The IMiD target CRBN determines HSP90 activity toward transmembrane proteins essential in multiple myeloma.

The complex architecture of transmembrane proteins requires quality control (QC) of folding, membrane positioning, and trafficking as prerequisites for cellular homeostasis and intercellular communication. However, it has remained unclear whether transmembrane protein-specific QC hubs exist. Here we identify cereblon (CRBN), the target of immunomodulatory drugs (IMiDs), as a co-chaperone that specifically determines chaperone activity of HSP90 toward transmembrane proteins by means of counteracting AHA1. This function is abrogated by IMiDs, which disrupt the interaction of CRBN with HSP90. Among the multiple transmembrane protein clients of CRBN-AHA1-HSP90 revealed by cell surface proteomics, we identify the amino acid transporter LAT1/CD98hc as a determinant of IMiD activity in multiple myeloma (MM) and present an Anticalin-based CD98hc radiopharmaceutical for MM radio-theranostics. These data establish the CRBN-AHA1-HSP90 axis in the biogenesis of transmembrane proteins, link IMiD activity to tumor metabolism, and nominate CD98hc and LAT1 as attractive diagnostic and therapeutic targets in MM.

Real-world data suggest effectiveness of the allogeneic mesenchymal stromal cells preparation MSC-FFM in ruxolitinib-refractory acute graft-versus-host disease.

BACKGROUND: Patients with steroid-refractory acute graft-versus-host disease (aGvHD) not tolerating/responding to ruxolitinib (RR-aGvHD) have a dismal prognosis. METHODS: We retrospectively assessed real-world outcomes of RR-aGvHD treated with the random-donor allogeneic MSC preparation MSC-FFM, available via Hospital Exemption in Germany. MSC-FFM is provided as frozen cell dispersion for administration as i.v. infusion immediately after thawing, at a recommended dose of 1-2 million MSCs/kg body weight in 4 once-weekly doses. 156 patients, 33 thereof children, received MSC-FFM; 5% had Grade II, 40% had Grade III, and 54% had Grade IV aGvHD. Median (range) number of prior therapies was 4 (1-10) in adults and 7 (2-11) in children. RESULTS: The safety profile of MSC-FFM was consistent with previous reports for MSC therapies in general and MSC-FFM specifically. The overall response rate at Day 28 was 46% (95% confidence interval [CI] 36-55%) in adults and 64% (45-80%) in children; most responses were durable. Probability of overall survival at 6, 12 and 24 months was 47% (38-56%), 35% (27-44%) and 30% (22-39%) for adults, and 59% (40-74%), 42% (24-58%) and 35% (19-53%) for children, respectively (whole cohort: median OS 5.8 months). CONCLUSION: A recent real-world analysis of outcomes for 64 adult RR-aGvHD patients not treated with MSCs reports survival of 20%, 16% and 10% beyond 6, 12 and 24 months, respectively (median 28 days). Our data thus suggest effectiveness of MSC-FFM in RR-aGvHD.

STR typing of skin swabs from individuals after an allogeneic hematopoietic stem cell transplantation.

One of the pre-requisites for forensic DNA analysis is the fact that all nucleated cells of a person carry the same genetic information. However, this is not the case for individuals who have received an allogeneic hematopoietic stem cell or bone marrow transplantation, as all new cells formed by the bone marrow no longer show the genetic information of the recipient but that of the donor, while all other cells still carry the original information before transplantation. Thus, STR typing of a blood sample after successful transplantation yields a DNA profile that differs from the recipient's original profile and corresponds to the donor genotype instead. Evidence from a routine case suggests that transplanted individuals may show donor alleles in skin swabs, as well. In order to examine this issue more closely, various skin swabs from 28 patients who have received an allogeneic hematopoietic stem cell transplantation were examined in this study. Swabs from the right and left palm, the back of the hand, one of the two upper arms, and the neck were collected from each person. Ninety-one of the 140 resulting swabs delivered useful results. All of those samples showed mixtures of recipient and donor DNA with different mixture ratios and the proportions of donor and recipient alleles revealed inter- and intra-individual differences. Those results were discussed with respect to graft versus host disease.

Conditioning with fludarabine and treosulfan compared to FLAMSA-RIC in allogeneic stem cell transplantation for myeloid malignancies: a retrospective single-center analysis.

