004, 145 children received SCT, and 17 (12 with hematologic malignancies and 5 with solid tumors) were enrolled as eligible subjects for this study. Positive blood cultures (sepsis) were present in six patients exclusively at the reinduction therapy but none at the first induction (P = .009). Three of the six patients progressed to septic shock. Moreover, all patients positive for blood cultures were those with hematologic malignancy (P = .007), and every patient with septic shock had received allogenic transplantation. Our results showed that reinduction chemotherapy needs attention for severe infectious complications, particularly among patients with hematologic malignancies receiving allogenic transplantations. Possible immaturity of the reconstructed systemic immune system and/or insufficient recovery of mucosal protective functions in the patients after SCT are discussed in view of their high susceptibility to severe infectious complications.

Early lymphocyte recovery and outcomes after umbilical cord blood transplantation (UCBT) for hematologic malignancies

Rapid lymphocyte recovery after bone marrow or peripheral blood transplantation is associated with improved survival. However, the impact of early lymphocyte recovery has not been examined after umbilical cord blood transplant (UCBT). We evaluated lymphocyte recovery in 360 consecutive patients with hematologic malignancy that underwent UCBT between 2001 and 2007. Uniform myeloablative (MA), reduced intensity conditioning (RIC) and graft-versus-host disease prophylaxis regimens were used. In multivariate analysis, an absolute leukocyte count (ALC) >200 × 10(6)/L at day 30 (n = 73) after MA conditioning was associated with superior 2-year overall survival (OS) (73% versus 61%; P = .02) (relative risk [RR]: 2.29; 95% confidence interval [CI]: 1.15-4.56), progression-free survival (PFS) (68% versus 54%; P = .05) (RR: 1.96; 95% CI: 0.99-3.86) and less transplant-related mortality (8% versus 28%, P < .01) (RR: 4.38; 95% CI: 1.65-11.60) compared to ≤200 × 10(6)/L (n = 43). Similarly, an ALC >200 × 10(6)/L at day 42 (n = 105) after RIC was associated with superior 2-year OS (59% versus 41%, P < .01) (RR: 2.10; 95% CI: 1.3-3.41) and PFS (46% versus 36%, P = .05) (RR: 1.58; 95% CI: 1.01-2.49) compared to ≤200 × 10(6)/L (n = 55). There was no significant relationship between ALC and relapse. Rapid lymphocyte recovery early after UCBT predicts better survival in patients with hematologic malignancies.

Plasma levels of IL-7 and IL-15 in the first month after myeloablative BMT are predictive biomarkers of both acute GVHD and relapse

T-cell reconstitution after allo-SCT initially depends on homeostatic peripheral expansion of donor T cells, the level of which may promote the differentiation of alloreactive and tumor-reactive effectors. IL-7 and IL-15 exert their effect as key homeostatic cytokines. We prospectively investigated plasma levels of IL-7 and IL-15 in a homogeneous group of 40 patients in CR of their hematologic malignancy undergoing myeloablative, fully (10/10) HLA-matched BMT. IL-7 and IL-15 proceeded along similar kinetic courses, peaking at wide ranges (3.8-30.2 and 14.3-66 pg/ml, respectively) on day +14 when all patients were profoundly lymphopenic. Occurrence and grade of subsequent acute GVHD were significantly associated with heightened day +14 IL-7 and IL-15 levels. Association of peak IL-7 level to grade 2-4 acute GVHD was confirmed by Cox multivariate analysis (hazard ratio (HR)=5.38; P=0.022). Malignancy relapse was significantly associated with reduced day +14 levels of IL-15 (Cox multivariate analysis: HR=0.93; P=0.035). Plasma IL-7 and IL-15 levels in the early post transplantation period are therefore biomarkers that can help predict subsequent development of acute GVHD and malignancy relapse.

The phenotypic and functional characteristics of umbilical cord blood and peripheral blood natural killer cells

Allogeneic hematopoietic cell transplantation can be curative for patients with high-risk acute leukaemia. Umbilical cord blood (UCB) is an increasingly used source of allogeneic stem cells for patients who are in need of a transplant, but do not have a sibling donor. This review highlights the similarities and differences between the natural killer (NK) cells obtained from adult peripheral blood (PB) and UCB. These two cell sources show similar percentages of NK cells, including the major CD56(dim) and CD56(bright) subpopulations. UCB also contains an additional CD56-CD16+ subset, not typically found in PB. In addition, there are a number of progenitor cell populations in UCB that can give rise to NK cells. Some studies showed that UCB NK cells express a relatively higher percentage of inhibitory receptors (CD94/NKG2A and killer-cell immunoglobulin-like receptors) and less adhesion molecules. Resting UCB NK cells also show significantly less cytotoxicity compared to PB NK cells. However, following cytokine stimulation, the cytotoxicity of UCB NK cells can be rapidly increased to levels that are comparable to PB NK cells. Activation and expansion protocols for UCB NK cells are briefly reviewed. Lastly, we outline the early use of UCB NK cells in clinical trials.

Pre-birth selection of umbilical cord blood donors

BACKGROUND

. The fact that only a small percentage of cord blood units (CBU) stored are actually used for transplantation contributes to raising the already high costs of their processing and cryopreservation. The identification of predictors allowing the early identification of suitable CBU would allow a reduction of costs for the collection, storage and characterisation of CBU with insufficient volume or cell numbers. In our bank we have adopted a cut-off value for using CBU of 8 x 10(8) nucleated cells and a volume >or= 60 mL.

