Effects of human herpesvirus 6B reactivation on cognitive function in cord blood transplant recipients: a prospective multicenter study

This prospective multicenter study aimed to determine the effects of human herpesvirus-6B (HHV-6B) reactivation on central nervous system (CNS) function in cord blood transplant (CBT) recipients. Our focus was to track HHV-6B reactivation and evaluate its association with delirium and cognitive function, specifically in the domains of verbal memory, attention/processing speed, and quality of life (QOL). A cohort of 38 patients participated in this study. Of the 37 patients evaluated, seven (18.9%) developed delirium, with six of these cases emerging after HHV-6B reactivation (median lag, 7 days). Evaluation of verbal memory showed that the final trial score for unrelated words at 70 days after transplantation was significantly lower than that before preconditioning (P = 0.004) among patients (n = 15) who experienced higher-level HHV-6B reactivation (median or higher maximum plasma HHV-6 DNA load for participating patients). Patients without higher-level reactivation did not show significant declines in verbal memory scores. QOL was assessed using the 36-item Short-Form Health Survey, and the social functioning score 1 year post-transplantation was significantly lower in patients who experienced higher-level HHV-6B reactivation than in those who did not. Our findings suggest that higher-level HHV-6B reactivation can detrimentally affect certain cognitive functions in CBT recipients.

Development of an umbilical cord blood transplantation-specific nonrelapse mortality risk assessment score

ABSTRACT

Higher rate of nonrelapse mortality (NRM) remains yet to be resolved in umbilical cord blood transplantation (UCBT). Considering that UCBT has some unique features compared with allogeneic hematopoietic cell transplantation from other graft sources, a UCBT-specific NRM risk assessment system is required. Thus, in this study, we sought to develop a UCBT-specific NRM Risk Assessment (CoBRA) score. Using a nationwide registry database, we retrospectively analyzed 4437 recipients who had received their first single-unit UCBT. Using the backward elimination method, we constructed the CoBRA score in a training cohort (n = 2687), which consisted of recipients age ≥55 years (score 2), hematopoietic cell transplantation-specific comorbidity index ≥3 (score 2), male recipient, graft-versus-host disease prophylaxis other than tacrolimus in combination with methotrexate, performance status (PS) 2 to 4, HLA allele mismatch ≥ 2, refined Disease Risk Index high risk, myeloablative conditioning, and CD34+ cell doses < 0.82 × 105/kg (score 1 in each). The recipients were categorized into 3 groups: low (0-4 points), intermediate (5-7 points), and high (8-11 points) groups according to the CoBRA score. In the validation cohort (n = 1750), the cumulative incidence of NRM at 2 years was 14.9%, 25.5%, and 47.1% (P < .001), and 2-year overall survival (OS) was 74.2%, 52.7%, and 26.3% (P < .001) in the low, intermediate, and high groups, respectively. In summary, the CoBRA score could predict the NRM risk as well as OS after UCBT. Further external validation will be needed to confirm the significance of the CoBRA score.

Comparative Analysis of Allogeneic Bone Marrow Transplantation Outcomes Between Japanese and Non-Japanese Populations

BACKGROUND

As the Japanese population may have less genetic diversity than other ethnic groups, treatment outcomes may be affected when allogeneic hematopoietic cell transplantation is performed in other races. However, evidence explaining the effect of racial differences is limited.

METHODS

We used the Japanese National Database to examine the outcomes of first allogeneic bone marrow transplantations (BMTs) performed between Japanese and non-Japanese patients from 1996 to 2021. We performed propensity score matching using sex, age group, underlying disease group, HLA mismatch, conditioning regimen intensity, and BMT implementation age to select Japanese-to-Japanese BMT patients as the controls.

RESULTS

The numbers of non-Japanese-to-Japanese and Japanese-to-non-Japanese BMT cases included in the analysis were 48 and 75, respectively, and the following outcomes were compared: overall survival, non-relapse mortality, acute graft-vs-host disease (GVHD) ≥ grade II, chronic GVHD, and engraftment of neutrophils and platelets. Most parameters did not differ when comparing BMTs according to ethnicity; only platelet engraftment was delayed in Japanese-to-non-Japanese BMT but not in non-Japanese-to-Japanese BMT.

CONCLUSIONS

The results of this study suggested that BMT performed in Japanese and non-Japanese patients has little effect on treatment outcomes. The results of this study may be useful for donor selection in Japan, where internationalization has progressed in recent years.

Allogeneic T cells cause acute renal injury after hematopoietic cell transplantation

Acute kidney injury (AKI) is a frequent complication of allogeneic hematopoietic cell transplantation (allo-HCT). There are many causes of AKI after allo-HCT, but it is unknown whether renal acute graft-versus-host disease (aGVHD) caused by direct allogeneic donor T-cell-mediated renal damage contributes. Here, we tested whether allogeneic donor T cells attack kidneys in murine models of aGVHD. To avoid confounding effects of nephrotoxic agents, we did not administer immunosuppressants for GVHD prophylaxis. We found that urinary N-acetyl-β-D-glucosaminidase, a marker of tubular injury, was elevated in allogeneic recipients on day 14 after allogeneic bone marrow transplantation. Donor major histocompatibility complex-positive cells were present and CD3+ T cells were increased in the glomerulus, peritubular capillaries, interstitium, and perivascular areas in the kidneys of allo-HCT recipient mice. These T cells included both CD4+ and CD8+ cells with elevated activation markers, increased exhaustion markers, and greater secretion of proinflammatory cytokines and cytotoxic proteins. Consistent with allo-T-cell-mediated renal damage, expression of neutrophil gelatinase-binding lipocalin, a marker of AKI, and elafin, a marker of aGVHD, were increased in renal tissue of allogeneic recipients. Because apoptosis of target cells is observed on histopathology of aGVHD target tissues, we confirmed that alloreactive T cells increased apoptosis of renal endothelial and tubular epithelial cells in cytotoxic T-lymphocyte assays. These data suggest that immune responses induced by donor T cells contribute to renal endothelial and tubular epithelial cell injury in allo-HCT recipients and that aGVHD may contribute to AKI after allo-HCT.

