Characteristics of Graft-Versus-Host Disease (GvHD) After Post-Transplantation Cyclophosphamide Versus Conventional GvHD Prophylaxis

Post-transplantation cyclophosphamide (PTCy) has been shown to effectively control graft-versus-host disease (GvHD) in haploidentical (Haplo) transplantations. In this retrospective registry study, we compared GvHD organ distribution, severity, and outcomes in patients with GvHD occurring after Haplo transplantation with PTCy GvHD prophylaxis (Haplo/PTCy) versus HLA-matched unrelated donor transplantation with conventional prophylaxis (MUD/conventional). We evaluated 2 cohorts: patients with grade 2 to 4 acute GvHD (aGvHD) including 264 and 1163 recipients of Haplo and MUD transplants; and patients with any chronic GvHD (cGvHD) including 206 and 1018 recipients of Haplo and MUD transplants, respectively. In comparison with MUD/conventional transplantation ± antithymocyte globulin (ATG), grade 3-4 aGvHD (28% versus 39%, P = .001), stage 3-4 lower gastrointestinal (GI) tract aGvHD (14% versus 21%, P = .01), and chronic GI GvHD (21% versus 31%, P = .006) were less common after Haplo/PTCy transplantation. In patients with grade 2-4 aGvHD, cGvHD rate after Haplo/PTCY was also lower (hazard ratio [HR] = .4, P < .001) in comparison with MUD/conventional transplantation without ATG in the nonmyeloablative conditioning setting. Irrespective of the use of ATG, non-relapse mortality rate was lower (HR = .6, P = .01) after Haplo/PTCy transplantation, except for transplants that were from a female donor into a male recipient. In patients with cGvHD, irrespective of ATG use, Haplo/PTCy transplantation had lower non-relapse mortality rates (HR = .6, P = .04). Mortality rate was higher (HR = 1.6, P = .03) during, but not after (HR = .9, P = .6) the first 6 months after cGvHD diagnosis. Our results suggest that PTCy-based GvHD prophylaxis mitigates the development of GI GvHD and may translate into lower GvHD-related non-relapse mortality rate.

Allogeneic Transplantation to Treat Therapy-Related Myelodysplastic Syndrome and Acute Myelogenous Leukemia in Adults

Patients who develop therapy-related myeloid neoplasm, either myelodysplastic syndrome (t-MDS) or acute myelogenous leukemia (t-AML), have a poor prognosis. An earlier Center for International Blood and Marrow Transplant Research (CIBMTR) analysis of 868 allogeneic hematopoietic cell transplantations (allo-HCTs) performed between 1990 and 2004 showed a 5-year overall survival (OS) and disease-free survival (DFS) of 22% and 21%, respectively. Modern supportive care, graft-versus-host disease prophylaxis, and reduced-intensity conditioning (RIC) regimens have led to improved outcomes. Therefore, the CIBMTR analyzed 1531 allo-HCTs performed in adults with t-MDS (n = 759) or t-AML (n = 772) between and 2000 and 2014. The median age was 59 years (range, 18 to 74 years) for the patients with t-MDS and 52 years (range, 18 to 77 years) for those with t-AML. Twenty-four percent of patients with t-MDS and 11% of those with t-AML had undergone a previous autologous (auto-) HCT. A myeloablative conditioning (MAC) regimen was used in 49% of patients with t-MDS and 61% of patients with t-AML. Nonrelapse mortality at 5 years was 34% (95% confidence interval [CI], 30% to 37%) for patients with t-MDS and 34% (95% CI, 30% to 37%) for those with t-AML. Relapse rates at 5 years in the 2 groups were 46% (95% CI, 43% to 50%) and 43% (95% CI, 40% to 47%). Five-year OS and DFS were 27% (95% CI, 23% to 31%) and 19% (95% CI, 16% to 23%), respectively, for patients with t-MDS and 25% (95% CI, 22% to 28%) and 23% (95% CI, 20% to 26%), respectively, for those with t-AML. In multivariate analysis, OS and DFS were significantly better in young patients with low-risk t-MDS and those with t-AML undergoing HCT with MAC while in first complete remission, but worse for those with previous auto-HCT, higher-risk cytogenetics or Revised International Prognostic Scoring System score, and a partially matched unrelated donor. Relapse remains the major cause of treatment failure, with little improvement seen over the past 2 decades. These data mandate caution when recommending allo-HCT in these conditions and indicate the need for more effective antineoplastic approaches before and after allo-HCT.

