Setting Of Allogeneic Stem Cell Transplantation Research Articles

Role of WT1 in Measurable Residual Disease Follow-Up in the Post Allogeneic Stem Cell Transplant Setting

Role of WT1 in Measurable Residual Disease Follow-Up in the Post Allogeneic Stem Cell Transplant Setting

Open-Label Randomized Controlled Study of Ciprofloxacin vs Rifaximin as Neutropenia Prophylaxis in Allogeneic Hematopoietic Stem Cell Transplantation

Loss of microbiota diversity has been clearly associated with poor outcomes in the allogeneic hematopoietic stem cell transplantation setting. However, the choice of the optimal antibiotic prophylaxis during the pre-engraftment phase remains unclear. We designed a prospective randomized study to compare our standard-of-care neutropenia prophylaxis (ciprofloxacin) with rifaximin. We enrolled 38 consecutive adult patients who underwent allogeneic hematopoietic stem cell transplantation setting and were randomly assigned to receive ciprofloxacin (20 patients) or rifaximin (18 patients) at day -1. Pretransplant and transplant characteristics did not differ between groups. Cumulative incidence (CI) of acute graft-vs-host disease grade II to IV and moderate/severe chronic graft-vs-host disease was similar in both groups. With a median follow-up of 13.2 months (range, 6.8-30.2) in surviving patients, the 1-year CI of relapse was 20.8% in ciprofloxacin vs 17.8% in rifaximin (P = .616). Importantly, the 1-year CI of treatment-related mortality was significantly reduced in the ciprofloxacin group (10.2% vs 27.8%, P = .032), leading to higher 1-year overall survival (88.9% vs 74.6%, P = .038). In Cox-regression multivariate analysis, antibiotic prophylaxis remained the only predictor of overall survival, independently of donor type, disease risk index, and moderate/severe chronic graft-vs-host disease. Further studies are needed to assess the effects on microbiota diversity and confirm these outcomes.

The Role of Fecal Microbiota Transplantation in the Allogeneic Stem Cell Transplant Setting.

Microbiota changes during allogeneic hematopoietic stem cell transplantation has several known causes: conditioning chemotherapy and radiation, broad-spectrum antibiotic administration, modification in nutrition status and diet, and graft-versus-host disease. This article aims to review the current knowledge about the close link between microbiota and allogeneic stem cell transplantation setting. The PubMed search engine was used to perform this review. We analyzed data on microbiota dysbiosis related to the above-mentioned affecting factors. We also looked at treatments aimed at modifying gut dysbiosis and applications of fecal microbiota transplantation in the allogeneic stem cell transplant field, with particular interest in fecal microbiota transplantation for graft-versus-host disease (GvHD), multidrug-resistant and clostridium difficile infections, and microbiota restoration after chemotherapy and antibiotic therapy.

Thrombocytopenia and Therapeutic Strategies after Allogeneic Hematopoietic Stem Cell Transplantation.

Thrombocytopenia following allogeneic hematopoietic stem cell transplantation is a usual complication and can lead to high morbidity and mortality. New strategies, such as the use of another graft versus host-disease prophylaxis, alternative donors, and management of infections, have improved the survival of these patients. The mechanisms are unknown; therefore, the identification of new strategies to manage this potentially serious problem is needed. Thrombopoietin receptor agonists are currently available to stimulate platelet production. Some small retrospective studies have reported their potential efficacy in an allogeneic stem cell transplant setting, confirming good tolerability. Recent studies with higher numbers of patients also support their safety and efficacy in this setting, hence establishing the use of these drugs as a promising strategy for this post-transplant complication. However, prospective trials are needed to confirm these results.

