Single-exon approach to non-invasive fetal RHD screening in early pregnancy: An update after 10 years' experience

BACKGROUND AND OBJECTIVES

Anti-D prophylaxis, administered to RhD-negative women, has significantly reduced the incidence of RhD immunization. Non-invasive fetal RHD screening has been used in Stockholm for more than 10 years to identify women who will benefit from prophylaxis. The method is based on a single-exon approach and is used in early pregnancy. The aim of this study was to update the performance of the method.

MATERIALS AND METHODS

The single exon assay from Devyser AB is a multiplex kit detecting both exon 4 of the RHD gene and the housekeeping gene GAPDH. Cell-free DNA was extracted from 1 ml of plasma from EDTA blood taken during early pregnancy, weeks 10-12. The genetic RHD results were compared with serological typing of newborns for a determination of sensitivity and specificity.

RESULTS

In total, 4337 pregnancies were included in the study; 44 samples (1%) were inconclusive either due to maternal RHD gene variants (n = 34) or technical reasons (n = 10). Of the remaining 4293 pregnancies, a total number of nine discrepant results were found. False positive results (n = 7) were mainly (n = 4) due to RHD gene variants in the child. False-negative results were found in two cases, of which one was caused by a technical error. None of the false-negative cases was due to RHD gene variants. Overall, the sensitivity of the method was 99.93% and specificity 99.56%.

CONCLUSION

The single-exon assay used in this study is correlated with high sensitivity and specificity.

The importance of graft cell composition in outcome after allogeneic stem cell transplantation in patients with malignant disease

BACKGROUND

Graft-versus-host disease (GVHD) and relapse remain majobstacles ftreatment success in allogeneic hematopoietic stem cell transplantation (HSCT). In the present study, we evaluated the immune cell profile of the graft to outcome after HSCT.

STUDY DESIGN AND METHOD

Flow cytometry data of graft cell subsets [CD34⁺ , CD3⁺ , CD19⁺ , CD4⁺ , CD8⁺ , CD3-CD56⁺ CD16⁺ , CD4⁺ CD127^low CD25^high ] from G-CSF primed peripheral blood stem cell (PBSC) donors was collected retrospectively from 299 patients with hematological malignancies undergoing HSCT between 2006 and 2013. The association to overall survival, transplant-related mortality (TRM), GVHD and probability of relapse was analyzed. Patients outcome from HLA-identical sibling (Sib) (n = 97) and unrelated donors (URD) (n = 202) were analyzed separately as all URD patients received anti-thymocyte globulin (ATG).

RESULTS

Five-year overall survival was similar in the two cohorts (68% (Sib) vs 65% (URD)). The relapse incidence was significantly lower in the Sib cohort (24% vs 35%, P = 0.04). Multivariate analysis in the URD group revealed an association between a higher CD8⁺ dose and less relapse (HR, 0.94; 95%CI, 0.90-0.98; P = 0.006) as well as an association between higher CD34⁺ dose and both higher TRM (HR, 1.09; 95%CI, 1.02-1.20; P = 0.02) and relapse (HR, 1.09; 95%CI, 1.01-1.17; P = 0.025). The Sib analysis showed an association between a higher graft CD19⁺ dose and more severe acute GVHD (HR, 1,09; 95%CI, 1.03-1.15; P = 0.003) and TRM (HR, 1.09; 95%CI, 1.01-1.17; P = 0.036). In addition, a higher CD4⁺ graft content was associated to an increased risk for chronic GVHD (HR, 1.02; 95%CI 1.00-1.04; P = 0.06).

CONCLUSION

These data indicate an importance of PBSC dongraft composition in patients with a hematological malignancy.

T Cell Receptor Excision Circle (TREC) Monitoring after Allogeneic Stem Cell Transplantation; a Predictive Marker for Complications and Clinical Outcome

Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established treatment modality for a variety of malignant diseases as well as for inborn errors of the metabolism or immune system. Regardless of disease origin, good clinical effects are dependent on proper immune reconstitution. T cells are responsible for both the beneficial graft-versus-leukemia (GVL) effect against malignant cells and protection against infections. The immune recovery of T cells relies initially on peripheral expansion of mature cells from the graft and later on the differentiation and maturation from donor-derived hematopoietic stem cells. The formation of new T cells occurs in the thymus and as a byproduct, T cell receptor excision circles (TRECs) are released upon rearrangement of the T cell receptor. Detection of TRECs by PCR is a reliable method for estimating the amount of newly formed T cells in the circulation and, indirectly, for estimating thymic function. Here, we discuss the role of TREC analysis in the prediction of clinical outcome after allogeneic HSCT. Due to the pivotal role of T cell reconstitution we propose that TREC analysis should be included as a key indicator in the post-HSCT follow-up.

Improved overall survival for pediatric patients undergoing allogeneic hematopoietic stem cell transplantation - A comparison of the last two decades

Pediatric protocols for allogeneic hematopoietic SCT have been altered during the last two decades. To compare the outcomes in children (<18 yr old), who underwent SCT at our center during 1992-2002 (P1) and 2003-2013 (P2). We retrospectively analyzed 188 patients in P1 and 201 patients in P2. The most significant protocol changes during P2 compared with P1 were a decrease in MAC protocols, particularly those containing TBI, an increase in RIC protocols, and altered GvHD prophylaxis. In addition, P2 had more patients with nonmalignant diagnoses (p = 0.002), more mismatched (MM) donors (p = 0.01), and more umbilical CB grafts (p = 0.03). Mesenchymal or DSCs were used for severe acute GvHD during P2. Three-yr OS in P1 was 58%, and in P2, it was 78% (p < 0.001). Improved OS was seen in both malignant disorders (51% vs. 68%; p = 0.05) and nonmalignant disorders (77% vs. 87%; p = 0.04). Multivariate analysis showed that SCT during P2 was associated with reduced mortality (HR = 0.57; p = 0.005), reduced TRM (HR = 0.57; p = 0.03), unchanged relapse rate, similar rate of GF, less chronic GvHD (HR = 0.49; p = 0.01), and more acute GvHD (HR = 1.77, p = 0.007). During recent years, OS has improved at our center, possibly reflecting the introduction of less toxic conditioning regimens and a number of other methodological developments in SCT.