MATERIALS AND METHODS

In 365 banked CBU, we evaluated the correlation between neonatal/gestational parameters and laboratory data used to assess their quality.

RESULTS

Biparietal diameter (BPD) and abdominal circumference were significantly and positively correlated with CBU volume (r(2)=0.12, p=0.0011 and r(2)=0.092, p=0.0063, respectively). Receiver operating characteristic (ROC) analysis showed that both parameters can be used to identify CBU with insufficient volume (BPD: area under the curve 0.69, 95% CI=0.57-0.82, p=0.004; abdominal circumference: area under the curve 0.67, 95% CI=0.54-0.79, p<0.01). BPD and head circumference, but not abdominal circumference or femoral length, were positively correlated with white blood cell (WBC) count (r(2)=0.215, p=0.031, and r(2)=0.299, p=0.015, respectively). Abdominal circumference, but not BPD, head circumference or femoral length, was statistically significantly correlated with the number of CD34(+) cells in the CBU. Weight at birth and placental weight were positively correlated with WBC count, blood volume, CD34(+) cell count, total colony-forming units and burst-forming units.

CONCLUSION

. Pre-birth assessment of BPD might allow the selection of donors who would yield CBU of sufficient volume and WBC count and avoid the costs of collecting, transferring, storing and analysing CBU with a high probability of resulting unsuitable for transplantation.

Immunotherapy for pediatric cancer

Improvements in adult cancer survivorship can be achieved from behavioral changes and adopting screening programs. Yet, these approaches cannot be readily applied to lower the morbidity and mortality from childhood cancers. Rather, pediatric oncologists must rely on procedures and therapies to treat, rather than prevent malignancies. The systematic application of chemotherapy, radiation therapy, and surgery has led to remarkable advances in survival but these improvements have come at a cost. Children routinely receive chemotherapy agents that were designed decades ago, and these drugs have predictable side effects that result in the loss of potential for long-term survivors. The advent of targeted applications of immune-based therapies offers children with cancer a new class of oncolytic therapies that may be used to treat disease refractory to conventional approaches and lessen the toxicity of current treatment regimens without compromising remission. This review explores how 3 components of the immune system--T cells, natural killer (NK) cells, and antibodies--can be used for therapy of pediatric malignancies.

Meta-analysis of HLA matching and the outcome of unrelated umbilical cord blood transplantation (CBT)

OBJECTIVE

The aim of this meta-analysis is to compare the HLA disparities and the outcome of UCBT, i.e. the disease-free survival (DFS), engraftment, graft-versus-host disease, (GVHD), and transplantation related mortality (TRM).

METHODS

We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Pubmed, IBMTR and critically appraised all relevant articles (1989.01-2008.12). Comparative studies are carried on HLA typing and cord blood transplantation with research on stem cells engraftment, GVHD, TRM, and DFS. A meta-analysis is performed using Review Manager 5.0 software and adopted funnel plot regression assessed the publication bias.

RESULTS

We got 882 records, and 10 trials totaling 1589 patients assessed. Pooled comparisons of studies of outcomes found that the incidence of neutrophil and platelet engraftment failure increased with HLA-mismatched antigen increased, >or=2-Ag mismatched group had a higher risk of >or=II degree GVHD and a lower DFS rate than the HLA matched group.

CONCLUSIONS

Our meta-analysis confirmed that with the HLA-mismatched antigen increased, the rate of graft failure, severe GVHD and TRM increased, and the DFS decreased. We cannot fully exclude the possibility of center biases in treatment and selection of patients and well-designed trials need to carry out.

Association of serum interleukin-7 levels with the development of acute graft-versus-host disease

PURPOSE

Morbidity from acute graft-versus-host disease (GVHD) limits the success of allogeneic hematopoietic stem-cell transplantation (HSCT) to treat malignancy. Interleukin-7 (IL-7), the principal homeostatic cytokine for T cells, is required for acute GVHD in murine models. In contrast to inflammatory cytokines (eg, IL-2, tumor necrosis factor alpha), IL-7 has not been studied extensively in the clinical transplant setting relative to its relationship with acute GVHD.

PATIENTS AND METHODS

We evaluated the association of serum IL-7 levels with acute GVHD in 31 patients who were uniformly treated in a prospective clinical trial with reduced-intensity allogeneic HSCT from human leukocyte antigen-identical siblings. GVHD prophylaxis consisted of cyclosporine and methotrexate. Serum IL-7 levels and lymphocyte populations were determined at enrollment, the day of transplantation before the allograft infusion, and at specified intervals through 12 months post-transplantation.

RESULTS

As expected, IL-7 levels were inversely correlated with T-cell populations (P < .00001). Acute GVHD was significantly associated with higher IL-7 levels at day +7 (P = .01) and day +14 (P = .00003) post-transplantation as well as with the allograft CD34(+) cell dose (P = .01). IL-7 levels at day +14 also correlated with the severity of acute GVHD (P < .0001). In logistic regression models, these factors were highly sensitive (up to 86%) and specific (100%) for classifying whether patients developed acute GVHD.

CONCLUSION

These data support preclinical observations that IL-7 plays a critical role in inducing acute GVHD and provide a rational basis for novel approaches to prevent and treat acute GVHD through modulation of the IL-7 pathway.

Liposomal amphotericin B prophylaxis of invasive mold infections in children post allogeneic stem cell transplantation

BACKGROUND

Invasive mold infections (IMI) are a leading cause of infectious mortality in allogeneic stem cell transplant (AlloSCT) recipients. Fluconazole, the current standard for fungal prophylaxis, is ineffective against molds. We initiated a pilot study to determine the safety and activity of prophylactic liposomal amphotericin B (AMB) in preventing IMI in pediatric and adolescent AlloSCT recipients during the first 100 days.