Allogeneic stem cell transplantation for children and adolescents/young adults with de novo blastic phase chronic myeloid leukemia in the tyrosine kinase inhibitor era

The analysis of 165 children and adolescents/young adults with de novo blastic phase chronic myeloid leukemia showed disease status at hematopoietic stem cell transplantation was a strong prognostic factor and clearly separated the patient outcomes.

Exocrine Pancreatic Insufficiency Possibly Related to Atypical Chronic Graft-versus-Host Disease

We report the case of a 66-year-old woman who presented with diarrhea and weight loss approximately 14 months after unrelated allogeneic bone marrow transplantation for acute myeloid leukemia. Her early post-transplant course was notable for mild acute skin graft-versus-host disease (GVHD) and biopsy-proven upper gastrointestinal (GI) acute GVHD, both of which resolved with treatment. She then developed weight loss and diarrhea treated with prednisolone for what was thought to be GI late acute GVHD. However, her diarrhea and weight loss persisted. Colonoscopy showed a grossly intact mucosa, and stool studies only confirmed steatorrhea. However, an atrophic pancreas was found on an abdominal computed tomography (CT) scan. Exocrine pancreatic enzymes, such as lipase and pancreatic amylase, were markedly decreased, yet pancreatic endocrine function remained intact. The patient's diarrhea and weight loss improved upon treatment with pancrelipase. Therefore, we suggest that her exocrine pancreatic insufficiency was likely partly caused by atypical chronic GVHD.

GATA-3 is a proto-oncogene in T-cell lymphoproliferative neoplasms

Neoplasms originating from thymic T-cell progenitors and post-thymic mature T-cell subsets account for a minority of lymphoproliferative neoplasms. These T-cell derived neoplasms, while molecularly and genetically heterogeneous, exploit transcription factors and signaling pathways that are critically important in normal T-cell biology, including those implicated in antigen-, costimulatory-, and cytokine-receptor signaling. The transcription factor GATA-3 regulates the growth and proliferation of both immature and mature T cells and has recently been implicated in T-cell neoplasms, including the most common mature T-cell lymphoma observed in much of the Western world. Here we show that GATA-3 is a proto-oncogene across the spectrum of T-cell neoplasms, including those derived from T-cell progenitors and their mature progeny, and further define the transcriptional programs that are GATA-3 dependent, which include therapeutically targetable gene products. The discovery that p300-dependent acetylation regulates GATA-3 mediated transcription by attenuating DNA binding has novel therapeutic implications. As most patients afflicted with GATA-3 driven T-cell neoplasms will succumb to their disease within a few years of diagnosis, these findings suggest opportunities to improve outcomes for these patients.

Ivabradine as an Adjuvant Agent for Severe Heart Failure Occurring in the Early Phase after Allogeneic Hematopoietic Cell Transplantation

Cardiotoxicity is a critical complication of allogeneic hematopoietic cell transplantation (allo-HCT). In particular, management of severe cardiotoxicity occurring in the early phases of allo-HCT is challenging. We encountered a case of severe cardiotoxicity resulting from AHF six days after allo-HCT, which resisted catecholamines and diuretics. The patient was treated with anthracycline-containing regimens and underwent myeloablative conditioning, including high-dose cyclophosphamide. As invasive circulatory assisting devices were contraindicated because of his immunocompromised status and bleeding tendency, we successfully treated the patient with ivabradine-containing medications. Ivabradine may therefore be considered an alternative drug for the treatment of severe cardiotoxicity induced by cytotoxic agents.

Successful treatment of acute pancreatitis associated with late-onset acute liver GVHD after second allogeneic hematopoietic cell transplantation

We report the case of a 28-year-old woman who developed upper abdominal pain and jaundice after a second unrelated allogeneic hematopoietic cell transplantation (allo-HCT) for acute lymphoid leukemia (ALL). Laboratory data showed elevated levels of liver enzymes, amylase, and lipase. Although acute pancreatitis was suspected, no structural lesions were detected. Liver biopsy was compatible with late-onset acute graft-versus-host disease (GVHD), which resolved following treatment with methylprednisolone (mPSL) and tacrolimus (TAC). In addition, her serum amylase level and abdominal pain rapidly resolved following acute GVHD-directed therapy. Acute pancreatitis concomitant with late-onset acute liver GVHD is extremely rare and has not been documented subsequent to a second allo-HCT.

Recent Advances of Acute Kidney Injury in Hematopoietic Cell Transplantation

Acute kidney injury (AKI) is a common complication of allogeneic hematopoietic cell transplantation (allo-HCT) and is associated with non-relapse mortality (NRM) and quality of life (QOL). Multiple factors may contribute to AKI during allo-HCT and are often present at the same time making it difficult to determine the cause of AKI in each patient. Nephrotoxic drugs, infections, thrombotic microangiopathy (TMA), and sinusoidal obstruction syndrome (SOS) are well described causes of AKI during allo-HCT. Acute graft-versus-host disease (aGVHD) is a major complication of allo-HCT that mainly targets the intestines, liver, and skin. However, recent studies suggest aGVHD may also attack the kidney and contribute to AKI following allo-HCT. For example, severe aGVHD is associated with AKI, suggesting a link between the two. In addition, animal models have shown donor immune cell infiltration and increased expression of inflammatory cytokines in recipient kidneys after allo-HCT. Therefore, aGVHD may also target the kidney and contribute to AKI following allo-HCT. Herein, we describe the etiology, diagnosis, risk factors, pathophysiology, prevention, and treatment of renal injury after allo-HCT. In addition, we highlight emerging evidence that aGVHD may contribute to the development of AKI after allo-HCT.

[Fecal metabolomic profiles in experimental murine bone marrow transplantation]

Graft-versus-host disease (GVHD) is a life-threating complication of allogeneic hematopoietic cell transplantation (allo-HCT). Prior studies have shown that gastrointestinal (GI) GVHD is associated with a reduction in intestinal microbiota diversity and a change in microbial metabolites. We conducted fecal metabolome analyses using a murine bone marrow transplantation. From this analysis, 290 metabolites were identified; of these, 18 metabolites were significantly or specifically higher and 12 were significantly or specifically lower in the allogeneic group than in the syngeneic one. Particularly, several metabolites in the choline metabolism and tryptophan metabolism were altered in the allogeneic group. Hierarchical clustering analysis demonstrated that the changed metabolites in the allogeneic group had similar profiles. Conclusively, we suggest that alloimmune responses are related to microbial metabolites in recipients receiving allo-HCT. The relationship between metabolites involved in GI GVHD and the intestinal microbiota and its physiological significance warrant further investigations.