Reduced intensity conditioning (RIC) and reduced toxicity conditioning (RTC) regimens enable allogeneic hematopoietic stem cell transplantation (alloSCT) to more patients due to reduction in transplant-related mortality (TRM). The conditioning regimens with fludarabine and treosulfan (Flu/Treo) or fludarabine, amsacrine, cytarabine (FLAMSA)-RIC have shown their efficacy and tolerability in various malignancies. So far, no prospective study comparing the two regimens is available. Two studies compared the regimens retrospectively, in which both provided similar outcome. In this retrospective, single-center analysis, these two regimens were compared with regard to outcome, rate of acute and chronic graft versus host disease (GvHD), and engraftment. 113 consecutive patients with myeloid malignancies who received Flu/Treo or FLAMSA-RIC conditioning prior to alloSCT between 2007 and 2019 were included. Except for age, previous therapies, and remission status before alloSCT, patient characteristics were well balanced. The median follow-up time within this analysis was 44 months. There was no significant difference in absolute neutrophil count (ANC) or platelet engraftment between the two conditioning regimens. Overall survival (OS), the relapse-free survival (RFS), and the TRM were not significantly different between the two cohorts. The rate of GvHD did not differ between the two groups. In summary, this retrospective analysis shows that there is no major difference regarding tolerability and survival between the Flu/Treo and FLAMSA-RIC regimens. Despite several limitations due to uneven distribution concerning age and remission status, we demonstrate that Flu/Treo and FLAMSA-RIC provide similar outcomes and are feasible in older and intensively pre-treated patients.

Treosulfan compared with reduced-intensity busulfan improves allogeneic hematopoietic cell transplantation outcomes of older acute myeloid leukemia and myelodysplastic syndrome patients: Final analysis of a prospective randomized trial.

The phase III study was designed to compare event-free survival (EFS) after treosulfan-based conditioning with a widely applied reduced-intensity conditioning (RIC) busulfan regimen in older or comorbid patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic cell transplantation (HCT). A previously reported confirmatory interim analysis of the randomized clinical study including 476 patients demonstrated statistically significant noninferiority for treosulfan with clinically meaningful improvement in EFS. Here, the final study results and pre-specified subgroup analyses of all 570 randomized patients with completed longer-term follow-up are presented. Patients presenting HCT-specific comorbidity index >2 or aged ≥50 years were randomly assigned (1:1) to intravenous (IV) fludarabine with either treosulfan (30 g/m2 IV) or busulfan (6.4 mg/kg IV) after stratification by disease risk group, donor type, and participating institution. The primary endpoint was EFS with disease recurrence, graft failure, or death from any cause as events. EFS of patients (median age 60 years) was superior after treosulfan compared to RIC busulfan: 36-months-EFS rate 59.5% (95% CI, 52.2-66.1) vs. 49.7% (95% CI, 43.3-55.7) with a hazard ratio (HR) of 0.64 (95% CI, 0.49-0.84), p = 0.0006. Likewise, overall survival (OS) with treosulfan was superior compared to busulfan: 36-month-OS rate 66.8% vs. 56.3%; HR 0.64 (95% CI, 0.48-0.87), p = 0.0037. Post hoc analyses revealed that these differences were consistent with the confirmatory interim analysis, and thereby the treosulfan regimen appears particularly suitable for older AML and MDS patients.

Allogeneic transplant procurement in the times of COVID-19: Quality report from the central European cryopreservation site.

BACKGROUND: Because of limitations of transportation imposed by the COVID-19 pandemic, current recommendation calls for cryopreservation of allogeneic stem cell transplants before patient conditioning. A single cell therapy laboratory was selected to function as the central cryopreservation hub for all European registry donor transplants intended for the Australian-Pacific region. We examined properties of these transplants to ascertain how quality is maintained. METHODS: We analyzed 100 pandemic-related allogeneic mobilized blood-derived stem cell apheresis products generated at 30 collection sites throughout Europe, shipped to and cryopreserved at our center between April and November of 2020. Products were shipped in the cool, subsequently frozen with DMSO as cryoprotectant. Irrespective of origin, all products were frozen within the prescribed shelf-life of 72 h. RESULTS: Prior to cryopreservation, viable stem cell and leukocyte count according to the collection site and our reference laboratory were highly concordant (r2 = 0.96 and 0.93, respectively) and viability was > 90% in all instances. Median nominal post-thaw recovery of viable CD34+ cells was 42%. Weakly associated with poorer CD34+ cell recovery was higher leukocyte concentration, but not time lag between apheresis or addition of cryopreservant, respectively, and start of freezing. The correlation between pre- and post-thaw CD34+ cell dose was high (r2 = 0.85), hence predictable. Neutrophil and platelet engraftment were prompt with no evidence of dose dependency within the range of administered cell doses (1.31-15.56 × 106 CD34+ cells/kg). CONCLUSIONS: General cryopreservation of allogeneic stem cell transplants is feasible. While more than half of the CD34+ cell content is lost, the remaining stem cells ensure timely engraftment.