PROCEDURE

Fifty-one patients (57 AlloSCT) were given AMB (3 mg/kg/day) intravenously, day 0-100. Median age 6 years, 32 males, 19 females. Donors: 33 unrelated and 2 related cord blood, 13 related and 1 unrelated peripheral blood stem cell and 8 related bone marrow (BM); 30 received myeloablative and 27 reduced intensity conditioning. Graft-versus-host disease (GVHD) prophylaxis comprised tacrolimus and mycophenolate mofetil.

RESULTS

Median follow-up is 557 days. AMB was generally well tolerated. The probability of developing >/=grade II acute GVHD and extensive chronic GVHD was 45% and 7%, respectively. Estimated 1-year OS is 62.4% for all patients with 78.8% and 26.7% for average-risk and poor-risk, respectively. The incidence of IMI was 0%.

CONCLUSIONS

These results suggest prophylactic AMB is tolerable and may prevent IMI, especially Aspergillus, during the first 100 days post AlloSCT in pediatric and adolescent patients. A randomized study is needed to determine the efficacy of this approach.

Absence of regulatory T-cell control of TH1 and TH17 cells is responsible for the autoimmune-mediated pathology in chronic graft-versus-host disease

Graft-versus-host disease (GVHD) remains the major complication after allogeneic bone marrow transplantation (BMT). The process whereby acute GVHD mediated by alloreactive donor T cells transitions into chronic GVHD, which is characterized by prominent features of auto-immunity, has long been unresolved. In this study, we demonstrate that GVHD-associated autoimmunity and, by extension, chronic GVHD is attributable to the progressive loss of CD4(+)CD25(+)Foxp3(+) regulatory T cells during the course of acute GVHD. This leads to the expansion of donor-derived CD4(+) T cells with T(H)1 and T(H)17 cytokine phenotypes that release proinflammatory cytokines and cause autoimmune-mediated pathological damage. These T cells are present early after transplantation, indicating that the pathophysiological events that lead to chronic GVHD are set in motion during the acute phase of GVHD. We conclude that the absence of CD4(+)CD25(+) regulatory T cells coupled with unregulated T(H)1 and T(H)17 cells leads to the development of autoimmunity and that donor-derived T(H)1 and T(H)17 cells serve as the nexus between acute and chronic GVHD.

Autologous peripheral blood stem cell transplantation for severe multiple sclerosis

We describe the results of a clinical trial to evaluate the feasibility and toxicity of autologous hematopoietic stem cell transplantation (auto-HSCT) for patients with progressive multiple sclerosis (MS). Fifteen patients (all patients with secondary progressive MS) were enrolled. The median expanded disability status scale (EDSS) score at baseline was 6.0 (range, 4.5-7.5). Peripheral blood stem cells were obtained by leukapheresis after mobilization with granulocyte colony-stimulating factor. In 9 patients, CD34+ cell selection was performed with a CliniMACS cell selection system, and 6 patients accepted infusion of unmodified peripheral blood stem cells. The modified BEAM (carmustine, teniposide, cytarabine, and melphalan) was the sole conditioning regimen used. The adverse effects included infections, mucositis, transient hepatotoxicity, and diarrhea. Three patients had flares of neurologic deterioration during mobilization, 8 patients had the same manifestation during transplantation, and 2 patients had similar flares within 3 months of transplantation. Six patients experienced continuous neurologic improvement after transplantation, 5 patients experienced neurologic progression, and 4 patients had stabilization of their disease. The confirmed progression-free rate was 63.8% at 49 months. The results of lymphocyte purging were no better than for no purging. Auto-HSCT proved to be safe and beneficial for some MS patients. Further studies are needed to establish the merit of this procedure for MS patients.

Immaturity of IL-18 gene expression and protein production in cord blood (CB) versus peripheral blood (PB) mononuclear cells and differential effects in natural killer (NK) cell development and function

We have previously demonstrated dysregulation of IL-12 and IL-15 gene and protein expression between activated cord blood (CB) versus peripheral blood (PB) mononuclear cells (MNCs). In the present study, we compared IL-18 gene expression and protein production and IL-18 mRNA half-life in basal versus activated CB versus PB MNCs, the effects of IL-18 +/- IL-12 on MNCs IFN-gamma protein production and ex vivo expansion and activation of CB with IL-12 + IL-2 + anti-CD3 +/- IL-18. Basal and activated levels of IL-18 were significantly higher in PB versus CB MNCs (P < 0.05). IL-18 mRNA was coincidental with protein levels and significantly lower in CB (P < 0.05) and its half-life significantly shorter in CB versus PB MNCs (P < 0.05). IL-18 synergistically with IL-12 induced IFN-gamma production from PB greater than CB MNCs (P < 0.05). NK cells expansion (P < 0.001) and cytotoxicity (P < 0.01) was significantly increased with IL-12 + IL-2 + anti-CD3 and IL-18. In summary IL-18 gene expression and protein production are significantly decreased in activated CB versus PB MNCs, in part secondary to increased degradation of CB IL-18 mRNA. These results may have implications for the mechanism(s) in part responsible for the immaturity of CB T-cell immunity.

Early Immune Reaction after Reduced-Intensity Cord-Blood Transplantation for Adult Patients

BACKGROUND

To investigate immune reactions after reduced-intensity cord-blood transplantation (RI-CBT).

