Relapses of multisystem/multifocal bone Langerhans cell histiocytosis in paediatric patients: Data analysis from the JLSG-96/02 study.

We assessed relapse patterns in paediatric patients with relapsed Langerhans cell histiocytosis (LCH) who were initially treated with the JLSG-96/02 protocol. We analysed 187 relapse events in 101 relapsed LCH patients [31 with multifocal bone (MFB) and 70 with multisystem (MS) at LCH diagnosis] among a total 317 patients enrolled in JLSG-96/-02 studies. Relapse of LCH was defined as an exacerbation of the non-active disease (NAD) condition. Of the 317 patients, 101 (31.9%) had the first relapse at 1.5 years after initiation of therapy. The first relapse and subsequent relapses did not differ between patients with MFB and MS disease. Of the 187 relapse events, relapse occurred as a single-system disease (n = 159; 85%), in which isolated bone relapse (n = 104; 55%) was the most common. Relapse at MS disease with the risk of organ involvement is extremely rare. After relapse(s), most patients underwent chemotherapy (122/187; 65%) and 87% of them achieved NAD status again. The incidence of permanent consequences was significantly higher in patients with relapses than in those without relapses. In the JLSG cohort, bone relapse most occurred in both MFB and MS patients. Most relapses could be effectively controlled by repeated administration of the initial chemotherapy.

Juvenile Hemochromatosis With Non-transfused Hemolytic Anemia Caused by a De Novo PIEZO1 Gene Mutation.

Differential diagnosis of juvenile hemochromatosis along with hemolytic anemia is often difficult. We report a 23-year-old woman with macrocytic hemolytic anemia with iron overload. The patient showed high serum ferritin and transferrin saturation and low serum transferrin and ceruloplasmin. We also noticed stomatocytes in her blood smear, which was confirmed by scanning electron microscopy. Target gene sequencing identified a mutation in PIEZO1 (heterozygous c.6008C>A: p.A2003D). This mutation was reported previously in a family with dehydrated hereditary stomatocytosis (DHS1, [OMIM 194380]), but in the current case, it was identified to be a de novo mutation. We underscore DHS1 in the differential diagnosis of iron overload associated with non-transfused hemolytic anemia in children and young adults.

Puzzling (IRIDA-Like and Hemolytic) Anemia in a Child With Idiopathic Pulmonary Hemosiderosis.

Before the diagnosis of idiopathic pulmonary hemosiderosis (IPH), unexplained or puzzling anemia may precede and delay in the diagnosis of pediatric IPH is common. A 5.8 years old female child initiated with iron-refractory iron deficiency anemia-like iron deficiency and hemolytic anemia and at 6.8 years of age IPH was materialized, when the patient showed the triad signs of IPH with hemosiderin-laden alveolar macrophages in gastric aspirate. Although time to the diagnosis was previously reported to be ranged from 16 to 30 months, in our case it took 12 months from the initial anemia to IPH diagnosis.

Bone lesions of Langerhans cell histiocytosis triggered by trauma in children.

BACKGROUND: Bone lesions of Langerhans cell histiocytosis (LCH) may be triggered by trauma. METHODS: The characteristics of pediatric patients in the JLSG-02 study cohort who developed a bone lesion at the trauma site at diagnosis of LCH were analyzed retrospectively. RESULTS: Of the 261 pediatric patients with LCH, 12 (4.6%), of median age 4.9 years, had trauma-triggered bone LCH lesions at diagnosis, making them significantly older than the remaining patients (P = 0.006). Trauma sites included the craniofacial regions in 10 patients and the lumbar spine and pelvis in one patient each. At the time of trauma, six patients had a bump at the site, whereas none had extradural hematomas or bone fractures. The median time from trauma to onset was 4 weeks. Of these 12 patients, three had isolated bone (IB) disease; four had multifocal bone (MFB) disease, including the bone lesion at the trauma site; and five had multisystem disease, including four with lesions in neighboring tissue and one with polyuria (posterior pituitary lesion) more than 1 year before the trauma-triggered bone lesion. Treatment responses were good in all 12 patients and none died, but relapses were observed in two patients, one each with IB and MFB disease. CONCLUSIONS: About 5% of pediatric patients with LCH developed new trauma-triggered bone lesions at a relatively old age. These lesions can manifest as IB, or, in patients with underlying LCH diseases, as MFB or multisystem. Good clinical outcomes were observed in these patients.

Long-term complications in uniformly treated paediatric Langerhans histiocytosis patients disclosed by 12 years of follow-up of the JLSG-96/02 studies.