CRP and ferritin in addition to the EASIX score predict CAR-T–related toxicity

AbstractThe Endothelial Activation and Stress Index (EASIX) score, defined as [(creatinine × lactate dehydrogenase [LDH])/platelets], is a marker of endothelial activation that has been validated in the allogeneic hematopoietic stem cell transplant setting. Endothelial activation is one of the mechanisms driving immune-mediated toxicities in patients treated with chimeric antigen receptor-T (CAR-T)-cell therapy. This study's objective was to evaluate the association between EASIX and other laboratory parameters collected before lymphodepletion and the subsequent onset of cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) those patients. Toxicity data were collected prospectively on 171 patients treated with axicabtagene ciloleucel (axi-cel) for large B-cell lymphoma (LBCL). CRS grades 2 to 4 were diagnosed in 81 (47%) patients and ICANS grades 2 to 4 in 84 (49%). EASIX combined with ferritin (EASIX-F) identified 3 risk groups with CRS grades 2 to 4 cumulative incidence of 74% (hazards ratio [HR], 4.8; 95% confidence interval [CI], 2.1-11; P < .001), 49% (HR, 2.3; 95% CI, 1.02-5; P = .04), and 23% (reference), respectively. EASIX combined with CRP and ferritin (EASIX-FC) identified 3 risk groups with an ICANS grade 2 to 4 cumulative incidence of 74% (HR, 3.6; 95% CI, 1.9-6.9; P < .001), 51% (HR, 2.1; 95% CI, 1.1-3.9; P = .025), and 29% (reference). Our results indicate that common laboratory parameters before lymphodepletion correlate with CAR-T–related toxicities and can help support clinical decisions, such as preemptive toxicity management, hospitalization length, and proper setting for CAR-T administration.

Use of Leflunomide for Treatment of Cytomegalovirus Infection in Recipients of Allogeneic Stem Cell Transplant

Background :Reactivation of cytomegalovirus (CMV) commonly occurs post allogeneic stem cell transplant (ASCT). The incidence is at least 40-50% in India, where most patients and donors are CMV seropositive. Ganciclovir, although the drug of choice, is expensive and associated with significant toxicities. Second line agents like foscarnet and cidofovir are not available in India leaving few therapeutic options. Leflunomide, an anti rheumatoid arthritis drug, acts by inhibiting virion assembly of CMV and has been effective in post renal transplant CMV infections. This drug is inexpensive and has a favourable toxicity profile. There have been only occasional case reports of leflunomide post ASCT. Here we report the efficacy of leflunomide in CMV reactivation in ASCT setting.Methods :All patients who underwent ASCT at our centre between April 2015 and February 2017 were included in this retrospective study. Serologic evaluation for CMV infections was done at baseline for all patients and donors. Conditioning regimens used were either myeloablative [total body irradiation (TBI)-cyclophosphamide (Cy)] or reduced intensity (fludarabine with either melphalan, or Cy or treosulfan +/- 2 gray TBI). Graft versus host disease (GVHD) prophylaxis used was cyclosporine or tacrolimus with methotrexate or mycofenolate mofetil for matched sibling donor (MSD) and matched unrelated donor (MUD) transplants. Post transplant Cy was used for haplo-identical transplants (HIT).Monitoring was done twice weekly using quantitative CMV DNA polymerase chain reaction (QPCR) on peripheral blood post transplant till day +120 or longer if patient was on steroids. Patients who were detected to have a positive QPCR greater than 500 copies/mL at 2 consecutive time points were started on pre-emptive therapy. Ganciclovir was the preferred agent for pre-emptive therapy, however in case of ongoing cytopenias, leflunomide was used. In case of clinical resistance to ganciclovir, leflunomide was added as second line. Leflunomide was started at a loading dose of 100 mg once a day for 3 days followed by daily maintenance dose of 20 mg till clearance of CMV (undetectable CMV DNA on QPCR at 2 consecutive time points) or intolerance. Failure of leflunomide was defined as > 1 log increase in CMV copy number at any time or if another anti CMV agent was added due to CMV disease or non-clearance. Invasive procedures such as broncho-alveolar lavage, colonoscopic biopsies, and liver biopsies were used to detect CMV disease, when clinically suspected.Results :Seventy patients underwent ASCT during this period. This included 47 MSD transplants, 18 HIT and 5 MUD transplants. There were 49 episodes of CMV reactivation in 43 patients (61%). The incidence was highest in HIT with 17 of 18 patients developing reactivation.Leflunomide was used in 24 (49%) of the 49 episodes of CMV reactivations. It was used as 1st line agent in 15 episodes and as 2nd line in 9. The median CMV copy number/ml was 0.82x 103 (range 0 to 13x103) on day of starting leflunomide. The median duration of use was 34 days (range 6 to 85 days). It was used pre-emptively in 20 episodes and as therapeutic (i.e. patient had end organ involvement) in 4. None of the patients had toxicity requiring stopping of the drug. Nine (38%) of the 24 CMV reactivation episodes cleared with leflunomide. When used as a 1st line agent, CMV infection cleared in 7 of the 15 episodes (46%) in comparison to ganciclovir as 1st line with which 12 (52%) of 23 episodes cleared.Seven of the 24 episodes had initial CMV burden more than 2 x 103 copies/mL. Leflunomide failed in all of these, as against clearance in 9 of the 17 episodes which had CMV less than 2 x 103 copies/mL. (p= 0.022). None of the patients who received leflunomide in therapeutic setting cleared CMV (0 of 4), compared to 9 of 20 with pre-emptive leflunomide. (p= NS).Conclusions:This is the largest study of using leflunomide for CMV reactivation in post ASCT setting to our knowledge. Leflunomide has considerable activity against CMV, however it is best used when CMV copies are less than 2000 /mL in pre-emptive setting. In therapeutic setting its role seems limited. A larger prospective study is warranted. DisclosuresNo relevant conflicts of interest to declare.

