Calcineurin inhibitor inhibits tolerance induction by suppressing terminal exhaustion of donor T cells after allo-HCT.

Calcineurin inhibitor-based graft-versus-host disease (GVHD) prophylaxis is standard in allogeneic hematopoietic stem cell transplantation (HCT) but fails to induce long-term tolerance without chronic GVHD (cGVHD) in a considerable number of patients. In this study, we addressed this long-standing question in mouse models of HCT. After HCT, alloreactive donor T cells rapidly differentiated into PD-1+ TIGIT+ terminally exhausted T cells (terminal Tex). GVHD prophylaxis with cyclosporine (CSP) suppressed donor T-cell expression of TOX, a master regulator to promote differentiation of transitory exhausted T cells (transitory Tex), expressing both inhibitory receptors and effector molecules, into terminal Tex, and inhibited tolerance induction. Adoptive transfer of transitory Tex, but not terminal Tex, into secondary recipients developed cGVHD. Transitory Tex maintained alloreactivity and thus PD-1 blockade restored graft-versus-leukemia (GVL) activity of transitory Tex and not terminal Tex. In conclusion, CSP inhibits tolerance induction by suppressing the terminal exhaustion of donor T cells, while maintaining GVL effects to suppress leukemia relapse.

Follow-up of patients with R/R FLT3-mutation-positive AML treated with gilteritinib in the phase 3 ADMIRAL trial.

The phase 3 ADMIRAL (NCT02421939; Study ID: 2215-CL-0301) trial showed superior overall survival in patients with relapsed/refractory FLT3-mutation-positive acute myeloid leukemia (AML) randomized 2:1 to receive the oral FMS-like tyrosine kinase 3 inhibitor gilteritinib vs those randomized to receive salvage chemotherapy (SC). Here we provide a follow-up of the ADMIRAL trial 2 years after the primary analysis to clarify the long-term treatment effects and safety of gilteritinib in these patients with AML. At the time of this analysis, the median survival follow-up was 37.1 months, with deaths in 203 of 247 and 97 of 124 patients in the gilteritinib and SC arms, respectively; 16 gilteritinib-treated patients remained on treatment. The median overall survival for the gilteritinib and SC arms was 9.3 and 5.6 months, respectively (hazard ratio, 0.665; 95% confidence interval [CI], 0.518, 0.853; two-sided P = .0013); 2-year estimated survival rates were 20.6% (95% CI, 15.8, 26.0) and 14.2% (95% CI, 8.3, 21.6). The gilteritinib-arm 2-year cumulative incidence of relapse after composite complete remission was 75.7%, with few relapses occurring after 18 months. Overall, 49 of 247 patients in the gilteritinib arm and 14 of 124 patients in the SC arm were alive for ≥2 years. Twenty-six gilteritinib-treated patients remained alive for ≥2 years without relapse; 18 of these patients underwent transplantation (hematopoietic stem cell transplantation [HSCT]) and 16 restarted gilteritinib as post-HSCT maintenance therapy. The most common adverse events of interest during years 1 and 2 of gilteritinib therapy were increased liver transaminase levels; adverse event incidence decreased in year 2. Thus, continued and post-HSCT gilteritinib maintenance treatment sustained remission with a stable safety profile. These findings confirm that prolonged gilteritinib therapy is safe and is associated with superior survival vs SC. This trial was registered at www.clinicaltrials.gov as #NCT02421939.

Hereditary thrombocythemia due to splicing donor site mutation of THPO in a Japanese family.

Thrombopoietin (THPO) is an essential factor for platelet production. Hereditary thrombocythemia (HT) is caused by a germline mutation of THPO, MPL, or JAK2 and is inherited in an autosomal-dominant manner. We identified a Japanese family with HT due to a point mutation of the splicing donor site of the THPO gene (THPO c.13 + 1G > A). Bone marrow biopsy showed increased megakaryocytes mimicking essential thrombocythemia. One affected family member developed chronic myeloid leukemia. We cloned the mutation and developed mutated and wild type THPO expression vectors. Molecular analysis showed that the mutation causes an exon 3 skipping transcript of THPO that abrogates a suppressive untranslated upstream open reading frame. Although the transcript levels of THPO mRNA were comparable, mutated transcripts were more efficiently translated and THPO protein expression was significantly higher than that of the wild type.

