Jörg Halter

Vaccination of allogeneic haematopoietic stem cell transplant recipients: report from the international consensus conference on clinical practice in chronic GVHD.

Patients lose protective immunity to vaccine-preventable diseases after haematopoietic stem cell transplantation (HSCT). Therefore, revaccination of HSCT recipients represents an important strategy for reducing morbidity and mortality associated with these infections. Since there is little consensus on vaccine recommendations and practices for allogeneic HSCT recipients with active chronic graft-versus-host disease (GVHD) the German-Austrian-Swiss-Consensus Conference on Clinical Practice in Chronic GVHD developed an immunization schedule with the aim to provide optimal patient care. The proposed vaccine recommendations include immunization against Haemophilus influenzae type b, pertussis, pneumococci, meningococci, tetanus, diphtheria, hepatitis A and B, measles, mumps and rubella, influenza, poliomyelitis, varicella-zoster virus, human papilloma virus, and tick-borne encephalitis with a particular focus on vaccination of patients with active chronic GVHD.

Order of application and liver toxicity in patients given BU and CY containing conditioning regimens for allogeneic hematopoietic SCT

BU–CY is the established non-TBI-based myeloablative conditioning regimen for allogeneic hematopoietic SCT. However, liver toxicity and hepatic veno-occlusive disease (VOD) are frequent life-threatening complications. Pharmacological considerations suggest that BU can trigger toxicity of subsequent CY. Recent animal data confirmed this hypothesis. Less liver toxicity and better outcomes were observed when mice were treated with the reversed order of CY and BU. We analyzed in this study liver toxicity and outcome in patients receiving BU–CY (16 patients) or CY–BU (59 patients). Liver function differed significantly with higher levels of liver function tests between day +10 and +30, and a higher cumulative incidence of VOD in the BU–CY cohort (2/16 (12.5%) vs 0/59 (0%), P=0.006). TRM was significantly higher in patients receiving BU–CY (cumulative incidence BU–CY 45%, CY–BU 17%, P=0.02), without yet translating into a significant survival difference (incidence for survival: BU–CY 38%, CY–BU 63%; hazard ratio 1.19 for BU–CY, 95% confidence interval 0.29–4.82, P=0.80). Rates of engraftment and relapse were not different. These data support the concepts derived from animal models in favor of CY–BU compared with traditional BU–CY and form the basis for prospective controlled comparisons.

Large Granular Lymphocyte Expansion after Allogeneic Hematopoietic Stem Cell Transplant Is Associated with a Cytomegalovirus Reactivation and Shows an Indolent Outcome

Expansions of CD3+ large granular lymphocytes (LGLs) after allogeneic hematopoietic stem cell transplantation (HSCT) have been described. We sought to evaluate incidence, characteristics, and clinical significance of persistent T cell (T-)LGL after HSCT. Fourteen of 215 recipients (7%) were diagnosed with LGL expansions. Thirteen showed a CD3+/CD8+ immunophenotype, 5 of them with clonal TCR-γ rearrangement. The lymphocytes appeared at a median of 16 months (range, 3-58 months) after HSCT and lasted for a median time of 31 months (range, 2-179 months). Cytomegalovirus (CMV) reactivation (P =xa0.001) and acute graft-versus-host disease (aGVHD) were associated with LGL expansion (P =xa0.02). In the multivariate analysis, only CMV reactivation showed a significant association with T-LGL expansion (relative risk [RR]: 5.063; 95% confidence interval [CI]: 1.586-16.160; P = .006). The observed posttransplantation LGL expansions, even if monoclonal, showed a chronic, indolent course. Our data indicate that such expansions may be considered as an expression of chronic stimulation, triggered by CMV reactivation rather than a malignant transformation.

GVHD after allogeneic haematopoietic SCT for AML: angiogenesis, vascular endothelial growth factor and VEGF receptor expression in the BM.

