Clinical Impact of Pretransplantation Physical Function on Transplantation after Allogeneic Hematopoietic Cell Transplantation in Older Adults.

Clinical research regarding the impact of pretransplantation physical function on transplantation outcomes in older adults remains limited. We retrospectively reviewed the charts of 150 consecutive patients age >55 years who underwent their first allogeneic hematopoietic cell transplantation (HCT) at our center between 2010 and 2021. We evaluated the clinical impact of pretransplantation physical function, including hand grip strength (HGS), knee extension strength (KES), and distance covered in a 6-minute walk test (6MWT), along with other clinical factors, on transplantation outcomes such as overall survival (OS), nonrelapse mortality (NRM), and cumulative incidence of disease relapse (CIR). There was no difference in OS, NRM, or CIR among the 3 age groups studied (56 to 60 years, 61 to 65 years, and 66 to 70 years). With regard to physical function tests, we divided the study patients into 2 groups based on the median HGS, KES, and 6MWT values: higher physical function and lower physical function groups. Because there were significant differences in HGS and KES between male and female patients, sex-specific threshold values were used. In a univariate analysis, OS tended to be better in the higher physical function group compared with the lower physical function group (4-year OS, 42.0% versus 32.0% in HGS, P = .14; 44.8% versus 37.8% in KES, P = .17; 46.7% versus 30.5% in 6MWT, P = .099). NRM was significantly lower in the higher physical function group (4-year NRM, 25.5% versus 39.9% in HGS, P = .045; 17.7% versus 38.0% in KES, P = .005; 22.5% versus 43.4% in 6MWT, P = .033). There was no significant difference in CIR between the higher and lower physical function groups (4-year CIR, 34.6% versus 28.7% in HGS, P = .38; 38.5% versus 25.8% in KES, P = .20; 33.0% versus 27.0% in 6MWT, P = .42). In multivariate analysis, the higher KES group (hazard ratio [HR], .54; 95% confidence interval [CI], .32 to .90) was significantly associated with better OS, as were female sex (HR, .48; 95% CI, .26 to .89) and low/intermediate Disease Risk Index (HR, 3.59; 95% CI, 2.04 to 6.31). Higher KES (HR, .37; 95% CI, .17 to .83) and female sex (HR .36; 95% CI, .13 to .998) were significantly associated with a reduced risk of NRM. Higher HGS and higher 6MWT tended to be associated with a reduced risk of NRM, but this trend was not statistically significant. Pretransplantation physical function, particularly the strength of the lower extremities, but not chronological age, is associated with NRM and OS after allogeneic HCT in adults age >55 years.

Substitution of calcineurin inhibitors with corticosteroids after allogeneic hematopoietic cell transplantation.

Combination of calcineurin inhibitors (CIs) with short-term methotrexate is a standard prophylactic regimen for graft-versus-host disease (GVHD). However, it is sometimes difficult to continue CIs due to adverse effects, such as renal impairment and fluid overload. In such cases, we replace CIs with corticosteroids, considering that full dose of CIs is equivalent to prednisolone (PSL) at 1 mg/kg. We retrospectively evaluated the clinical significance of replacement of CIs with corticosteroids after allogeneic hematopoietic cell transplantation (HCT). We evaluated 42 patients switched from CIs to corticosteroids within 90 days among the 479 patients who underwent allogeneic HCT at our center between 2007 and 2019. Renal impairment (n = 33), fluid overload (n = 13), and thrombotic microangiopathy (n = 3) were the main reasons for switching. Although creatinine and body weight returned to baseline at 4 weeks after switching, 100-day non-relapse mortality was high (57.1%). Grade II-IV acute GVHD was seen in 10 (24.4%) patients who did not have it before switching treatment (n = 41). In conclusion, CIs were switched to corticosteroids in patients with severe clinical conditions. The incidence of acute GVHD was acceptable. Although the short-term mortality rate was high, improvement of renal function or fluid overload was observed in a certain proportion of the patients.

The hepatic niche leads to aggressive natural killer cell leukemia proliferation through the transferrin-transferrin receptor 1 axis.

