Kazuhiko Kakihana

Fecal microbiota transplantation for patients with steroid-resistant acute graft-versus-host disease of the gut

Increasing evidence indicates that the gut microbiota is closely associated with acute graft-versus-host disease (aGVHD) in stem cell transplantation (SCT). Fecal microbiota transplantation (FMT) could represent an alternative treatment option for aGVHD. However, FMT for SCT patients carries a potential risk of infection by infused microbiota because of the severely immunosuppressed status. We therefore conducted a pilot study to evaluate the safety of FMT in SCT. A total of 4 patients with steroid-resistant (n = 3) or steroid-dependent gut aGVHD (n = 1) received FMT. No severe adverse events attributed to FMT were observed. All patients responded to FMT, with 3 complete responses and 1 partial response. Temporal dynamics of microbiota seemed to be linked to the gut condition of patients and peripheral effector regulatory T cells also increased during response to FMT. FMT was safely performed in our patients and might offer a novel therapeutic option for aGVHD. This trial was registered at the University Hospital Medical Information Network (https://upload.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000017575) as #UMIN000015115.

HLA-Haploidentical Peripheral Blood Stem Cell Transplantation with Post-Transplant Cyclophosphamide after Busulfan-Containing Reduced-Intensity Conditioning

Allogeneic hematopoietic stem cell transplantation (allo-SCT) using post-transplant cyclophosphamide (PTCy) is increasingly performed. We conducted a multicenter phase II study to evaluate the safety and efficacy of PTCy-based HLA-haploidentical peripheral blood stem cell transplantation (PTCy-haploPBSCT) after busulfan-containing reduced-intensity conditioning. Thirty-one patients were enrolled; 61% patients were not in remission and 42% patients had a history of prior allo-SCT. Neutrophil engraftment was achieved in 87% patients with a median of 19 days. The cumulative incidence of grades II to IV and III to IV acute graft-versus-host disease (GVHD) and chronic GVHD at 1 year were 23%, 3%, and 15%, respectively. No patients developed severe chronic GVHD. Day 100 nonrelapse mortality (NRM) rate was 19.4%. Overall survival, relapse, and disease-free survival rates were 45%, 45%, and 34%, respectively, at 1 year. Subgroup analysis showed that patients who had a history of prior allo-SCT had lower engraftment, higher NRM, and lower overall survival than those not receiving a prior allo-SCT. Our results suggest that PTCy-haploPBSCT after busulfan-containing reduced-intensity conditioning achieved low incidences of acute and chronic GVHD and NRM and stable donor engraftment and low NRM, particularly in patients without a history of prior allo-SCT.

A variant-type MLL/SEPT9 fusion transcript in adult de novo acute monocytic leukemia (M5b) with t(11;17)(q23;q25)

As a result of recurrent chromosomal translocations in acute leukemias, the mixed-lineage-leukemia (MLL) gene fuses with a variety of partner genes, which include several members of the septin gene family. SEPT9 is a very rare but recurrent fusion partner of MLL, and has recently been implicated in the oncogenesis of various malignancies. Herein, we report a case of de novo acute monocytic leukemia (M5b) with t(11;17)(q23;q25). MLL involvement was revealed by fluorescent in situ hybridization (FISH) analysis, and an MLL/SEP9 fusion transcript was detected by RT–PCR. Sequencing analysis further showed that, in contrast to originally reported cases, MLL exon 8 was fused not with SEPT9 exon 3 but with exon 2, which codes for the unique N-terminal region of the SEPT9_v1 isoform, the region implicated in the regulation of gene expression and cell proliferation. We did not detect any mutation of FLT3, which was expressed at a relatively low level in the leukemic cells. Relapsing after a very short complete remission, the leukemia progressed rapidly and became fatal in spite of intensive therapies including hematopoietic stem cell transplantation. It is thus suggested that, in common with the original MLL/SEPT9 cases, monocytic differentiation and a poor prognosis may also be associated with acute myeloid leukemia with the variant MLL/SEPT9 fusion transcript.

The significant impact of acute kidney injury on CKD in patients who survived over 10 years after myeloablative allogeneic SCT.

There are no well-defined studies of chronic kidney disease (CKD) among long-term survivors after hematopoietic SCT. A retrospective longitudinal study was conducted to characterize CKD in 77 subjects that had undergone myeloablative allogeneic SCT, all of whom had their serum creatinine (Cr) levels followed-up during the 10-year period after SCT. Their mean (range) survival time was 14.4 (10.5–20.2) years. CKD was defined as a persistent decrease in the Cr-based estimated glomerular filtration rate to below 60 mL/min/1.73 m2. Acute kidney injury (AKI) was defined as an increase in Cr within the first 100 days after SCT, and its severity was classified into three stages according to the AKIN criteria. Kaplan–Meier and Cox proportional hazards regression analyses evaluated the association between AKI and the incidence of CKD. The cumulative incidence of CKD increased over time and reached 34% at 10 years. After adjusting for known risks for post-SCT CKD, each AKIN stage was strongly associated with the incidence of CKD. The incidence of CKD probably increases over time among subjects who are alive at >10 years after SCT. This study places a new emphasis on AKI as an important risk factor for CKD in post-SCT subjects.