A unique three-way Philadelphia chromosome variant t(4;9;22)(q21;q34;q11.2) in a newly diagnosed patient with chronic phase chronic myeloid leukemia: a case report and review of the literature

Background

Chronic myeloid leukemia is a hematologic malignancy associated with the fusion of two genes: BCR and ABL1. This fusion results from a translocation between chromosomes 9 and 22, which is called the Philadelphia chromosome. Although the Philadelphia chromosome is present in more than 90% of patients with chronic myeloid leukemia, 5–8% of patients with chronic myeloid leukemia show complex variant translocations. Herein, we report a unique case of a three-way translocation variant in chronic phase chronic myeloid leukemia.

Case presentation

A 40-year-old Asian male who presented with leukocytosis was diagnosed with chronic phase chronic myeloid leukemia. Cytogenetic karyotyping analysis showed 46,XY,t(4;9;22)(q21;q34;q11.2). He was treated with bosutinib and then changed to dasatinib because of intolerance, and MR4.5 (BCR-ABL/ABL ≦ 0.0032%, international scale) was achieved after 17 months of continuous treatment.

Conclusion

This was the 14th case of t(4;9;22), in particular, a new variant Ph translocation involved in chromosome 4q21 and the first successful case treated with tyrosine kinase inhibitors in the world. We summarize previous case reports regarding three-way variant chromosome translocation, t(4;9;22) and discuss how this rare translocation is linked to prognosis.

[Two-year remission of a relapsed primary gastric peripheral T-cell lymphoma treated with total gastrectomy followed by adjuvant chemotherapy]

A 67-year-old man was diagnosed with a submucosal primary gastric T-cell lymphoma (PGTL) via upper gastroenteroscopy following an annual health check-up. He received six cycles of CHOP and achieved a complete remission. However, the patient relapsed 4 months post therapy. A second remission, which was maintained for years, was achieved after surgical gastrectomy followed by adjuvant chemotherapies. Prior reports have shown that surgery combined with chemotherapies was curative for patients with newly-diagnosed PGTL. In this report, surgery combined with chemotherapies was successfully applied for early-relapsed PGTL.

[Recent advances in pathophysiology, diagnosis and treatment of steroid-refractory graft-versus-host disease]

Acute graft-versus-host disease (GVHD) is a major life-threating complication that occurs after allogeneic cell transplantation. Although steroids remain the first-line treatment, approximately one-third of patients will eventually develop steroid-resistant or steroid-refractory GVHD (SR-GVHD), which has an extremely poor prognosis. Many novel strategies that showed promising response rates in early phase I/II trials for the prevention and treatment of acute GVHD exhibited disappointing effects on patient survival in the SR-GVHD setting. The discovery of novel treatments has been further complicated by the absence of a clinically-relevant animal model. Nevertheless, the combined knowledge from translational studies using bone marrow transplantation models and clinical trials including SR-GVHD patients has begun to reveal novel mechanisms for inhibiting T cell signaling and promoting tissue regeneration, which has contributed to a better understanding of the SR-GVHD pathophysiology. Herein, we discuss recently elucidated cellular and molecular mechanisms that may provide the rational for novel biologically-driven treatments for SR-GVHD.

Other Iatrogenic Immunodeficiency-Associated Lymphoproliferative Disorders, Diffuse Large B-Cell Lymphoma Type, in a Patient with Behçet's Disease Treated with Cyclosporine A

A 40-year-old man had been treated for Behçet's disease (BD) with cyclosporine A (CsA) for 14 years. He presented multiple lymphadenopathies with fever. Histological examination of surgical biopsy showed other iatrogenic immunodeficiency-associated lymphoproliferative disorders, diffuse large B-cell lymphoma type with positivity for Epstein-Barr virus encoding RNA-1 (EBER-1). BCL2-IgH, BCL6-IgH, and MYC-IgH translocations were not detected. CsA was stopped, and R-CHOP therapy was initiated. However, his lymphoma was chemotherapy resistant and rapidly progressed. To the best of our knowledge, this is the first case of diffuse large B-cell lymphoma that occurred in a BD patient treated with CsA reported in English. Both BD and CsA are associated with the pathogenesis of lymphoma. We also describe extremely rare cases in the form of a literature review.

A Rare Chromosome Abnormality with der(16)t(1;16)(q12;q11.2) in Blast Crisis of Chronic Myeloid Leukemia

Although tyrosine kinase inhibitors markedly improve the clinical outcome of chronic myeloid leukemia (CML), blast crisis in CML (CML-BC) still has a poor prognosis. Many chromosomal abnormalities have been reported in CML-BC and may contribute to therapeutic resistance, disease progression, and prognosis. Herein, we report a rare chromosome abnormality with der(16)t(1;16)(q12;q11.2) in CML-BC. It has been demonstrated that this chromosomal abnormality is associated with disease progression and poor prognosis in other malignancies, such as Ewing sarcoma. A 70-year-old man with CML who had been treated with imatinib and dasatinib was admitted to our hospital after complaining for several weeks of fatigue and dyspnea and diagnosed with CML-BC. His tumor cells presented additional chromosomal abnormality with der(16)t(1;16)(q12;q11.2), which has never been reported in CML cases. We successfully treated him using cytotoxic agents combined with ponatinib, and this chromosome abnormality was detected via G-banding. Our patient has lived for over 8 months without any progression with ponatinib treatment alone. Although the biological function of this chromosomal abnormality remains unclear, the satellite DNA of 1q12, which induces genomic instability in other malignancies, and the loss of 16q may contribute to the disease progression of CML in this case. In conclusion, this paper is the first to report on the case of CML-BC with der(16)t(1;16)(q12;q11.2).