Langerhans cell histiocytosis (LCH) is a rare inflammatory myeloid neoplasia derived from immature myeloid dendritic cells with the mitogen-activated protein kinase (MAPK) pathway gene mutation. LCH is rarely fatal, but patients develop various permanent consequences (PCs). We report the frequencies of LCH-related PCs in paediatric patients (n = 317) treated by the JLSG-96/02 AraC-containing regimens. One-third of LCH patients had at least one PC at a median follow-up of 12 years. Central nervous system (CNS)-related PCs (neurological and endocrinological) accounted for 21·5%, non-CNS-related 16·7%. We require novel therapeutic measures to further reduce the frequency of LCH-related PCs.

Virus-triggered secondary hemophagocytic lymphohistiocytosis.

Primary (familial/hereditary) and secondary (non-familial/hereditary) hemophagocytic lymphohistiocytosis (HLH) are hyperinflammatory and hypercytokinemic syndromes. Secondary HLH includes infection- (eg viral/bacterial/fungal/parasitic) and non-infection- (eg collagen disease or malignancy) related diseases. Viral HLH is the major type among all age groups. Secondary viral HLH and primary HLH must be differentiated carefully because primary HLH can be associated with viral infection(s), and the outcome is dismal without a timely diagnosis and hematopoietic stem cell transplantation (HSCT). Epstein-Barr virus (EBV)-related HLH (EBV-HLH) is the most common type of viral HLH in childhood. For non-EBV-HLH, appropriate treatment of viral infection, followed by immunomodulatory agent(s) such as corticosteroids, intravenous immunoglobulin or cyclosporine A, is usually successful; however, recent SARS-CoV-2-related HLH may become life-threatening. EBV-HLH may occur heterogeneously associated with the primary infection, with chronic active EBV infection or with underlying primary HLH. Although immunomodulatory agent(s) are effective in the majority of EBV-HLH cases, management differs from that of non-EBV-HLH because severe and refractory cases may require etoposide-containing HLH-1994/2004 regimens or other experimental agents. The novel agent, emapalumab (an anti-IFN-γ monoclonal antibody) can be used to treat EBV-HLH cases to avoid the risk of secondary malignancy due to etoposide. Finally, HSCT is required for refractory EBV-HLH cases and can also be curative in some other cases.

[Successful unrelated cord blood transplantation for extensive meningeal juvenile xanthogranuloma developing after treatment of Langerhans cell histiocytosis in a child].

A 2-year and 4-month-old boy developed Langerhans cell histiocytosis (LCH) at the left parietal region of the skull. After treatment with chemotherapy, the patient achieved remission but experienced three relapses. After 3 years, he complained of headache, blurred vision, and lethargy. Brain magnetic resonance imaging revealed multiple dura-based meningeal masses. Biopsy was performed, and the patient was then diagnosed with juvenile xanthogranuloma (JXG). The analysis of both LCH/JXG tissues revealed BRAF V600E mutation. The JXG masses were not responsive to prednisolone, which was injected locally, radiotherapy (24 Gy), and chemotherapy (2-chlorodeoxy-adenosine). In addition, since the patient developed macrophage activation syndrome associated with systemic JXG progression, he received unrelated cord blood transplantation (u-CBT) at the age of 10 years and 11 months. Engraftment was performed at day 42, and significant GVHD was not observed. Four months after CBT, the patient was treated with infliximab (Remicade®) and dexamethasone palmitate (Limethasone®). The size of the intracranial JXG masses gradually decreased after u-CBT and disappeared after 4 years. Currently, the patient is doing well at the age of 25 years and is receiving androgen replacement therapy.

Central diabetes insipidus in pediatric patients with Langerhans cell histiocytosis: Results from the JLSG-96/02 studies.

PURPOSE: We analyzed central diabetes insipidus (CDI) development in pediatric patients with Langerhans cell histiocytosis (LCH) treated according to the Japan LCH Study Group (JLSG) regimen, which is the combination chemotherapy including cytarabine (Ara-C). METHODS: Retrospective data from 317 patients (multisystem disease (MS), n = 206; multiple focal bone (MFB), n = 111) treated according to the JLSG-96/02 regimens were analyzed. RESULTS: The median follow-up duration was 10.6 years (range, 0.1-21.1). A total of 50/317 (15.8%) patients developed CDI (MFB, n = 4; MS, n = 46). Of the 50 cases, CDI was already present at the time of LCH diagnosis (pre-CDI) in 25, and it newly developed after the diagnosis and initiation of treatment (post-CDI) in the other 25 cases. The cumulative incidence of post-CDI at 10-year calculated by Kaplan-Meier analysis was 9.0% for total and 12.0% for MS patients. A positive correlation with LCH lesions at the CNS risk sites at diagnosis was found in pre-CDI cases (17/164 vs 8/171; P = 0.0359), but not in post-CDI cases (14/129 vs 11/163; P = 0.254). Multivariate analysis showed that relapse at the CNS risk sites was significantly associated with post-CDI development (hazard ratio: 4.70; 95% CI, 1.29-17.1, P < 0.05). CONCLUSIONS: In the JLSG-96/02 studies, CDI developed in 15.8% of the cohort in which half as pre- and the other half as post-CDI. Relapse, particularly at the CNS risk sites, was linked with the development of post-CDI.