Safety of a Weekly Administration of 10 mg/kg of Liposomal Amphotericin B for Antifungal Prophylaxis in Allogeneic Stem-Cell Transplant and Acute Leukemia Patients.

BackgroundOptimal antifungal prophylaxis approach for patients undergoing chemotherapy, acute leukaemia (AL) or allogeneic stem cell transplant (ASCT) for haematological malignancies has yet to be identified in this high risk setting.Patient and MethodsAn open-label, pilot multicentre study - initiated at Henri Mondor and St-Louis Hospitals (10 patients), Paoli-Calmettes Institute being secondary involved (13 patients) - was conducted between February 2004 and June 2005 in adult patients receiving induction or consolidation chemotherapy for AL or a myeloablative conditioning regimen for ASCT. Patients were either treated for 4 weeks (AL) from the beginning of chemotherapy or 8 weeks (ASCT) from transplant. Treatment consisted of a 2 hour weekly infusion of 10mg/kg liposomal amphotericin B (LAB). Premedication was not allowed prior to day 1 study drug infusion. The primary endpoint was the incidence of reported adverse events occurring during the course of prophylaxis treatment.ResultsTwenty three patients (14 males and 9 females), mean age 44 years (range: 20 to 79) were treated in this interim analysis (8 ASCT and 15 AL). Safety was monitored with particular attention to infusion-related reactions (IRRs) and nephrotoxicity. In a total of 60 infusions, 5 IRRs (8.3%) occurred (flush, shock, thoracic pain, bone pain and dyspnoea). These were exclusively observed on day one in 5 patients (21%). Seven patients (30%) reached serum creatinine (SCr) ≥1.5 times their baseline values. In the AL group, no patient discontinued LAB or required dose reduction during the study. In the ASCT group, 4 patients discontinued after the first infusion, 3 for IRRs and one for SCr increase related to the study drug and other factors, including reactions to concomitant drugs. One additional ASCT patient had discontinued study drug following the third infusion for SCr increase. Mean duration of prophylaxis was 18 days (range: 10–28) in the AL patients and 14 days (range: 6–31) in the ASCT patients.ConclusionA weekly dose of 10 mg/kg appears to be very well tolerated during induction or consolidation therapy for AL. In the ASCT setting where multiple drugs are concomitantly administered, appropriate timing for the initiation of high dose LAB prophylaxis is yet to be determined in order to optimise the safety profile of this regimen.

Use of Sysmex Hematology Analyzer based Hematopoietic Progenitor Cell (XN-HPC) Count in Allogeneic Peripheral Blood Stem Cell Transplant Setting; Is It Substantially Reliable?