Plasma Exchange as an Initial Treatment for Severe Bleeding Induced by Acquired Factor V Deficiency: A Case Report and Mini Literature Review

Acquired factor V deficiency (AFVD) is a rare autoimmune bleeding disorder. Unlike acquired hemophilia, bypass therapies with recombinant activated factor VII and activated prothrombin complex concentrates are ineffective for severe bleeding due to AFVD. Although several treatment strategies have been attempted, a standard of care for severe hemorrhage induced by AFVD is lacking. Herein, we report a case of AFVD with severe bleeding that responded to plasma exchange (PE) combined with immunosuppression. We also reviewed previously reported AFVD cases with severe hemorrhage and suggest that PE may be an effective initial treatment for AFVD-induced severe hemorrhage.

Safety and efficacy of anti-programmed cell death-1 monoclonal antibodies before and after allogeneic hematopoietic cell transplantation for relapsed or refractory Hodgkin lymphoma: a multicenter retrospective study

We conducted a multicenter study on anti-programmed cell death-1 monoclonal antibodies (anti-PD-1 mAbs) before/after allogeneic hematopoietic cell transplantation (allo-HCT) for Hodgkin lymphoma. Anti-PD-1 mAbs were administered to 25 patients before allo-HCT and to 20 after allo-HCT. In pre-allo-HCT setting, the median interval from the last administration to allo-HCT was 59 days. After allo-HCT, 12 patients developed non-infectious febrile syndrome requiring high-dose corticosteroid. The cumulative incidences of grade II-IV acute graft-versus-host disease (aGvHD) were 47.1%. Eight patients who had GvHD prophylaxis with post-transplant cyclophosphamide (PTCy) had less frequent aGvHD (grade II-IV, 14.6% versus 58.8%; P = 0.086). The 1 year overall survival (OS), relapse/progression, and non-relapse mortality rates were 81.3%, 27.9%, and 8.4%. In post-allo-HCT setting, the median interval from allo-HCT to the first administration was 589 days. The overall and complete response rates were 75% and 40%. At 100 days after anti-PD-1 therapy, the cumulative incidences of grade II-IV aGvHD, moderate-to-severe chronic GvHD, and grade 3-4 immune-related toxicity were 15.0%, 30.0%, and 30.0%. While the 1 year relapse/progression rate was 47.4%, the 1 year OS probability was 89.7%. In conclusion, immune-related complications were frequent despite modifications of GvHD prophylaxis or anti-PD-1 mAb dosing. In anti-PD-1-mAb-pretreated patients, PTCy-based GvHD prophylaxis may be effective.

Good prognosis for follicular lymphoma with estrogen receptor α-positive follicular dendritic cells

Follicular lymphoma (FL) has a meshwork of follicular dendritic cells (FDCs). We previously demonstrated the presence of estrogen receptor alpha (ERα)⁺CD23⁺ FDCs in grades 1‐2 FL. The significance of FDCs as a prognostic factor in FL remains unknown. The current study aimed to compare clinicopathological features, including prognosis, between FL with and without ERα⁺ FDCs. This study evaluated the clinicopathological significance of ERα expression in 70 FL patients by immunostaining. The presence of ERα mRNA on FDCs from 5 FL patients was confirmed by CD21/ERα double staining (immunohistochemistry and in situ hybridization). We defined patients with frequent ERα expression as the ERα^high group and those with infrequent ERα expression as the ERα^low group. Thirty‐two patients were assigned to the ERα^high group (45.7%), and 38 patients were assigned to the ERα^low group (54.3%). Both overall survival (OS) and progression‐free survival (PFS) were significantly better in the ERα^high group than in the ERα^low group (OS, log‐rank, P = .0465; PFS, log‐rank, P = .0336). Moreover, high ERα expression on FDCs was an independent prognostic factor for OS in both the univariate ([hazard ratio] HR, 0.163; P = .0260) and multivariate (HR, 0.050; P = .0188) analyses and for PFS in both the univariate (HR, 0.232; P = .0213) and multivariate (HR, 0.084; P = .0243) analyses. ERα mRNA expression was detected in CD21⁺ FDCs within the neoplastic follicles of FL patients. In conclusion, a neoplastic follicular microenvironment with ERα‐positive FDCs might affect the grade and presence of the follicular pattern of FL and improve patient prognosis.

A case of iatrogenic immunodeficiency-associated colonic lymphoma complicating ulcerative colitis

Background

Ulcerative colitis (UC) is one of the major types of inflammatory bowel diseases and is associated with a significantly increased risk of not only lymphoproliferative disorders but also lymphomas, of which most cases are related to the long-term usage of immunosuppressants. Here, we demonstrate a very rare case of other iatrogenic immunodeficiency-associated colonic diffuse large B-cell lymphoma (Oii-DLBCL) complicating UC and rectal perforation. In addition, we reviewed the clinicopathological features of previous cases of DLBCL related to UC.

Case presentation

A 68-year-old man was diagnosed with left-sided UC 26 months prior. Although he was followed by immunosuppressive therapy with azathioprine and infliximab, an emergency total proctocolectomy was performed due to rectal perforation. The resected specimen exhibited irregular wall thickening and elevated multinodular lesions extending from the mid-transverse colon to the rectum, measuring up to 52 cm in length. Histologically, the lesion was diagnosed as Oii-DLBCL and crypt abscess surrounded by mixed inflammatory cell was remained.

Conclusion

Oii-DLBCL complicating UC with rectal perforation is extremely rare. Macro- and microscopic findings are important for early diagnosis of the lesion.

SNARE protein SEC22B regulates early embryonic development

The highly conserved SNARE protein SEC22B mediates diverse and critical functions, including phagocytosis, cell growth, autophagy, and protein secretion. However, these characterizations have thus far been limited to in vitro work. Here, we expand our understanding of the role Sec22b plays in vivo. We utilized Cre-Lox mice to delete Sec22b in three tissue compartments. With a germline deletion of Sec22b, we observed embryonic death at E8.5. Hematopoietic/endothelial cell deletion of Sec22b also resulted in in utero death. Notably, mice with Sec22b deletion in CD11c-expressing cells of the hematopoietic system survive to adulthood. These data demonstrate Sec22b contributes to early embryogenesis through activity both in hematopoietic/endothelial tissues as well as in other tissues yet to be defined.