Impact of the Covid-19 pandemic and ensuing online teaching on pre-clinical medical education.

BACKGROUND: Major disruptions and changes in education have occurred worldwide as a result of the coronavirus disease (COVID-19) pandemic and the ensuing shift from in-person to online education. However, the effect of such changes on medical education, its magnitude, and the learning domains impacted by such rapid changes have not been adequately addressed, particularly with regard to objective assessment approaches. METHODS: Second-year medical students enrolled in our Medical English Course between 2019 and 2021 were recruited from Hokkaido University, Japan (N = 321) to participate in this study. We evaluated the potential impact of teaching styles on the academic performance of students before (2019; face-to-face) and during (2020; online; 2021; in-person and online) the pandemic. We examined the potential effect of three teaching styles--in-person (2019), online (2020), and a combination of these (2021) on the academic performance of medical students using: (i) subjective assessment of self-reported general English skills, including reading, writing, listening, and speaking; and (ii) objective assessment of medical terminology scores, evidence-based medicine (EBM) skills, and final written exam scores. RESULTS: In-person education significantly improved listening and speaking skills in 2019 (p < 0.001). This trend was observed for writing skills in an online course in 2020 (p = 0.001). With the combined teaching method, students reported significant improvements in all four English skills. In our objective assessments, medical terminology improved significantly post-test versus pre-test for all three teaching styles, and we found that the online course did not adversely affect the gain in medical terminology knowledge during the course. Additionally, we did not find any significant differences across the three applied teaching styles regarding EBM skill levels. It is noteworthy that the students taking online courses had a significantly higher final exam score (mean ± SD; 82.8 ± 8.2) than in in-person (78.6 ± 8.8) and combined (79.7 ± 12.1) teaching styles. CONCLUSIONS: In our study, the online/combined courses showed better academic outcomes compared to the face-to-face course in the preclinical clerkship. Although the current results need to be replicated on a larger scale, online/combined courses can continue and evolve in the post-pandemic education of medical students. Medical schools and institutions should consider incorporating such courses, especially combined courses, into their curricula in the future to improve the effectiveness, accessibility, and flexibility of medical education.

Prognostic factors in patients in the terminal phase of haematological malignancies who are receiving home medical care.

Although there are many prognostic models for patients in the terminal phase of solid tumours, a reliable prognostic scoring system in patients in the terminal phase of haematological malignancies (HM) has not been established. We retrospectively evaluated 180 patients in the terminal phase of HM who were receiving home medical care (HMC). Multivariate analyses revealed that clinician's estimate, consciousness, loss of appetite, dyspnoea, neutrophil count, lymphocyte count, and lactate dehydrogenase were associated with overall survival (OS). Based on this result, we developed a novel prognostic scoring system, the Japan palliative haematological oncology prognostic estimates, in which four risk groups were shown to clearly differ in survival (p < 0.001): a low-risk group (n = 41, median OS of 434 days), an intermediate-low-risk group (n = 80, median OS of 112 days), an intermediate-high-risk group (n = 38, median OS of 31.5 days), and a high-risk group (n = 21, median OS of 10 days). This is the first investigation of prognostic factors that influence the OS of patients in the terminal phase of HM who are receiving HMC. Providing patients with reliable information about their prognosis is important for them to consider how to spend their remaining life.

Humoral response to mRNA-based COVID-19 vaccine in patients with immune thrombocytopenia.

Data for COVID-19 vaccine response in patients with immune thrombocytopenia (ITP) are very limited. In a study of 28 patients with ITP, anti-severe acute respiratory syndrome coronavirus 2 spike antibody titres were measured after vaccination. The seroconversion rate for ITP patients was 91.3%, comparable to that in healthy controls (HCs). However, the antibody titre in ITP patients was significantly lower than that in HCs and declined with ageing. Furthermore, the antibody titre in ITP patients who received a minimum prednisolone dose of at least 5 mg/day at any time-point at or after initial vaccination was lower than that in other patients.

Subclinical minute FLT3-ITD clone can be detected in clinically FLT3-ITD-negative acute myeloid leukaemia at diagnosis.