Impact of depth of clinical response on outcomes of acute myeloid leukemia patients in first complete remission who undergo allogeneic hematopoietic cell transplantation

Acute myeloid leukemia (AML) patients often undergo allogeneic hematopoietic cell transplantation (alloHCT) in first complete remission (CR). We examined the effect of depth of clinical response, including incomplete count recovery (CRi) and/or measurable residual disease (MRD), in patients from the Center for International Blood and Marrow Transplantation Research (CIBMTR) registry. We identified 2492 adult patients (1799 CR and 693 CRi) who underwent alloHCT between January 1, 2007 and December 31, 2015. The primary outcome was overall survival (OS). Multivariable analysis was performed to adjust for patient-, disease-, and transplant-related factors. Baseline characteristics were similar. Patients in CRi compared to those in CR had an increased likelihood of death (HR: 1.27; 95% confidence interval: 1.13-1.43). Compared to CR, CRi was significantly associated with increased non-relapse mortality (NRM), shorter disease-free survival (DFS), and a trend toward increased relapse. Detectable MRD was associated with shorter OS, shorter DFS, higher NRM, and increased relapse compared to absence of MRD. The deleterious effects of CRi and MRD were independent. In this large CIBMTR cohort, survival outcomes differ among AML patients based on depth of CR and presence of MRD at the time of alloHCT. Further studies should focus on optimizing post-alloHCT outcomes for patients with responses less than CR.

What is the outcome in patients with acute leukaemia who survive severe acute graft-versus-host disease?

BACKGROUND

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic haematopoietic stem cell transplantation (HSCT). With new promising therapies, survival may improve for severe aGVHD.

OBJECTIVES

We wanted to analyze the long-term outcome in patients who survive severe aGVHD.

METHODS

This study was a landmark analysis of 23 567 patients with acute Leukaemia who survived for more than 6 months after HSCT, 2002-2014. Patients alive after severe aGVHD (n = 1738) were compared to controls.

RESULTS

Patients with severe aGVHD had higher non-relapse mortality (NRM) and higher rate of extensive chronic GVHD (cGVHD) than the controls (P < 10^-5 ). The probability of relapse was significantly lower in the severe aGVHD group, but Leukaemia-free survival (LFS) and overall survival were significantly lower than for the controls (P < 10^-5 ). Five-year LFS in patients with severe aGVHD was 49%, as opposed to 61% in controls with no or mild GVHD and 59% in patients with moderate GVHD.

CONCLUSIONS

HSCT patients who survive severe aGVHD have higher risk of developing extensive cGVHD, a higher NRM, a lower relapse probability, and lower LFS than other HSCT patients. This study is a platform for outcome analysis in patients treated with novel therapies for acute GVHD.

Is there a stronger graft-versus-leukemia effect using HLA-haploidentical donors compared with HLA-identical siblings?

Haploidentical hematopoietic stem cell transplants (HSCTs) are increasingly used, but it is unknown whether they have a stronger graft-versus-leukemia (GVL) effect. We analyzed 10 679 acute leukemia patients who underwent HSCT from an HLA-matched sibling donor (MSD, n=9815) or a haploidentical donor (⩾2 HLA-antigen disparity, n=864) between 2007 and 2012, reported to the European Group for Blood and Marrow Transplantation. In a Cox regression model, acute and chronic graft-versus-host disease (GVHD) was added as time-dependent variables. There was no difference in probability of relapse between recipients of haploidentical and MSD grafts. Factors of importance for relapse after T-cell-replete grafts included remission status at HSCT, Karnofsky score ⩽80, acute GVHD of grade II or higher and chronic GVHD (P<10(-5)). Patients with post-transplant cyclophosphamide (n=194) had similar outcome as other T-cell-replete haploidentical transplants (n=369). Non-relapse mortality was significantly higher in the haploidentical group compared with that in MSD patients (P<10(-5)). Leukemia-free survival was superior in the MSD patients receiving T-cell-replete (P<10(-5)) or T-cell-depleted grafts (P=0.0006). The risk of relapse was the same in acute leukemia patients who received haploidentical donor grafts as in those given MSD transplants, suggesting a similar GVL effect.

A prospective randomized toxicity study to compare reduced-intensity and myeloablative conditioning in patients with myeloid leukaemia undergoing allogeneic haematopoietic stem cell transplantation

BACKGROUND

To our knowledge, no randomized toxicity studies have been conducted to compare myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC) in allogeneic haematopoietic stem cell transplantation (HSCT).

METHODS

Adult patients ≤60 years of age with myeloid leukaemia were randomly assigned (1 : 1) to treatment with RIC (n = 18) or MAC (n = 19) in this Phase II single-centre toxicity study.

RESULTS

There was a maximum median mucositis grade of 1 in the RIC group compared with 4 in the MAC group (P < 0.001). Haemorrhagic cystitis occurred in eight of the patients in the MAC group and none in the RIC group (P < 0.01). Results of renal and hepatic tests did not differ significantly between the two groups. RIC-treated patients had faster platelet engraftment (P < 0.01) and required fewer erythrocyte and platelet transfusions (P < 0.001) and less total parenteral nutrition (TPN) than those treated with MAC (P < 0.01). Cytomegalovirus (CMV) infection was more common in the MAC group (14/19) than in the RIC group (6/18) (P = 0.02). Donor chimerism was similar in the two groups with regard to CD19 and CD33, but was delayed for CD3 in the RIC group. Five-year transplant-related mortality (TRM) was approximately 11% in both groups, and rates of relapse and survival were not significantly different. Patients in the MAC group with intermediate cytogenetic acute myeloid leukaemia had a 3-year survival of 73%, compared with 90% among those in the RIC group.