Aggressive natural killer cell leukemia (ANKL) is a rare lymphoid neoplasm frequently associated with Epstein-Barr virus, with a disastrously poor prognosis. Owing to the lack of samples from patients with ANKL and relevant murine models, comprehensive investigation of its pathogenesis including the tumor microenvironment (TME) has been hindered. Here we established 3 xenograft mice derived from patients with ANKL (PDXs), which enabled extensive analysis of tumor cells and their TME. ANKL cells primarily engrafted and proliferated in the hepatic sinusoid. Hepatic ANKL cells were characterized by an enriched Myc-pathway and proliferated faster than those in other organs. Interactome analyses and in vivo CRISPR-Cas9 analyses revealed transferrin (Tf)-transferrin receptor 1 (TfR1) axis as a potential molecular interaction between the liver and ANKL. ANKL cells were rather vulnerable to iron deprivation. PPMX-T003, a humanized anti-TfR1 monoclonal antibody, showed remarkable therapeutic efficacy in a preclinical setting using ANKL-PDXs. These findings indicate that the liver, a noncanonical hematopoietic organ in adults, serves as a principal niche for ANKL and the inhibition of the Tf-TfR1 axis is a promising therapeutic strategy for ANKL.

[Anti-MDA5 antibody-positive rapidly progressive interstitial lung disease after allogeneic hematopoietic cell transplantation successfully treated with triple immunosuppressive therapy].

A 34-year-old man with KMT2A-MLLT1 acute myeloid leukemia in first complete remission underwent allogeneic peripheral blood stem cell transplantation from his HLA-matched sister after conditioning with busulfan/cyclophosphamide. He did not have severe graft-versus-host disease, but he developed interstitial pneumonia six months after transplantation when his oral cyclosporine A (CsA) dose was reduced to 10 mg/day. He was given prednisolone (PSL), which temporarily improved his respiratory condition, but he quickly deteriorated when PSL was reduced. Anti-MDA5 antibody was found to be positive after additional testing, and a three-drug combination of intravenous cyclophosphamide+PSL+CsA was initiated for anti-MDA5 antibody positive rapidly progressive interstitial lung disease, which was effective for interstitial pneumonia. He received a successful living-donor lung transplant from his younger brother and sister. We present a case of rapidly progressive anti-MDA5 antibody positive interstitial lung disease in which the patient's respiratory condition improved after triple therapy and subsequent living-donor lung transplantation.

Clinical features of febrile neutropenia and bloodstream infection in autologous hematopoietic cell transplantation: Comparison to those in intensive chemotherapy for acute myeloid leukemia.

BACKGROUND: In autologous hematopoietic cell transplantation (HCT), myelosuppression and mucosal damage are more severe than those in conventional chemotherapy because of high-dose chemotherapy, but the duration of neutropenia is shorter due to stem cell rescue. METHODS: We retrospectively evaluated febrile neutropenia (FN) and bloodstream infection (BSI) in 208 patients who underwent their first autologous HCT at our institution between 2007 and 2019. They were compared to those in patients who underwent intensive chemotherapy for acute myeloid leukemia (AML) (130 induction/salvage and 191 consolidation). RESULTS: The median neutropenic period in autologous HCT, AML induction/salvage and consolidation was 9, 26.5, and 19 days, respectively. The incidence of FN was 93.8%, 92.3%, and 81.7%, and that of BSI in initial FN was 7.2%, 7.5% and 26.3%, respectively. The incidence of oral mucositis (≥ grade 2) was 63.1%, 9.2% and 12.2%, and that of diarrhea (≥ grade 2) was 53.3%, 9.2% and 6.4%, respectively. Although there were significant differences in the incidence of shaking chills, the degree of fever and the value of CRP between patients with and without BSI in initial FN of AML chemotherapy, no significant risk factors or predictive factors for BSI were identified in autologous HCT. CONCLUSIONS: The profile of infectious complications in autologous HCT was characterized by a high incidence of FN maybe due to mucosal damage. On the other hand, the incidence of BSI was lower compared to that in AML consolidation chemotherapy.

Chronic active Epstein-Bar virus infection complicated by pulmonary artery hypertension.