Standardized monitoring of cytomegalovirus-specific immunity can improve risk stratification of recurrent cytomegalovirus reactivation after hematopoietic stem cell transplantation.

Recurrence of cytomegalovirus reactivation remains a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation. Monitoring cytomegalovirus-specific cellular immunity using a standardized assay might improve the risk stratification of patients. A prospective multicenter study was conducted in 175 intermediate- and high-risk allogeneic hematopoietic stem cell transplant recipients under preemptive antiviral therapy. Cytomegalovirus-specific cellular immunity was measured using a standardized IFN-γ ELISpot assay (T-Track® CMV). Primary aim was to evaluate the suitability of measuring cytomegalovirus-specific immunity after end of treatment for a first cytomegalovirus reactivation to predict recurrent reactivation. 40/101 (39.6%) patients with a first cytomegalovirus reactivation experienced recurrent reactivations, mainly in the high-risk group (cytomegalovirus-seronegative donor/cytomegalovirus-seropositive recipient). The positive predictive value of T-Track® CMV (patients with a negative test after the first reactivation experienced at least one recurrent reactivation) was 84.2% in high-risk patients. Kaplan-Meier analysis revealed a higher probability of recurrent cytomegalovirus reactivation in high-risk patients with a negative test after the first reactivation (hazard ratio 2.73; p=0.007). Interestingly, a post-hoc analysis considering T-Track® CMV measurements at day 100 post-transplantation, a time point highly relevant for outpatient care, showed a positive predictive value of 90.0% in high-risk patients. Our results indicate that standardized cytomegalovirus-specific cellular immunity monitoring may allow improved risk stratification and management of recurrent cytomegalovirus reactivation after hematopoietic stem cell transplantation. This study was registered at www.clinicaltrials.gov as #NCT02156479.

An Eschar-like souvenir from a journey to Colombia: Ecthyma gangrenosum as a differential diagnosis of tropical diseases in immunocompromised patients - a case report.

BACKGROUND: Ecthyma gangrenosum (EG) is a cutaneous infectious disease characterized by eschar-like skin ulcers typically caused by Pseudomonas aeruginosa. Here, we report a case of relapsing EG in a patient who had returned from a trip to Colombia, thus establishing EG as an important differential diagnosis of tropical diseases, and demonstrating that even long-term antibiotic treatment can result in only partial remission of EG. CASE PRESENTATION: A 77-year-old man with underlying chronic lymphocytic leukemia (CLL) on ibrutinib treatment was admitted because of a superinfected mosquito bite on the left ear and multiple partially necrotic skin lesions disseminated all over the entire body five days after returning from a trip to Colombia. The initial clinical suspicion of a tropical disease (leishmaniosis, systemic mycosis, or others) could not be confirmed. During the diagnostic workup, microbiological cultures of the skin biopsies and bronchoalveolar lavage revealed Pseudomonas aeruginosa, leading to a diagnosis of EG. Initial antibiotic treatment resulted in partial remission. However, the patient had to be re-admitted due to a relapse 3-4 weeks after the first episode. Finally, the patient was successfully treated with a combined approach consisting of antibiotics, recurrent surgical incisions, and administration of immunoglobulins. CONCLUSIONS: In conclusion, EG should be considered as a differential diagnosis in immunosuppressed patients presenting with eschar-like skin ulcers. A combined treatment approach seems to be the best choice to achieve clinical cure and avoid relapse.

Cyclophosphamide plus etoposide is a safe and effective mobilization regimen in patients with multiple myeloma.