CONCLUSION

Reduced-intensity conditioning had several advantages compared with MAC, including less mucositis, less haemorrhagic cystitis, faster platelet engraftment, the need for fewer transfusions and less TPN, and fewer CMV infections. Both regimens were tolerated and TRM was low.

Effects of spleen status on early outcomes after hematopoietic cell transplantation

To assess the impact of spleen status on engraftment, and early morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT), we analyzed 9,683 myeloablative allograft recipients from 1990 to 2006; 472 had prior splenectomy (SP), 300 splenic irradiation (SI), 1,471 with splenomegaly (SM), and 7,440 with normal spleen (NS). Median times to neutrophil engraftment (NE) and platelet engraftment (PE) were 15 vs 18 days and 22 vs 24 days for the SP and NS groups, respectively (P<0.001). Hematopoietic recovery at day +100 was not different across all groups, however the odds ratio of days +14 and +21 NE and day +28 PE were 3.26, 2.25 and 1.28 for SP, and 0.56, 0.55, and 0.82 for SM groups compared to NS (P<0.001), respectively. Among patients with SM, use of peripheral blood grafts improved NE at day +21, and CD34+ cell dose >5.7 × 10(6)/kg improved PE at day+28. After adjusting variables by Cox regression, the incidence of GVHD and OS were not different among groups. SM is associated with delayed engraftment, whereas SP prior to HCT facilitates early engraftment without having an impact on survival.

Increased risk of gastrointestinal acute GVHD following the addition of melphalan to busulfan/cyclophosphamide conditioning

Risk factors associated with the development of aGVHD in the gastrointestinal tract have not been studied in depth. We retrospectively assessed 25 pediatric patients with MDS and JMML and compared the treatment outcome of two different conditioning regimens. Seventeen children (68%) underwent conditioning with busulfan (Bu), cyclophosphamide (Cy), and melphalan (Mel) and eight children (32%) with Bu and Cy. Gastrointestinal aGVHD stages II-IV (day 0-100) were observed in 47% (eight of 17) of the patients in the BuCyMel group and in none (0 of 8) in the BuCy group (p < 0.05). In patients who developed gastrointestinal aGVHD stages III-IV, a 24-h variation in the Bu concentration with a nighttime peak was noted. HC and liver aGVHD stages II-IV were observed in 47% (eight of 17) and 35% (six of 17) after BuCyMel conditioning and in 0% (0 of 17) and 12.5% (one of eight) after BuCy conditioning. The overall survival rate was 53% (nine of 17) in the BuCyMel group and 62.5% (five of eight) in the BuCy group. In conclusion, the addition of melphalan to the BuCy conditioning regimen resulted in severe gastrointestinal complications and did not improve overall survival.

Bone marrow or peripheral blood stem cell transplantation from unrelated donors in adult patients with acute myeloid leukaemia, an Acute Leukaemia Working Party analysis in 2262 patients

BACKGROUND

No survival benefit of using blood stem cells instead of bone marrow (BM) has been shown in matched unrelated donor (MUD) transplantation.

DESIGN AND METHODS

In a retrospective registry analysis, we compared the use of blood stem cells (n = 1502) and BM (n = 760) from unrelated donors in patients aged 18-60 years with acute myeloid leukaemia (AML) undergoing myeloablative conditioning between 1997 and 2008. The blood stem cell recipients were older (P < 0.01), had more advanced disease (P < 0.0001) and received less total body irradiation (P < 0.0001) and more antithymocyte globulin (P = 0.01).

RESULTS

Recovery of neutrophils and platelets was faster with blood stem cells (P < 0.0001). The incidence of acute graft-versus-host disease (GVHD) was similar, but there was more chronic GVHD in the blood stem cell group [hazard ratio (HR) = 1.29, P = 0.02]. There were no significant differences in nonrelapse mortality (NRM), relapse incidence and leukaemia-free survival (LFS) between the two groups amongst patients with AML in remission. In patients with advanced leukaemia, NRM was lower (HR = 0.61, P = 0.02) and LFS was prolonged (HR = 0.67, P = 0.002) when blood stem cells were used. At 3 years, LFS for all patients, regardless of remission status, was 41% for both treatment groups. The outcome was not affected after multivariable analysis adjusted for confounders.

CONCLUSION

Blood stem cells compared with BM in MUD transplantation for patients with AML in remission resulted in the same rates of LFS. In patients with advanced leukaemia, the blood stem cell group had reduced NRM and improved LFS.