Transplanted Bone Marrow-Derived Cells Contribute to Human Adipogenesis

Because human white adipocytes display a high turnover throughout adulthood, a continuous supply of precursor cells is required to maintain adipogenesis. Bone marrow (BM)-derived progenitor cells may contribute to mammalian adipogenesis; however, results in animal models are conflicting. Here we demonstrate in 65 subjects who underwent allogeneic BM or peripheral blood stem cell (PBSC) transplantation that, over the entire lifespan, BM/PBSC-derived progenitor cells contribute ∼10% to the subcutaneous adipocyte population. While this is independent of gender, age, and different transplantation-related parameters, body fat mass exerts a strong influence, with up to 2.5-fold increased donor cell contribution in obese individuals. Exome and whole-genome sequencing of single adipocytes suggests that BM/PBSC-derived progenitors contribute to adipose tissue via both differentiation and cell fusion. Thus, at least in the setting of transplantation, BM serves as a reservoir for adipocyte progenitors, particularly in obese subjects.

An ex vivo RT-qPCR-based assay for human peripheral leukocyte responsiveness to glucocorticoids in surgically induced inflammation

Introduction

An assay to determine glucocorticoid (GC) responsiveness in humans could be used to monitor GC non-responsiveness in states of GC insufficiency and could provide a tool to adapt GC treatment to individual patients. We propose an ex vivo assay to test GC responsiveness in peripheral leukocytes. The assay was evaluated in a human experimental model of surgery-induced inflammation.

Patients and methods

Changes in expression of the GC-regulated genes GILZ, IL1R2, FKBP5, and HLA-DR and glucocorticoid receptor alpha (GRα) were determined by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) in peripheral leukocytes from surgical patients and healthy blood donors (total n=60) in response to low (1 nM) and high (1 µM) dexamethasone (DEX). The final selection of a suitable endogenous control gene was based on the studies of stability during DEX treatment and inflammation. Correlations between pre- and postoperative GC-induced gene expression, the postoperative systemic inflammatory and metabolic response (CRP, IL-6, white blood cell count, cytokines, resistin, free fatty acids, glucose, insulin, and adiponectin), and the clinical outcome were analyzed. The length of stay in the intensive care unit (ICU-LOS), the length of stay in the hospital, and postoperative complications were used to measure clinical outcome.

Results

When the blood donors were compared to the patients, there were no significant differences in the regulation of the genes in response to DEX, except for GRα. Preoperative, but not postoperative, gene regulation of GILZ and GRα was negatively correlated to ICU-LOS (P<0.05 and P<0.01, respectively). Preoperative GILZ and FKBP5 gene regulation was negatively correlated to postoperative systemic TNFα and MIP-1α levels.

Conclusion

We suggest that this assay could be used to determine GC responsiveness. An alteration in preoperative GC responsiveness may be related to a patient’s ability to recover from surgically induced inflammatory stress.

Antigen-induced regulation of T-cell motility, interaction with antigen-presenting cells and activation through endogenous thrombospondin-1 and its receptors

Antigen recognition reduces T-cell motility, and induces prolonged contact with antigen-presenting cells and activation through mechanisms that remain unclear. Here we show that the T-cell receptor (TCR) and CD28 regulate T-cell motility, contact with antigen-presenting cells and activation through endogenous thrombospondin-1 (TSP-1) and its receptors low-density lipoprotein receptor-related protein 1 (LRP1), calreticulin and CD47. Antigen stimulation induced a prominent up-regulation of TSP-1 expression, and transiently increased and subsequently decreased LRP1 expression whereas calreticulin was unaffected. This antigen-induced TSP-1/LRP1 response down-regulated a motogenic mechanism directed by LRP1-mediated processing of TSP-1 in cis within the same plasma membrane while promoting contact with antigen-presenting cells and activation through cis interaction of the C-terminal domain of TSP-1 with CD47 in response to N-terminal TSP-1 triggering by calreticulin. The antigen-induced TSP-1/LRP1 response maintained a reduced but significant motility level in activated cells. Blocking CD28 co-stimulation abrogated LRP1 and TSP-1 expression and motility. TCR/CD3 ligation alone enhanced TSP-1 expression whereas CD28 ligation alone enhanced LRP1 expression. Silencing of TSP-1 inhibited T-cell conjugation to antigen-presenting cells and T helper type 1 (Th1) and Th2 cytokine responses. The Th1 response enhanced motility and increased TSP-1 expression through interleukin-2, whereas the Th2 response weakened motility and reduced LRP1 expression through interleukin-4. Ligation of the TCR and CD28 therefore elicits a TSP-1/LRP1 response that stimulates prolonged contact with antigen-presenting cells and, although down-regulating motility, maintains a significant motility level to allow serial contacts and activation. Th1 and Th2 cytokine responses differentially regulate T-cell expression of TSP-1 and LRP1 and motility.

Hypogammaglobulinemia in children after allogeneic hematopoietic stem cell transplantation: a cytokine mediated immunoglobulin isotype class switch arrest?

BACKGROUND

Hypogammaglobulinemia (hypo-IgG) is common early post-HSCT in children, occasionally necessitating long-term immunoglobulin (Ig) G replacement therapy. IgG replacement may not reduce mortality, although infectious complications are decreased

PROCEDURE

Clinical data and samples from 86 children were analyzed retrospectively with the aim to identify risk factors for developing long-term hypo-IgG (i.e., requiring ≥ 3 months IgG replacement) post-HSCT and studying the underlying biology. Laboratory studies covered serum cytokines, IGHG2 genotyping and routine laboratory investigations. Results were analyzed statistically.

RESULTS

Forty-eight percent of the children developed long-term hypo-IgG. These children were younger (<5 years) and had higher acute GvHD incidence, but had better overall survival (88% vs. 69%, P = 0.036). Significantly lower Ig levels post-HSCT but equal immune cell recovery were seen in patients with long-term hypo-IgG compared with those of transient or no hypo-IgG. Pre-HSCT IL-6 and -7 and post-HSCT BAFF and APRIL levels were significantly higher in the long-term hypo-IgG group.

CONCLUSIONS

Findings suggests an unfavorable cytokine milieu for graft-derived immune recovery, possibly inducing Ig isotype class switch arrest. Younger age, acute GvHD, and higher pre-HSCT IL-6 levels were identified as significant risk factors for long-term hypo-IgG. Long-term hypo-IgG post-HSCT does not need to be unfavorable and could be an effect of deteriorated cytokine signaling.