Chronic active Epstein-Bar virus infection (CAEBV) is known to cause various symptoms. Although pulmonary artery hypertension (PAH) has been reported as a cardiovascular complication of CAEBV, the mechanisms of PAH and the effects of treatment have not been fully elucidated. We experienced 4 adult patients with CAEBV complicated by PAH. All of them received treatment for PAH with a vasodilator followed by chemotherapy with or without allogeneic hematopoietic cell transplantation for CAEBV. In all of these patients, the transtricuspid pressure gradient improved under treatment with vasodilator, and further improvement was observed under treatment for CAEBV in 3 patients. Autopsy was performed in 2 patients, which revealed EBER-positive cells and a change in the pulmonary artery at each stage in the pathology. In conclusion, EBV-infected cells can cause vasculitis and finally PAH. However, PAH complicated with CAEBV can be improved by PAH medication and treatment of CAEBV.

Very early death within 30 days after diagnosis in patients with acute myeloid leukemia.

Acute myeloid leukemia (AML) is a malignancy that requires immediate treatment. However, the factors that predict very early mortality are not well known. We retrospectively analyzed 70 patients who were newly diagnosed with AML at our institution between 2014 and 2020. Very early death within 30 days after the initial consultation with a hematologist occurred in eight patients, including seven men. They were older than 30-day survivors (70.5 vs. 47 years, P < 0.01). In addition, four patients with a low score on the Glasgow Coma Scale (GCS) at diagnosis died within 30 days, and half of the early death group died due to cerebral hemorrhage. We next tried to predict early death using a ROC curve. Age, hemoglobin (Hb), estimated glomerular filtration rate (eGFR) and the international normalized ratio of prothrombin time (PT-INR) all had an area under the curve of greater than 0.8 for predicting very early death. A multivariate analysis revealed that older age (OR = 1.14, P = 0.033), Hb (OR = 0.48, P = 0.05), and low GCS (OR = 140.0, P = 0.0073) were significantly associated with very early death. Further studies will be needed to confirm which patients are at high risk for early death and to improve the treatment strategy for such patients.

Interstitial lung disease with anti-melanoma differentiation-associated gene 5 antibody after allogeneic hematopoietic stem cell transplantation.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody is one of auto-immune antibodies which is associated with a rare subtype of dermatomyositis (DM), and MDA5-DM is well-characterized by rapid progressive interstitial lung disease (ILD) which in part resembles pulmonary complications after allogeneic hematopoietic cell transplantation (allo-HCT). However, previous studies about anti-MDA5 antibody after allo-HCT were extremely limited. Here, we present 4 cases of ILD with anti-MDA5 antibody after allo-HCT. All of the cases showed rapidly progressive clinical course and 3 of 4 cases died despite intensive immunosuppressive therapies which included prednisolone, cyclophosphamide and calcineurin inhibitor. Additionally, 3 of 4 cases had tested positive for anti-MDA5 antibody by using cryopreserved plasma which were collected about 2-3 months before the diagnosis of MDA5-DM-ILD. It suggests that an inflammatory condition due to MDA5-DM-ILD might have sub-clinically occurred before the development of respiratory failure. The current cases suggest that the clinical feature was relatively similar to classical MDA5-DM-ILD, although it is difficult to distinguish MDA5-DM-ILD from chronic GVHD and other pulmonary complications after allo-HCT. Since clinical courses of MDA5-DM-ILD is considerably aggressive, it is important to discriminate MDA5-DM-ILD from other complications after allo-HCT.

Pancreatic atrophy and recovery after allogeneic hematopoietic cell transplantation.

BACKGROUND: Pancreatic atrophy after allogeneic hematopoietic cell transplantation (HCT) is one of the symptoms associated with chronic graft-versus-host disease (GVHD). Although pancreatic atrophy has been considered to cause exocrine insufficiency and weight loss, it is not yet clear what kinds of recipients can be expected to recover their body weight (BW) or pancreatic thickness. In addition, the effect of pancreatic atrophy on the prognosis has not been clarified. METHODS: We retrospectively analyzed 170 recipients who received allogeneic bone marrow transplantation or peripheral blood stem cell transplantation, and evaluated them using the CT scan images obtained closest to 1, 2, 3, and 4 years after HCT. RESULTS: Fifty-five recipients (32.4%) demonstrated pancreatic atrophy, and 11 (20%) of them recovered their pancreatic thickness. While recipients without pancreatic atrophy gradually recovered their BW (P < 0.001), those with atrophy did not (P = 0.12). Moderate and severe chronic GVHD tended to be slightly more common in the atrophy group (47.3% vs 38.3%), whereas the pancreatic thickness tended to recover in these recipients (30.8% vs 10.3%). HCT from a female donor to a male recipient showed superior pancreatic recovery compared to other donor and recipient sex combinations. Pancreatic atrophy treated as a significantly associated with inferior survival (HR 4.91, P < 0.001) and an increased risk of non-relapse mortality (HR 8.75, P < 0.001). CONCLUSIONS: These results suggest that it is important to monitor pancreatic thickness after HCT. Further prospective investigations are warranted to clarify the significance of pancreatic atrophy on clinical outcomes.