Disturbances in dental development and craniofacial growth in children treated with hematopoietic stem cell transplantation

OBJECTIVES

To investigate the correlation between age, degree of disturbances in dental development, and vertical growth of the face in children treated with hematopoietic stem cell transplantation (HSCT).

PATIENTS

39 long-term survivors of HSCT performed in childhood and transplanted before the age of 12, at a mean age of 6.8±3.3 years.

METHODS

Panoramic and cephalometric radiographs were taken at a mean age of 16.2 years. For each patient two age- and sex-matched healthy controls were included. The area of three mandibular teeth was measured and a cephalometric analysis was performed.

RESULTS

The mean area of the mandibular central incisor, first and second molar was significantly smaller in the HSCT group, and the vertical growth of the face was significantly reduced, especially in the lower third, compared to healthy controls. A statistically significant correlation between age at HSCT, degree of disturbances in dental development, and vertical growth of the face was found. Children subjected to pre-HSCT chemotherapy protocols had significantly more growth reduction in vertical craniofacial variables compared to children without pre-HSCT chemotherapy. Conditioning regimens including busulfan or total body irradiation had similar deleterious effects on tooth area reduction and craniofacial parameters.

CONCLUSIONS

The younger the child is at HSCT, the greater the impairment in dental and vertical facial development. This supports the suggestion that the reduction in lower facial height found in SCT children mainly is a result of impaired dental development and that young age is a risk factor for more severe disturbances.

Stromal cells from term fetal membrane are highly suppressive in allogeneic settings in vitro

Bone marrow-derived mesenchymal stromal cells (BM-MSCs) have immunosuppressive properties and have been used to treat steroid-refractory acute graft-versus-host disease (GVHD) in stem cell transplant patients. Cells with similar capacities can also be found in term placental tissue. We have isolated stromal cells from term fetal membrane (FMSCs), umbilical cords (UCSCs) and placental villi (PVSCs) as well as from bone marrow and compared their immunoregulatory capacity in allogeneic settings. We found that FMSCs and UCSCs suppressed proliferation significantly in mixed lymphocyte reactions (MLRs), whereas PVSCs showed inconsistent suppressive effects. When added to MLR cultures, FMSCs suppressed the production of interferon (IFN)-γ and interleukin (IL)-17, whereas UCSCs and PVSCs promoted the production of IL-17 instead. Secretion of IL-10 was increased after addition of FMSCs and UCSCs. In this setting, BM-MSCs had no significant effect on secretion of IFN-γ, IL-17 or IL-10 in MLR cultures. When analysing the expression of adhesion markers, we noted that FMSCs expressed the highest levels of CD29 (β1), CD49d (α4) and CD54 (ICAM-1) compared to the other types of stromal cells. Thus, our data indicate that stromal cells isolated from term fetal membrane have great immunosuppressive capacity in terms of proliferation and production of proinflammatory cytokines from alloreactive T cells, and also promote anti-inflammatory IL-10. They express high levels of integrins that may be of importance in homing to inflamed tissues. Fetal membrane may provide a valuable source of cells with immunosuppressive properties and could possibly be used for treatment of acute GVHD and other inflammatory disorders.

Hematopoietic stem cell transplantation in severe congenital neutropenia

BACKGROUND

Severe congenital neutropenia (SCN) is an immunodeficiency characterized by disturbed myelopoiesis and an absolute neutrophil count (ANC) <0.5 × 10(9)/L. SCN is also a premalignant condition; a significant proportion of patients develop myelodysplastic syndrome or leukemia (MDS/L). Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for SCN.

PROCEDURE

Since 2004, eight HSCT have been performed in seven patients at our center. The indications were transformation to MDS/L (n = 2), granulocyte colony-stimulating factor receptor (CSF3R) mutation(s) (n = 2), granulocyte colony-stimulating factor (G-CSF) resistance (n = 2), and at the patient's own request (n = 1).

RESULTS

The mean age at transplantation was 13 years (2.8-28 years) (mean follow-up 32 months, range 21-60). Three patients harbored ELANE mutations, three HAX1 mutations, and in one patient no causative mutation was identified. Two of the ELANE mutations were novel mutations. Three patients initially received myeloablative conditioning and four had reduced intensity conditioning (RIC). Three grafts were from HLA-identical siblings, three from matched unrelated donors and two were cord blood units. Engraftment occurred in all patients. Two of seven (29%) patients died; both had MDS/L and both were among the three that underwent myeloablative conditioning. One patient has chronic GVHD 2 years post-transplant.

CONCLUSIONS

The role of HSCT should be explored further in patients with SCN. In particular, the influence of the conditioning regime needs to be evaluated in a larger cohort of patients.