Posttransplantation Bone Marrow Assessment by Quantifying Hematopoietic Cell-Derived mRNAs in Plasma Exosomes/Microvesicles

BACKGROUND Bone marrow (BM) aspiration often can be a painful medical procedure. It is unavoidable, however, because hematopoietic precursor cells (HPC) exist only in BM and few escape to peripheral blood (PB). We hypothesized that HPCs might release exosomes and microvesicles (EMV) in BM, and the resulting EMV would penetrate into PB. Such BM-derived EMV might be identified in PB by measuring specific mRNAs produced by HPC. METHODS Human plasma was applied to an EMV-capture filter plate. After centrifugation, captured EMV were lysed on the filter plate. Resulting lysates were transferred to an oligo(dT)-immobilized microplate for mRNA isolation followed by reverse transcription PCR (RT-PCR). Using this system, myeloid-, erythroid-, and megakaryocyte-lineage-specific poly(A)(+) mRNAs were quantified in plasma obtained from 18 patients who had undergone hematopoietic stem cell transplantation (HSCT). RESULTS When fluorescent liposomes were applied to the filter plate, more than 95% of applied liposomes were absorbed. When human plasma was applied, a scanning electron microscope showed EMV-like particles on the membrane of the filter plate. After RT-PCR, various HPC-specific mRNAs were detected, and the results were equivalent to those derived from the standard ultracentrifugation method. The levels of these mRNAs were undetectable after HSCT and became detectable 1-2 weeks after HSCT, a substantially earlier time point than with traditional hematological analysis. The recovery of EMV mRNA at day 15 corresponded to the final clinical outcome at day 180. CONCLUSIONS HPC-derived mRNAs in plasma EMV may represent new biomarkers for the assessment of BM condition and could reduce the necessity for frequent BM aspiration.

Serial monitoring of T315I BCR-ABL mutation by Invader assay combined with RT-PCR

We recently developed an Invader assay combined with reverse transcriptase polymerase-chain-reaction in order to quantify T315I bcr-abl transcripts. Using this assay, we serially monitored T315I bcr-abl transcripts in chronic myeloid leukemia (CML) patients whose bcr-abl transcripts were still detectable at 6 months after starting imatinib therapy. Although, we continued to monitor bcr-abl transcripts in 14 CML patients (13 chronic phases and 1 accelerated phase) for up to 12 months, there were no patients who were apparently resistant to imatinib due to the T315I mutation. In contrast, in a case of Philadelphia chromosome-positive acute lymphoid leukemia being treated with chemotherapy including imatinib, we monitored both wild-type and T315I bcr-abl transcripts, and found increased levels of T315I transcripts during relapse (0% at the time of diagnosis and 54.8% at relapse). Thus, our new approach could be a useful tool to study the kinetics of mutant clones and the pharmacokinetics of drug resistance with regard to the T315I mutation.

Pre-transplant risk factors for cryptogenic organizing pneumonia/bronchiolitis obliterans organizing pneumonia after hematopoietic cell transplantation

Cryptogenic organizing pneumonia (COP), previously known as bronchiolitis obliterans organizing pneumonia (BOOP), is a significant complication after allogeneic hematopoietic SCT (HCT). However, the pathogenesis of this complication has not yet been elucidated. Therefore, we identified the pre-transplant risk factors for the development of COP/BOOP using the Japan transplant registry database between 2005 and 2009. Among 9550 eligible recipients, 193 experienced COP/BOOP (2%). HLA disparity (odds ratio (OR) 1.51, P=0.05), female-to-male HCT (OR 1.53, P=0.023), and PBSC transplant (OR 1.84, P=0.0076) were significantly associated with an increased risk of COP/BOOP. On the other hand, BU-based myeloablative conditioning (OR 0.52, P=0.033), or fludarabine-based reduced-intensity conditioning (OR 0.50, P=0.0011) in comparison with a TBI-based regimen and in vivo T-cell depletion (OR 0.46, P=0.055) were associated with a lower risk. Of the 193 patients with COP/BOOP, 77 died, including non-relapse death in 46 (59%). Pulmonary failure and fatal infection accounted for 41% (n=19) and 26% (n=12) of the non-relapse death. Allogeneic immunity and conditioning toxicity could be associated with COP/BOOP. Prospective studies are required to elucidate the true risk factors for COP/BOOP and to develop a prophylactic approach.

A case-control study of bronchiolitis obliterans syndrome following allogeneic hematopoietic stem cell transplantation.

Bronchiolitis obliterans syndrome (BOS) is a significant complication after allogeneic hematopoietic stem cell transplantation (HSCT). However, the pathogenesis and risks for the development of BOS have remained unclear. Therefore, a case–control study was conducted to investigate the risk factors for the development of BOS, which included the largest number of BOS cases; 196 patients with BOS were identified and compared with 1960 control recipients. The following were identified as significantly higher risk factors for the development of BOS: female recipients (OR 1.47, P = 0.019), ABO‐mismatch HSCT (minor mismatch, OR 1.67, P = 0.015; major mismatch, OR 1.73, P = 0.012; bidirectional mismatch, OR 1.96, P = 0.018), busulfan+cyclophosphamide‐based myeloablative conditioning (OR 1.74, P = 0.016), and acute graft‐versus‐host disease (GVHD) involving the skin (OR 1.55, P = 0.011). On the other hand, the risk for the development of BOS was significantly lower in patients receiving cord blood transplantation (OR 0.26, P = 0.0011). With respect to other target organs of chronic GVHD, ocular involvement was significantly associated with BOS (OR 2.53, P < 0.001). Prospective studies are required to elucidate the risk factors for the development of BOS, and future investigations should focus on finding a prophylactic approach against BOS based on these findings.

Fatal intracranial hemorrhage following administration of recombinant thrombomodulin in a patient after cord blood transplantation

Fatal intracranial hemorrhage following administration of recombinant thrombomodulin in a patient after cord blood transplantation

Post‐transplant maintenance therapy with azacitidine and gemtuzumab ozogamicin for high‐risk acute myeloid leukaemia

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