Low-Intensity Immunosuppressive Therapy for Chronic Graft-versus-Host Disease.

In general, the initial systemic treatment for chronic graft-versus-host disease (cGVHD) is 0.5 to 1 mg/kg of prednisolone (PSL). However, patients without high-risk features are sometimes treated with a calcineurin inhibitor (CI) or PSL at lower doses. Here we retrospectively evaluated patients with cGVHD who were treated with low-intensity immunosuppressive therapy (IST), defined as CI with or without PSL at <.25 mg/kg. The primary outcome was failure-free survival (FFS), and we evaluated current FFS (cFFS) considering the state transition between low-intensity IST and high-intensity IST defined as the administration of >.25 mg/kg of PSL or immunosuppressants other than CI or PSL. Fifty-four patients were evaluated, few of whom had a low performance status and intestinal or lung involvement. FFS at 24 months after treatment was 50.0% (95% confidence interval [CI], 36.0% to 62.3%). Risk factors for failure were use of IST before 6 months post-transplantation (hazard ratio [HR], 2.16; 95% CI, 1.05 to 2.16; P = .036) and transplantation from a female donor to a male recipient (HR, 2.65; 95% CI, 1.29 to 5.48; P = .008). At 6 months, 44.0% of patients had achieved a complete or partial response without a change in treatment. cFFS at 36 months was 67.0% (95% CI, 51.8 to 79.4%), which was greater than simple FFS (43.2%; 95% CI, 36.6% to 52.8%). There was no difference in simple FFS according to the National Institutes of Health global score. However, cFFS at 3 years varied according to the global score (mild, 91.7%; moderate, 64.0%; severe, 43.8%; P = .036). Low-intensity IST for cGVHD was effective in patients without high-risk features.

Successful Treatment of the TEMPI Syndrome with Pomalidomide Plus Dexamethasone Followed by Autologous Stem Cell Transplantation.

TEMPI syndrome is a rare disease associated with plasma cell neoplasms. Although previous studies have reported that bortezomib is effective as a first-line treatment for TEMPI syndrome, some cases are refractory to this treatment. Pomalidomide, a kind of immunomodulatory drug, is widely used for the treatment of relapsed or refractory multiple myeloma and could be administered without dose modification in patients with renal dysfunction. We present a case of bortezomib-refractory TEMPI syndrome with renal insufficiency that was successfully treated with a combination of pomalidomide and low-dose dexamethasone with minimal adverse effects, followed by autologous hematopoietic stem cell transplantation (ASCT). To the best of our knowledge, this is the first case of TEMPI syndrome that was successfully treated with pomalidomide. Pomalidomide may be suitable for patients who do not respond to a proteasome inhibitor-based treatment. In addition, a subsequent ASCT could also be effective for achieving a further treatment response.

Comparison of the impact of two post-remission therapy regimens on cardiac events in acute myeloid leukemia patients undergoing allogeneic hematopoietic stem cell transplantation.

High-dose cytarabine (HD-AraC) or anthracycline-containing chemotherapies are used as post-remission therapy for acute myeloid leukemia (AML) patients. However, it remains unclear which regimen would be better as post-remission therapy before allogeneic hematopoietic stem cell transplantation (allo-HSCT). Thus, we compared the incidence of cardiac events and event-free survival (EFS) after allo-HSCT at two Japanese hospitals between HD-AraC and anthracycline-containing post-remission therapy to clarify the safety of post-remission therapy. Of a total of 132 patients, 68 received HD-AraC (HD-AraC group) and 64 received anthracycline-containing chemotherapy (ANT group). HD-AraC was preferentially selected for core-binding factor AML patients (p = 0.008). The median cumulative anthracycline dose was 115.2 mg/m2 in the HD-AraC group and 318.7 mg/m2 in the ANT group (p < 0.0001). Cardiac events were observed in 18 (13.6%) patients during the follow-up period. The 3-year cumulative incidence of cardiac events was 9.1% in the HD-AraC group and 11.0% in the ANT group (p = 0.70). EFS at 3 years after allo-HSCT was 40.9% in the HD-AraC group and 39.6% in the ANT group (p = 0.51). In conclusion, incidence of cardiac events did not differ significantly between post-remission therapy regimens in AML patients who underwent allo-HSCT.