Recent advances in next-generation sequencing (NGS) have enabled the detection of subclinical minute FLT3-ITD. We selected 74 newly diagnosed, cytogenetically normal acute myeloid leukaemia (AML) samples in which FLT3-ITD was not detected by gel electrophoresis. We sequenced them using NGS and found minute FLT3-ITDs in 19 cases. We compared cases with clinically relevant FLT3-ITD (n = 37), cases with minute FLT3-ITD (n = 19) and cases without detectable FLT3-ITD (n = 55). Molecular characteristics (location and length) of minute FLT3-ITD were similar to those of clinically relevant FLT3-ITD. Survival of cases with minute FLT3-ITD was similar to that of cases without detectable FLT3-ITD, whereas the relapse rate within 1 year after onset was significantly higher in cases with minute FLT3-ITD. We followed 18 relapsed samples of cases with clinically FLT3-ITD-negative at diagnosis. Two of 3 cases with minute FLT3-ITD relapsed with progression to clinically relevant FLT3-ITD. Two of 15 cases in which FLT3-ITD was not detected by NGS relapsed with the emergence of minute FLT3-ITD, and one of them showed progression to clinically relevant FLT3-ITD at the second relapse. We revealed the clonal dynamics of subclinical minute FLT3-ITD in clinically FLT3-ITD-negative AML. Minute FLT3-ITD at the initial AML can expand to become a dominant clone at relapse.

Humoral response to mRNA-based COVID-19 vaccine and booster effect of a third dose in patients with mature T cell and NK-cell neoplasms.

Patients with lymphoid malignancies have impaired humoral immunity caused by the disease itself and its treatment, placing them at risk for severe coronavirus disease-19 (COVID-19) and reduced response to vaccination. However, data for COVID-19 vaccine responses in patients with mature T cell and NK-cell neoplasms are very limited. In this study of 19 patients with mature T/NK-cell neoplasms, anti-severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike antibodies were measured at 3 months, 6 months, and 9 months after the second mRNA-based vaccination. At the time of the second and third vaccinations, 31.6% and 15.4% of the patients were receiving active treatment. All patients received the primary vaccine dose and the third vaccination rate was 68.4%. In patients with mature T/NK-cell neoplasms, both seroconversion rate (p < 0.01) and antibody titers (p < 0.01) after the second vaccination were significantly lower than those in healthy controls (HC). In individuals who received the booster dose, patients had significantly lower antibody titers than those in HC (p < 0.01); however, the seroconversion rate in patients was 100%, which was the same as that in HC. The booster vaccine resulted in a significant increase of antibodies in elderly patients who had shown a response that was inferior to that in younger patients after two doses of vaccination. Since higher antibody titers and higher seroconversion rate reduced the incidence of infection and mortality, vaccination more than three times may have the advantage for patients with mature T/NK-cell neoplasms, especially in elderly patients. Clinical trial registration number: UMIN 000,045,267 (August 26th, 2021), 000,048,764 (August 26th, 2022).

Dominant-negative type of IKZF1 deletion showed a favorable prognosis in adult B-cell acute lymphoblastic leukemia.

IKZF1 deletion is a recurrent genomic alteration in B-cell acute lymphoblastic leukemia (B-ALL) and is divided into dominant-negative (DN) and loss of function (LOF) deletions. The prognostic impact of each deletion has not been fully elucidated. We retrospectively analyzed 117 patients with adult B-ALL including 60 patients with BCR::ABL1-positive B-ALL and 57 patients with BCR::ABL1-negative B-ALL by the fluorescence in situ hybridization (FISH) method for IKZF1 deletion and multiplex PCR for the 4 most common IKZF1 deletions (∆4-7, ∆2-7, ∆2-8, and ∆4-8). Samples, in which IKZF1 deletion was detected by FISH but a specific type of deletion was not identified by the PCR, were categorized as "other." Patients were classified into a DN group that had at least 1 allele of ∆4-7 (n = 23), LOF and other group (n = 40), and wildtype group (n = 54). DN type IKZF1 deletions were found in 33.3% of BCR::ABL1-positive cases and 5.2% of BCR::ABL1-negative cases. LOF and other type IKZF1 deletions were found in 43.4% of BCR::ABL1-positive cases and 24.6% of BCR::ABL1-negative cases. Patients with the DN group showed significantly higher overall survival (OS) than that of the LOF and other and WT groups (P = 0.011). Multivariate analysis including age, WBC counts, complex karyotype, and DN type IKZF1 deletion showed that the DN type of IKZF1 deletion (HR = 0.22, P = 0.013) had a positive impact and age ≥ 65 (HR = 1.92, P = 0.029) had a negative impact on OS. The prognostic impact of IKZF1 deletion depends on the type of deletion and DN type of IKZF1 deletion showed better prognosis in adult B-ALL patients.Clinical trial registration This study was part of a prospective observational study (Hokkaido Leukemia Net, UMIN000048611). It was conducted in compliance with ethical principles based on the Helsinki Declaration and was approved by the institutional review board of Hokkaido University Hospital (#015-0344).