Fetal membrane cells for treatment of steroid-refractory acute graft-versus-host disease

The placenta protects the fetus from the mother's immune system. We have previously found that fetal membrane cells (FMCs) isolated from term placenta prevent alloreactivity in vitro. FMCs share many features with bone marrow-derived mesenchymal stromal cells (MSCs), which we previously introduced to treat severe acute graft-versus-host disease (GVHD). Here, we tested FMCs for treatment of steroid-refractory acute GVHD. After two passages in culture, approximately 10(9) FMCs were obtained from one single placenta, although not all cells from passage 0 and passage 1 were used for expansion. The FMCs were positive for CD29, CD44, CD73, CD90, CD105, and CD49d but were negative for hematopoietic, endothelial, and epithelial markers. Microsatellite polymorphism analysis showed that FMCs were of maternal origin. All FMCs used showed normal karyotype. Nine patients who had undergone hematopoietic stem cell transplantation (HSCT) and who had developed steroid-refractory grade III-IV acute GVHD were given 0.9-2.8 × 10(6) FMCs per kg at 15 infusions. Median age was 57 years. There was no toxicity from infusion of FMCs in eight patients. One patient had seizures after infusion. Two of eight evaluable patients had a complete response and four had a partial response, giving an overall response rate of 75%. Two patients showed no response at all. Three patients are alive from 6 to 21 months after HSCT. One patient is well and two have chronic GVHD. Thus, FMCs may be successfully used for immune modulation and tissue repair.

A research study of the association between maternal microchimerism and systemic lupus erythematosus in adults: a comparison between patients and healthy controls based on single-nucleotide polymorphism using quantitative real-time PCR

BACKGROUND

Naturally acquired microchimerism may arise in the mother and her child during pregnancy when bidirectional trafficking of cells occurs through the placental barrier. The occurrence of maternal microchimerism (maternal cells in the offspring) has been associated with several autoimmune diseases, especially in children. Systemic Lupus erythematosus (SLE) is an autoimmune disorder with a resemblance to graft-versus-host disease. The aim of this study was to investigate the association between maternal microchimerism in the blood and SLE.

METHODOLOGY/PRINCIPAL FINDINGS

Thirty-two patients with SLE, 17 healthy brothers of the patients, and an additional 12 unrelated healthy men were the subjects in this study. A single-nucleotide polymorphism unique to each mother was identified, and maternal microchimerism in the study group and in the control group was detected using a quantitative real-time polymerase chain reaction technique. No differences in the frequency or the concentration of maternal cells were apparent in the blood of patients with SLE or in that of the controls. Two patients and one control tested positive for maternal microchimerism, but the positive subjects were all negative at a follow-up 16 years later. The sensitivity of the method was estimated to 1/10.000.

CONCLUSIONS/SIGNIFICANCE

These results show no association between SLE and maternal microchimerism. The frequency of maternal microchimerism in the blood of adults overall may be lower than earlier reported.

Rapid salvage treatment with virus-specific T cells for therapy-resistant disease

BACKGROUND

Viral infections are major complications after allogeneic hematopoietic stem cell transplantation (HSCT). During posttransplant immunosuppression the regular T-cell control is compromised. Even if treatment strategies against infections caused by herpes viruses such as cytomegalovirus, Epstein-Barr virus, and adenovirus have improved, the mortality rate is still considerable. If primary antiviral therapy fails or cannot be tolerated, adoptive therapy with virus-specific cytotoxic T cells (CTL) can be utilized.

METHODS

In this study, we used virus-specific CTLs to treat 8 patients suffering from severe viral infections after allogeneic HSCT. Using positive selection with HLA multimers and magnetic beads, we isolated CTLs from both frozen donor material as well as third-party donors within hours.

RESULTS

At 90 days after CTL infusions 7 out of 8 patients were still living. CTLs infused from third-party donors were detected in 5 of 6 patients up to 76 days after infusion. No graft-versus-host disease associated with CTL infusions was observed.

CONCLUSIONS

Our separation approach offers a rapid alternative for adoptive CTL therapy if primary antiviral treatment strategies fail. Because no prolonged expansion steps are needed, this method may be used for early treatment of patients suffering from life-threatening infectious complications.

Thymic function after allogeneic stem cell transplantation is dependent on graft source and predictive of long term survival

T-cell deficiency after allogeneic stem cell transplantation (ASCT) is common and has major impact on clinical outcome. In this retrospective study 210 patients were analyzed with regards to levels of T-cell receptor excision circles (TRECs) during the first 24 months after transplantation. We could for the first time show a significant correlation between the use of bone marrow grafts and higher TREC levels >6 months post-ASCT (p<0.001). Treatment with anti-thymocyte globulin was correlated with lower TREC levels ≤6 months post-ASCT (p<0.001). Patients with TREC levels above median at 3 months had a superior overall survival, 80% vs. 56% (p=0.002), and lower transplantation-related mortality, 7% vs. 21% (p=0.01). We conclude that graft source and conditioning regimen may have a significant effect on T-cell reconstitution after ASCT and can thus affect outcome. These results strongly support the use of TREC measurement as part of the standard repertoire of immunological monitoring after ASCT.

Mesenchymal stem cells inhibit thymic reconstitution after allogeneic cord blood transplantation

Cord blood (CB) as a source of stem cells has been a successful addition to the field of allogeneic stem cell transplantation (ASCT). The increased human leukocyte antigen (HLA) permissiveness of CB grafts has made it possible for more patients to undergo treatment. The drawback is that patients suffer from a longer period of compromised immunity. We analyzed T-cell receptor excision circles (TRECs), immunoglobulin G (IgG), and immunoglobulin M (IgM) levels after cord blood transplantation (CBT) in 50 patients transplanted at our center. These immunological parameters were compared retrospectively with clinical factors and complications. We found that TREC levels after CBT were lower in adults, patients with myeloablative conditioning, and in patients with a lower nucleated cell dose in the graft. In addition mesenchymal stem cells (MSC) as co-infusion at the time of CBT had a negative effect on TREC reconstitution. This was found to be associated with decreased overall survival for this patient category. Reduced IgM and IgG levels post-CBT were associated with a major AB0 mismatch, and infusion of MSCs. Our results highlight the importance of close monitoring of the immune reconstitution after CBT. In addition it shows a potentially new suppressive effect of MSCs on the immune system.