Risk factors and outcomes of definite or clinical idiopathic pneumonia syndrome after allogeneic hematopoietic stem cell transplantation.

Idiopathic pneumonia syndrome (IPS) is a fatal pulmonary complication after allogeneic hematopoietic stem cell transplantation (allo-HCT). However, it is often difficult to diagnose IPS, since a considerable number of IPS patients are critically ill, which makes it difficult for them to undergo bronchoscopy. In this study, we explored the risk factors of IPS based on two definitions. Definite IPS was diagnosed based on the results of bronchoscopy, whereas clinical IPS was diagnosed based on the clinical condition and bronchoscopy was not mandatory. Among 444 allo-HCT recipients at our center, 30 definite IPS and 54 clinical IPS were identified. In a multivariable analysis, a high ferritin level was associated with a higher incidence of definite IPS, whereas clinical IPS was frequently associated with older age, MAC, high ferritin level, low %DLCO and second allo-HCT due to graft failure. These risk factors may contribute to the accurate and early diagnosis of IPS.

Comparison of cryoprotectants in hematopoietic cell infusion-related adverse events.

BACKGROUND: The standard cryoprotectant for human cellular products is dimethyl sulfoxide (DMSO), which is associated with hematopoietic cell infusion-related adverse events (HCI-AEs) in hematopoietic stem cell transplantation including peripheral blood stem cell (PBSC) transplantation (PBSCT). DMSO is often used with hydroxyethyl starch (HES), which reduces DMSO concentration while maintaining the postthaw cell recovery. The cryoprotectant medium CP-1 (Kyokuto Pharmaceutical Industrial) is widely used in Japan. After mixture of a product with CP-1, DMSO and HES concentrations are 5% and 6%, respectively. However, the safety profile of CP-1 in association with HCI-AEs has not been investigated. STUDY DESIGN AND METHODS: To compare CP-1 with other cryoprotectants, we conducted a subgroup analysis of PBSCT recipients in a prospective surveillance study for HCI-AEs. Moreover, we validated the toxicity of CP-1 in 90 rats following various dose administration. RESULTS: The PBSC products cryopreserved with CP-1 (CP-1 group) and those with other cryoprotectants, mainly 10% DMSO (non-CP-1 group), were infused into 418 and 58 recipients, respectively. The rate of ≥grade 2 HCI-AEs was higher in the CP-1 group, but that of overall or ≥grade 3 HCI-AEs was not significantly different, compared to the non-CP-1 group. Similarly, after propensity score matching, ≥grade 2 HCI-AEs were more frequent in the CP-1 group, but the ≥grade 3 HCI-AE rate did not differ significantly between the groups. No significant toxicity was detected regardless of the CP-1 dose in the 90 rats. CONCLUSIONS: Infusion of a CP-1-containing PBSC product is feasible with the respect of HCI-AEs.

Prognostic impact of chromosomal changes at relapse after allogeneic hematopoietic cell transplantation for acute myeloid leukemia or myelodysplastic syndrome.

Chromosome analysis is a powerful prognostic tool in myeloid malignancies. Recipients who experience relapse after allogeneic hematopoietic cell transplantation (allo-HCT) often show chromosomal changes between diagnosis and relapse. However, the clinical impact of chromosomal changes and the efficacy of post-relapse treatment according to chromosomal changes have not been fully investigated. We retrospectively analyzed 72 recipients who had experienced relapse after allo-HCT for acute myeloid leukemia or myelodysplastic syndrome. We categorized them into two groups: with or without clonal chromosomal changes at relapse after allo-HCT. Post-relapse survival was shorter in the clonal chromosomal change group (median 117 days vs 275 days, P = 0.019). Moreover, acquisition of chromosome 7 abnormality or complex changes tended to be associated with inferior survival in a univariate analysis (median 92 days vs median 173 days, P = 0.043), and this adverse impact was confirmed in a multivariate analysis (hazard ratio 2.07, P = 0.024). The patterns of chromosomal changes from diagnosis to relapse after allo-HCT were heterogenous, and further investigations are required to clarify the effect of individual chromosomal changes.