MATERIALS AND METHODS

We reviewed medical records of 57 adult RI-CBT recipients. Preparative regimen comprised fludarabine, total-body irradiation, and either melphalan (n=51) or busulfan (n=6). Graft-versus-host disease (GvHD) prophylaxis was cyclosporine. PostRI-CBT immune reactions were classified according to time course: pre-engraftment immune reactions (PIR), engraftment syndrome (ES), and GvHD.

RESULTS

Forty-five patients achieved engraftment at a median of day 19. PIR was characterized by high-grade fever and weight gain and developed on a median of day 9 in 35 of the 45 evaluable patients, including 3 who did not achieve engraftment. PIR subsided spontaneously in 12 patients, whereas corticosteroids were required in the other 23. ES and grade I to IV acute GvHD developed in 36 and 29 patients, respectively. GvHD could not be distinguished from preceding PIR or ES in 10 patients. Causes of the 32 nonrelapse mortalities included GvHD (n=5) and PIR (n=1). There were no significant differences in relapse and nonrelapse deaths between patients with PIR and those without it (18% vs. 5%, and 60% vs. 65%, respectively).

CONCLUSIONS

Immune reactions after RI-CBT can be categorized into three distinct subtypes.

Characterization of banked umbilical cord blood hematopoietic progenitor cells and lymphocyte subsets and correlation with ethnicity, birth weight, sex, and type of delivery: a Cord Blood Transplantation (COBLT) Study report

BACKGROUND

The Cord Blood Transplantation (COBLT) Study banking program was initiated in 1996. The study goals were to develop standard operating procedures for cord blood (CB) donor recruitment and banking and to build an ethnically diverse unrelated CB bank to support a transplantation protocol.

STUDY DESIGN AND METHODS

The hematopoietic progenitor cell (HPC) and lymphocyte subset (LS) content of approximately 8000 CB units were characterized, and these results were correlated with donor ethnicity, birth weight, gestational age, sex, and type of delivery.

RESULTS

There was a significant correlation of CD34+ cell count with colony-forming unit (CFU)-granulocyte-macrophage (r=0.68, p<0.001), CFU-granulocyte-erythroid-macrophage-megakaryocyte (r=0.52, p<0.001), burst-forming unit-erythroid (BFU-E; r=0.61, p<0.001), and total CFUs (r=0.67, p<0.001). Nucleated red blood cell count was significantly correlated with total CD34+ (r=0.56, p<0.001), total CFU (r=0.50, p<0.001), BFU-E (r=0.48, p<0.001), and counts of CD34+ subsets (p<0.001). Caucasian ethnicity was significantly correlated with higher CD3+/CD4+, CD19+, and CD16+/CD56+ LSs. Furthermore, CD34+/CD38- and CD34+/CD61+ CB units (HPC-C) were significantly lower in African American and Asian persons compared to Caucasian and Hispanic persons. Male sex was associated with significantly fewer CD3+/CD4+, CD19+, and CD16+/CD56+ but increased CD3+/CD8+ LSs (p<0.001). Finally, cesarean section was associated with significantly higher total CFU and CD16+/CD56+ but lower CD3+/CD4+, CD3+/CD8+, and CD19+ LSs.

CONCLUSION

These results provide a standard and range for uniformly processed HPC-C progenitor cells and LSs. CB progenitor cells and/or LSs may in the future predict for rapidity of engraftment, incidence of graft-versus-host disease, speed and quality of immunore- constitution, graft-versus-tumor effects, and/or success of gene transfection after CB transplantation.

Hematopoietic stem cell transplantation using umbilical cord blood progenitors: review of current clinical results

SUMMARY

Umbilical cord blood (CB) has been rapidly established as an alternative source of stem cells to bone marrow for allogeneic-related and unrelated hematopoietic transplantation. To date, almost 70 000 CB units are available for transplantation and more than 2000 CB transplants (CBT) have been performed, mostly in children, for the treatment of a variety of malignant and nonmalignant conditions. Considerable experience has been rapidly accumulated in this field and many aspects of CBT have been elucidated, while other questions remain unresolved. A concise review of the clinical results achieved after related and unrelated CBT is presented and discussed.

Umbilical cord blood transplantation in adults using myeloablative and nonmyeloablative preparative regimens

Unrelated umbilical cord blood (UCB) transplantation has recently been explored in an increasing number of adult patients. The relative ease of procurement and the lower-than-anticipated risk of severe acute graft-versus-host disease has made UCB transplantation an appealing alternative to bone marrow-derived hematopoietic stem cells. The use of reduced-intensity or nonmyeloablative preparative regimens to allow engraftment of UCB broadens the scope of patients who may benefit from allogeneic immunotherapy, including elderly and medically infirm patients with no matched sibling donor. This review summarizes the available data on the use of UCB as an alternative source of hematopoietic stem cell transplantation in adult patients.

A comparison of ex vivo expanded DCs derived from cord blood and mobilized adult peripheral blood plastic-adherent mononuclear cells: decreased alloreactivity of cord blood DCs

BACKGROUND

Cord blood (CB) has been used as an alternative source of transplantable allogeneic stem cells for a variety of malignant and non-malignant diseases. However, we have demonstrated delayed recovery of T- and B-cell function, and T-cell subsets post unrelated CB transplantation (UCBT), and deficiencies of CB mononuclear cells (MNC) in producing cytokines, including G-CSF, GM-CSF, M-CSF, IL-12, and IL-15. In this study we have investigated the ex vivo generation of DC from CB versus mobilized adult peripheral blood (APB) for later use as adoptive cellular immunotherapy.