Comparative analysis of BU and CY versus CY and TBI in full intensity unrelated marrow donor transplantation for AML, CML and myelodysplasia

We retrospectively compared clinical outcomes in 1593 T-replete unrelated donor (URD) marrow transplant recipients with AML, MDS and CML who received myeloablative conditioning regimens of either BU and CY (BuCy), standard-dose Cy/TBI (1000-1260 cGy) or high-dose Cy/TBI (1320-1500 cGy). Subjects were drawn from patients transplanted between 1991 and 1999 facilitated by the National Marrow Donor Program. Patients who received high-dose Cy/TBI regimens were slightly younger, more likely to receive a mismatched transplant and to have intermediate or advanced disease compared with patients in the BuCy or standard-dose TBI group. Neutrophil recovery was significantly higher in the standard-dose CY/TBI group compared with the high-dose Cy/TBI or BuCy group. Patients who received the high-dose Cy/TBI regimen had an increased risk of developing grades III-IV aGVHD when compared with the control group who received BuCy (P = 0.011). OS, disease-free survival (DFS), TRM and relapse were not significantly different between any of the regimens. We conclude that BuCy, standard-dose and high-dose Cy/TBI regimens have equivalent efficacy profiles for OS, DFS, TRM and relapse risk in patients undergoing T-replete URD marrow transplantation for AML, CML and MDS.

Targeted monitoring of patients at high risk of post-transplant lymphoproliferative disease by quantitative Epstein-Barr virus polymerase chain reaction

BACKGROUND

Epstein-Barr virus (EBV)-associated post-transplantation lymphoproliferative disease (PTLD) is a serious complication after allogeneic stem cell transplantation (SCT). The likelihood of PTLD is increased in the presence of specific risk factors. Monitoring of EBV DNA load and early administration of rituximab in patients with high EBV loads is recommended for high-risk patients.

METHODS

Patients at high risk of EBV-associated PTLD were defined as those showing an EBV serological mismatch between donor and recipient, those with lymphoma, those given cord blood grafts, and those with primary EBV disease before SCT. High-risk patients were prospectively monitored by weekly measurement of EBV DNA by quantitative polymerase chain reaction assay, and rituximab was given when the EBV load reached 10,000 copies/mL or symptoms were suggestive of EBV disease. During the study period (July 2005 to the end of June 2007) 131 patients underwent SCT, of whom 53 had high risk factors. A historical control group transplanted between January 2003 to the end of June 2005 was retrospectively used to evaluate the effect of the prospective monitoring strategy.

RESULTS

Of the patients, 30% were positive for EBV DNA at least once; 10% of patients with EBV DNAemia developed PTLD. Risk factors of EBV DNAemia were younger age (P=0.04), receiving transplants from mismatched family or unrelated donors (P=0.01), and acute graft-versus-host disease grades II-IV (P=0.001). The overall frequency of PTLD was 3%; 5.7% in the high-risk group and 1.3% in the standard-risk group. Previous splenectomy (P=0.046) was the only significant risk factor associated with PTLD. In the control group, 6 of 150 patients (4%) developed PTLD; 5/53 (9.4%) in the high-risk group and 1/97 (1%) in the standard-risk group. Human leukocyte antigen-mismatched donors (P<0.01) and EBV-positive donors/EBV-negative recipients (P=0.01) had a significant impact on the risk of PTLD.

CONCLUSION

A targeted monitoring strategy among patients at a high risk of EBV-associated PTLD might be helpful to decrease the risk of development of PTLD. However, larger prospective studies are needed to verify this hypothesis.

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.

Bone marrow transplantation in three patients with multiple myeloma

Three patients with multiple myeloma received bone marrow grafts from HLA-identical sibling donors. One of the patients, with IgA kappa myeloma, refractory to alkeran-prednisone therapy, is well and still without sign of disease 26 months post transplantation. A second patient with Bence-Jones kappa myeloma is well, and skeletal pain and Bence-Jones proteinuria has disappeared 2 months after transplantation. A third patient with IgG-lambda myeloma died of effusive pericarditis shortly after transplantation. Bone marrow transplantation may be indicated in a selective group of patients with multiple myeloma.

Lymphocytes from multitransfused uremic patients have poor MLC reactivity

Lymphocytes from uremic patients showed statistically significantly lower (P less than 0.01) MLC reactivity against pooled stimulator cells as compared with lymphocytes from age matched controls. A consistently low MLC reactivity was recorded in lymphocytes from patients who had received more than 20 units of blood and the lowest responses were seen with cells from patients with multispecific anti-HLA-antibodies. Removal of B cells and removal of phagocytic cells from the responder cells resulted in a significant (P less than 0.05) increase in MLC reactivity in the uremic but not in the control group. Both addition of enriched B cells to autologous enriched T cells and addition of adherent cells to non-adherent autologous cells caused a slight supression of MLC reactivity. PHA reactivity was lower (P less than 0.001) in lymphocytes from the multitransfused patients compared to cells from age matched controls. However, no difference in PHA responses were recorded between lymphocytes from uremic patients who had received less than 20 units of blood and controls.