Autologous or allogeneic hematopoietic cell transplantation for relapsed or refractory PTCL-NOS or AITL.

Fit patients with peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL) in relapsed or refractory (R/R) disease status often receive salvage chemotherapy followed by autologous hematopoietic stem cell transplantation (autoHCT) or allogeneic HCT (alloHCT). However, there is no consensus on the type of HCT that should be applied for such patients. Herein, we retrospectively evaluated the survival outcome of 760 adult R/R PTCL-NOS or AITL patients who underwent the first HCT. Among them, 318 relapsed after first remission (REL) and 442 were refractory to the primary therapy (PIF). The 4-year overall survival (OS) of autoHCT and alloHCT was 50 and 50% for REL patients, and 52 and 49% for PIF patients, respectively. In the multivariable analysis, alloHCT tended to be associated with better progression-free survival (PFS) in REL (hazard ratio [HR] 0.74; 95% confidence interval [CI]: 0.53-1.03), and significantly better PFS in PIF (HR 0.64; 95% CI: 0.46-0.88) compared with autoHCT. The subgroup analysis with propensity-score matching showed that alloHCT was associated with better OS for REL-sensitive and PIF-nonremission disease. This study suggested that the advantage of alloHCT for R/R PTCL-NOS or AITL is different, depending on the disease status at HCT.

Deletion of Y chromosome before allogeneic hematopoietic stem cell transplantation in male recipients with female donors.

The graft-versus-leukemia (GVL) effect is one of the curative mechanisms of allogeneic hematopoietic stem cell transplantation (allo-HCT). H-Y antigens, which are encoded by Y chromosome, are important targets of the GVL effect. Thus, deletion of the Y chromosome (del[Y]) might cause the GVL effect to deteriorate in a transplantation involving a female donor and male recipient, although the clinical significance of the del(Y) group remains to be elucidated. In this study, we evaluated adult male patients who underwent allo-HCT between 2010 and 2019 in Japan. There were 155 cases in the del(Y) group and 4149 cases without del(Y) who underwent female-to-male allo-HCT. Del(Y) was significantly associated with inferior overall survival (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.00-1.53; P = .049) and an increased risk of relapse (HR, 1.40; 95% CI, 1.08-1.80; P = .0098) in multivariate analyses. There was no significant difference in nonrelapse mortality between recipients with and without del(Y) (HR, 1.08; 95% CI, 0.769-1.51; P = .67). In contrast, del(Y) was not significantly associated with any clinical outcomes in the cohort of male-to-male allo-HCT. A higher incidence of relapse might have been caused by attenuation of the GVL effect resulting from a lack of H-Y antigens. Because a GVL effect resulting from sex mismatch may not be expected in men with del(Y) who undergo allo-HCT with a female donor, additional post-allo-HCT strategies might be required to prevent disease relapse.

Emergence of clone with PHF6 nonsense mutation in chronic myelomonocytic leukemia at relapse after allogeneic HCT.

Disease relapse is a major cause of treatment failure after allogeneic hematopoietic cell transplantation (HCT) and the mechanisms of relapse remain unclear. We encountered a 58-year-old man with chronic myelomonocytic leukemia (CMML) that relapsed after haploidentical HCT from his daughter. Peripheral blood samples collected at HCT and at relapse were analyzed, and CD14+/CD16- monocytes that typically accumulate in CMML were isolated by flow cytometry. Whole-exome sequencing of the monocytes revealed 8 common mutations in CMML at HCT. In addition, a PHF6 nonsense mutation not detected at HCT was detected at relapse. RNA sequencing could not detect changes in expression of HLA or immune-checkpoint molecules, which are important mechanisms of immune evasion. However, gene set enrichment analysis (GSEA) revealed that a TNF-α signaling pathway was downregulated at relapse. Ubiquitination of histone H2B at lysine residue 120 (H2BK120ub) at relapse was significantly decreased at the protein level, indicating that PHF6 loss might downregulate a TNF-α signaling pathway by reduction of H2BK120ub. This case illustrates that PHF6 loss contributes to a competitive advantage for the clone under stress conditions and leads to relapse after HCT.