Improved survival after allogeneic hematopoietic stem cell transplantation in recent years. A single-center study

We analyzed the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) over the past 2 decades. Between 1992 and 2009, 953 patients were treated with HSCT, mainly for a hematologic malignancy. They were divided according to 4 different time periods of treatment: 1992 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009. Over the years, many factors have changed considerably regarding patient age, diagnosis, disease stage, type of donor, stem cell source, genomic HLA typing, cell dose, type of conditioning, treatment of infections, use of granulocyte-colony stimulating factor (G-CSF), use of mesenchymal stem cells, use of cytotoxic T cells, and home care. When we compared the last period (2006-2009) with earlier periods, we found slower neutrophil engraftment, a higher incidence of acute graft-versus-host disease (aGVHD) of grades II-IV, and less chronic GVHD (cGHVD). The incidence of relapse was unchanged over the 4 periods (22%-25%). Overall survival (OS) and transplant-related mortality (TRM) improved significantly in the more recent periods, with the best results during the last period (2006-2009) and a 100-day TRM of 5.5%. This improvement was also apparent in a multivariate analysis. When correcting for differences between the 4 groups, the hazard ratio for mortality in the last period was 0.59 (95% confidence interval [CI]: 0.44-0.79; P < .001) and for TRM it was 0.63 (CI: 0.43-0.92; P = .02). This study shows that the combined efforts to improve outcome after HSCT have been very effective. Even though we now treat older patients with more advanced disease and use more alternative HLA nonidentical donors, OS and TRM have improved. The problem of relapse still has to be remedied. Thus, several different developments together have resulted in significantly lower TRM and improved survival after HSCT over the last few years.

Maternal microchimerism in juvenile tonsils and adenoids

During pregnancy small amounts of cells pass between the mother and the fetus, and this transfer may give rise to a chimeric state that persist for years in both individuals. Both fetal and maternal microchimerism (MMc) have been associated with different autoimmune disorders. Information about MMc in tissues of healthy individuals is sparse but is important when looking for maternal cells within affected tissues of certain diseases. The aim of this study was to investigate the occurrence of maternal cells in tonsils and adenoids of 20 healthy children between the ages of 2 and 15 years. All the children underwent surgery because of recurrent tonsillitis or respiratory obstruction. MMc was detected using an RT-PCR assay based on differences in gene polymorphisms between mother and child. We found maternal cells in the tonsils and/or adenoids in four of 20 children. This frequency is less than the frequency of maternal cells found in the peripheral blood of healthy adults but in agreement with the previously reported frequency of maternal chimerism in control tissues

Characterization of long-term mixed donor-donor chimerism after double cord blood transplantation

Double cord blood transplantation (DCBT) with two matched or partially matched cord blood units has been implemented successfully to circumvent the limitations of graft cell dose associated with single CBT. After DCBT, sustained haematopoiesis is derived almost exclusively from only one of the donated units. None the less, we previously observed two of six evaluable DCBT patients still having mixed donor-donor chimerism at 28 and 45 months post-transplantation, respectively. In the present study we utilize flow cytometry techniques to perform the first thorough analysis of phenotype and functionality of cord blood units in patients with mixed donor-donor chimerism. Our results suggest that the two stable cord blood units are different phenotypically and functionally: one unit shows more naive T cells, lower T cell cytokine production and higher frequencies of natural killer cells, the other shows higher frequencies of well-differentiated and functional lymphocytes. Additionally, in comparison with control patients having a single prevailing cord blood unit, the patients with donor-donor chimerism exhibit less overall T cell cytokine production and a smaller fraction of memory T cells. Furthermore, our results indicate that human leucocyte antigen-C match of donor units may partly explain the development of a donor-donor mixed chimerism.

A novel haplo-identical adoptive CTL therapy as a treatment for EBV-associated lymphoma after stem cell transplantation

Epstein-Barr virus (EBV)-related malignancies such as post-transplant lymphoproliferative disease (PTLD) are severe complications after allogeneic stem cell transplantation and solid-organ transplantation. In immunosuppressed transplant recipients, the activity of EBV-specific CTLs are often decreased or absent which leads to an increased risk of developing PTLD. If primary treatment modalities of PTLD fail, the most efficient way of treating the malignancy is adopting EBV-specific CTLs from the donor or, more recently, third-party donors. However, both are time consuming and expensive and often it is too late to administer cells to the patient. We have for the first time, using a rapid isolation protocol of EBV-specific T cells, treated and cured a patient suffering from PTLD with multiple-associated tissue lesions, using her haplo-identical mother as a donor. This treatment approach paves way for a new possibility to within-days treat patients with life-threatening EBV-associated malignancies.

Allogeneic hematopoietic SCT in patients with non-malignant diseases, and importance of chimerism

In this retrospective study, we evaluated the chimerism status and outcome in 58 patients (64 transplants) with non-malignant diseases. Reduced intensity conditioning (RIC) was given in half of the transplants. Mixed chimerism (MC) was defined as >1% recipient cells. Two consecutive samples showing >30% recipient cells were defined as high chimerism (high MC). Patients with high MC and the management of these patients were analyzed in greater detail. The overall survival rate was 87%. In total, 23 transplants were donor chimerism (DC) and 41 transplants showed some degree of MC. The incidence of MC was 78 and 50% after RIC and myeloablative conditioning, respectively (P=0.04). Acute GVHD of grades II-III was more common in patients with DC (39%) than in patients with MC (8%) (P=0.002). Owing to high MC, donor lymphocyte infusions were given in 17 cases. The level of MC was reduced in seven cases, unchanged in four cases, increased in one case and there was graft rejection in five cases. A second transplant was carried out in six cases with rejections, five are alive and in remission. We conclude that patients with non-malignant diseases, who develop MC after transplant have less acute GVHD. Despite the high incidence of MC, overall survival is promising.

Evidence for no relevance of anti-major histocompatibility complex class I-related chain a antibodies in liver transplantation

The polymorphic major histocompatibility complex class I-related chain A (MICA) antigen is being increasingly recognized as a potential target molecule for immune cells during allograft rejection. Here we studied whether MICA is a target antigen for antibodies in liver transplant patients. Eighty-four patients were investigated for the presence of MICA antibodies before and after liver transplantation with MICA-transfected cells and flow cytometry. MICA typing was performed by polymerase chain reaction. Expression of MICA in liver cells was determined by reverse-transcription polymerase chain reaction, Western blotting, and flow cytometry. Liver biopsy specimens from liver transplant patients were examined for MICA expression. A total of 22 of 84 (26%) patients had MICA antibodies either pre-transplant (8/84, 9.5%) or post-transplant (14/84, 17%). No correlation between rejection frequencies (14/22, 63%) or other clinical parameters was observed in patients with MICA antibody versus those without MICA antibody (29/62, 47% P = not significant). We found weak messenger RNA expression for MICA in liver cells but no protein or cell surface expression. In addition, no MICA expression in liver biopsy sections from liver transplant patients was observed at any time point, including rejections. Thus, our preliminary results demonstrate no causal relationship between the presence of MICA antibodies and liver allograft rejections. Therefore, it is likely that MICA may not be an important target antigen during liver allograft rejections.