Acquired Factor V Deficiency Associated with CFPM Administration.

BACKGROUND: Acquired factor V deficiency (AFVD) caused by Factor V (FV) inhibition is a rare event, characterized by prolonged prothrombin time and activated partial thromboplastin time. To date, various factors were reported as triggers for developing FV inhibitor. Clinical symptoms range from asymptomatic to life-threatening bleeding. Case Report and Conclusions: Here, we report an 84-year-old Japanese male on hemodialysis due to renal failure who developed subcutaneous hemorrhage after administration of cefepime (CFPM) to treat bacteremia. Deficient FV activity (< 1.0%) was identified and AFVD with FV inhibitor titer of 9 BU/mL was diagnosed. Although the patient had multiple risks for developing FV inhibitor, CFPM was thought to be the major culprit in this case. After the diagnosis, oral prednisolone (30 mg/day) was initiated, but the patient died of respiratory/cardiac failure, unrelated to AFVD.

Merkel cell polyomavirus and Langerhans cell neoplasm.

BACKGROUND: The relationship between various external agents such as pollen, food, and infectious agents and human sensitivity exists and is variable depending upon individual's health conditions. For example, we believe that the pathogenetic potential of the Merkel cell polyomavirus (MCPyV), the resident virus in skin, is variable and depends from the degree of individual's reactivity. MCPyV as well as Epstein-Barr virus, which are normally connected with humans under the form of subclinical infection, are thought to be involved at various degrees in several neoplastic and inflammatory diseases. In this review, we cover two types of Langerhans cell neoplasms, the Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH), represented as either neoplastic or inflammatory diseases caused by MCPyV. METHODS: We meta-analyzed both our previous analyses, composed of quantitative PCR for MCPyV-DNA, proteomics, immunohistochemistry which construct IL-17 endocrine model and interleukin-1 (IL-1) activation loop model, and other groups' data. RESULTS: We have shown that there were subgroups associated with the MCPyV as a causal agent in these two different neoplasms. Comparatively, LCS, distinct from the LCH, is a neoplastic lesion (or sarcoma) without presence of inflammatory granuloma frequently observed in the elderly. LCH is a proliferative disease of Langerhans-like abnormal cells which carry mutations of genes involved in the RAS/MAPK signaling pathway. We found that MCPyV may be involved in the development of LCH. CONCLUSION: We hypothesized that a subgroup of LCS developed according the same mechanism involved in Merkel cell carcinoma pathogenesis. We proposed LCH developed from an inflammatory process that was sustained due to gene mutations. We hypothesized that MCPyV infection triggered an IL-1 activation loop that lies beneath the pathogenesis of LCH and propose a new triple-factor model.

Thrombotic Microangiopathy-Like Hemolysis in Vitamin B12 Deficiency-Related Macrocytic Anemia.

BACKGROUND: Hemolytic features in patients with pernicious anemia have not been emphasized. METHODS: Seven Japanese patients at 60 - 88 years of age with vitamin B12 deficiency-related hemolytic anemia were assessed. RESULTS: Serum vitamin B12 levels in these cases were 46 - 89 pg/mL (normal reference range: 233 - 914 pg/mL). Clinically, the patients presented with thrombotic microangiopathy (TMA)-like hemolytic features (including macrocytic anemia, schistocytes on blood smears, high serum lactate dehydrogenase, hyperbilirubinemia, and low serum haptoglobin). Six cases had type A gastritis (assessed by esophagogastroduodenoscopy with hypergastrinemia) with additional laboratory data of high plasma homocysteine levels and anti-intrinsic factor/anti-parietal cell antibodies. One case was in post-gastrectomy condition. Following treatment with vitamin B12, anemia resolved within 4 weeks in five of the seven cases except for two cases of delayed response. CONCLUSIONS: In elderly patients exhibiting hemolytic features in association with macrocytic anemia, vitamin B12 deficiency should be considered in the differential diagnosis.

Inflammatory serum cytokines and chemokines increase associated with the disease extent in pediatric Langerhans cell histiocytosis.