Allogeneic stem cell transplantation remains the only curative option for various benign and malignant hematological disorders. The procedure of allogeneic stem cell transplantation entails the administration of adequate doses of hematopoietic progenitor cells, aiming for complete and sustained hematopoietic reconstitution. Hematopoietic progenitors are obtained either through a bone marrow harvest or from GCSF-mobilized peripheral blood of the identified donor. Over the years various modalities have been utilized to establish the adequacy of harvested stem cell product e.g. Colony-forming unit– granulocyte monocyte (CFU-GM) assay, total mononuclear cell count (MNC), and CD34+ cell count

Implementing a Feasible Exercise Programme in an Allogeneic Haematopoietic Stem Cell Transplantation Setting-Impact on Physical Activity and Fatigue.

Physical exercise for patients treated with allogeneic haematopoietic stem cell transplantation (allo-HSCT) has shown positive effects on the quality of life and fatigue in experimental trials. However, there is a need for longitudinal evaluation of exercise programmes implemented in a real-world clinical setting. The aim of this prospective study was to evaluate the impact of an exercise programme introduced before allo-HSCT on physical activity and fatigue before, during and after in-patient care. A structured exercise programme, including strength and endurance exercises, was implemented at a Swedish university hospital four weeks before transplantation, continuing during in-patient care and after discharge. Between March 2016 and May 2018, 67 adult patients, 33 women and 34 men with a mean age of 55.5 years participated. Fatigue was measured by the Multidimensional Fatigue Inventory at four time points. The patients documented their exercises on a checklist each week during the entire study period. The fatigue trajectory differed between various sub-groups, thus individualized supervision and support to maintain motivation is needed. In conclusion, a structured yet realistic exercise programme before admission is beneficial for allo-HSCT patients in order to reduce fatigue and prepare them for transplantation both physically and mentally.

Peripheral Blood Stem Cell Harvest HPC Count Is an Effective Surrogate Marker for CD34+ Cell Count in Allogeneic Stem Cell Transplant Setting

OBJECTIVE: We assessed the predictive potential of XN-HPC for CD34+ cell count as obtained through Sysmex automated hematology analyzers (XN-1000). METHODS: This study was conducted at the National Institute of Blood Diseases and Bone Marrow Transplantation in 84 donors between December 2012 and December 2017 in the first phase and later validated in 112 donors between December 2017 and December 2018. Sysmex XN-1000 and BD FACS Calibur estimated XN-HPC and CD34+ cells of peripheral blood apheresis product, respectively. Spearman's correlation was assessed between XN-HPC and CD34+ cell count followed by receiver operating characteristic curve calculation to determine the XN-HPC cutoff for a CD34+ count of ≥2 million cells/kg of recipient's body weight RESULTS: There is a moderately positive correlation (P value = .003) between XN-HPC and CD34+ count. Receiver operating characteristic curve analyses demonstrated that a cutoff value for XN-HPC of ≥1·845×106cells/kg of recipient's body weight has a specificity and sensitivity of 100% and 78·2%, respectively, for predicting the CD34+ count of ≥2 million cells/kg of recipient's body weight. This cutoff value of XN-HPC was prospectively validated in 112 donors. The positive predictive value was found to be 100%, while negative predictive value was 17%. CONCLUSION: XN-HPC has a highly promising potential to serve as a cost-effective and time-saving surrogate for CD34+ cell count.

Safety of the Recombinant Herpes-Zoster Subunit Vaccine in Allogeneic Stem Cell Transplant Patients