Maternal microchimerism in human fetal tissues

OBJECTIVE

The aim of the present study was to analyze the presence of maternal cells in human fetal tissues in the second trimester.

STUDY DESIGN

Tissues from 11 second-trimester fetuses terminated because of social reasons or because of malformations and/or trisomy were investigated. By cell sorting and polymerase chain reaction amplification, we studied the presence of maternal CD3+, CD19+, CD34+, and CD45+ in different fetal tissues and in placenta.

RESULTS

In the group of fetuses with normal karyotype and normal autopsy findings, 4 of 5 fetuses were positive for maternal microchimerism. In the group in which the fetuses were diagnosed with trisomy 21 and/or malformations, we found cells of maternal origin in 3 of 6 fetuses.

CONCLUSION

The results from this study indicate that maternal microchimerism is a common phenomenon in the second-trimester fetuses. Maternal cells of lymphoid and myeloid lineages and hematopoietic progenitors are widely distributed in the second-trimester fetuses.

Endometrial endothelial cells are derived from donor stem cells in a bone marrow transplant recipient

BACKGROUND

The endometrium is a dynamic, cyclically regenerating tissue: a unique model of physiological angiogenesis in adults. However, the source of new endothelial cells (ECs) for vessel regrowth is obscure. We studied if male EC could be detected in the endometrial blood vessels of female human or mouse recipients of haematological stem cells from male donors.

METHODS

Endometrial biopsies, obtained from one patient after non-myeloablative allogeneic bone marrow transplantation and two controls, were analysed by immunohistochemistry of CD34 and VEGFR2 antibodies for the immunophenotyping of EC, and FISH probes for the detection of donor cells. Chimerism was analysed using real-time PCR. The same experiment was also applied on the animal model.

RESULTS

At the time of a Caesarean section in a female bone marrow transplanted patient, an average 14% of her endometrial EC were donor-derived. One year later, that figure was 10%. In contrast, none of two non-transplanted females demonstrated a mismatch in endometria at Caesarean section. In samples from female mice, harvested 40 days after a haematological stem cell transplant, a 6% average of donor-derived EC was detected.

CONCLUSIONS

Bone marrow-derived endothelial progenitors contribute to the formation of new blood vessels in the endometrium.

Tissue repair using allogeneic mesenchymal stem cells for hemorrhagic cystitis, pneumomediastinum and perforated colon

Mesenchymal stem cells (MSC) possess anti-inflammatory properties and participate in tissue repair. We used MSC to heal therapy-induced tissue toxicity. Ten consecutive patients, treated with MSC due to tissue toxicity following allogeneic hematopoietic stem cell transplantation, (ASCT) were included. Their median age was 48 (13-64) years. Seven had hemorrhagic cystitis grades 2-5, two had pneumomediastinum and one had perforated colon and peritonitis. MSC donors were mainly third-party, HLA-mismatched (n=11), HLA-haploidentical (n=3) and, in two cases, the HLA-identical ASCT sibling donors. MSC were given intravenously, the median cell dose was 1.0 (range 0.7-2)x10(6)/kg. In five patients, the severe hemorrhagic cystitis cleared after MSC infusion. Gross hematuria disappeared after median 3 (1-14) days. Two patients had reduced transfusion requirements after MSC infusion, but died of multiorgan failure. In one of them, MSC donor DNA was demonstrated in the urinary bladder. In two patients, pneumomediastinum disappeared after MSC infusions. A patient with steroid-resistant graft-versus-host disease of the gut experienced perforated diverticulitis and peritonitis that was reversed twice by MSC. MSC is a novel treatment for therapy-induced tissue toxicity.

Fludarabine-based disease-specific conditioning or conventional myeloablative conditioning in hematopoietic stem cell transplantation for treatment of non-malignant diseases

Fludarabine-based conditioning (FBC) was given to 24 patients and conventional myeloablative conditioning (MC) to 33 patients, most children, before hematopoietic stem cell transplantation (HSCT) for non-malignant diseases. The donors were human leukocyte antigen (HLA)-A, -B, -DRbeta1-identical related (33%) or unrelated (67%). In the FBC group, two grafts failed versus three in the MC group; all were successfully regrafted. Fever was more common in the MC patients (P=0.003). Bacteremia occurred in 25% of the FBC group and 50% in the MC group (P=0.1). In the FBC group, platelet engraftment was faster and transfusions were fewer (P<0.05). Mucositis and renal function were similar in the two groups. The MC group had higher maximum bilirubin (P=0.03) and less often normal spirometry (P=0.04) after HSCT. A 7-year-old girl in the MC group had permanent alopecia. No patients had severe acute graft-versus-host disease (GVHD). Chronic GVHD was rare. Complete donor CD3+ chimerism was more common in the MC group (P=0.01), but CD33+ engraftment was better with FBS (P=0.03). Treatment-related mortality was 4 and 15%, and 5-year survival was 89 and 85% in the FBC and MC groups. Although survival was similar, FBC is a promising alternative to MC in non-malignant disorders.

Human liver sinusoidal endothelial cells induce apoptosis in activated T cells: a role in tolerance induction

BACKGROUND

The liver may have a role in peripheral tolerance, by serving as a site for trapping, apoptosis and phagocytosis of activated T cells. It is not known which hepatic cells are involved in these processes. It was hypothesised that liver sinusoidal endothelial cells (LSEC) which are strategically placed for participation in the regulation of sinusoidal blood flow, and express markers involved in recognition, sequestration and apoptosis, may contribute to peripheral tolerance by inducing apoptosis of activated T cells.

METHODS

By using immunoassays and western blot analysis, the fate of activated T cells when incubated with human LSEC isolated from normal healthy livers was investigated.