There is increasing evidence suggesting that both angiogenesis and endothelial injury are involved in GVHD. To study the dynamics of angiogenesis, we examined 26 patients with AML who had undergone allogeneic haematopoietic SCT. All were in CR and had either acute GVHD (aGVHD) or chronic GVHD (cGVHD). We performed immunohistochemical studies of BM microvessel density (MVD) using Abs against vascular-endothelial (VE)-cadherin, CD34 and CD105, and expression of vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 and VEGFR-2. At the time of diagnosis, the MVD in AML patients was higher than that in the normal controls, and the MVD decreased after induction chemotherapy. Patients with aGVHD had a significantly higher MVD than patients without aGVHD. Conversely, patients with cGVHD did not have a significantly different MVD. In previous aGVHD, we also found more VEGF+ megakaryocytes. XY FISH in sex-mismatched patients showed that the BM blood vessels consisted mainly of recipient endothelial cells. Taken together, these results suggest that new vessel formation and the VEGF/VEGFR system are involved in aGVHD.

Graft source determines human hematopoietic progenitor distribution pattern within the CD34(+) compartment

The CD34+ compartment of grafts for clinical allogeneic hematopoietic cell transplantation (HCT) is very heterogeneous. It contains hematopoietic stem cells and several different progenitor cell populations. This study assesses (1) the content of these populations in clinical grafts from G-CSF-mobilized PBMCs, BM and cord blood, (2) the functional correlation of the graft composition with time to engraftment of neutrophils, platelets and reticulocytes and (3) donor age-related changes. Quantitative flow cytometry showed that the distribution of the progenitor subsets differed significantly between the graft sources and that donor age-related changes occur. In patients after myeloablative allogeneic HCT, accelerated platelet and reticulocyte engraftment correlated with the content of common myeloid and/or megakaryocyte erythroid progenitors in the graft. These findings show that a better understanding of the progenitor compartment in human hematopoietic grafts could lead to improved strategies for the development of cellular therapies, for example in situations where platelet engraftment is delayed.

Progenitor cell therapy for sacral pressure sore: a pilot study with a novel human chronic wound model

IntroductionChronic wounds are a major health-care issue, but research is limited by the complexity and heterogeneity in terms of wound etiology as well as patient-related factors. A suitable animal model that replicates the situation in humans is not available. Therefore, the aim of the present work is to present a standardized human wound model and the data of a pilot study of topically applied progenitor cells in a sacral pressure sore.MethodsThree patients underwent cell harvest from the iliac crest at the time of the initial debridement. Forty-eight hours after bone marrow harvest and debridement, the CD34+ selected cell suspension was injected into the wound. With the aid of a laser scanner, three-dimensional analyses of wound morphometry were performed until the defect was reconstructed with a local flap 3 weeks after debridement.ResultsDecreases in volume to 60%u2009±u20096% of baseline on the sham side and to 52%u2009±u20093% of baseline on the cell side were measured. Histologic work-up revealed no signs of metaplastic, dysplastic, or neoplastic proliferation/differentiation after progenitor cell treatment. CD34+ cells were detected in the biopsies of day 0.ConclusionsThe pressure sore wound model allows investigation of the initial 3 weeks after cell-based therapy. Objective outcome analysis in terms of wound volume and histology can be performed without, or with, minimal additional morbidity, and the anatomy of the sacral area allows a control and study side in the same patient. Therefore, this model can serve as a standard for wound-healing studies.Trial registrationClinicalTrials.gov NCT00535548.