<h3>Introduction</h3> After allogeneic stem cell transplant (SCT), varicella zoster virus (VZV) necessitates long term chemoprophylaxis due to limitations of the live vaccine. The recombinant subunit vaccine containing VZV glycoprotein E with AS01_B adjuvant system (HZ/su, or Shingrix) has safety and efficacy data after autologous transplantation. However, data is absent in the setting of allogeneic SCT. Due to the highly immunogenic AS01b subunit component, concerns regarding stimulation of graft versus host disease (GVHD) reaction have prompted some institutions to avoid routine HZ/su vaccination early after SCT. <h3>Objectives</h3> The primary objective was to evaluate the total number of GVHD events following post-transplant vaccinations. <h3>Methods</h3> Single center retrospective chart review of SCT patients who received post-transplant vaccinations within their first year of transplant. Patients who received HZ/su + post-transplant vaccines between 2017 and 2018 were compared to a control arm who received only the post-transplant vaccines between 2015 and 2016. We collected data regarding timing of the vaccines, presence of IS therapy at time of vaccination, and changes in GVHD therapy after vaccination. We assessed GVHD events within 3 months after each vaccination. <h3>Results</h3> Forty-seven patients received HZ/su + post-transplant- vaccines compared to 49 control patients who received only the post-transplant vaccines. More patients in the control arm were on IS at time of vaccination. Being on IS was a risk factor for GVHD events, especially in the control group. Although there were more alternative donor transplant patients receiving HZ/su vaccine, there were no increase in events. <h3>Conclusion</h3> Overall, HZ/su vaccine does not seem to increase the incidence of GVHD events after vaccination. However, the presence of IS at the time of vaccination may be associated with an increased risk of GVHD events. Given the limitations of our study, prospective trials are needed to evaluate timing and risk factors to consider before HZ/su vaccination.

Multidimensional Geriatric Assessment for Elderly Patients (≥60 years) Submitted for Allogeneic Stem Cell Transplantation. a French (Paris) - Italian (Brescia) 10-Years Experience on 228 Patients

Mohty: Jazz Pharmaceuticals: Honoraria, Research Funding.

Eltrombopag: Role in Cytopenias Following Hematopoietic Stem Cell Transplantation.

Eltrombopag is a small molecule oral agonist of the thrombopoietin receptor. Initially used for improving thrombocytopenia in chronic immune thrombocytopenia (ITP), it was later found to be efficacious in various other etiologies of thrombocytopenia as well as inherited marrow failure syndromes. Lately, it has been used for thrombocytopenia and poor graft function after allogeneic hematopoietic stem cell transplantation (HSCT) without any severe adverse events. Although prospective evidence of the efficacy is limited, there are increasing reports on the safety and efficacy with Eltrombopag in post HSCT thrombocytopenia and poor graft function. This provides an exciting opportunity for further research to evaluate both efficacy and cost-effectiveness of the use of Eltrombopag in this scenario. Here we review the current evidence on the indications for the use of Eltrombopag in the post allogeneic hematopoietic stem cell transplant setting.

An investigation of the utility of plasma Cytomegalovirus (CMV) microRNA detection to predict CMV DNAemia in allogeneic hematopoietic stem cell transplant recipients.

Precise identification of patients at highest risk for developing Cytomegalovirus (CMV) DNAemia may improve CMV infection management in the allogeneic hematopoietic stem cell transplantation (allo-HSCT) setting. Here, we studied the potential use of detecting free CMV micro(mi)RNAs circulating in plasma for predicting CMV DNAemia in this clinical scenario. A total of 62 adult allo-HSCT recipients were included in this prospective observational multicenter study. Plasma CMV DNA load was monitored using the CMV RealTime CMV PCR (Abbott Molecular, Des Plaines, IL, USA). Detection of mature CMV miRNAs in plasma drawn by days + 7, + 14 and + 30 after allo-HSCT was performed using the miScript PCR System (Qiagen, Hilden, Germany). Assays could be optimized for five out of the seven targeted CMV miRNAs: UL36-5p, US33-5p, UL148D, UL22A-5p and UL112-3p. Of the 62 patients included in the study, 42 developed a first episode of CMV DNAemia at a median of 35days after allo-HSCT. All targeted CMV miRNA were detected early after transplantation, with CMV miRNA US33-5p and UL112-3p the most commonly found species at any time point; nevertheless, neither the detection rate of CMV miRNAs nor their abundance allowed discrimination between patients with subsequent CMV DNAemia and those with no CMV DNAemia. The data presented herein do not support any predictive utility of these CMV miRNAs for first episodes of CMV DNAemia in a cohort consisting primarily of allo-HSCT patients receiving haploidentical allografts.

Incidence, risk factors, and outcome of pulmonary invasive fungal disease after respiratory virus infection in allogeneic hematopoietic stem cell transplantation recipients.