Clinical implications of NUP98::NSD1 fusion at diagnosis in adult FLT3-ITD positive AML.

OBJECTIVES: The cryptic fusion oncogene NUP98::NSD1 is known to be associated with FLT3-ITD mutation in acute myeloid leukemia (AML), and an independent poor prognostic factor in pediatric AML. However, there are little data regarding the clinical significance of NUP98::NSD1 in adult cohort. METHODS: We conducted a multicenter retrospective study to investigate the prevalence, clinical characteristics, and prognostic impact of NUP98::NSD1 in adult FLT3-ITD-positive AML patients. RESULTS: In a total of 97 FLT3-ITD-positive AML patients, six cases (6.2%) were found to harbor the NUP98::NSD1 fusion transcript. NUP98::NSD1 positive cases had significantly higher platelet counts and a higher frequency of FAB-M4 morphology than NUP98::NSD1 negative cases. NUP98::NSD1 was found to be mutually exclusive with NPM1 mutation, and was accompanied by the WT1 mutation in three of the six cases. The presence of NUP98::NSD1 fusion at the time of diagnosis predicted poor response to cytarabine-anthracycline-based intensive induction chemotherapy (induction failure rate: 83% vs. 36%, p = .038). Five of the six cases with NUP98::NSD1 underwent allogeneic hematopoietic stem cell transplantation (HSCT). Two of the five cases have successfully maintained remission, with one of them being rescued through a second HSCT. CONCLUSIONS: Detecting NUP98::NSD1 in adult FLT3-ITD-positive AML is crucial to recognizing chemotherapy-resistant group.

Safety and efficacy of tisagenlecleucel in patients with relapsed or refractory B-cell lymphoma: the first real-world evidence in Japan.

BACKGROUND: Tisagenlecleucel, an autologous CD19-directed T-cell immunotherapy, can induce a durable response in adult patients with relapsed/refractory (r/r) B-cell lymphoma. METHODS: To elucidate the outcome of chimeric antigen receptor (CAR) T-cell therapy in Japanese, we retrospectively analyzed the outcomes of 89 patients who received tisagenlecleucel for r/r diffuse large B-cell lymphoma (n = 71) or transformed follicular lymphoma (n = 18). RESULTS: With a median follow-up of 6.6-months, 65 (73.0%) patients achieved a clinical response. The overall survival (OS) and event-free survival (EFS) rates at 12 months were 67.0% and 46.3%, respectively. Overall, 80 patients (89.9%) had cytokine release syndrome (CRS), and 6 patients (6.7%) had a grade ≥ 3 event. ICANS occurred in 5 patients (5.6%); only 1 patient had grade 4 ICANS. Representative infectious events of any grade were cytomegalovirus viremia, bacteremia and sepsis. The most common other adverse events were ALT elevation, AST elevation, diarrhea, edema, and creatinine elevation. No treatment-related mortality was observed. A Sub-analysis showed that a high metabolic tumor volume (MTV; ≥ 80 ml) and stable disease /progressive disease before tisagenlecleucel infusion were both significantly associated with a poor EFS and OS in a multivariate analysis (P < 0.05). Notably, the combination of these 2 factors efficiently stratified the prognosis of these patients (HR 6.87 [95% CI 2.4-19.65; P < 0.05] into a high-risk group). CONCLUSION: We report the first real-world data on tisagenlecleucel for r/r B-cell lymphoma in Japan. Tisagenlecleucel is feasible and effective, even in late line treatment. In addition, our results support a new algorithm for predicting the outcomes of tisagenlecleucel.