METHODS

CB and APB-adherent MNC were cultured in serum-free media with GM-CSF IL-4, FLT-3 ligand, tumor growth factor-beta (TGF-beta), and tumor necrosis factor-alpha (TNF-alpha) for 7 days. Morphology, phenotype, immunohistochemistry, clonogenic activity, and alloreactivity in MLR were evaluated.

RESULTS

CB and APB monocyte-derived ex vivo expanded DC expressed similar DC markers CD83 (31.27+ 11.7% versus 34.0+ 5.2%, CB versus APB), CD1a (23.4+ 4.2% versus 27.6+ 6.3%), and CD80 (21.97+ 12.01% versus 27.7+ 5.95). Immunohistochemistry showed that cells with DC morphology expressed CDla but not CD14. Neither FLT-3 ligand nor TGF-fl enhanced DC expansion. Addition of 10% autologous plasma to CB cultures promoted greater cell survival and a 150% increase in CDla + /CD80+ cell recovery. CB DC were 62% as effective stimulators of adult allogeneic T-cels as APB DC (p < .05) in allogeneic MLR.

DISCUSSION

While phenotypically similar, CB and APB DC have differential potency in allogeneic MLR, which may account for the difference in GvHD and infection incidence and severity between UCBT and allogeneic stem cell transplantation, and may require a different approach for adoptive cellular immunotherapy. The mechanism(s) associated with these differences require further elucidation.

Elevated serum interleukin-15 level in acute graft-versus-host disease after hematopoietic cell transplantation

OBJECTIVE

To correlate serum cytokine levels and the development of acute graft-versus-host disease (GVHD), the authors conducted a prospective study on serial measurements of interferon (IFN)-gamma and interleukin (IL)-10, IL-12 and IL-15.

METHODS

The cytokines were measured in 27 subjects by enzyme-linked immunosorbent assay serially for the first 2 months after hematopoietic cell transplantation.

RESULTS

Nineteen subjects with acute GVHD had significantly higher mean peak serum levels of IFN-gamma and IL-15 than the baseline levels at the start of conditioning. The peak level occurred soon after stem cell infusion and returned to the pretransplantation state in the second month. In contrast, there was lesser difference between the mean peak serum levels of IFN-gamma, IL-10, and IL-15 and the baseline level in the eight subjects without GVHD. The peak serum level for IL-15 was, in addition, significantly higher among GVHD subjects than those without GVHD in the first month posttransplantation. However, the level of IL-15 showed no correlation with the severity of GVHD.

CONCLUSIONS

These changes point to a possible role of systemic cytokine secretion in the development of acute GVHD. Elevated levels of IL-15 early in the posttransplant period could be a helpful laboratory predictor of acute GVHD.

Cord blood transplantation from unrelated donors: a preliminary report from the Japanese Cord Blood Bank Network

As a source for hematopoietic stem cell transplantation (HSCT), cord blood transplantation from unrelated donors (UCBT) is now considered as an acceptable alternative to patients who need unrelated HSCT. To confirm the findings that mismatched UCBT is feasible, we discussed here the results for 477 patients with hematologic malignancies and non-malignancies who were subjected to UCBT coordinated by the Japanese Cord Blood Bank Network (JCBBN). From February 1997 to October 2001, 411 patients with malignancies and 66 with non-malignancies had UCBT through the cord blood bank in the JCBBN; 311 patients had HLA 0-1 mismatched UCBT; 165, had a 2-4 HLA mismatch. The Kaplan-Meier estimates for 3-year disease-free survival rate (DFS) were 35.2 +/- 2.8% in malignant diseases, and 33.6 +/- 7.2% in patients with non-malignant diseases. The HLA disparity had no effect on DFS, incidence of acute graft-versus-host disease, or engraftment. As reported previously, we also noted the importance of graft cell dose in determining survival in UCBT. Major advantages of UCBT include its rapid availability compared with unrelated donor bone marrow, and tolerance of an HLA mismatch at 2 loci, which will enable extension of the donor pool. This review outlines the latest UCBT progress, with emphasis on practical considerations in HLA-mismatched umbilical cord blood selection.

Ex vivo expansion, maturation, and activation of umbilical cord blood-derived T lymphocytes with IL-2, IL-12, anti-CD3, and IL-7. Potential for adoptive cellular immunotherapy post-umbilical cord blood transplantation

OBJECTIVES

We investigated whether umbilical cord blood (UCB) T cells could be ex vivo expanded and activated in short-term culture for potential utilization as adoptive cellular immunotherapy post-umbilical cord blood transplantation (UCBT).

METHODS

Fresh UCB mononuclear cells (MNCs) were isolated by Ficoll density centrifugation. Cryopreserved UCB mononuclear cells were thawed and washed with 2.5% human serum albumin and 5% dextrose in isotonic saline. The nonadherent MNC fraction were then plated in a serum-free cocktail of IL-2, IL-12, and anti-CD3 with and without IL-7 for 48 hours. Proliferation, cytotoxicity, TH1 (IFN-gamma), CD25, and CD45RO assays were performed.

