Histopathological maturation in juvenile xanthogranuloma: a blueberry muffin infant mimicking aleukemic leukemia cutis.

Juvenile xanthogranuloma (JXG) is usually identified by Touton giant cells, so their absence can complicate diagnosis. We encountered a case of non-typical neonatal JXG lacking Touton giant cells, which was difficult to differentiate from aleukemic leukemia cutis because of overlapping histopathological characteristics. A 1 month-old girl presented with a blueberry muffin rash and multiple 1-2 cm nodules within the subcutaneous and deeper soft tissues. Blood tests revealed pancytopenia. The initial nodule biopsy showed mononuclear cell infiltration, suggestive of mature monocytes or histiocytes, but no Touton giant cells. Bone marrow examination showed no evidence of leukemia. Despite worsening of the rash, pancytopenia, and weight gain over the following month, the results of the second biopsy remained consistent with the initial findings. Consequently, we provisionally diagnosed aleukemic leukemia cutis and initiated chemotherapy. After two courses of chemotherapy, the pancytopenia improved, but the nodules only partially regressed. A third biopsy of the nodule was performed to evaluate the histological response, and revealed Touton giant cells, confirming the diagnosis of JXG. In conclusion, distinguishing non-typical JXG from aleukemic leukemia cutis is challenging. This case highlights the importance of multiple biopsies and the potential for histopathological maturation.

Irisin protected hemopoietic stem cells and improved outcome of severe bone marrow failure.

Acquired aplastic anemia (AA) is a bone marrow failure (BMF) disease, characterized by fatty bone marrow (BM) and BM hypocellularity resulted from auto-immune dysregulated T cells-mediated destruction of BM haemopoietic stem cells (HPSC). The objective of this study was to investigate potential therapeutic effect of irisin, a molecule involved in adipose tissue transition, on AA mouse model. Our results showed that the concentration of irisin in serum was lower in AA patients than in healthy controls, suggesting a role of irisin in the pathogenesis of AA. In the AA mice, irisin administration prolonged the survival rate, prevented or attenuated peripheral pancytopenia, and preserved HPSC in the BM. Moreover, irisin also markedly reduced BM adipogenesis. In vitro results showed that irisin increased both cell proliferation and colony numbers of HPSC. Furthermore, our results demonstrated that irisin upregulated the expression of mitochondrial ATPase Inhibitory Factor 1 (IF1) in HPSC, inhibited the activation of mitochondrial fission protein (DRP1) and enhanced aerobic glycolysis. Taken together, our findings indicate novel roles of irisin in the pathogenesis of AA, and in the protection of HPSC through stimulation of proliferation and regulation of mitochondria function, which provides a proof-of-concept for the application of irisin in AA therapy.

Pancytopenia in celiac disease-A case series of 20 children.

Pancytopenia in children with celiac disease (CeD) is postulated to be due to nutritional deficiency such as vitamin B12, folate and copper or an autoimmune process resulting in aplastic anemia with hypoplastic marrow. In the present case series, we report the profile and explore the etiology of pancytopenia among children with CeD. There are only a few case reports of pancytopenia in children with CeD. We enrolled newly diagnosed cases of CeD and pancytopenia presenting in the celiac disease clinic over three years. Detailed evaluation was carried out for the cause of pancytopenia. We followed up on the cases for compliance and response to gluten-free diet at three months, six months and 12 months. Twenty patients were eligible for inclusion. They were divided into two groups: one with aplastic anemia with hypoplastic marrow labeled as Gp CeD-AA and the other with megaloblastic/nutritional anemia labeled as Gp CeD-MA. Patients in Gp CeD-MA presented with classical symptoms of CeD as recurrent diarrhea, abdomen distension, pallor and poor weight gain. They had none or just one transfusion requirement and had an early and complete recovery from pancytopenia. Patients in Gp CeD-AA presented with atypical symptoms such as epistaxis, short stature, fever, pallor and weakness. They had a multiple blood transfusion requirement and had delayed and partial recovery from pancytopenia. Pancytopenia is not a disease in itself but is the presentation of an underlying disease. It can occur due to various coexisting disorders in children with CeD, which can be as simple as nutritional deficiencies to as complex as an autoimmune process or malignancy. CeD should be included in the differential diagnosis of aplastic anemia as CeD and aplastic anemia both have a similar pathological process involving T cell destruction of tissues.