Phase I study of alvocidib plus cytarabine/mitoxantrone or cytarabine/daunorubicin for acute myeloid leukemia in Japan.

Therapeutic improvements are needed for patients with acute myeloid leukemia (AML), particularly those who have relapsed or who have treatment-refractory (R/R) AML or newly diagnosed patients with poor prognostic factors. Alvocidib (DSP-2033), a potent cyclin-dependent kinase 9 inhibitor, has previously demonstrated promising clinical activity for the treatment of AML. In this multicenter, open-label, uncontrolled, 3 + 3 phase I study, we investigated the safety and tolerability of alvocidib administered in combination with either cytarabine and mitoxantrone (ACM) for R/R AML or cytarabine/daunorubicin (A + 7 + 3) for newly diagnosed AML. Alvocidib was administered to all patients as a 30-min intravenous (i.v.) bolus (30 mg/m2 /d), followed by a continuous i.v. infusion over 4 h on days 1-3 (60 mg/m2 /d). A total of 10 patients were enrolled: six received ACM (at two dose levels of cytarabine and mitoxantrone) and four received A + 7 + 3. Alvocidib was tolerated and no dose-limiting toxicities were observed. All patients experienced adverse events, of which diarrhea was the most frequent (100%); hematologic events were also common. Alvocidib concentration peaked at the end of dosing (4.5 h after start of administration), plasma accumulation after repeated dosing was minimal and urinary excretion was negligible. The rate of complete remission/complete remission with incomplete hematologic recovery was 66.7% with the ACM regimen in R/R AML, including four complete remission (median duration 13.6 months), and 75% (three complete remission) with the A + 7 + 3 regimen. Further development of alvocidib in hematologic malignancies is warranted. The trial is registered with Clinicaltrials.gov, NCT03563560.

Humoral response to mRNA-based COVID-19 vaccine in patients with myeloid malignancies.

Data on the response to the COVID-19 vaccine in patients with myeloid malignancy, who are at severe risk in case of infection, have not emerged. In a study of 69 patients with myeloid malignancies, including 46 patients with acute myeloid leukaemia (AML) and 23 patients with myelodysplastic syndrome (MDS), anti-spike SARS-CoV-2 antibody titres were measured 3 months after the second mRNA-based vaccination. Seroconversion rates for AML and MDS were 94.7% and 100% respectively, with no significant difference from healthy controls (HCs). Patients with MDS showed a significantly lower antibody titre than that in HCs or AML patients. In AML patients, the antibody titres were comparable to those in HCs when treatment was completed, but lower in patients under maintenance therapy. The response to COVID-19 vaccine appears to be related to disease and treatment status. Patients with myeloid malignancies may be more responsive to vaccines than patients with lymphoid malignancies.

Dynamic change in peripheral blood WT1 mRNA levels within three cycles of azacitidine predict treatment response in patients with high-risk myelodysplastic syndromes.

Azacitidine (AZA) improves overall survival (OS) in patients with high-risk myelodysplastic syndromes (MDS). However, predictive factors for response to AZA remain largely unknown. To elucidate whether dynamic change in peripheral blood (PB) Wilms' Tumor 1 (WT1) mRNA levels could predict response to AZA, we retrospectively identified 75 treatment-naïve patients with high-risk MDS who received at least 3 cycles of AZA. We classified patients into 4 groups, low-increase (LI), low-stable (LS), high-decrease (HD), and high-stable (HS) based on the dynamic change in PB WT1 mRNA levels within 3 cycles of AZA. Cumulative incidence of overall response after 10 cycles of AZA was significantly higher in LS/HD than in HS/LI (75.5% vs 4.5%, P < 0.001). The median OS for LS/HD was 18.2 months (95% CI, 12.8-28.1 months), whereas it was 11.6 months for HS/LI (95% CI, 6.6-14.1 months; P < 0.001). Multivariate analysis demonstrated that poor-/very poor-IPSS-R cytogenetic risk and HS/LI were independently associated with poor OS (poor-/very poor-IPSS-R cytogenetic risk: HR, 2.26; 95% CI, 1.10-4.68, P = 0.03, HS/LI: HR, 2.32; 95% CI, 1.21-4.46, P = 0.01). Patients with HS/LI did not show any further response to continuous AZA, and they should be considered for alternative therapy from earlier cycles.