RESULTS

Proliferation studies demonstrated a significant increase in the proliferative ability of the UCB MNCs incubated in anti-CD3, IL-2, IL-12, and IL-7 (fresh--p < 0.005, and thawed--p < 0.001). The combination of all four agonists significantly induced expression of CD45 RO (fresh--p < 0.05, and thawed--p < 0.001) in both the CD4(+) and CD8(+) T cells expressing CD25 (fresh UCB--p < 0.01 [CD4] and p < 0.005 [CD8], respectively; thawed UCB--p < 0.001 [CD4] and p < 0.001 [CD8]). Intracellular cytokine profiles also revealed a significant increase in the production of IFN-gamma (TH1 cells) (fresh UCB--p < 0.005, and thawed UCB--p < 0.001). The combination also significantly increased the killing of K562-labeled target cells (fresh--p < 0.0001, and thawed--0.731 +/- 0.03 vs 0.16 +/- 0.01) (p < 0.001).

CONCLUSIONS

These data suggest that the ex vivo combination of IL-2, IL-12, anti-CD3, and IL-7 significantly enhances the proliferation, activation, maturation, and cytotoxic potential of UCB T cells of both fresh and thawed UCB MNC. Further studies, however, are required to determine whether these ex vivo--expanded MNC could also potentially exacerbate acute or chronic graft-vs-host disease and/or other toxicities if utilized post-UCBT.

A broad T-cell repertoire diversity and an efficient thymic function indicate a favorable long-term immune reconstitution after cord blood stem cell transplantation

Cord blood (CB) is used increasingly as a source of hematopoietic stem cells because of a lower risk of acute and chronic graft-versus-host disease (GVHD). However, there is some concern regarding the ability to adequately reconstitute host immune response due to the immaturity and naivety of CB T cells. This study was designed to evaluate T-cell reconstitution using combined approaches of phenotyping, analysis of alphabeta T-cell receptor (TCR) diversity, and assessment of ex vivo thymic function by measuring TCR rearrangement excision circles (TRECs). Ten patients who underwent CB transplantation for high-risk hematologic disorders were compared to a reference group of 19 age- and GVHD-matched patients who underwent transplantation with non-T cell-depleted bone marrow from an HLA-identical sibling donor. TREC values correlated with the relative number of naive T cells and with TCR repertoire polyclonality. During the first year after transplantation, TCR repertoires were highly abnormal and TREC values low in both groups. Notably, 2 years after transplantation onward TREC values as well as TCR diversity were higher in CB recipients than in recipients of bone marrow transplants. These data indicate an efficient thymic regeneration pathway from CB lymphoid progenitors despite the low number of cells infused compared to bone marrow, arguing for a complete clinical immune recovery after CB transplantation.

Transient hematopoietic stem cell rescue using umbilical cord blood for a lethally irradiated nuclear accident victim

We performed stem cell rescue and allogeneic skin transplantation on a lethally neutron-irradiated nuclear accident victim. HLA-DRB1 mismatched unrelated umbilical cord blood cells (2.08 x 10(7)/kg recipient body weight) were transplanted to an 8-10 Gy equivalent neutron-irradiated patient because of a lack of a suitable bone marrow or peripheral blood donor. Pre-transplant conditioning consisted of anti-thymocyte gamma-globulin alone, and GVHD prophylaxis was a combination of cyclosporine (CYA) and methylprednisolone (mPSL). Granulocyte colony-stimulating factor (G-CSF), erythropoietin (EPO), and thrombopoietin (TPO) were concurrently administered after transplantation. The absolute neutrophil count reached 0.5 x 10(9)/l on day 15, the reticulocyte count rose above 1% on day 23, and the platelet count was over 50 x 10(9)/l on day 27, respectively. Cytogenetic studies of blood and marrow showed donor/recipient mixed chimerism. Rapid autologous hematopoietic recovery was recognized after withdrawal of CYA and mPSL. Repeated pathological examinations of the skin revealed no evidence of acute GVHD. Eighty-two days after the irradiation, skin transplantation was performed to treat radiation burns. Almost 90% of the transplanted skin engrafted. Immunological examination after autologous hematopoietic recovery revealed an almost normal T cell count. However, immune functions were severely impaired. The patient died from infectious complication 210 days after the accident.

NK cells recover early and mediate cytotoxicity via perforin/granzyme and Fas/FasL pathways in umbilical cord blood recipients

Umbilical cord blood (UCB) is now widely accepted as a source of stem cells in patients with malignant hematologic and genetic disorders. We have recently reported that in a series of 30 pediatric UCB transplant recipients comparable outcome to that anticipated with other unrelated stem cell sources. In our series, however, the probability of GVHD for grade III-IV was 9% and no UCB recipient developed chronic GVHD. The reason for the low incidence of GVHD after UCB transplantation is not fully understood. Because functional NK cells are among the first population of lymphocytes to be detected in UCB transplant recipients, 2 months post-transplant on average, we wanted to establish whether NK cells could be implicated in reducing the risk of GVHD. Here, we confirm that early NK cells detected in UCB transplant recipients activate the granzyme/perforin lytic pathway and, in addition, they can mediate Fas/Fas ligand (FasL) activity, a finding not previously reported. Both pathways develop simultaneously and are detectable months before the other lymphocytes, notably CD8 are fully functional. Our contention, therefore, is that the low GVHD observed in UCB recipients may be partially due to early NK cells.