High-dose chemotherapy followed by autologous stem cell transplantation is a major component in the treatment of patients with multiple myeloma. As a prerequisite, the successful collection of a sufficient number of viable peripheral blood hematopoietic CD34+ cells is critical. A common standard protocol for mobilization is currently not defined and critically discussed especially in German-speaking Europe. In times of the Covid-19 pandemic, safe and effective strategies have to be chosen to minimize hospitalization times and severe courses. In this single-center retrospective analysis, safety and efficacy of cyclophosphamide plus etoposide (CE) and growth-factor support (n = 33) was compared to cyclophosphamide mono treatment and growth-factor support (n = 49) in 82 patients with multiple myeloma at first diagnosis. CE was superior to cyclophosphamide mono with a significantly higher number of collected CD34+ cells (15.46 × 106 CD34+ cells/kg vs. 9.92 × 106 CD34+ cells/kg), significantly faster engraftment of granulocytes after stem cell transplantation (day 10.5 vs. day 11.6), shorter duration of the inpatient stay (17.47 days vs. 19.16 days) and significantly less transfusions (8.82 % vs. 30.61 % patients receiving transfusions). The safety profile was comparable in both groups and in line with published data. We conclude that CE is a safe and highly effective mobilization protocol in patients with multiple myeloma at first diagnosis and appears to be superior to the commonly used cyclophosphamide mono regimen.

Outcomes of Haploidentical Transplantation in Patients with Relapsed Multiple Myeloma: An EBMT/CIBMTR Report.

Allogeneic hematopoietic cell transplantation (allo-HCT) using siblings and matched donors has the potential for long-term disease control in a subset of high-risk patients with multiple myeloma (MM); however, the data on using haploidentical donors in this disease are limited. We conducted a retrospective analysis to examine the outcomes of patients with MM who underwent haploidentical allo-HCT within European Society for Blood and Marrow Transplantation/Center for International Blood and Marrow Transplant Research centers. A total of 96 patients underwent haploidentical allo-HCT between 2008 and 2016. With a median follow-up of 24.0 months (range, 13.2 to 24.9 months), 97% (95% confidence interval [CI], 93% to 100%) of patients had neutrophil engraftment by day 28, and 75% (95% CI, 66% to 84%) achieved platelet recovery by day 60. Two-year progression-free survival (PFS) was 17% (95% CI, 8% to 26%), and overall survival (OS) was 48% (95% CI, 36% to 59%). At 2 years, the cumulative risk of relapse/progression was 56% (95% CI, 45% to 67%), and 1-year nonrelapse mortality (NRM) was 21% (95% CI, 13% to 29%). The incidences of acute graft-versus-host-disease (GVHD) grades II-IV by 100 days and chronic GVHD at 2 years were 39% (95% CI, 28% to 49%) and 46% (95% CI, 34% to 59%), respectively. On univariate analysis, use of post-transplantation cyclophosphamide (PT-Cy) (54% [95% CI, 41% to 68%] versus 25% [95% CI, 1% to 48%]; P =.009) and use of bone marrow as source of stem cells (72% [95% CI, 55% to 89%] versus 31% [95% CI, 17% to 46%]; P = .001) were associated with improved OS at 2 years. Disease status, patient sex, intensity of conditioning regimen, recipient/donor sex mismatch, and cytomegalovirus serostatus had no impact on OS, PFS, or NRM. Haploidentical transplantation is feasible for patients with multiply relapsed or high-risk MM, with an encouraging 2-year OS of 48% and an NRM of 21% at 1 year, supporting further investigation of haploidentical allo-HCT in suitable candidates with MM.

HLA-Mismatched Donors in Patients with Myelodysplastic Syndrome: An EBMT Registry Analysis.

Recently, haploidentical transplantation (haplo) using post-transplant cyclophosphamide (PTCy) has been reported to give very encouraging results in patients with hematological malignancies. Patients who have no HLA-matched donor currently have the choice between a mismatched unrelated donor, an unrelated cord blood (CB) donor, and a haploidentical related donor. The aim of our study is to compare the outcome of patients with myelodysplastic syndrome (MDS) who have been transplanted from a haploidentical donor using PTCy, an HLA-mismatched unrelated donor (marrow or peripheral blood stem cells), or an unrelated mismatched CB donor. A total of 833 MDS patients from the European Group for Blood and Marrow Transplantation (EBMT) registry, transplanted between 2011 and 2016, were identified. The potential benefit of haplo was compared with mismatched unrelated and CB donors in an adjusted and weighted model taking into account potential confounders and other prognostic variables. Haplo was at lower risk of acute graft-versus-host disease (GVHD) than mismatched unrelated donor (P = .010) but at similar risk than CB. Progression-free survival was better after haplo (versus mismatched unrelated, P = .056; versus CB, P = .003) and overall survival tended to be superior after haplo (versus mismatched unrelated, P = .082; versus CB, P = .002). Nonrelapse mortality was not significantly different between haplo and mismatched unrelated donors. Relapse risk was not influenced by the type of donor. In conclusion, patients with MDS from the EBMT registry receiving hematopoietic stem cell transplantation from a haplo donor have significantly better outcome than those receiving hematopoietic stem cell transplantation from a CB donor and at least similar or better outcome than with a mismatched unrelated donor. Prospective studies comparing the type of donors will be needed to confirm this assumption.