RESULTS

Evidence that activated (approximately 30%) but not non-activated T cells undergo apoptosis on incubation with human LSEC in mixed cell cultures is provided. No difference in the results was observed when unstimulated and cytokine-stimulated LSEC were used. T cell-LSEC contact is required for induction of apoptosis. Apoptosis induced by LSEC was associated with caspase 8 and 3 activity and strong expression of the proapoptotic molecule Bak. Transforming growth factor beta (TGFbeta) produced constitutively by LSEC is partly responsible for the caspase-induced apoptosis, as neutralising antibodies to TGFbeta markedly attenuated apoptosis, up regulated the antiapoptotic molecule Bcl-2 and partially blocked caspase-3 activity.

CONCLUSION

These findings broaden the potential role of LSEC in immune tolerance and homeostasis of the immune system. This study may provide insight for exploring the mechanisms of immune tolerance by liver allografts, immune escape by some liver pathogens including hepatitis C and pathogenesis of liver diseases.

Unrelated versus related allogeneic stem cell transplantation after reduced intensity conditioning

BACKGROUND

The use of reduced intensity conditioning (RIC) regimens in allogeneic hematopoietic stem cell transplantation (HSCT) has increased over the past five years.

PATIENTS

In this study, involving 137 patients, we compared the outcome after RIC in patients receiving grafts from matched unrelated donors (MUD; n=74) and sibling donors (n=63). The MUD and sibling groups were comparable regarding diagnosis, including solid tumors and hematological malignancies, and conditioning regimens.

RESULTS

Engraftment was successful in most patients (88%), with no significant difference between MUD and sibling transplants. Cytomegalovirus (CMV) infection was more common in the MUD group (65%) than in the sibling group (46%) (P=0.04). No difference in severe acute graft-versus-host disease (GVHD) was found between the groups. However, the incidence of chronic GVHD was higher after sibling transplants. This was probably due to higher donor age in this group, since this was the only significant risk factor for chronic GVHD in multivariate analysis. The incidence of transplant related mortality (TRM) was significantly higher after MUD transplantation (40%) than after sibling transplantation (16%) (P<0.01). Because relapse/disease progression was more common after sibling transplantation, there was no significant difference in overall survival between the two groups.

CONCLUSION

Using unrelated donors after RIC is feasible, but it resulted in more CMV infection and increased transplant-related mortality. Survival was comparable to that of sibling transplants.

Inhibition of heavy chain and beta2-microglobulin synthesis as a mechanism of major histocompatibility complex class I downregulation during Epstein-Barr virus replication

The mechanisms of major histocompatibility complex (MHC) class I downregulation during Epstein-Barr virus (EBV) replication are not well characterized. Here we show that in several cell lines infected with a recombinant EBV strain encoding green fluorescent protein (GFP), the virus lytic cycle coincides with GFP expression, which thus can be used as a marker of virus replication. EBV replication resulted in downregulation of MHC class II and all classical MHC class I alleles independently of viral DNA synthesis or late gene expression. Although assembled MHC class I complexes, the total pool of heavy chains, and beta2-microglobulin (beta2m) were significantly downregulated, free class I heavy chains were stabilized at the surface of cells replicating EBV. Calnexin expression was increased in GFP+ cells, and calnexin and calreticulin accumulated at the cell surface that could contribute to the stabilization of class I heavy chains. Decreased expression levels of another chaperone, ERp57, and TAP2, a transporter associated with antigen processing and presentation, correlated with delayed kinetics of MHC class I maturation. Levels of both class I heavy chain and beta2m mRNA were reduced, and metabolic labeling experiments demonstrated a very low rate of class I heavy chain synthesis in lytically infected cells. MHC class I and MHC class II downregulation was mimicked by pharmacological inhibition of protein synthesis in latently infected cells. Our data suggest that although several mechanisms may contribute to MHC class I downregulation in the course of EBV replication, inhibition of MHC class I synthesis plays the primary role in the process.

Mesenchymal stem cells for treatment of therapy-resistant graft-versus-host disease

BACKGROUND

Mesenchymal stem cells (MSC) have immunomodulatory effects. The aim was to study the effect of MSC infusion on graft-versus-host disease (GVHD).

METHODS

We gave MSC to eight patients with steroid-refractory grades III-IV GVHD and one who had extensive chronic GVHD. The MSC dose was median 1.0 (range 0.7 to 9)x10(6)/kg. No acute side-effects occurred after the MSC infusions. Six patients were treated once and three patients twice. Two patients received MSC from HLA-identical siblings, six from haplo-identical family donors and four from unrelated mismatched donors.

RESULTS

Acute GVHD disappeared completely in six of eight patients. One of these developed cytomegalovirus gastroenteritis. Complete resolution was seen in gut (6), liver (1) and skin (1). Two died soon after MSC treatment with no obvious response. One of them had MSC donor DNA in the colon and a lymph node. Five patients are still alive between 2 months and 3 years after the transplantation. Their survival rate was significantly better than that of 16 patients with steroid-resistant biopsy-proven gastrointestinal GVHD, not treated with MSC during the same period (P = 0.03). One patient treated for extensive chronic GVHD showed a transient response in the liver, but not in the skin and he died of Epstein-Barr virus lymphoma.

CONCLUSION

MSC is a very promising treatment for severe steroid-resistant acute GVHD.

Endogenous thrombospondin-1 is a cell-surface ligand for regulation of integrin-dependent T-lymphocyte adhesion

Lymphocyte adhesion to cells and extracellular matrix (ECM) via integrins plays a pivotal role for the function of the immune system. We show here that endogenous thrombospondin-1 (TSP-1) is a cell-surface ligand for cis interaction of surface receptors in T lymphocytes controlled by integrins and the T-cell antigen receptor (TCR/CD3). Stimulation of CD3 triggers rapid surface expression of TSP-1 in quiescent T cells, whereas activated cells express TSP-1 constitutively. Endogenous TSP-1 is attached to lipoprotein receptor-related protein 1 (LRP1/CD91) and calreticulin (CRT) on the cell surface through its NH2-terminal domain. Adhesion via integrins to ICAM-1 or ECM components up-regulates TSP turnover dramatically from a low level in nonadherent cells, whereas CD3 stimulation inhibits TSP turnover through interference with CD91/CRT-mediated internalization. Integrin-associated protein (IAP/CD47) is essential for TSP turnover and adhesion through interaction with the C-terminal domain of TSP-1 in response to triggering signals delivered at the NH2-terminal. These results indicate that endogenous TSP-1 connects separate cell-surface receptors functionally and regulates T-cell adhesion.