Polyclonal antibody secretion in human lymphocytes induced by killed staphylococcal bacteria and by lipopolysaccharide

Preparations of Staphylococcus aureus strains Cowan 1 and Wood 46 and of lipopolysaccharide (LPS) were found to act as polyclonal B-cell-activating substances for human splenic and blood lymphocytes. All three substances induced polyclonal antibody secretion in blood and spleen cell cultures, as tested against fluorescein isothiocyanate-coupled sheep erythrocytes by a modification of the local hemolysis-in-gel assay. Antibodies were of IgM class, as shown by inhibition of plaque formation by anti-IgM but not by anti-IgG or anti-IgA antisera. All these substances also consistently induced the formation of intracellular immunoglobulin and increased DNA synthesis in stimulated spleen cells. In blood lymphocytes Staph. aureus Cowan 1 induced a consistent increase in DNA synthesis, whereas Staph, aureus Wood and LPS often gave low or no increase in DNA synthesis. Peak antibody formation was observed on day 3 in spleen cells and on day 6 in blood lymphocyte cultures. Stimulation into high-rate immunoglobulin secretion occurred with all PBAs also in B-cell-enriched cell suspensions but not in T-cell-enriched cells. Optimal responses were, however, always noted in unseparated cell suspensions. It is concluded that preparations of killed bacteria can be useful tools for the clinical evaluation of both specific and nonspecific antibody-forming ability in cells from different groups of patients.

No increased trapping of multipotent mesenchymal stromal cells in bone marrow filters compared with other bone marrow cells

BACKGROUND

Multipotent mesenchymal stromal cells (MSC) are candidates for cellular therapy in regenerative medicine and as treatment of graft-versus-host-disease (GvHD) after hematopoietic stem cell (HSC) transplantation. It has been suggested that MSC may be trapped in bone marrow (BM) filters during the stem cell procurement and lost from the HSC graft.

METHODS

We investigated filtered BM and filters from six HSC donors. MSC were expanded from the two sources and investigated by flow cytometry, doubling capacity, differentiation ability and suppression in mixed lymphocyte cultures.

RESULTS

A range of 0.3-3.4% cells was trapped in the filters. By flow cytometry, there was no difference in the proportions of different cell types between the filter-retrieved and filtered BM cells. The phenotype, immunosuppressive capacity, differentiation and growth were equal in MSC expanded from the two cell sources.

DISCUSSION

Given the low number of trapped cells, filters do not appear to be a good source of MSC. When intended for clinical transplantation, MSC need to be expanded ex vivo to achieve sufficient doses for a clinical effect.

Risk factors for acute graft-versus-host disease grades II-IV after reduced intensity conditioning allogeneic stem cell transplantation with unrelated donors: a single centre study

We analysed factors associated with moderate to severe acute GVHD in 111 patients treated with fludarabin-based reduced intensity conditioning (RIC) and allogeneic haematopoietic stem cell transplantation (HSCT). Most patients had a haematological malignancy. Donors were 97 HLA-A, -B and -DRbeta1 identical unrelated and 14 HLA-A, -B or -DRbeta1 allele mismatched unrelated donors. In the univariate analysis, we found ten factors associated with acute GVHD. These were diagnosis (P=0.06), GVHD prophylaxis with combinations other than CsA+MTX (P=0.006), graft nucleated (P<0.001) and CD34 (P<0.001) cell-dose, bidirectional ABO mismatch (P=0.001), conditioning (P=0.002), hospital vs home-care (P=0.06), ATG dose (P<0.001), donor herpes virus serology (P=0.07) and an immunized female donor to male recipient (P=0.05). In the multivariate analysis, three factors remained significant: a high CD34 cell dose (P<0.001), low dose (4 mg/kg) ATG (P<0.001), and an immunized female donor to male recipient (P<0.01). Patients receiving a CD34 cell dose > or =17.0 x 10(6) per kg had a higher incidence of GVHD, 53.7%, compared to 22.3% in patients receiving a lower dose (P=0.002). In patients without any of these risk factors (n=70), the incidence of acute GVHD was 14.1%, while it was 38.0 and 85.0% in patients with one (n=29) or two (n=10) risk factors (P<0.001). We concluded that risk factors for acute GVHD using RIC are similar as using myeloablative conditioning.

Immunomodulation by mesenchymal stem cells and clinical experience

Mesenchymal stem cells (MSCs) from adult marrow can differentiate in vitro and in vivo into various cell types, such as bone, fat and cartilage. MSCs preferentially home to damaged tissue and may have therapeutic potential. In vitro data suggest that MSCs have low inherent immunogenicity as they induce little, if any, proliferation of allogeneic lymphocytes. Instead, MSCs appear to be immunosuppressive in vitro. They inhibit T-cell proliferation to alloantigens and mitogens and prevent the development of cytotoxic T-cells. In vivo, MSCs prolong skin allograft survival and have several immunomodulatory effects, which are presented and discussed in the present study. Possible clinical applications include therapy-resistant severe acute graft-versus-host disease, tissue repair, treatment of rejection of organ allografts and autoimmune disorders.