Tumor incidence in related hematopoietic stem cell donors

Late malignancies have been discussed as a potential risk for growth factor mobilized donors of hematopoietic stem cells. Little is known about the incidence and potential risk factors. This single center retrospective cohort study evaluated all HLA-identical sibling pairs with hematopoietic stem cell transplantation (HSCT) for a hematological malignancy, treated from 1974 to 2001 at the University Hospital of Basel. Three hundred eighteen pairs were identified, 291 donors (92%) could be contacted. Median observation time was 13.8 years (range 5–32 years). Sixteen (5%) donors had developed a total of 18 tumors, 17 recipients a secondary tumor. According to the age- and sex-adapted cancer incidence, 3.3 tumors in male and 6.8 in female donors were expected, 3 (relative risk (RR): 0.91, 95% confidence interval: 0.19–2.66) and 4 (RR: 0.58, 95% confidence interval: 0.16–1.48), respectively, were found in donors between 0 and 49 years. Between 50 and 69 years, 4.5 tumors in males and 4.8 in females were expected, 5 (RR: 1.11, 95% confidence interval: 0.36–2.59) and 6 (RR: 1.23, 95% confidence interval: 0.45–2.67), respectively, were observed. Tumors do occur in donors of hematopoietic stem cells at least at the rate as expected in a normal population; whether incidence exceeds expected rates needs to be determined in larger international cohorts.

Combination therapy for multidrug-resistant cytomegalovirus disease.

Multidrug‐resistant (MDR) cytomegalovirus (CMV) emerged after transient responses to ganciclovir, foscarnet, and cidofovir in a CMV‐seropositive recipient who underwent allogeneic hematopoietic stem cell transplantation from a CMV‐seronegative donor. Experimental treatments using leflunomide and artesunate failed. Re‐transplantation from a CMV‐seropositive donor supported by adoptive transfer of pp65‐specific T cells and maribavir was followed by lasting suppression. This case illustrates that successful MDR CMV therapy may require individualized multidisciplinary approaches.

Cyclosporine levels and rate of graft rejection following non-myeloablative conditioning for allogeneic hematopoietic SCT.

Hematopoietic SCT (HSCT) after non-myeloablative conditioning is associated with reduced TRM, and increased risk of graft rejection. Although preclinical data have shown the importance of post transplant immunosuppression in achieving engraftment, little is known about the role of CSA in the clinical setting of non-myeloablative transplantation. In a retrospective analysis of patients treated with allogeneic HSCT after fludarabine and 2u2009Gy TBI, 15 of 77 evaluable patients (20%) experienced primary (n=2) or secondary graft rejection at a median of 66 days post transplant. Mean day 1–28 CSA trough levels were inversely associated with day 28 chimerism (median 99, 85 and 70% for mean CSA <300, 300–600 and >600u2009ng/mL, respectively; P=0.003). A similar association was observed for the cumulative incidence of graft rejection, which occurred in 8% (<300u2009ng/mL), 26% (300–600u2009ng/mL) and 50% (>600u2009ng/mL, P=0.005) of patients. The detrimental effect of high CSA levels on engraftment was confirmed in multivariable models and was found to operate comparably in sibling and unrelated donor transplants. Impairment of donor T-cell function by high serum levels of CSA might account for this finding, which should be verified in a larger patient group to better understand the role of CSA in non-myeloablative transplantation.

Sideroblastic changes of the bone marrow can be predicted by the erythrogram of peripheral blood

The diagnosis of sideroblastic anemia is based on bone marrow aspiration, and the detection of ring sideroblasts (RS) in iron staining. The finding of laboratory parameters to approach this diagnosis still remains a great challenge. In this study, we analyzed the value of a specific erythrogram pattern from peripheral blood, produced by the ADVIA®120 cell counter, to predict sideroblastic changes in the bone marrow. In a two step‐design study, we first showed that 32/38 consecutive patients reporting ≥15% RS had such a pattern in the erythrogram. In the second step, we prospectively identified over a period of 32u2003months 21 patients with this typical erythrogram; 20/21 had ≥15% RS in the bone marrow. Hence, by this validation, we confirm that the erythrogram is highly predictive of RS in the bone marrow. The interpretation of the erythrogram should become daily practice in hematology to improve the efficacy to detect sideroblastic changes.