Bone marrow oxalosis with pancytopenia in a patient with short bowel syndrome: Report of a case and review of the literature.

Systemic oxalosis is a condition in which calcium oxalate crystals deposit into various bodily tissues. Although this may occur as the result of a rare primary syndrome in which an error of glyoxylate metabolism causes an overproduction of oxalate, it is more often seen as a secondary process characterized by increased enteric oxalate absorption. Here, we describe a patient with short bowel syndrome on long-term parenteral nutrition support who developed a unique manifestation of systemic oxalosis, leading to deposition of oxalate crystals within the bone marrow contributing to pancytopenia. In this report, in addition to reviewing the literature on this presumably rare manifestation of oxalosis, we also discuss its pathogenesis in the setting of short bowel syndrome and its management, including prevention.

Efficacy of JAK1/2 inhibition in murine immune bone marrow failure.

Immune aplastic anemia (AA) is a severe blood disease characterized by T-lymphocyte- mediated stem cell destruction. Hematopoietic stem cell transplantation and immunosuppression are effective, but they entail costs and risks, and are not always successful. The Janus kinase (JAK) 1/2 inhibitor ruxolitinib (RUX) suppresses cytotoxic T-cell activation and inhibits cytokine production in models of graft-versus-host disease. We tested RUX in murine immune AA for potential therapeutic benefit. After infusion of lymph node (LN) cells mismatched at the major histocompatibility complex [C67BL/6 (B6)⇒CByB6F1], RUX, administered as a food additive (Rux-chow), attenuated bone marrow hypoplasia, ameliorated peripheral blood pancytopenia, preserved hematopoietic progenitors, and prevented mortality, when used either prophylactically or therapeutically. RUX suppressed the infiltration, proliferation, and activation of effector T cells in the bone marrow and mitigated Fas-mediated apoptotic destruction of target hematopoietic cells. Similar effects were obtained when Rux-chow was fed to C.B10 mice in a minor histocompatibility antigen mismatched (B6⇒C.B10) AA model. RUX only modestly suppressed lymphoid and erythroid hematopoiesis in normal and irradiated CByB6F1 mice. Our data support clinical trials of JAK/STAT inhibitors in human AA and other immune bone marrow failure syndromes.

[The characterization analysis of pathogenic T cells in immune-mediated aplastic anemia mouse model].

Objective: This study aims, in addition to characterizing pathogenic T cells trafficking to bone marrow (BM) and other organs, to establish immune-mediated AA C.B10 mouse model by DsRed mouse (B6 background) lymph nodes (LN) cells infusion after a total body irradiation (TBI) . Methods: The C.B10 mice received a 5 Gy TBI and then were infused with DsRed mouse (B6 background) LN cells at 5×10(6)/mouse via a tail vein injection. The severity of bone marrow failure (BMF) was observed by mononuclear cell count in bone marrow and peripheral blood cell count. On days 3, 6, 9, and 12, mice were sacrificed and collected BM, spleens, LN, or thymus to analyze the dynamic change and activation status of donor T cells in these organs by a flow cytometry. At day 12, the donor-derived T cells from BM, spleens, and LN were sorted to collect the DsRed(+)CD3(+)CD4(+) T cells and DsRed(+)CD3(+)CD8(+) T cells for RNA isolation and gene expression analyses by PCR array. Results: Relative to control animals that received 5 Gy TBI without LN cell infusion, AA mice developed severe BMF with dramatic decrease in total BM cells, hemoglobin, white blood cells, and platelets in peripheral blood on days 9 and 12 after the LN cell infusion. The frequencies of DsRed(+) T cells trafficking to BM, LN, and spleens increased with time. Surprisingly, although the DsRed(+) T cells in BM increased dramatically at a level much higher than those in the spleens and LN on day 12, there were very few DsRed(+) T cells in BM on days three and six, which was significantly lower than those in spleens or LN. The frequency of DsRed(+) T cells in thymus was the lowest during the whole process. On day 12, the DsRed(+)CD3(+)CD4(+) T cells of BM, LN, and spleens from AA mice were (91.38±2.10) %, (39.78±6.98) %, and (67.87±12.77) %, respectively. On the contrary, the DsRed(+)CD3(+)CD8(+)T cells of BM, LN, and spleens were (98.21±1.49) %, (94.06±4.20) %, and (96.29±1.23) %, respectively. We assessed the donor T cell phenotypes using the CD44 and CD62L markers and found that almost all of the DsRed(+)CD4(+) or DsRed(+)CD8(+) T cells in BM were effector memory T cell phenotype from day 9 to day 12. Meanwhile, transcriptome analyses showed higher expression in CD38, IFN-γ, LAG3, CSF1, SPP1, and TNFSF13B in BM DsRed(+)CD4(+) and DsRed(+)CD8(+) T cells. However, there was a lower expression in FOXP3 and CTLA4 in BM DsRed(+)CD4(+) T cells than those in spleens and LN. Conclusions: The DsRed LN cells infusion to induce BMF in CB10 mice enabled to track the donor-derived pathogenic T cells. Besides previously published findings in this model, we demonstrated that donor CD4(+) and CD8(+) T cells primarily homed to spleens and LN, expanded and differentiated, then infiltrated in BM with a terminal effector memory phenotype. The T cells infiltrated in BM showed more activation and less immunosuppression characteristics compared to those homing to spleens and LN during the BMF development.