[Bing-Neel syndrome successfully treated with tirabrutinib].

Bing-Neel syndrome (BNS) is a rare disease manifestation of Waldenström's macroglobulinemia characterized by abnormal lymphoplasmacytoid cells infiltration of the central nervous system. In September 2019, a 46-year-old man presented to a previous hospital with hand tremors, nausea, and dysuria. Demyelination of cerebral white matter and the spinal cord was discovered using MRI. Steroid pulse therapy was used to treat inflammatory demyelinating disease, and it provided temporary relief, but the symptoms returned when the steroids were stopped. He was referred to our hospital in June 2020, for further evaluation with the possibility of hematological malignancy. BNS was diagnosed based on the presence of abnormal lymphoplasmacytoid cells in the bone marrow and cerebrospinal fluid (CSF), as well as the presence of the MYD88L265P mutation in the CSF specimen. In July 2020, BR (bendamustine, rituximab) therapy was administered, but it was ineffective. Oral administration of tirabrutinib, which was recently approved for WM, began in August 2020. He has achieved long-term remission and steroid withdrawal, with no notable side effects. This is the second report of successful treatment of BNS with tirabrutinib. More research is needed to confirm tirabrutinib's efficacy in the treatment of BNS.

High lymphocyte counts before antithymocyte globulin administration predict acute graft-versus-host disease.

Antithymocyte globulin (ATG) reduces severe acute and chronic graft-versus-host disease (GVHD) in allogeneic peripheral blood stem cell transplantation (PBSCT). However, risk factors for severe acute GVHD in PBSCT using ATG remain to be determined. We conducted a single-center, retrospective study to analyze the association of acute GVHD requiring systemic corticosteroid (SC-aGVHD) with absolute lymphocyte counts (ALC) before the administration of ATG or conditioning in 53 patients with HLA-matched PBSCT using low-dose thymoglobulin (2 mg/kg) after myeloablative conditioning. The cumulative incidence of SC-aGVHD was 17.0% and ALC before ATG were significantly higher in patients with SC-aGVHD compared to that in patients without it (median, 0.15 × 109/L vs 0.06 × 109/L, P = 0.047). The cumulative incidence of SC-aGVHD was significantly higher in patients with high ALC before ATG (≥ 0.15 × 109/L) than in those with low ALC (38.5% vs 10.0%, P = 0.016). Non-relapse mortality (NRM) was also significantly higher in the high ALC before ATG group than the low ALC before ATG group (2-year NRM: 23.9% vs 6.0%, P = 0.048), leading to worse survival (2-year overall survival: 69.2% vs 83.5%, P = 0.039). Our study suggested that high ALC before ATG is a risk factor for SC-aGVHD.

Gilteritinib versus chemotherapy in Japanese patients with FLT3-mutated relapsed/refractory acute myeloid leukemia.

BACKGROUND: Until recently, no effective targeted therapies for FLT3-mutated (FLT3mut+) relapsed/refractory (R/R) acute myeloid leukemia (AML) were available in Japan. The FLT3 inhibitor, gilteritinib, was approved in Japan for patients with FLT3mut+ R/R AML based on the phase 3 ADMIRAL trial, which demonstrated the superiority of gilteritinib over salvage chemotherapy (SC) with respect to overall survival (OS; median OS, 9.3 vs 5.6 months, respectively; hazard ratio, 0.64 [95% confidence interval 0.49, 0.83]; P < 0.001). METHODS: We evaluated the Japanese subgroup (n = 48) of the ADMIRAL trial, which included 33 patients randomized to 120-mg/day gilteritinib and 15 randomized to SC. RESULTS: Median OS was 14.3 months in the gilteritinib arm and 9.6 months in the SC arm. The complete remission/complete remission with partial hematologic recovery rate was higher in the gilteritinib arm (48.5%) than in the SC arm (13.3%). After adjustment for drug exposure, fewer adverse events (AEs) occurred in the gilteritinib arm than in the SC arm. Common grade ≥ 3 AEs related to gilteritinib were febrile neutropenia (36%), decreased platelet count (27%), and anemia (24%). CONCLUSION: Findings in Japanese patients are consistent with those of the overall ADMIRAL study population.