Differential expression of estrogen receptor-α on follicular dendritic cells from patients with grade 1-2 and grade 3 follicular lymphoma

Hormone therapy has been used for patients with estrogen receptor alpha (ERα)–positive breast cancers. Recently, some studies reported the expression of ERα on neoplastic cells from B‐cell lymphomas. However, there has been only one report of ERα expression on the follicular dendritic cells (FDCs) that structurally and functionally support the microenvironment of follicular lymphomas (FLs). The objective of this study was to investigate the frequency of ERα expression on FDCs in nonneoplastic reactive lymphoid tissues and to compare the frequency of ERα expression on FDCs in the axillary lymph nodes between patients with and without antiestrogen therapy and among patients with grades 1‐3 of FL. Reverse transcription–polymerase chain reaction was performed to detect ERα mRNA in FL. In nonneoplastic germinal centers (GCs) from patients with tonsillitis or reactive lymphadenitis, ERα was expressed in the light zone. ERα‐positive cells strongly correlated with the width of GCs (r_s = 0.81, P < 0.01) and the CD21‐positive (r_s = 0.69, P < 0.01) and CD23‐positive (r_s = 0.83, P < 0.01) FDC meshwork. The axillary lymph nodes had fewer ERα‐positive cells, smaller GCs, and a looser CD21‐ and CD23‐positive FDC meshwork with hormone therapy than without hormone therapy (P < 0.01). Neoplastic follicles of G1‐2 FL had more ERα‐positive cells and a larger CD23⁺ FDC meshwork than those of G3 FL (P < 0.01). ERα mRNA was detected in both G1‐2 FL and G3 FL by reverse transcription–polymerase chain reaction. In conclusion, these results suggested that antiestrogen hormone therapy may decrease the number of ERα‐positive FDCs and that the responses mediated by the estrogen‐ERα interaction on FDCs may differ between G1‐2 FL and G3 FL.

[Immune-mediated neuropathy with anti-ganglioside antibodies in diffuse large B-cell lymphoma]

A 70-year-old man having a mass lesion on his right lower abdomen for 2 months was admitted to our hospital for diagnosis. Upon admission, the patient experienced bilateral upper and lower limb weakness, which aggravated. He underwent nerve conduction study and was diagnosed with axonal neuropathy. Diagnosis of diffuse large B-cell lymphoma (DLBCL) was accomplished via biopsy of the mass lesion, with positive laboratory tests for anti-ganglioside antibodies. Based on these results, immune-mediated DLBCL-induced polyneuropathy was suspected, and chemotherapy (R-CHOP) was immediately started. Limb weakness improved and completely resolved. After six courses of R-CHOP, no evidence of DLBCL was observed on PET/CT (i.e., complete metabolic remission). The patient lived without DLBCL relapse or neurological symptoms after remission. Only few reports regarding immune-mediated polyneuropathy induced by malignant lymphoma are available in the literature, which, together with this case, suggest that prompt control of malignant lymphoma is crucial for favorable prognosis of neuropathy.

Mitochondrial Deacetylase SIRT3 Plays an Important Role in Donor T Cell Responses after Experimental Allogeneic Hematopoietic Transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) through its graft-versus-tumor (GVT) effects is a curative therapy against many hematological malignancies. However, GVT is linked to harmful graft-versus-host disease (GVHD) after allo-HCT. Both GVT and GVHD require allogeneic T cell responses, which is an energetically costly process that causes oxidative stress. Sirtuin 3 (SIRT3), a mitochondrial histone deacetylase (HDAC), plays an important role in cellular processes through inhibition of reactive oxygen species (ROS). Nonmitochondrial class of HDACs regulate T cell responses, but the role of mitochondrial HDACs, specifically SIRT3, on donor T cell responses after allo-HCT remains unknown. In this study, we report that SIRT3-deficient (SIRT3^-/-) donor T cells cause reduced GVHD severity in multiple clinically relevant murine models. The GVHD protective effect of allogeneic SIRT3^-/- T cells was associated with a reduction in their activation, reduced CXCR3 expression, and no significant impact on cytokine secretion or cytotoxic functions. Intriguingly, the GVHD protective effect of SIRT3^-/- T cells was associated with a reduction in ROS production, which is contrary to the effect of SIRT3 deficiency on ROS production in other cells/tissues and likely a consequence of their deficient activation. Notably, the reduction in GVHD in the gastrointestinal tract was not associated with a substantial reduction in the GVT effect. Collectively, these data reveal that SIRT3 activity promotes allogeneic donor T cell responses and ROS production without altering T cell cytokine or cytolytic functions and identify SIRT3 as a novel target on donor T cells to improve outcomes after allo-HCT.

Microbial metabolite sensor GPR43 controls severity of experimental GVHD

Microbiome-derived metabolites influence intestinal homeostasis and regulate graft-versus-host disease (GVHD), but the molecular mechanisms remain unknown. Here we show the metabolite sensor G-protein-coupled receptor 43 (GPR43) is important for attenuation of gastrointestinal GVHD in multiple clinically relevant murine models. GPR43 is critical for the protective effects of short-chain fatty acids (SCFAs), butyrate and propionate. Increased severity of GVHD in the absence of GPR43 is not due to baseline differences in the endogenous microbiota of the hosts. We confirm the ability of microbiome-derived metabolites to reduce GVHD by several methods, including co-housing, antibiotic treatment, and administration of exogenous SCFAs. The GVHD protective effect of SCFAs requires GPR43-mediated ERK phosphorylation and activation of the NLRP3 inflammasome in non-hematopoietic target tissues of the host. These data provide insight into mechanisms of microbial metabolite-mediated protection of target tissues from the damage caused allogeneic T cells.