BackgroundThere is growing evidence that community‐acquired respiratory virus (CARV) increases the risk of pulmonary invasive fungal disease (IFD) in the allogeneic hematopoietic stem cell transplantation (allo‐HSCT) setting. To date, there is a lack of knowledge regarding the risk factors (RFs), as well as the most critical period for subsequent onset of IFD after CARV infections in allo‐HSCT recipients.MethodsIn this prospective longitudinal observational CARV survey, we analyzed the effect of CARV on subsequent IFD development in 287 adult allo‐HSCT recipients diagnosed with 597 CARV episodes from December 2013 to December 2018. Multiplex PCR panel assays were used to test CARVs in respiratory specimens.FindingsTwenty‐nine out of 287 allo‐HSCT recipients (10%) developed IFD after a CARV episode. The median time of IFD onset was 21 days (range, 0‐158 days) from day of the first CARV detection. Generalized estimating equation model identified 4 risk factors for IFD: ATG‐based conditioning regimen [odds ratio (OR) 2.34, 95% confidence interval (CI) 1.05‐5.2, P = .038], CARV lower respiratory tract disease (OR 10.6, 95% CI 3.7‐30.8, P < .0001), CARV infection during the first year after transplant (OR 5.34, 95% CI 1.3‐21.8, P = .014), and corticosteroids during CARV (OR 2.6, 95% CI 1.1‐6.3, P = .03).ConclusionAllo‐HSCT recipients conditioned with ATG and under corticosteroid therapy at the time of CARV LRTD during the first year after transplant may require close monitoring for subsequent IFD.

Viral Infections in Allogeneic Hematopoietic Stem Cell Transplant Recipients: Literature Review

Hematopoietic stem cell transplant (HSCT) recipients are at an increased risk of bacterial, viral, fungal and parasitic infections. Past exposures to infections, the degree of immunosuppression, prolonged neutropenia and presence of graft versus host disease (GVHD) are some of the factors which make HSCT recipients more susceptible to infections. Viral infections have emerged as a major challenge causing high morbidity and mortality in stem cell transplant recipients. Myeloablative conditioning regimens and GVHD prevention strategies which may delay immune reconstitution and serologic status of donors and recipients affect the incidence of viral infections. Community-acquired respiratory and gastrointestinal viral infections like respiratory syncytial virus, rhinovirus adenovirus, influenza, norovirus and reactivation of latent viruses like herpes simplex virus, cytomegalovirus (CMV) are some of the important pathogens increasing the morbidity and mortality in transplant recipients. Clinical manifestations range from asymptomatic carriage to severe disease. Due to lack of effective agents to treat viral infections and emerging resistance patterns, preventive and prophylactic strategies are valuable. Our review article provides an overview of commonly encountered viral infections and their management in an allogeneic stem cell transplant setting in the adult age group.

PS1539 A COMPARISON OF POST ALLOGENEIC STEM CELL TRANSPLANT CHIMERISM ANALYSIS METHODS: HIGH THROUGHPUT SNP GENOTYPING ANALYSED BY MALDI‐TOF MASS SPECTROMETRY VS. SHORT TANDEM REPEAT (STR) MARKER ANALYSIS