Molecular monitoring of T-cell chimerism early after allogeneic stem cell transplantation may predict the occurrence of acute GVHD grades II-IV

Mixed chimerism (MC) within CD4+ and CD8+ T cell days 7 and 10 after allogeneic stem cell transplantation (SCT) was compared with the occurrence of acute graft-vs.-host disease (GVHD) in 34 patients after SCT. Acute GVHD was diagnosed in 22 patients within the first 3 months after SCT, 15 of these developed acute GVHD grades II-IV. The difference in the clearance rate of host T cell between the two days were compared. We found a significantly higher risk (p = 0.005) for developing acute GVHD grades II-IV in patients with complete donor CD4+ T-cell chimerism day 7 after SCT together with patients who increased 50% or more in donor CD4+ T cells between days 7 and 10 after SCT. Our data suggest that molecular monitoring of MC early after transplantation may be useful as a diagnostic tool in predicting the occurrence of moderate to severe acute GVHD after SCT.

Biliary epithelial cell antibodies induce expression of toll-like receptors 2 and 3: a mechanism for post-liver transplantation cholangitis?

Studies to determine the role of preformed antibodies to biliary epithelial cells (BECs) in liver transplant rejections have been initiated. However, the clinical importance of these antibodies in the posttransplantation period still remains to be elucidated. Reactivity to BECs isolated from a normal healthy liver was investigated in sera of 56 patients before and after liver transplantation (LTX) using flow cytometry. Functional capacity of BEC antibodies was determined by the ability to induce expression of Toll-like receptors (TLRs) on BECs. Cytokine and chemokine production induced by BEC antibodies was determined by enzyme-linked immunosorbent assay. In all, 7 patients (13%) had BEC antibodies only pre-LTX, 14 (25%) only after LTX, 18 (32%) both before and after LTX, and 17 (30%) had no detectable antibodies. Presence of preformed BEC antibodies correlated with acute rejections (P < 0.03). Deposition of immunoglobulins in bile ducts was detected in biopsies of patients during rejections. Significantly higher numbers of patients with post-LTX antibodies (9 of 32) developed cholangitis, compared with 0 of 17 without antibodies (P < 0.02). Specificity studies indicated that these antibodies were both non-HLA- and HLA-specific. Normal BECs expressed mRNA but not the proteins for the TLRs. However, treatment with F(ab')2 fragments of BEC antibodies induced protein expression of TLRs 2 and 3 and significantly high production of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, epithelial neutrophil activating peptide (ENA)-78, and IL-8. In conclusion, BEC antibodies via induction of TLR2 and TLR3 expression, as well as inflammatory cytokine and chemokine production may induce epithelial cell inflammatory responses to bacterial components and contribute to posttransplantation cholangitis.

Difference in gene expression between human fetal liver and adult bone marrow mesenchymal stem cells

BACKGROUND AND OBJECTIVES

Mesenchymal stem cells (MSC) are progenitor cells that are capable of differentiating into mesenchymal tissues. Fetal and adult MSC have similar morphology but differ in proliferative, differentiating and immunosuppressive properties. Further exploring their differences could help in choosing the right source for cellular therapy.

DESIGN AND METHODS

The gene expression profiles of undifferentiated MSC derived from first trimester fetal liver and adult bone marrow were compared by serial analysis of gene expression, and validated by either reverse transcription polymerase chain reaction or immunoblotting of selected genes. The immunophenotype was compared by flow cytometry and cell ELISA.

RESULTS

Seventy genes were differentially induced two-fold or more in fetal MSC compared to adult MSC. These involved transcripts regulating germ plasm and limb patterning, brain and early muscle development. Transcripts implicated in cell cycle promotion, chromatin regulation and DNA repair were also more abundant in fetal MSC. Ninety-seven genes were decreased two-fold or more in fetal MSC, including transcripts involved in smooth muscle and keratinocyte differentiation and transcripts for immunological genes. Although phenotypically largely similar, fetal MSC had a higher expression of ICAM1 and contained intracellular deposits of HLA-G while expression of HLA class I and II molecules and VCAM1 was increased in adult MSC.

INTERPRETATION AND CONCLUSIONS

This study reports the first extensive investigation of the differences in gene expression profiles between fetal and adult MSC. The results suggest that fetal MSC have higher proliferative capacity and are less lineage committed than adult MSC.

Only a specific subset of human peripheral-blood monocytes has endothelial-like functional capacity

The monocyte population in blood is considered a possible source of endothelial precursors. Because endothelial-specific receptor tyrosine kinases act as regulators of endothelial cell function, we investigated whether expression of the vascular endothelial growth factor receptor-2 (VEGFR-2) on monocytes is important for their endothelial-like functional capacity. Peripheral-blood monocytes expressing vascular endothelial growth factor receptor-2 (VEGFR-2), or CD14+/VEGFR-2+, were isolated, and their phenotypic, morphologic, and functional capacities were compared with those of monocytes negative for this marker (CD14+/VEGFR-2-). CD14+/VEGFR-2+ cells constituted approximately 2% +/- 0.5% of the total population of monocytes and 0.08% +/- 0.04% of mononuclear cells in blood. CD14+/VEGFR-2+ cells exhibited the potential to differentiate in vitro into cells with endothelial characteristics. The cells were efficiently transduced by a lentiviral vector driving expression of the green fluorescence protein (GFP). Transplantation of GFP-transduced cells into balloon-injured femoral arteries of nude mice significantly contributed to efficient reendothelialization. CD14+/VEGFR-2- did not exhibit any of these characteristics. These data demonstrate that the expression of VEGFR-2 on peripheral blood monocytes is essential for their endothelial-like functional capacity and support the notion of a common precursor for monocytic and endothelial cell lineage. Our results help clarify which subpopulations may restore damaged endothelium and may participate in the maintenance of vascular homeostasis.

Expression of Vascular Endothelial Growth Factor Receptor-2 or Tie-2 on Peripheral Blood Cells Defines Functionally Competent Cell Populations Capable of Reendothelialization

BACKGROUND

Receptor tyrosine kinases that include vascular endothelial growth factor (VEGFR)-1, VEGFR-2, and Tie-2 regulate cardiovascular development and physiological and pathological angiogenesis. We were interested in the phenotypic and functional characterization of peripheral blood cells expressing these receptors and their therapeutic potential in vascular injury.