SAMD9L autoinflammatory or ataxia pancytopenia disease mutations activate cell-autonomous translational repression.

Sterile α motif domain-containing protein 9-like (SAMD9L) is encoded by a hallmark interferon-induced gene with a role in controlling virus replication that is not well understood. Here, we analyze SAMD9L function from the perspective of human mutations causing neonatal-onset severe autoinflammatory disease. Whole-genome sequencing of two children with leukocytoclastic panniculitis, basal ganglia calcifications, raised blood inflammatory markers, neutrophilia, anemia, thrombocytopaenia, and almost no B cells revealed heterozygous de novo SAMD9L mutations, p.Asn885Thrfs*6 and p.Lys878Serfs*13. These frameshift mutations truncate the SAMD9L protein within a domain a region of homology to the nucleotide-binding and oligomerization domain (NOD) of APAF1, ∼80 amino acids C-terminal to the Walker B motif. Single-cell analysis of human cells expressing green fluorescent protein (GFP)-SAMD9L fusion proteins revealed that enforced expression of wild-type SAMD9L repressed translation of red fluorescent protein messenger RNA and globally repressed endogenous protein translation, cell autonomously and in proportion to the level of GFP-SAMD9L in each cell. The children's truncating mutations dramatically exaggerated translational repression even at low levels of GFP-SAMD9L per cell, as did a missense Arg986Cys mutation reported recurrently as causing ataxia pancytopenia syndrome. Autoinflammatory disease associated with SAMD9L truncating mutations appears to result from an interferon-induced translational repressor whose activity goes unchecked by the loss of C-terminal domains that may normally sense virus infection.

Pretransplant bone marrow cellularity and blood count recovery are not associated with relapse or survival risk following allogeneic stem cell transplant for AML in CR.

INTRODUCTION: Allogeneic hematopoietic cell transplantation (HCT) can be curative for acute myeloid leukemia (AML). Novel therapies may render patients' bone marrow hypocellularity and lead to prolonged post-therapy pancytopenia. Patients' bone marrow cellularity (BMC) at pretransplant assessment and post-treatment pancytopenia (classification CR-incomplete [CRi]) may manifest AML persistence. METHODOLOGY: We retrospectively examined the impact of BMC and ELN response (ELNr) on a single-center cohort of 337 patients who underwent allogeneic HCT for AML in CR1. RESULTS: Median follow-up was 33 months. Overall survival (OS) for the whole cohort was 55.8% at 2 years, while cumulative incidence of relapse (CIR) was 20.8%, and non-relapse mortality was 27.5%. OS and CIR were not significantly different between BMC groups; and neither was ELNr. ELNr CRi was associated with BMC aplastic and hypocellular marrow states (P < 2.6e-8). Multivariate analysis confirmed neither BMC nor attainment of ELNr CR vs CRi affected OS or relapse. Significant factors for survival included age at transplant, cytogenetic risk, development of acute Gr II-IV GvHD, and moderate-severe chronic GvHD, while cytogenetic risk and chronic GvHD affected relapse. CONCLUSION: Neither ELNr status nor pretransplant BMC influenced relapse post-HCT or OS. Hypocellularity and CRi are not negative prognostic factors for post-HCT outcomes of AML.