A Critical Analysis of the Role of SNARE Protein SEC22B in Antigen Cross-Presentation

Cross-presentation initiates immune responses against tumors and viral infections by presenting extracellular antigen on MHC I to activate CD8⁺ T cell-mediated cytotoxicity. In vitro studies in dendritic cells (DCs) established SNARE protein SEC22B as a specific regulator of cross-presentation. However, the in vivo contribution of SEC22B to cross-presentation has not been tested. To address this, we generated DC-specific Sec22b knockout (CD11c-Cre Sec22b^fl/fl) mice. Contrary to the paradigm, SEC22B-deficient DCs efficiently cross-present both in vivo and in vitro. Although in vitro small hairpin RNA (shRNA)-mediated Sec22b silencing in bone-marrow-derived dendritic cells (BMDCs) reduced cross-presentation, treatment of SEC22B-deficient BMDCs with the same shRNA produced a similar defect, suggesting the Sec22b shRNA modulates cross-presentation through off-target effects. RNA sequencing of Sec22b shRNA-treated SEC22B-deficient BMDCs demonstrated several changes in the transcriptome. Our data demonstrate that contrary to the accepted model, SEC22B is not necessary for cross-presentation, cautioning against extrapolating phenotypes from knockdown studies alone.

Detection of Minimal Bone Marrow involvement of Blastic Plasmacytoid Dendritic Cell Neoplastic Cells - CD303 immunostaining as a diagnostic tool

Blastic plasmacytoid dendritic cell (pDC) neoplasm (BPDCN) is a relatively rare hematological malignancy with significantly complex clinicopathological features that are still unclear. This study aimed to analyze the clinicopathological data of BPDCN and evaluate immunohistochemical detection of minimal bone marrow (BM) involvement. In this study, we examined skin and BM lesions from 6 patients with BPDCN. Neoplastic cells tested positive for CD303 (polyclonal, 100%; monoclonal, 40%) in the skin lesions and for CD303 (polyclonal, 100%; monoclonal, 67%) in the BM clots. Although immunostaining of CD4, CD56, CD123, CD303, and TCLl detected minimal BM involvement in 3 patients, morphological identification was challenging in the BM clots stained with hematoxylin-eosin. In conclusion, our results demonstrate the significance of observing BM smears to detect neoplastic cells and that immunohistochemical examination, including CD303 antibodies, is useful to detect minimal BM involvement. This study is the first to report the expression of thymic stromal lymphopoietin (TSLP) and its receptor in BPDCN cells. Therefore, the TSLP/TSLP receptor axis may be associated with the proliferation of BPDCN, and consequently, the survival of patients.

Siglec-G represses DAMP-mediated effects on T cells

The role of negative regulators or suppressors of the damage-associated molecular pattern-mediated (DAMP-mediated) stimulation of innate immune responses is being increasingly appreciated. However, the presence and function of suppressors of DAMP-mediated effects on T cells, and whether they can be targeted to mitigate T cell-dependent immunopathology remain unknown. Sialic acid-binding immunoglobulin-like lectin G (Siglec-G) is a negative regulator of DAMP-mediated responses in innate immune cells, but its T cell-autonomous role is unknown. Utilizing loss-of-function-based (genetic knockout) and gain-of-function-based (agonist) approaches, we demonstrate that in the presence of certain DAMPs, Siglec-G suppressed in vitro and in vivo T cell responses. We also demonstrate that its T cell-autonomous role is critical for modulating the severity of the T cell-mediated immunopathology, graft-versus-host disease (GVHD). Enhancing the Siglec-G signaling in donor T cells with its agonist, a CD24Fc fusion protein, ameliorated GVHD while preserving sufficient graft-versus-tumor (GVT) effects in vivo. Collectively, these data demonstrate that Siglec-G is a potentially novel negative regulator of T cell responses, which can be targeted to mitigate GVHD.

Danger Signals and Graft-versus-host Disease: Current Understanding and Future Perspectives

Graft-versus-host response after allogeneic hematopoietic stem cell transplantation (allo-HCT) represents one of the most intense inflammatory responses observed in humans. Host conditioning facilitates engraftment of donor cells, but the tissue injury caused from it primes the critical first steps in the development of acute graft-versus-host disease (GVHD). Tissue injuries release pro-inflammatory cytokines (such as TNF-α, IL-1β, and IL-6) through widespread stimulation of pattern recognition receptors (PRRs) by the release of danger stimuli, such as damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). DAMPs and PAMPs function as potent stimulators for host and donor-derived antigen presenting cells (APCs) that in turn activate and amplify the responses of alloreactive donor T cells. Emerging data also point towards a role for suppression of DAMP induced inflammation by the APCs and donor T cells in mitigating GVHD severity. In this review, we summarize the current understanding on the role of danger stimuli, such as the DAMPs and PAMPs, in GVHD.

Genome-Wide STAT3 Binding Analysis after Histone Deacetylase Inhibition Reveals Novel Target Genes in Dendritic Cells

STAT3 is a master transcriptional regulator that plays an important role in the induction of both immune activation and immune tolerance in dendritic cells (DCs). The transcriptional targets of STAT3 in promoting DC activation are becoming increasingly understood; however, the mechanisms underpinning its role in causing DC suppression remain largely unknown. To determine the functional gene targets of STAT3, we compared the genome-wide binding of STAT3 using ChIP sequencing coupled with gene expression microarrays to determine STAT3-dependent gene regulation in DCs after histone deacetylase (HDAC) inhibition. HDAC inhibition boosted the ability of STAT3 to bind to distinct DNA targets and regulate gene expression. Among the top 500 STAT3 binding sites, the frequency of canonical motifs was significantly higher than that of noncanonical motifs. Functional analysis revealed that after treatment with an HDAC inhibitor, the upregulated STAT3 target genes were those that were primarily the negative regulators of proinflammatory cytokines and those in the IL-10 signaling pathway. The downregulated STAT3-dependent targets were those involved in immune effector processes and antigen processing/presentation. The expression and functional relevance of these genes were validated. Specifically, functional studies confirmed that the upregulation of IL-10Ra by STAT3 contributed to the suppressive function of DCs following HDAC inhibition.