Factors affecting lymphocyte subset reconstitution after either related or unrelated cord blood transplantation in children -- a Eurocord analysis

Immune recovery after cord blood transplantation (CBT) is of concern owing to the low number of lymphocytes transferred with the graft and their immaturity. Risk factors influencing lymphocyte subset reconstitution related to disease, patient, donor and transplant were studied in 63 children (< 16 years), given either related (n = 14) or unrelated (n = 49) CBT for malignant (n = 33) or non-malignant diseases (n = 30). Only children with sustained myeloid engraftment were analysed. Absolute numbers of T (CD3(+), CD4(+), CD8(+)), B and natural killer (NK) cells were reported 2--3, 6, 9, 12 and 12--24 months after CBT. Median patient age was 4.0 years (0--15) and median follow-up was 23 months (1.7--61.0). Twenty-six patients received human leucocyte antigen (HLA)-matched CBT and 37 received HLA-mismatched CBT. The median number of nucleated cells (NCs) collected/recipient weight was 6.1 x 10(7)/kg. In this selected population, the estimate 2 year survival was 85%. Lymphocyte reconstitution (defined as the median time to reach the normal value of age-matched healthy children) was 3, 6 and 8 months for NK, B and CD8(+) cells, while it was 11.7 months for both CD3(+) and CD4(+) lymphocytes. In the multivariate analysis, factors favouring T-cell recovery were: related donor (P = 0.002); higher NCs/kg (P = 0.005) and recipient cytomegalovirus (CMV)-positive serology (P = 0.04). Presence of acute graft-versus-host disease (GVHD) delayed T-cell recovery (P = 0.04). To summarize, in children with sustained myeloid engraftment the concern that lymphocyte recovery after CBT could be delayed does not appear to be substantiated by our results.

Similar myeloid recovery despite superior overall engraftment in NOD/SCID mice after transplantation of human CD34(+) cells from umbilical cord blood as compared to adult sources

Umbilical cord blood (UCB), bone marrow (BM) and mobilized peripheral blood (mPB) are used as sources of hematopoietic stem cells for transplantation. The NOD/SCID mouse model was used to compare the lineage-specific repopulating potential of CD34(+) cells derived from these sources. Six to 8 weeks after transplantation, blood, BM, spleen, liver and thymus, were harvested, and analyzed by flow cytometry using CD34, CD45, myeloid, and lymphoid lineage-specific antibodies. Fifty percent engraftment of human cells in bone marrow of mice was estimated to be reached with 0.55 x 10(6) CD34(+) UCB cells or with 7.9 x 10(6) CD34(+) cells from adult sources, illustrating a 10-fold superiority of UCB CD34(+) cells to engraft NOD/SCID mice. Lineage-specific characterization of engrafted human cells showed that the high engraftment potential of CD34(+) cells from UCB was due to a preferential B cell development (2-81%). In contrast, comparable percentages of myeloid cells were found following transplantation of CD34(+) cells from UCB, BM and mPB (1-38%), and occurred at significant levels only at relatively high doses. Since the CD34 content of UCB transplants is usually at least one log lower than of transplant from adult sources, these results correspond to the clinical findings with UCB transplantation showing a relatively high overall engraftment, but delayed myeloid recovery.

Cell-surface trafficking and release of flt3 ligand from T lymphocytes is induced by common cytokine receptor gamma-chain signaling and inhibited by cyclosporin A

The flt3 ligand (FL) is a growth and differentiation factor for primitive hematopoietic precursors, dendritic cells, and natural killer cells. Human T lymphocytes express FL constitutively, but the cytokine is retained intracellularly within the Golgi complex. FL is mobilized from the cytoplasmic stores and its serum levels are massively increased during the period of bone marrow aplasia after stem cell transplantation (SCT). Signals that trigger the release of FL by T cells remain unknown. This study shows that interleukin (IL)-2, IL-4, IL-7, and IL-15, acting through a common receptor gamma chain (gammac), but not cytokines interacting with other receptor families, are efficient inducers of cell surface expression of membrane-bound FL (mFL) and secretion of soluble FL (sFL) by human peripheral blood T lymphocytes. The gammac-mediated signaling up-regulated FL in a T-cell receptor-independent manner. IL-2 and IL-7 stimulated both FL messenger RNA (mRNA) expression and translocation of FL protein to the cell surface. Cyclosporin A (CsA) inhibited gammac-mediated trafficking of FL at the level of transition from the Golgi to the trans-Golgi network. Accordingly, serum levels of sFL and expression of mFL by T cells of CsA-treated recipients of stem cell allografts were reduced approximately 2-fold (P <.01) compared to patients receiving autologous grafts. The conclusion is that FL expression is controlled by gammac receptor signaling and that CsA interferes with FL release by T cells. The link between gammac-dependent T-cell activation and FL expression might be important for T-cell effector functions in graft acceptance and antitumor immunity after SCT.

Analysis of engraftment, graft-versus-host disease, and immune recovery following unrelated donor cord blood transplantation

Unrelated cord blood (UCB) is being used as a source of alternative hematopoietic stem cells for transplantation with increasing frequency. From November 1994 to February 1999, 30 UCB transplant procedures were performed for both malignant and nonmalignant diseases in 27 children, aged 0.4 to 17.1 years. Patients received either HLA-matched (n = 3) or 1- or 2-antigen–mismatched (n = 27) UCB following 1 of 2 standardized preparative and graft-versus-host disease regimens (hyperfractionated total body irradiation, cyclophosphamide, and antithymocyte globulin [ATG] with cyclosporine A and methotrexate; or busulfan, melphalan, and ATG with cyclosporine A and prednisone). The median time to neutrophil and platelet engraftment was 27 days (12-60 days) and 75 days (33-158 days) posttransplantation, respectively. No correlation was noted between neutrophil and platelet engraftment and nucleated cells per kilogram, CD34+ cells per kilogram infused, or cytomegalovirus status of recipient. The cumulative probability of acute grade 2 or greater graft-versus-host disease (GVHD) was 37.2%, and of grade 3 or greater GVHD was 8.8%. No patients developed chronic GVHD. CD4, CD19, and natural killer cell recovery was achieved at a median of 12, 6, and 2 months, respectively. CD8 recovery was delayed at a median of 9 months. Normal mitogen response was achieved at 6 to 9 months. The probability of survival, disease-free survival, and event-free survival at 1 year was 52.3% (34.1%-70.5%), 54.7% (34.5%-74.9%) and 49.6% (29.9%-69.4%), respectively. This series of 30 UCB transplants suggests that although CD8 cell recovery is delayed, the pattern of immune reconstitution with UCB is similar to that reported for other stem cell sources.