Gray Platelet Syndrome Presenting With Pancytopenia, Splenomegaly, and Bone Marrow Fibrosis.

OBJECTIVES: Gray platelet syndrome (GPS) is a rare platelet storage pool disorder associated with a marked decrease or absence of platelet α-granules and their contents. It is characterized clinically by mild to moderate bleeding; moderate macrothrombocytopenia with large, agranular platelets; splenomegaly; and bone marrow fibrosis. Electron microscopy confirms markedly reduced or absent α-granules in platelets and megakaryocytes. The classic description of GPS is caused by homozygous mutations in NBEAL2 (neurobeachinlike 2). METHODS: A 28-year-old Hispanic man with a history of easy bruising and occasional episodes of epistaxis sought treatment for pancytopenia and splenomegaly. Peripheral blood smear and bone marrow analysis, electron microscopy, and next-generation sequencing were performed. RESULTS: Large and agranular platelets were present in the peripheral blood. There was bone marrow fibrosis. Electron microscopy of the platelets showed absence of α-granules. Next-generation sequencing revealed a germline apparently homozygous nonsense variant in the NBEAL2 gene: c.5674C>T, p.Gln1892X (p.Q1829X). CONCLUSIONS: The differential diagnosis of GPS includes a myeloid neoplasm such as myelodysplastic syndrome with bone marrow fibrosis. The availability of diagnostic genetic panels for hereditable platelet disorders can assist in the recognition of GPS and other platelet disorders. We also describe a previously unreported pathogenic germline homozygous nonsense variant in the NBEAL2 gene: c.5674C>T, p.Gln1892X (p.Q1829X) in a patient with GPS.

Bone marrow trephine biopsies from posterior superior iliac crest in neonates.

Cytopenias are common among neonates in neonatal intensive care units (NICU). Although, bone marrow aspirations (BMAs) are often performed as part of diagnostic workup, but trephine bone marrow biopsies (BMBs) have not been reported from living neonates. BMB is indispensable to accurately assess the cellularity and architecture. There is paucity of literature regarding the technique of BMB in neonates. In this report, for the first time, we describe trephine BMB from posterior superior iliac crest (PSIC) using 18-gauge BMA needle in six living neonates admitted to NICU where BMB findings helped in understanding the underlying mechanism and diagnosis of cytopenias.

Immunodeficiency and bone marrow failure with mosaic and germline TLR8 gain of function.

Inborn errors of immunity (IEI) are a genetically heterogeneous group of disorders with a broad clinical spectrum. Identification of molecular and functional bases of these disorders is important for diagnosis, treatment, and an understanding of the human immune response. We identified 6 unrelated males with neutropenia, infections, lymphoproliferation, humoral immune defects, and in some cases bone marrow failure associated with 3 different variants in the X-linked gene TLR8, encoding the endosomal Toll-like receptor 8 (TLR8). Interestingly, 5 patients had somatic variants in TLR8 with <30% mosaicism, suggesting a dominant mechanism responsible for the clinical phenotype. Mosaicism was also detected in skin-derived fibroblasts in 3 patients, demonstrating that mutations were not limited to the hematopoietic compartment. All patients had refractory chronic neutropenia, and 3 patients underwent allogeneic hematopoietic cell transplantation. All variants conferred gain of function to TLR8 protein, and immune phenotyping demonstrated a proinflammatory phenotype with activated T cells and elevated serum cytokines associated with impaired B-cell maturation. Differentiation of myeloid cells from patient-derived induced pluripotent stem cells demonstrated increased responsiveness to TLR8. Together, these findings demonstrate that gain-of-function variants in TLR8 lead to a novel childhood-onset IEI with lymphoproliferation, neutropenia, infectious susceptibility, B- and T-cell defects, and in some cases, bone marrow failure. Somatic mosaicism is a prominent molecular mechanism of this new disease.

Acquisition of monosomy 7 and a RUNX1 mutation in Pearson syndrome.