Phase I/II study on cytarabine and idarubicin combined with escalating doses of clofarabine in newly diagnosed patients with acute myeloid leukaemia and high risk for induction failure (AMLSG 17-10 CIARA trial).

This open-label, multicentre phase I/II study determined the maximum tolerated dose (MTD), safety and efficacy of clofarabine administered with cytarabine and idarubicin in newly diagnosed acute myeloid leukaemia (AML) patients lacking favourable genetic aberrations. The MTD was 30 mg/m2 clofarabine for patients below and above 60 years. The most frequently reported grade 3-4 non-haematological adverse events were infectious and gastrointestinal toxicities. Complete remission (CR)/CR with incomplete recovery rate was 67%. Allogeneic haematopoietic cell transplantation in first remission was feasible in a high proportion of younger AML patients and probably contributed to the favourable outcome compared to historical controls.

Evaluation of the new continuous mononuclear cell collection protocol versus an older version on two different apheresis machines.

BACKGROUND: Cell separators are routinely used to collect CD34+ blood stem cells in the context of customized stem cell transplantation procedures. The Spectra Optia (Terumo BCT) is a novel development of the precursor instrument, the Cobe Spectra (Terumo BCT). STUDY DESIGN AND METHODS: In this report, 146 autologous and 42 allogeneic donors undergoing apheresis on the Cobe Spectra using the mononuclear cell (MNC) program 4.7 or on the Spectra Optia using the new continuous mononuclear cell (cMNC) program 11.2 are compared. RESULTS: Viability of cells and collection efficacy within the apheresis products was comparable for autologous and allogeneic products collected with the MNC or cMNC method. However, we found a reduced duration of the apheresis procedure and lower hematocrit within the apheresis products when using the cMNC in autologous and allogeneic donors. Moreover, allogeneic donors collected substantially more CD34+ cells per kilogram of body weight when using the cMNC method. Differences in platelets before and after apheresis were substantially smaller in this cohort when compared to the cohort collected with the MNC method. Neutrophil and platelet engraftment after autologous or allogeneic transplantation with a product collected with the MNC procedure was comparable to a transplantation with a product processed according to the cMNC method. CONCLUSION: Comparison of the MNC (Cobe Spectra) and the cMNC (Spectra Optia) methods demonstrated an equal performance and outcome. However, advantages were present using the cMNC method with respect to apheresis duration and hematocrit within the apheresis product (autologous/allogeneic donors) and numbers of CD34+ cells collected, especially in allogeneic donors.

Structured reporting adds clinical value in primary CT staging of diffuse large B-cell lymphoma.

OBJECTIVES: To evaluate whether template-based structured reports (SRs) add clinical value to primary CT staging in patients with diffuse large B-cell lymphoma (DLBCL) compared to free-text reports (FTRs). METHODS: In this two-centre study SRs and FTRs were acquired for 16 CT examinations. Thirty-two reports were independently scored by four haematologists using a questionnaire addressing completeness of information, structure, guidance for patient management and overall quality. The questionnaire included yes-no, 10-point Likert scale and 5-point scale questions. Altogether 128 completed questionnaires were evaluated. Non-parametric Wilcoxon signed-rank test and McNemar's test were used for statistical analysis. RESULTS: SRs contained information on affected organs more often than FTRs (95 % vs. 66 %). More SRs commented on extranodal involvement (91 % vs. 62 %). Sufficient information for Ann-Arbor classification was included in more SRs (89 % vs. 64 %). Information extraction was quicker from SRs (median rating on 10-point Likert scale=9 vs. 6; 7-10 vs. 4-8 interquartile range). SRs had better comprehensibility (9 vs. 7; 8-10 vs. 5-8). Contribution of SRs to clinical decision-making was higher (9 vs. 6; 6-10 vs. 3-8). SRs were of higher quality (p < 0.001). All haematologists preferred SRs over FTRs. CONCLUSIONS: Structured reporting of CT examinations for primary staging in patients with DLBCL adds clinical value compared to FTRs by increasing completeness of reports, facilitating information extraction and improving patient management. KEY POINTS: • Structured reporting in CT helps clinicians to assess patients with lymphoma. • This two-centre study showed that structured reporting improves information content and extraction. • Patient management may be improved by structured reporting. • Clinicians preferred structured reports over free-text reports.