METHODS AND RESULTS

VEGFR-1+, VEGFR-2+, and Tie-2+ cells constituted approximately 3.0+/-0.2%, 0.8+/-0.5%, and 2.0+/-0.3%, respectively, of the total population of mononuclear cells in blood. Phenotypic analysis demonstrated that all 3 cell populations mainly expressed markers of monocytic/macrophage lineage. Only VEGFR-2+ and Tie-2+ cells phenotypically, morphologically, and functionally differentiated to endothelial cells after culture, whereas VEGFR-1+ cells did not. None of the cell types proliferated in vitro. Only freshly isolated VEGFR-2+ or Tie-2+ cells but not VEGFR-2- or Tie-2- cell populations significantly contributed to efficient endothelialization of balloon-injured femoral arteries of nude mice. Furthermore, these cells also differentiated into -actin-positive smooth muscle cells. Administration of bromodeoxyuridine to animals transplanted with human endothelial progenitor cells showed that VEGFR-2+ and Tie-2+ cells proliferated in vivo.

CONCLUSIONS

These data demonstrate that expression of VEGFR-2 and/or Tie-2 on peripheral blood cells defines functionally competent cell populations that proliferate in vivo and that contribute to reendothelialization. These findings may have implications for a cell-based approach in vascular diseases.

Indium-111-labelled donor-lymphocyte infusion by way of hepatic artery and radio-frequency ablation against liver metastases of renal and colon carcinoma after allogeneic hematopoietic stem-cell transplantation

BACKGROUND

In patients with metastatic solid cancer, antitumor effects occur after allogeneic stem-cell transplantation (SCT). However, this treatment is not as effective in the liver as against pulmonary and lymph-node metastases. To intensify the effect of donor-lymphocyte infusions (DLI) against liver metastases, intra-arterial (IA) cell injection by way of the hepatic artery (HA) can be used.

METHODS

To trace infused cells, three patients with colorectal, three with renal, and one with breast carcinoma were treated with Indium-111 (111-In)-oxinate-labeled lymphocytes. Four patients received the DLI IA, all after radio-frequency ablation (RFA) of liver metastases. Three patients with other metastases received 111-In DLI intravenously (IV). One of them had RFA before SCT.

RESULTS

Localization of the IA 111-In DLI activity on scintigrams homed to the liver. After IA injection, the liver to sternum ratio of radioactivity was higher compared with IV injection. Cells (CD3+, 19+, and 56+) of donor origin in biopsies of liver metastasis in two patients treated with IA injection increased to 80% to 100%. Two of four patients treated using the IA DLI showed stable size and number of liver metastases for 5 and 21 months, respectively. Both are alive 18 and 34 months after SCT. Two of three patients receiving DLI IV are doing well, with a stable metastatic disease or still without metastases 21 and 20 months after cell infusions (26 and 34 months after SCT), respectively. Three patients died because of progressive disease.

CONCLUSION

When infused by way of the HA, 111-In-labeled lymphocytes home to the liver and its metastases. The liver metastasis infiltrating cells of donor origin increased. DLI by way of the HA combined with RFA may be used to treat liver metastases after SCT.

Adult porcine islets produce MCP-1 and recruit human monocytes in vitro

Type 1 diabetes can be cured by transplantation of isolated pancreatic islets. Because of the shortage of human donor tissue, adult porcine islets (APIs) constitute a possible alternative tissue source. Upon intraportal injection, islets are subjected to an instant blood-mediated inflammatory reaction (IBMIR) leading to blood clotting, leukocyte islet-infiltration, islet damage and insulin release. Xenogeneic islets surviving IBMIR are rejected in a cellular process involving CD4(+) T lymphocytes and macrophages. We have investigated whether APIs themselves produce and secrete chemokines and/or inflammatory cytokines that may contribute to IBMIR and/or cell-mediated rejection. APIs, cultured for 1, 4, 8 and 11 days post-isolation, expressed mRNA for monocyte chemoattractant protein-1 (MCP-1), IL-1beta and TNF-alpha. API culture supernatants induced migration of human monocytes, which was significantly blocked by an anti-human MCP-1 antibody (Ab). Immunohistochemistry revealed MCP-1 in the cytoplasm of alpha- and beta-cells in isolated islets and in islets in situ. However, APIs or their supernatants were not able to activate human aortic endothelial cells (HAECs) in vitro, and neither IL-1beta nor TNF-alpha were detected by enzyme-linked immunosorbent assay (ELISA) in API culture supernatants. Both recombinant porcine IL-1beta and TNF-alpha were able to activate human endothelial cells (ECs) inducing CD62E and CD106 expression as analyzed by flow cytometry. In conclusion, MCP-1 secreted by APIs may contribute to both IBMIR and rejection by attracting monocytes into the islet; monocytes which upon transformation into macrophages will potentiate antigen presentation and execute islet rejection.

A Comparison of Nonmyeloablative and Reduced-Intensity Conditioning for Allogeneic Stem-Cell Transplantation

BACKGROUND

Nonmyeloablative (NM) conditioning and reduced-intensity conditioning (RIC) are increasingly used for allogeneic hematopoietic stem-cell transplantation. Such regimens have not been compared.

METHODS

The primary endpoint was graft-versus-host disease (GVHD). Secondary endpoints included transfusions, engraftment, and transplant-related mortality (TRM). NM conditioning (n=24) consisted of fludarabine and 2-Gy total-body irradiation followed by immunosuppression with cyclosporine A (CsA) combined with mycophenolate mofetil (MMF). The RIC (n=34) protocol consisted of fludarabine combined with busulfan or cyclophosphamide, antithymocyte globulin, and posttransplant immunosuppression CsA plus methotrexate. Diagnoses included hematologic malignancies and solid tumors. Donors were 34 human leukocyte antigen-identical siblings and 24 unrelated donors. Chimerism was analyzed by polymerase chain reaction of minisatellites.

RESULTS

Graft failure occurred in 6 of 24 in the NM group and in 1 of 34 in the RIC group, which was a significant difference (odds ratio [OR], 22.6; P=0.02). The NM group also had less leukopenia and required fewer erythrocyte and platelet transfusions than the RIC group. The time to and proportion of CD3, CD19, and CD45 donor chimerism were similar in both groups. The cumulative incidence of grades II to IV acute GVHD was higher in the NM group (59% vs. 12%; OR, 26.9; P<0.001), but we found no difference in the cumulative incidence of chronic GVHD (41% vs. 61%). TRM was 42% in the NM group and 20% in the RIC patients (relative hazard, 11.6; P=0.03).

CONCLUSIONS

NM conditioning with posttransplant immunosuppression using CsA and MMF resulted in less leukopenia and fewer transfusions, but resulted in more cases of graft failure, acute GVHD, and TRM than in RIC patients.