SAG/Rbx2-Dependent Neddylation Regulates T-Cell Responses

Neddylation is a crucial post-translational modification that depends on the E3 cullin ring ligase (CRL). The E2-adapter component of the CRL, sensitive to apoptosis gene (SAG), is critical for the function of CRL-mediated ubiquitination; thus, the deletion of SAG regulates neddylation. We examined the role of SAG-dependent neddylation in T-cell-mediated immunity using multiple approaches: a novel T-cell-specific, SAG genetic knockout (KO) and chemical inhibition with small-molecule MLN4924. The KO animals were viable and showed phenotypically normal mature T-cell development. However, in vitro stimulation of KO T cells revealed significantly decreased activation, proliferation, and T-effector cytokine release, compared with WT. Using in vivo clinically relevant models of allogeneic bone marrow transplantation also demonstrated reduced proliferation and effector cytokine secretion associated with markedly reduced graft-versus-host disease. Similar in vitro and in vivo results were observed with the small-molecule inhibitor of neddylation, MLN4924. Mechanistic studies demonstrated that SAG-mediated effects in T cells were concomitant with an increase in suppressor of cytokine signaling, but not NF-κB translocation. Our studies suggest that SAG is a novel molecular target that regulates T-cell responses and that inhibiting neddylation with the clinically available small-molecule MLN4924 may represent a novel strategy to mitigate T-cell-mediated immunopathologies, such as graft-versus-host disease.

A Sec22b knockout mouse offers novel insights into the molecular mechanisms of crosspresentation

Crosspresentation critically contributes to the adaptive immune response to tumors and viral infection by presenting extracellular antigen on MHC I to activate CD8 T cells. However, its molecular regulation is poorly understood. Using in vitro shRNA-mediated knockdown (KD) methods, another group had shown that Sec22b, an ER-SNARE, specifically regulates crosspresentation. Thus, we tested the hypothesis that Sec22b would mediate crosspresentation in vivo. We generated DC-specific Sec22b knockout (KO) mice, which have an intact, functional immune system. After adoptively transferring OT-I T cells into these mice, then injecting with soluble OVA i.p., we analyzed OT-I T cell proliferation to measure crosspresentation. Surprisingly, we saw no difference in OVA crosspresentation by KO versus FL mice. This observation was verified in vitro using KO DCs from BM and spleen crosspresenting soluble and insoluble OVA. We concluded Sec22b is not necessary for crosspresentation, invalidating our hypothesis. However, we were able to reproduce the reduced crosspresentation by shRNA-mediated KD of Sec22b. Intriguingly, when we treated KO BMDCs with the same Sec22b-targeting shRNA, we again observed reduced crosspresentation comparable to that seen in shRNA-treated WT BMDCs. This suggested the shRNA mediates crosspresentation through its effects on an off-target gene. RNAseq data on shRNA-treated BMDCs provided a candidate list of potential crosspresentation mediators. Our data demonstrates that (a) Sec22b is not necessary for crosspresentation, (b) there may be a novel critical mediator of crosspresentation targeted by the shRNA, and (c) extrapolating mechanisms or phenotypes based on KD studies alone must be done with caution.

Mature T cell responses are controlled by microRNA-142

T cell proliferation is critical for immune responses; however, the molecular mechanisms that mediate the proliferative response are poorly understood. MicroRNAs (miRs) regulate various molecular processes, including development and function of the immune system. Here, utilizing multiple complementary genetic and molecular approaches, we investigated the contribution of a hematopoietic-specific miR, miR-142, in regulating T cell responses. T cell development was not affected in animals with a targeted deletion of Mir142; however, T cell proliferation was markedly reduced following stimulation both in vitro and in multiple murine models of graft-versus-host disease (GVHD). miR-142-deficient T cells demonstrated substantial cell-cycling defects, and microarray and bioinformatics analyses revealed upregulation of genes involved in cell cycling. Moreover, 2 predicted miR-142 target genes, the atypical E2F transcription factors E2f7 and E2f8, were most highly upregulated in miR-142-deficient cells. Clustered regularly interspaced short palindromic repeat interference-mediated (CRISPRi-mediated) silencing of E2F7 and E2F8 in miR-142-deficient T cells ameliorated cell-cycling defects and reduced GVHD, and overexpression of these factors in WT T cells inhibited the proliferative response. Together, these results identify a link between hematopoietic-specific miR-142 and atypical E2F transcription factors in the regulation of mature T cell cycling and suggest that targeting this interaction may be relevant for mitigating GVHD.

Ikaros deficiency in host hematopoietic cells separates GVL from GVHD after experimental allogeneic hematopoietic cell transplantation

The graft-versus-leukemia (GVL) effect following allogeneic hematopoietic stem cell transplantation (allo-HCT) is critical for its curative potential. Hwever, GVL is tightly linked to graft-versus-host disease (GVHD). Among hematological malignancies, acute lymphoblastic leukemia (ALL) is the most resistant to GVL, although the reasons for this remain poorly understood. Clinical studies have identified alterations in Ikaros (Ik) transcription factor as the major marker associated with poor outcomes in ALL. We have shown that the absence of Ik in professional host-derived hematopoietic antigen-presenting cells (APCs) exacerbates GVHD. However, whether Ik expression plays a role in resistance to GVL is not known. In this study we used multiple clinically relevant murine models of allo-HCT to explore whether Ik expression in hematopoietic APCs and/or leukemic cells is critical for increasing resistance to GVL and thus inducing relapse. We found that Ik deficiency in host APCs failed to enhance GVL despite increased GVHD severity. Mechanistic studies with bone marrow (BM) chimeras and tetramer analyses demonstrated reduced tumor-specific immunodominant (gag+) antigen responses in the [B6Ik^-/-→B6] group. Loss of GVL was observed when both the leukemia cells and the host APCs were deficient in Ik. We found that calreticulin (CRT) expression in host antigen-presenting dendritic cells (DCs) of Ik^-/- animals was significantly lower than in wild-type animals. Rescuing CRT expression in Ik^-/- DCs improved leukemic-specific cytotoxic T cell function. Together, our data demonstrate that the absence of Ikaros in host hematopoietic cells promotes resistance to GVL despite increasing GVHD and thus provides a potential mechanism for the poor outcome of Ik^-/- ALL patients.