[Emergence of mutation in the colony-stimulating factor 3 receptor gene during follow-up of unclassifiable myeloproliferative neoplasm].

A 25-year-old male with a medical history of stress polycythemia was admitted to a previous hospital for leukocytosis, anemia, and thrombocytopenia. Bone marrow examination revealed left-shifted myeloid hyperplasia without increased blasts and normal male karyotype. No mutations of JAK2, V617F, and colony-stimulating factor 3 receptor gene (CSF3R) were detected. Fluorescence in-situ hybridization for BCR-ABL1 and FIP1L1-PDGFRA were negative. Based on these findings, a diagnosis of an unclassifiable myeloproliferative neoplasm was made, and he was started on hydroxyurea treatment. He was referred to our hospital in April 2016 for transfusion dependence. Bone marrow examination performed at our hospital revealed granulocytic dysplasia and CSF3R T618I was detected. After induction therapy, CSF3R T618I became undetectable, and he went on to undergo allogeneic stem cell transplantation in October 2016. He has been in remission for >4 years posttransplantation. CSF3R T618I is one of the genes responsible for chronic neutrophilic leukemia and atypical chronic myeloid leukemia, suggesting its involvement in the pathogenesis of this case.

Vitamin A-coupled liposomes containing siRNA against HSP47 ameliorate skin fibrosis in chronic graft-versus-host disease.

Chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (SCT) is characterized by multiorgan fibrosis and profoundly affects the quality of life of transplant survivors. Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, plays a critical role in collagen synthesis in myofibroblasts. We explored the role of HSP47 in the fibrotic process of cutaneous chronic GVHD in mice. Immunohistochemical analysis showed massive fibrosis with elevated amounts of collagen deposits and accumulation of F4/80+ macrophages, as well as myofibroblasts expressing HSP47 and retinol-binding protein 1 in the skin after allogeneic SCT. Repeated injection of anti-colony-stimulating factor (CSF-1) receptor-blocking antibodies significantly reduced HSP47+ myofibroblasts in the skin, indicating a macrophage-dependent accumulation of myofibroblasts. Vitamin A-coupled liposomes carrying HSP47 small interfering RNA (siRNA) (VA-lip HSP47) delivered HSP47 siRNA to cells expressing vitamin A receptors and knocked down their HSP47 in vitro. Intravenously injected VA-lip HSP47 were specifically distributed to skin fibrotic lesions and did not affect collagen synthesis in healthy skin. VA-lip HSP47 knocked down HSP47 expression in myofibroblasts and significantly reduced collagen deposition without inducing systemic immunosuppression. It also abrogated fibrosis in the salivary glands. These results highlight a cascade of fibrosis in chronic GVHD; macrophage production of transforming growth factor ß mediates fibroblast differentiation to HSP47+ myofibroblasts that produce collagen. VA-lip HSP47 represent a novel strategy to modulate fibrosis in chronic GVHD by targeting HSP47+ myofibroblasts without inducing immunosuppression.

Ruxolitinib protects skin stem cells and maintains skin homeostasis in murine graft-versus-host disease.

Graft-versus-host disease (GVHD) is the major complication after allogeneic stem cell transplantation (SCT). Emerging evidence indicates that GVHD leads to injury of intestinal stem cells. However, it remains to be investigated whether skin stem cells could be targeted in skin GVHD. Lgr5+ hair follicle stem cells (HFSCs) contribute to folliculogenesis and have a multipotent capacity to regenerate all epithelial cells in repair. We studied the fate of Lgr5+ HFSCs after SCT and explored the novel treatment to protect Lgr5+ HFSCs against GVHD using murine models of SCT. We found that GVHD reduced Lgr5+ HFSCs in association with impaired hair regeneration and wound healing in the skin after SCT. Topical corticosteroids, a standard of care for a wide range of skin disorders including GVHD, damaged HFSCs and failed to improve skin homeostasis, despite of their anti-inflammatory effects. In contrast, JAK1/2 inhibitor ruxolitinib significantly ameliorated skin GVHD, protected Lgr5+ HFSCs, and restored hair regeneration and wound healing after SCT. We, for the first time, found that GVHD targets Lgr5+ HFSCs and that topical ruxolitinib represents a novel strategy to protect skin stem cells and maintain skin homeostasis in GVHD.