Patients' outcome after rescue plerixafor administration for autologous stem cell mobilization: a single-center retrospective analysis.

BACKGROUND: Plerixafor is predominantly used for patients mobilizing inadequate stem cell numbers for autologous transplantation after stimulation with granulocyte-colony-stimulating factor (G-CSF). STUDY DESIGN AND METHODS: We here report on 300 patients undergoing stem cell mobilization with G-CSF, among them 36 poor mobilizers (CD34+ cell counts < 50 × 106 /L blood) receiving G-CSF alone and 49 receiving G-CSF in combination with plerixafor for rescue intervention. Mobilization efficacy and short-time outcome after autologous stem cell transplantation were analyzed and compared in the respective subgroups. RESULTS: Out of 49 patients treated with plerixafor and G-CSF, 46 (94%) collected sufficient hematopoietic stem cell numbers although the number was clearly inferior in poor mobilizers. Compared to good mobilizers, viability of CD34+ cells analyzed after collection was slightly reduced in poor mobilizers independent of the application of plerixafor. A total of 232 patients underwent autologous stem cell transplantation, among them 26 poor mobilizers who received only G-CSF and 31 patients who received G-CSF in combination with plerixafor. Time until neutrophil engraftment was in median 1 day later in poor mobilizers irrespective of the application of plerixafor. Platelet engraftment was in median 2 days delayed in patients mobilized with G-CSF and plerixafor compared to 1 day in poor mobilizers treated with G-CSF only. Frequency of detected CD38+ CD138+ CD45- CD56+ plasma cells in the apheresis products of myeloma patients was comparable for all groups. CONCLUSION: Our data demonstrate that plerixafor is highly effective as rescue measurement after mobilization failure with G-CSF alone and short-term clinical outcome after stem cell transplantation is comparable.

Activity of therapeutic JAK 1/2 blockade in graft-versus-host disease.

Graft-versus-host-disease (GVHD) is a severe complication of allogeneic hematopoietic cell transplantation (allo-HCT) characterized by the production of high levels of proinflammatory cytokines. Activated Janus kinases (JAKs) are required for T-effector cell responses in different inflammatory diseases, and their blockade could potently reduce acute GVHD. We observed that inhibition of JAK1/2 signaling resulted in reduced proliferation of effector T cells and suppression of proinflammatory cytokine production in response to alloantigen in mice. In vivo JAK 1/2 inhibition improved survival of mice developing acute GVHD and reduced histopathological GVHD grading, serum levels of proinflammatory cytokines, and expansion of alloreactive luc-transgenic T cells. Mechanistically, we could show that ruxolitinib impaired differentiation of CD4(+) T cells into IFN-γ- and IL17A-producing cells, and that both T-cell phenotypes are linked to GVHD. Conversely, ruxolitinib treatment in allo-HCT recipients increased FoxP3(+) regulatory T cells, which are linked to immunologic tolerance. Based on these results, we treated 6 patients with steroid-refractory GVHD with ruxolitinib. All patients responded with respect to clinical GVHD symptoms and serum levels of proinflammatory cytokines. In summary, ruxolitinib represents a novel targeted approach in GVHD by suppression of proinflammatory signaling that mediates tissue damage and by promotion of tolerogenic Treg cells.

Targeted positron emission tomography imaging of CXCR4 expression in patients with acute myeloid leukemia.