Evaluation of intervention strategy based on CMV-specific immune responses after allogeneic SCT

Late occurring CMV disease is an important problem after allogeneic SCT and has been associated with poor CMV-specific immunity. We conducted a prospective study of 58 patients studied at 3-6 months after allo-SCT, to base the antiviral therapy on monitoring of CMV-specific immunity. Reactivation of CMV was measured by quantitative PCR, and intracellular IFN-gamma production was analysed by FACS and enzyme-linked immunospot. Antiviral therapy was deferred in patients with documented CMV-specific immunity without symptoms of CMV disease or severe GVHD. Nineteen episodes of CMV reactivation were assessable. The strategy was correctly applied in 16/19 episodes. Therapy was deferred in 5/19 (none of these patients developed CMV disease) and was given according to the strategy in 11/19 episodes. Two patients received antiviral therapy despite having T cell-specific immunity. There was a tendency that patients with late CMV reactivation had weak CD8 T cell immunity at 3 months (P=0.06). The donors' serostatus influenced the strength of both CD4 and CD8 immunity at 3 months after SCT (P<0.01). There was no effect as regards the type of conditioning, donor type, stem cell source or acute GVHD. Monitoring the immunity of SCT patients may allow more targeted use of antiviral therapy.

Cyclosporine A (CsA) 2-h concentrations vary between patients without correlation to graft-versus-host disease after allogeneic haematopoietic stem cell transplantation

Cyclosporine A (CsA) therapy based on 2-h concentrations (C2) after oral administration has demonstrated low acute rejection rates after solid organ transplantation. We analysed the correlation between C2 and trough (C0) levels of oral CsA therapy in samples obtained twice in consecutive weeks from 58 patients during their first admission for allogeneic haematopoietic stem cell transplantation. Also 8-h concentration curves were obtained from 23 patients. The mean (range) CsA dose was 332 (167-763) and 255 (113-575) mg/day for patients with matched unrelated donor (MUD) and human leukocyte antigen identical sibling donor (Sib), respectively. Median (range) C0 and C2 were 254 (145-332) and 898 (419-1466) ng/ml in MUD patients, and 130 (93-265) and 554 (196-988) ng/ml in Sib patients. In MUD patients with either aGVHD grade < II or > or = II, the median C2 were 915 (419-1466) and 890 (519-1399) ng/ml, respectively. In Sib patients with aGVHD grade < II or grade > or = II, the median C2 were 552 (404-718) and 539 (196-988) ng/ml, respectively. The median C2 levels were comparable in patients with or without severe infections. Interindividual variations in CsA uptake and metabolism may explain the wide variation of C2 levels without prediction for increased risk for severe aGVHD or infectious complication when C0 guided the CsA dosing.

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.

Transplantation of mesenchymal stem cells to enhance engraftment of hematopoietic stem cells

Seven patients underwent treatment with mesenchymal stem cells (MSCs), together with allogeneic hematopoietic stem cell transplantation (HSCT). MSCs were given to three patients for graft failure and four patients were included in a pilot study. HSCT donors were three human leukocyte antigen (HLA)-identical siblings, three unrelated donors and one cord blood unit. The conditioning was myeloablative in four patients and reduced in three patients. MSC donors were HLA-identical siblings in three cases and haploidentical in four cases. Neutrophil counts >0.5 x 10(9)/l was reached at a median of 12 (range 10-28) days. Platelet counts >30 x 10(9)/l was achieved at a median of 12 (8-36) days. Acute graft-versus-host disease (GVHD) grade 0-I was seen in five patients. Two patients developed grade II, which in one patient evolved into chronic GVHD. One severe combined immunodeficiency (SCID) patient died of aspergillosis, the others are alive and well. One patient, diagnosed with aplastic anemia had graft failure after her first transplantation and severe Henoch-Schönlein Purpura (HSP). After retransplantation of MSCs and HSCs, she recovered from both the HSP and aplasia. Thus, co-transplantation of MSC resulted in fast engraftment of absolute neutrophil count (ANC) and platelets and 100% donor chimerism, even in three patients regrafted for graft failure/rejection.

Mesenchymal stem cells stimulate antibody secretion in human B cells

Mesenchymal stem cells (MSC) have immunomodulatory effects and inhibit T-cell responses to alloantigens and mitogens in vitro and in vivo. We wanted to examine the effect of MSC on human B cells. MSC stimulated IgG production, measured in an enzyme-linked immunospot (ELIspot) assay in blood and spleen lymphocytes. MSC only induced a low proliferation. When a semipermeable membrane separated MSC and mononuclear cells, the IgG production was stimulated in unfractionated lymphocytes. In contrast, enriched B cells required cell contact with MSC to produce IgG. Co-cultures of MSC and lymphocytes increased IFN-gamma production. MSC produce IL-6, and addition of MSC to spleen cells dramatically increased IL-6 levels. After lymphocyte stimulation with lipopolysaccharide (LPS), cytomegalovirus or varicella zoster virus, MSC either stimulated or inhibited IgG response, depending on the level of stimulation by LPS or the viral antigens. Similar results were obtained for enriched B cells. To conclude, MSC stimulate B-cell antibody secretion. The IgG secretion by activated B cells may be stimulated or inhibited by the addition of MSC, depending on the level of stimulation.