Aging is associated with increased regulatory T-cell function

Regulatory T-cell (Treg, CD4(+) CD25(+)) dysfunction is suspected to play a key role in immune senescence and contributes to increased susceptibility to diseases with age by suppressing T-cell responses. FoxP3 is a master regulator of Treg function, and its expression is under control of several epigenetically labile promoters and enhancers. Demethylation of CpG sites within these regions is associated with increased FoxP3 expression and development of a suppressive phenotype. We examined differences in FoxP3 expression between young (3-4 months) and aged (18-20 months) C57BL/6 mice. DNA from CD4(+) T cells is hypomethylated in aged mice, which also exhibit increased Treg numbers and FoxP3 expression. Additionally, Treg from aged mice also have greater ability to suppress effector T-cell (Teff) proliferation in vitro than Tregs from young mice. Tregs from aged mice exhibit greater redox remodeling-mediated suppression of Teff proliferation during coculture with DCs by decreasing extracellular cysteine availability to a greater extent than Tregs from young mice, creating an adverse environment for Teff proliferation. Tregs from aged mice produce higher IL-10 levels and suppress CD86 expression on DCs more strongly than Tregs from young mice, suggesting decreased T-cell activity. Taken together, these results reveal a potential mechanism of higher Treg-mediated activity that may contribute to increased immune suppression with age.

Microbial metabolites modulate GI mucosal damage from graft versus host disease (GHVD). (MUC4P.850)

The microbiome of the GI tract is known to affect GI mucosal responses and regulate disease processes. GI tract damage is the major cause for graft versus host disease (GVHD) mortality. Studies have shown the microbiome affects the course of allogeneic bone marrow transplant and modulates GVHD. However, little is known about the microbial metabolites crucial for achieving the effects of the microbiome on immune responses, specifically GVHD. We examined the metabolome of naïve mice and murine recipients of syngeneic (B6→B6) and allogeneic (B6→BALB/c) BMT, in an unbiased way. We made a surprising observation that short chain fatty acids (SCFA), including butyrate, were altered in the intestinal epithelium but not in the luminal contents of allo-BMT recipients. Butyrate, a known metabolite of the microbiome was previously shown to have HDAC inhibitor (HDACi) and salutary effects on the intestinal epithelium. Additionally, recent data showed systemic chemical inhibition of HDAC protects GI epithelium from GVHD severity. The decrease of butyrate in the epithelial cells of the small intestine (P&lt;0.03) suggested poor uptake of butyrate following allo-BMT. Consistent with this notion, we found that treatment of epithelial cells with butyrate confers protection from irradiation and decreases allo-induced cell death. Our results suggest that the microbiome regulates the damage from allogeneic GVHD due to the reduction in the tissue level of the SCFA-metabolite and HDACi, butyrate.

Neddylation regulates T cell responses. (TRAN3P.914)

Post-translational modifications (PTM) of proteins regulate cellular processes by proteasomal degradation. PTM of Cullin-RING ligase (CRL) protein via neddylation and the presence of its critical adapter element, sensitive to apoptosis gene (SAG) protein, modulate the process of neddylation-dependent ubiquitination. The role of neddylated proteins in regulating T cells is not known. We explored the role of neddylation in T cells by utilizing two different, but complementary approaches. We generated a T-cell specific knockout (SLCK-KO) of SAG (critical for the neddylation process) and utilized a small molecule inhibitor specific for neddylation (MLN4924). Phenotypic analysis of thymic and splenic T cells from SLCK-KO showed no differences when compared to WT. In vitro analysis of SLCK-KO T cells, with either allo-splenocytes or non-specific CD3/CD28 antibodies demonstrated reduced activation (CD69, CD44), proliferation, and secretion of T helper signature cytokines (IFNγ, IL-4, IL-17) (P&lt;0.003). In vivo studies utilizing multiple MHC disparate models of BMT (B6→BALB/c, B6→B6D2F1), demonstrated that SLCK-KO T cells in the recipient animals caused reduced severity of GVHD and increased survival (P&lt;0.01). Similar results were obtained in vitro and in vivo with small molecule, MLN4924. Our results demonstrate a novel biological role for neddylation in regulating T cell functions in vitro and in vivo.

The role of dendritic cells in graft-versus-tumor effect

Dendritic cells (DCs) are the most potent antigen presenting cells. DCs play a pivotal role in determining the character and magnitude of immune responses to tumors. Host and donor hematopoietic-derived DCs play a critical role in the development of graft-versus-host disease (GVHD) following allogeneic hematopoietic cell transplantation. GVHD is tightly linked with the graft-versus-tumor (GVT) effect. Although both host and donor DCs are important regulators of GVHD, the role of DCs in GVT is poorly understood. GVT is caused by donor T cells that attack recipient tumor cells. The donor T cells recognize alloantigens, and tumor specific antigens (TSAs) are mediating GVHD. The process of presentation of these antigens, especially TSAs remains unknown. Recent data suggested that DC may be essential role for inducing GVT. The mechanisms that DCs possess may include direct presentation, cross-presentation, cross-dressing. The role they play in GVT will be reviewed.

Allogeneic T cell responses are regulated by a specific miRNA-mRNA network

Donor T cells that respond to host alloantigens following allogeneic bone marrow transplantation (BMT) induce graft-versus-host (GVH) responses, but their molecular landscape is not well understood. MicroRNAs (miRNAs) regulate gene (mRNA) expression and fine-tune the molecular responses of T cells. We stimulated naive T cells with either allogeneic or nonspecific stimuli and used argonaute cross-linked immunoprecipitation (CLIP) with subsequent ChIP microarray analyses to profile miR responses and their direct mRNA targets. We identified a unique expression pattern of miRs and mRNAs following the allostimulation of T cells and a high correlation between the expression of the identified miRs and a reduction of their mRNA targets. miRs and mRNAs that were predicted to be differentially regulated in allogeneic T cells compared with nonspecifically stimulated T cells were validated in vitro. These analyses identified wings apart-like homolog (Wapal) and synaptojanin 1 (Synj1) as potential regulators of allogeneic T cell responses. The expression of these molecular targets in vivo was confirmed in MHC-mismatched experimental BMT. Targeted silencing of either Wapal or Synj1 prevented the development of GVH response, confirming a role for these regulators in allogeneic T cell responses. Thus, this genome-wide analysis of miRNA-mRNA interactions identifies previously unrecognized molecular regulators of T cell responses.