Acute myeloid leukemia originates from leukemia-initiating cells that reside in the protective bone marrow niche. CXCR4/CXCL12 interaction is crucially involved in recruitment and retention of leukemia-initiating cells within this niche. Various drugs targeting this pathway have entered clinical trials. To evaluate CXCR4 imaging in acute myeloid leukemia, we first tested CXCR4 expression in patient-derived primary blasts. Flow cytometry revealed that high blast counts in patients with acute myeloid leukemia correlate with high CXCR4 expression. The wide range of CXCR4 surface expression in patients was reflected in cell lines of acute myeloid leukemia. Next, we evaluated the CXCR4-specific peptide Pentixafor by positron emission tomography imaging in mice harboring CXCR4 positive and CXCR4 negative leukemia xenografts, and in 10 patients with active disease. [(68)Ga]Pentixafor-positron emission tomography showed specific measurable disease in murine CXCR4 positive xenografts, but not when CXCR4 was knocked out with CRISPR/Cas9 gene editing. Five of 10 patients showed tracer uptake correlating well with leukemia infiltration assessed by magnetic resonance imaging. The mean maximal standard uptake value was significantly higher in visually CXCR4 positive patients compared to CXCR4 negative patients. In summary, in vivo molecular CXCR4 imaging by means of positron emission tomography is feasible in acute myeloid leukemia. These data provide a framework for future diagnostic and theranostic approaches targeting the CXCR4/CXCL12-defined leukemia-initiating cell niche.

Long-term experiences in cryopreservation of mobilized peripheral blood stem cells using a closed-bag system: a technology with potential for broader application.

BACKGROUND: In several European countries, preparation of cellular products with open manufacturing systems as used for cryopreservation of peripheral blood stem cells (PBSCs) needs to be performed in a clean-room facility. However, this form of manufacturing is highly expensive and laborious. Thus, safe techniques providing improved efficacy regarding time and material, which are in accordance with legal requirements are highly desirable. STUDY DESIGN AND METHODS: We have developed, validated, and applied a simple method for cryopreservation of PBSCs within a functionally closed-bag system using the closed cryo freeze prep set. This process fulfills good manufacturing practice requirements and allows for the cryopreservation of PBSCs without a clean-room facility. In addition to cryopreservation of PBSCs, we have recently successfully modified our system for processing, portioning, and cryopreservation of allogeneic donor lymphocytes. RESULTS: Since 2010, cryopreservation of PBSCs using a closed-bag system has been performed in our facility on a routine basis and 210 patients and healthy donors have been included in this analysis. No significant reduction in viability of CD34+ cells and no process-related contamination were observed. Outcome of hematopoietic stem cell transplantation regarding time of engraftment and infectious complications is comparable to products manufactured in conventional clean-room facilities. CONCLUSION: Our data confirm that cryopreservation of PBSCs within a functionally closed-bag system is safe, effective, and economical. Furthermore, the system has the potential to be extended to other manufacturing processes of cellular products.

Clinical challenge: fatal mucormycotic osteomyelitis caused by Rhizopus microsporus despite aggressive multimodal treatment.

BACKGROUND: Mucormycosis is an invasive mycotic disease caused by fungi in the zygomycetes class. Although ubiquitous in the environment, zygomycetes are rarely known to cause invasive disease in immunocompromised hosts with a high mortality even under aggressive antifungal and surgical therapy. Clinically, mucormycosis frequently affects the sinus occasionally showing pulmonary or cerebral involvement. However skeletal manifestation with Rhizopus microsporus (RM) osteomyelitis leading to emergency surgical proximal femoral resection with fatal outcome has not been described yet. CASE PRESENTATION: We report the case of a 73-year-old male suffering from myelodysplastic syndrome with precedent bone marrow transplantation. Six months after transplantation he consulted our internal medicine department in a septic condition with a four week history of painful swelling of the right hip. Radiography, computed tomography and magnetic resonance imaging revealed multiple bone infarcts in both femurs. In the right femoral head, neck and trochanteric region a recent infarct showed massive secondary osteomyelitis, breaking through the medial cortex. Emergency surgical proximal femoral resection was performed due to extensive bone and soft tissue destruction. Microbiological and basic local alignment search tool (BLAST) analysis revealed RM. Amphotericin B and posaconazole treatment with septic revision surgery was performed. However the disease ran a rapid course and was fatal two months after hospital admission. CONCLUSION: This alarming result with extensive RM osteomyelitis in the proximal femur of an immunocompromised patient may hopefully warn medical staff to perform early imaging and aggressive surgical supported multimodal treatment in similar cases.