Background:Monitoring of donor chimerism levels is required in the post allogeneic stem cell transplant (SCT) setting to assess engraftment status. Chimerism levels can be assessed by a variety of methods including XY FISH (sex‐mismatch), microsatellite short tandem repeat (STR) analysis or single nucleotide polymorphism (SNP) genotyping by Q‐PCR. MALDI‐TOF Mass spectrometry (MS) is an alternative technique which can be used for high‐throughput SNP genotyping analysis for the purposes of post‐SCT monitoring. MALDI‐TOF MS offers rapid automated analysis and report generation compared to our existing STR methodology which requires expert analysis. We have evaluated MALDI‐TOF MS SNP genotyping as an alternative to STR analysis for chimerism status.Aims:1. To validate the use of the MALDI‐TOF MS SNP assay for clinical post‐SCT chimerism analysis across a range of transplant types (sibling, matched unrelated and double cord transplants). 2. To assess the accuracy and reproducibility of the assay across a range of defined recipient percentages using specifically prepared chimeric DNA samples. 3. To define the limits of sensitivity for detection of mixed chimerism. 4. To define the lowest DNA input concentration which permits detection of mixed chimerism.Methods:MALDI‐TOF MS SNP genotyping covers a panel of 92 SNPs. Locus specific multiplex PCR is followed by single base extension into the SNP site and detection with MALDI‐TOF MS. Mixed chimerism is assessed by analyzing the cumulative skew in genotyping data across informative SNPs. STR analysis comprises fluorescently tagged PCR of a panel of 16 highly polymorphic microsatellites. Relative peak height analysis of donor and recipient peaks is performed post‐PCR to give chimerism levels.114 post‐SCT clinical samples from 38 single donor and two double cord donor transplants were analyzed by both methods to assess the concordance of results obtained.Synthetic chimeras representing known % levels of donor and recipient DNA (1, 2, 5, 10, 30 and 50% recipient) were prepared and analyzed by both methods to assess accuracy and reproducibility across a range of recipient percentages and also to determine the limit of sensitivity for detection of mixed chimerism.DNA dilutions of the synthetic 2% recipient chimera were prepared in order to define the minimum acceptable DNA template concentration for detection of mixed chimerism in both assays.Results:Good concordance between methodologies was seen across all clinical samples tested, with greatest variation seen between 40–60% chimerism levels. Analysis of synthetic chimera samples also showed good concordance, with greatest variation seen at the expected 50% chimerism level.Analysis of the synthetic chimeras defined the sensitivity of detection for recipient DNA at 2% by both systems. The minimum input template DNA concentration for detection of mixed chimerism was shown to be 1ng/μl for MALDI‐TOF MS and 2ng/μl for STR analysis.Summary/Conclusion:The MALDI‐TOF MS SNP Assay gave highly comparable results to STR analysis for determination of post‐SCT chimerism levels and offered identical sensitivity to STR analysis for detection of mixed chimerism. The assay could reliably detect mixed chimerism at DNA concentrations as low as 1ng/μl. Results analysis and report generation is fully automated, taking less than 20 seconds per sample compared to STR analysis which takes 5–10 minutes of expert analysis per sample. We conclude that MALDI‐TOF MS SNP analysis offers a viable alternative to STR chimerism analysis with comparable accuracy and sensitivity and significantly increased analytical speed.

Diagnostic Parameters of Adenoviremia in Pediatric Stem Cell Transplant Recipients.

Despite recent progress in the diagnostic risk assessment of human adenovirus (HAdV) infections in immunocompromised patients, clinical complications mediated by these viruses continue contributing to significant morbidity and mortality, particularly in the pediatric hematopoietic allogeneic stem cell transplant (HSCT) setting. Current data highlight the importance of monitoring stool samples to assess the risk of invasive HAdV infections in children undergoing HSCT. The advent of novel, more effective antiviral treatment options might permit successful virus control even at the stage of systemic infection, thus increasing the interest in optimized HAdV monitoring in peripheral blood (PB). We have screened over 300 pediatric HCST recipients by serial monitoring of stool and PB specimens, and identified 31 cases of invasive HAdV infection by quantitative pan-adenovirus RQ-PCR analysis of consecutive PB specimens. The diagnostic parameters assessed included HAdV peak levels (PL) and the time-averaged area under the curve (AAUC) of virus copy numbers. The predictive value for patient outcome reflected by non-relapse and HAdV-related mortality was determined. The patients were assigned to quartiles based on their PL and AAUC, and the readouts were highly correlated (p < 0.0001). Non-relapse mortality in patients by AAUC quartile (lowest to highest) was 26, 50, 75, and 86%, respectively, and AAUC was strongly correlated with non-relapse mortality (p < 0.0001), while the association between PL and non-relapse mortality was less pronounced (p = 0.013). HAdV-related mortality was absent or very low in patients within the two lower quartiles of both PL and AAUC, and increased to ≥70% in the upper two quartiles. Despite the significant correlation of PL and AAUC with patient outcome, it is necessary to consider that the risk of non-relapse mortality even within the lowest quartile was still relatively high, and it might be difficult therefore to translate the results into differential treatment approaches. By contrast, the correlation with HAdV-related mortality might permit the identification of a low-risk patient subset. Nevertheless, the well-established correlation of HAdV shedding into the stool and intestinal expansion of the virus with the risk of invasive infection will expectedly remain an essential diagnostic parameter in the pediatric HSCT setting.