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.

Mesenchymal stem cells are susceptible to human herpesviruses, but viral DNA cannot be detected in the healthy seropositive individual

Allogeneic stem cell transplantation is often complicated by reactivation of herpesviruses. Mesenchymal stem cells (MSC) are immunomodulatory and may be used to treat graft-versus-host disease. We investigated if herpesviruses infect and can be transmitted by MSC, and if MSC suppress immune responses to various infectious agents. Mesenchymal stem cells from healthy seropositive donors were evaluated with polymerase chain reaction for the most common herpesviruses: cytomegalovirus (CMV), herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2, Epstein-Barr virus (EBV) and varicella zoster virus. The cytopathological effect (CPE) was investigated and viral antigens analyzed by immunofluorescence after in vitro exposure to CMV, HSV-1 and EBV. We also studied MSC effect on lymphocyte stimulation induced by various infectious agents. No viral DNA could be detected in MSC isolated from healthy seropositive individuals. However, a CPE was noted and intracellular viral antigens detected after infection in vitro by CMV and HSV-1, but not by EBV. The CMV and HSV-1 infections were productive. Lymphocyte proliferation by herpesviruses, candida mannan and protein A from Staphylococcus aureus was suppressed by MSC. The data indicate that the risk of herpesvirus transmission by transplantation of MSC from healthy seropositive donors is low. However, MSC may be susceptible to infection if infused in a patient with CMV or HSV-1 viremia. MSC transplantation may compromise the host's defense against infectious agents.

Allogeneic haematopoietic stem cell transplantation for metastatic renal carcinoma in Europe

BACKGROUND

An allogeneic antitumour effect has been reported for various cancers. We evaluated the experience of allogeneic haematopoietic stem cell transplantation (HSCT) for renal cell carcinoma (RCC) in 124 patients from 21 European centres.

PATIENTS AND METHODS

Reduced intensity conditioning and peripheral blood stem cells from an HLA-identical sibling (n = 106), a mismatched related (n = 5), or an unrelated (n = 13) donor were used. Immunosuppression was cyclosporine alone, or combined with methotrexate or mycophenolate mofetil. Donor lymphocyte infusions (DLI) were given to 42 patients. The median follow-up was 15 (range 3-41) months.

RESULTS

All but three patients engrafted. The cumulative incidence of moderate to severe, grades II-IV acute GVHD was 40% and for chronic GVHD it was 33%. Transplant-related mortality was 16% at one year. Complete (n = 4) or partial (n = 24) responses, median 150 (range 42-600) days post-transplant, were associated with time from diagnosis to HSCT, mismatched donor and acute GVHD II-IV. Factors associated with survival included chronic GVHD (hazards ratio, HR 4.12, P < 0.001), DLI (HR 3.39, P < 0.001), <3 metastatic sites (HR 2.61, P = 0.002) and a Karnofsky score >70 (HR 2.33, P = 0.03). Patients (n = 17) with chronic GVHD and given DLI had a 2-year survival of 70%.

CONCLUSION

Patients with metastatic RCC, less than three metastatic locations and a Karnofsky score >70% can be considered for HSCT. Posttransplant DLI and limited chronic GVHD improved the patient survival.

Long-term follow-up of patients treated at home during the pancytopenic phase after allogeneic haematopoietic stem cell transplantation

To prevent neutropenic infections, patients are kept in isolation rooms after allogeneic haematopoietic stem cell transplantation (ASCT). Patients living within one hours' driving distance from our unit were given the opportunity of treatment at home after ASCT during the pancytopenic phase. We compared 36 patients treated at home during March 1998 until December 2000, with 54 controls treated in the hospital during September 1995 and September 2001. The incidence of grades II-IV acute graft-versus-host disease (GVHD) was lower in the home care group compared to the controls, that is, 17 vs 44% (P < 0.01). The cumulative incidence of chronic GVHD was 52% in the home care group, compared to 57% in the controls. Transplant-related mortality (TRM) was 13% in the home care patients vs 44% in the controls (P = 0.002). The probability of relapse was similar in the two groups. The 4-year survival was 63% in the home care patients compared to 44% in the controls (P = 0.04). Home care after ASCT is a novel approach that resulted in less TRM, similar incidence of chronic GVHD and relapse, and improved long-term survival compared to controls treated in the hospital.