Analysis of engraftment, graft-versus-host disease, and immune recovery following unrelated donor cord blood transplantation

Unrelated cord blood (UCB) is being used as a source of alternative hematopoietic stem cells for transplantation with increasing frequency. From November 1994 to February 1999, 30 UCB transplant procedures were performed for both malignant and nonmalignant diseases in 27 children, aged 0.4 to 17.1 years. Patients received either HLA-matched (n = 3) or 1- or 2-antigen–mismatched (n = 27) UCB following 1 of 2 standardized preparative and graft-versus-host disease regimens (hyperfractionated total body irradiation, cyclophosphamide, and antithymocyte globulin [ATG] with cyclosporine A and methotrexate; or busulfan, melphalan, and ATG with cyclosporine A and prednisone). The median time to neutrophil and platelet engraftment was 27 days (12-60 days) and 75 days (33-158 days) posttransplantation, respectively. No correlation was noted between neutrophil and platelet engraftment and nucleated cells per kilogram, CD34+ cells per kilogram infused, or cytomegalovirus status of recipient. The cumulative probability of acute grade 2 or greater graft-versus-host disease (GVHD) was 37.2%, and of grade 3 or greater GVHD was 8.8%. No patients developed chronic GVHD. CD4, CD19, and natural killer cell recovery was achieved at a median of 12, 6, and 2 months, respectively. CD8 recovery was delayed at a median of 9 months. Normal mitogen response was achieved at 6 to 9 months. The probability of survival, disease-free survival, and event-free survival at 1 year was 52.3% (34.1%-70.5%), 54.7% (34.5%-74.9%) and 49.6% (29.9%-69.4%), respectively. This series of 30 UCB transplants suggests that although CD8 cell recovery is delayed, the pattern of immune reconstitution with UCB is similar to that reported for other stem cell sources.

Autosomal dominant thrombocytopenia: incomplete megakaryocyte differentiation and linkage to human chromosome 10

We studied a large kindred with nonsyndromic autosomal dominant thrombocytopenia to define the phenotype and used genomic linkage analysis to determine the locus of the abnormal gene. Affected family members are characterized by lifelong moderate thrombocytopenia (mean = 42.7 × 109/L) with moderate propensity toward easy bruising and minor bleeding. Megakaryocytes are present in bone marrow with reduced frequency, and there are no apparent abnormalities of myeloid or erythroid cells. This type of inherited thrombocytopenia has no evident association with hematopoietic malignancy or progression to aplastic anemia. In the past, members of this family have failed therapeutic trials of immunosuppression and splenectomy. In our investigation, we found that affected individuals had normal platelet size compared with unaffected family members and modestly increased thrombopoietin levels. Hematopoietic colony assays from bone marrow and peripheral blood demonstrated that megakaryocyte precursors (CFU-Mk) were dramatically increased in both number and size in affected individuals. Bone marrow cells grown in liquid culture with thrombopoietin failed to develop polyploid cells greater than 8N. Also, electron microscopy demonstrated that megakaryocytes from an affected individual had markedly delayed nuclear and cytoplasmic differentiation. Genome-wide linkage analysis established a single locus for the disease gene on the short arm of chromosome 10 with a maximum 2-point lod score of 5.68 (at θ = 0). By recruiting additional family members, the genomic region was narrowed to 17 centimorgans. We conclude that a gene in this locus plays an important role in megakaryocyte endomitosis and terminal maturation.

Autosomal dominant thrombocytopenia: incomplete megakaryocyte differentiation and linkage to human chromosome 10

We studied a large kindred with nonsyndromic autosomal dominant thrombocytopenia to define the phenotype and used genomic linkage analysis to determine the locus of the abnormal gene. Affected family members are characterized by lifelong moderate thrombocytopenia (mean = 42.7 × 109/L) with moderate propensity toward easy bruising and minor bleeding. Megakaryocytes are present in bone marrow with reduced frequency, and there are no apparent abnormalities of myeloid or erythroid cells. This type of inherited thrombocytopenia has no evident association with hematopoietic malignancy or progression to aplastic anemia. In the past, members of this family have failed therapeutic trials of immunosuppression and splenectomy. In our investigation, we found that affected individuals had normal platelet size compared with unaffected family members and modestly increased thrombopoietin levels. Hematopoietic colony assays from bone marrow and peripheral blood demonstrated that megakaryocyte precursors (CFU-Mk) were dramatically increased in both number and size in affected individuals. Bone marrow cells grown in liquid culture with thrombopoietin failed to develop polyploid cells greater than 8N. Also, electron microscopy demonstrated that megakaryocytes from an affected individual had markedly delayed nuclear and cytoplasmic differentiation. Genome-wide linkage analysis established a single locus for the disease gene on the short arm of chromosome 10 with a maximum 2-point lod score of 5.68 (at θ = 0). By recruiting additional family members, the genomic region was narrowed to 17 centimorgans. We conclude that a gene in this locus plays an important role in megakaryocyte endomitosis and terminal maturation.