Senescent Mesenchymal Stem Cells Present at the Early Post Allogeneic Hematopoietic Stem Cell Transplantation Period Are Associated with an Increased Incidence of Acute Graft-Versus Host Disease and Increased Plasma Levels of Fas Ligand

IntroductionMesenchymal stem cells (MSC) are a key component of the hematopoietic niche. In the allogeneic hematopoietic stem cell transplantation (allo-HSCT) setting, the bone marrow stroma, and thus, their MSC remain of host origin. In a preliminary study we observed that, some patients at the early post allo-HSCT period, presented senescent bone marrow (BM) MSC, a finding that has not been previously described nor studied.The aims of our current study were: a) To multiparametrically characterize BM MSC at the early post allo-HSCT period (day +21). b) To confirm senescence of MSC and correlate with clinical and biological parameters (including biomarkers). c) To compare these cells with those from healthy donors.MethodsWe obtained BM samples on the day +21 post allo-HSCT from 136 patients. MSC were isolated, ex-vivo expanded and characterized, according to the criteria of the International Society for Cellular Therapy. We also obtained samples from peripheral blood at same day +21, for the study of biomarkers, which were analyzed by Luminex technique. The data were correlated with information from complete blood counts (CBC), and the morphological study of the bone marrow the same day. MSC from healthy donors were used as control.ResultsPatient baseline and transplant related characteristics are detailed in table 1. MSC were expanded ex-vivo showing normal growth, which were cryopreserved in passage 3 in the 33% (n=45/136) of the patients (Group-MSC-N). On the other hand, the remaining 67% (n=91/136), MSC showed premature signs of senescence, thus, not reaching to passage 1 (Group-MSC-S). Full BM chimerism on day+21 was seen in both groups (p=0.03). Concerning acute graft versus-host disease (aGVHD), in the Group-MSC-S, the incidence was 73% compared to 44% in the Group-MSC-N (p=0.001). The median time of the onset of aGVHD was 43 and 37 days respectively (p=0.04). The majority of cases presented with grades I-II in both groups. Plasma levels of biomarkers showed increased levels of Fas Ligand in the Group-MSC-S (p=0.009). There were no statistically significant differences regarding mortality nor relapse rates.ConclusionsBone marrow Mesenchymal stem cells may be severely damaged in some allo-HSCT recipients early after transplantation (day+21). This fact strongly correlates with the risk of development of acute GVHD. [Display omitted] DisclosuresDíez-Campelo:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Management of adenovirus infection in patients after haematopoietic stem cell transplantation: State-of-the-art and real-life current approach: A position statement on behalf of the Infectious Diseases Working Party of the European Society of Blood and Marrow Transplantation.

The important insights gained over the past years in diagnosis and treatment of invasive adenoviral infections provide new paradigms for the monitoring and clinical management of these life-threatening complications. A meeting was held to discuss and subsequently disseminate the current advances in our understanding of the aetiology/pathogenesis and future treatment options facilitating effective control or prevention of adenovirus-related diseases in the allogeneic haematopoietic stem cell transplant setting. Invited experts in the field discussed recent progress with leading members of the Infectious Diseases Working Party of the European Society of Blood and Marrow Transplantation at the "State-of-the-art" Meeting in Poznan, Poland, in October 2017. In this review article, the panel of experts presents a concise summary of the current evidence based on published data from the last 15years and on recent achievements resulting from real-life practice. The present position statement reflects an expert opinion on current approaches to clinical management of adenovirus infections in patients undergoing allogeneic haematopoietic stem cell transplant and provides graded recommendations of the panel for diagnostic approaches and preemptive therapy reflecting the present state of knowledge.