Pearson syndrome (PS) is a very rare and often fatal multisystem disease caused by deletions in mitochondrial DNA that result in sideroblastic anemia, vacuolization of marrow precursors, and pancreatic dysfunction. Spontaneous recovery from anemia is often observed within several years of diagnosis. We present the case of a 4-month-old male diagnosed with PS who experienced prolonged severe pancytopenia preceding the emergence of monosomy 7. Whole-exome sequencing identified two somatic mutations, including RUNX1 p.S100F that was previously reported as associated with myeloid malignancies. The molecular defects associated with PS may have the potential to progress to advanced myelodysplastic syndrome .

Bone Marrow Sarcoidosis with Pancytopenia and Renal Failure Presenting as Fever of Unknown Origin: The Pivotal Role of 18F-FDG PET/CT in Lesion Detection.

We describe a case of fever of unknown origin (FUO), renal failure, and pancytopenia. Initially, lymph proliferative disorder was suspected; therefore, bone marrow biopsy and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) were performed. Bronchoscopy and lung biopsy were performed because of abnormal FDG uptake in both lung fields. Imaging data and laboratory and histological results confirmed sarcoidosis with bone marrow invasion. The patient was discharged after favorable response to corticosteroid therapy. Sarcoidosis may present as FUO without typical specific presentations in the skin or lungs. Combined 18F-FDP PET/CT helped identify the biopsy site and confirmed the sarcoidosis diagnosis.

Bone marrow stromal cell therapy improves survival after radiation injury but does not restore endogenous hematopoiesis.

The only available option to treat radiation-induced hematopoietic syndrome is allogeneic hematopoietic cell transplantation, a therapy unavailable to many patients undergoing treatment for malignancy, which would also be infeasible in a radiological disaster. Stromal cells serve as critical components of the hematopoietic stem cell niche and are thought to protect hematopoietic cells under stress. Prior studies that have transplanted mesenchymal stromal cells (MSCs) without co-administration of a hematopoietic graft have shown underwhelming rescue of endogenous hematopoiesis and have delivered the cells within 24 h of radiation exposure. Herein, we examine the efficacy of a human bone marrow-derived MSC therapy delivered at 3 h or 30 h in ameliorating radiation-induced hematopoietic syndrome and show that pancytopenia persists despite MSC therapy. Animals exposed to radiation had poorer survival and experienced loss of leukocytes, platelets, and red blood cells. Importantly, mice that received a therapeutic dose of MSCs were significantly less likely to die but experienced equivalent collapse of the hematopoietic system. The cause of the improved survival was unclear, as complete blood counts, splenic and marrow cellularity, numbers and function of hematopoietic stem and progenitor cells, and frequency of niche cells were not significantly improved by MSC therapy. Moreover, human MSCs were not detected in the bone marrow. MSC therapy reduced crypt dropout in the small intestine and promoted elevated expression of growth factors with established roles in gut development and regeneration, including PDGF-A, IGFBP-3, IGFBP-2, and IGF-1. We conclude that MSC therapy improves survival not through overt hematopoietic rescue but by positive impact on other radiosensitive tissues, such as the intestinal mucosa. Collectively, these data reveal that MSCs could be an effective countermeasure in cancer patients and victims of nuclear accidents but that MSCs alone do not significantly accelerate or contribute to recovery of the blood system.

Pembrolizumab-induced pancytopenia in a patient with squamous cell lung cancer.

Immune checkpoint inhibitors (ICIs) are reportedly effective against many kinds of neoplasm, but may be responsible for several kinds of immune-related adverse events (irAEs). Among these irAEs, the incidence of myelosuppression due to ICIs is relatively low. Corticosteroids are needed to control most cases of myelosuppression. Here, we report an 88-year-old woman with squamous cell lung cancer who was administered pembrolizumab. After five cycles of pembrolizumab, she developed severe pancytopenia. The pancytopenia improved under observation without steroid administration after cessation of pembrolizumab. During recovery from this irAE, the patient also maintained long-term antitumor efficacy. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: There are several kinds of immune-related adverse events. We encountered a case of pembrolizumab-induced pancytopenia with squamous cell lung cancer. WHAT THIS STUDY ADDS: Corticosteroids are needed to control most cases of myelosuppression induced by ICIs, but pancytopenia induced by pembrolizumab in our case improved without steroids.