OBJECTIVE: Langerhans cell histiocytosis (LCH) is characterized by immature dendritic cell proliferation, infiltration of LCH lesions by various inflammatory cells, and a lesional cytokine storm. It is classified into three groups on the basis of disease extent, namely, multisystem with risk-organ involvement (MS+), multisystem without risk-organ involvement (MS-), and single-system (SS) disease. We comprehensively analyzed whether serum levels of cytokines/chemokines reflect the disease extent. METHODS: Serum samples from 52 children with LCH (eight, 25, and 19 with MS+, MS-, and SS, respectively) and 34 control children were analyzed quantitatively for 48 humoral factors. DNA samples extracted from biopsied LCH lesions from 12 patients were tested for BRAF V600E status. RESULTS: The LCH patients had significantly higher serum levels of IL-1Ra, IL-3, IL-6, IL-8, IL-9, IL-10, IL12, IL-13, IL-15, IL-17, IL-18, TNF-α, G-CSF, M-CSF, MIF, HGF, VEGF, CCL2, CCL3, CCL7, CXCL1, and CXCL9 than the controls by univariate analysis. Of these IL-9, IL-15 and MIF were significant by multivariate analysis; but not differed between MS and SS diseases. MS disease associated with significantly higher IL-2R, IL-3, IL-8, IL-18, M-CSF, HGF, CCL2, CXCL1, and CXCL9 levels than SS disease by univariate analysis. Of these, CCL2 and M-CSF were significant by multivariate analysis. IL-18 levels were significantly higher in MS+ disease than MS- disease. The LCH patients with BRAF V600E mutation had higher serum levels of CCL7. CONCLUSION: Numerous inflammatory cytokines and chemokines play a role in LCH. Of those, more specific ones reflect the disease extent (MS vs. SS and MS+ vs. MS-) or the BRAF V600E mutation status. It is thought that the most responsible cytokines and chemokines involved in the poor outcome may become future candidate therapeutic targets in LCH.

Spontaneous Regression of Pulmonary Nodules Presenting as Epstein-Barr Virus-related Atypical Infectious Mononucleosis.

BACKGROUND: Pulmonary nodules associated with Epstein-Barr virus (EBV)-related atypical infectious mononucleosis have rarely been described. OBSERVATIONS: A 12-year-old Japanese boy, upon admission, revealed multiple small round nodules (a total of 7 nodules in 4 to 8 mm size) in the lungs on computed tomography. The hemorrhagic pharyngeal tonsils with hot signals on 18F-fluorodeoxyglucose-positron emission tomography-computed tomography were biopsied revealing the presence of EBV-encoded small nuclear RNA (EBER)-positive cells; however, no lymphoma was noted. The patient was diagnosed as having atypical EBV-infectious mononucleosis associated with primary EBV infection. Pulmonary nodules markedly reduced in numbers and sizes spontaneously over a 2-year period. CONCLUSIONS: Differential diagnosis of pulmonary nodules in childhood should include atypical EBV infection.

Case Reports of Severe Congenital Neutropenia Treated With Unrelated Cord Blood Transplantation With Reduced-intensity Conditioning.

Allogeneic stem cell transplantation is a curative treatment for severe congenital neutropenia (SCN). However, a standard conditioning regimen and donor source have not been established. We report 3 consecutive cases of SCN who were successfully treated by cord blood transplantation (CBT) with reduced-intensity conditioning consisting of fludarabine, melphalan, and low-dose total body irradiation. All cases achieved complete donor chimerism without severe infectious complications and have maintained normal neutrophil counts for between 3 and 9 years after CBT. These results suggest that CBT with reduced-intensity conditioning can be an alternative therapy for SCN when human leukocyte antigen-matched bone marrow donor is unavailable.

Acute-phase ITIH4 levels distinguish multi-system from single-system Langerhans cell histiocytosis via plasma peptidomics.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a proliferative disorder in which abnormal Langerhans cell (LC)-like cells (LCH cells) intermingle with inflammatory cells. Whether LCH is reactive or neoplastic remains a controversial matter. We recently described Merkel cell polyomavirus (MCPyV) as a possible causative agent of LCH and proposed interleukin-1 loop model: LCH is a reactive disorder with an underlying oncogenic potential and we now propose to test this theory by looking for acute markers of inflammation. We detected MCPyV-DNA in the peripheral blood cells of patients with high-risk organ-type (LCH-risk organ (RO) (+)) but not those with non-high-risk organ-type LCH (LCH-RO (-)); this difference was significant. LCH-RO (-) is further classified by its involvement of either a single organ system (SS-LCH) or multiple organ systems (MS-LCH). In patients with LCH-RO (-), MCPyV-DNA sequences were present in LCH tissues, and significant differences were observed between LCH tissues and control tissues associated with conditions such as dermatopathic lymphadenopathy and reactive lymphoid hyperplasia. Although MCPyV causes subclinical infection in nearly all people and 22 % of healthy adults will harbor MCPyV in their buffy coats, circulating monocytes could serve as MCPyV reservoirs and cause disseminated skin lesions. METHODS: Plasma sample from 12 patients with LCH-RO (-) (5 MS-LCH and 7 SS-LCH) and 5 non-LCH patients were analyzed by peptidomics. Mass spectrometry (MS) spectra were acquired and peptides exhibiting quantitative differences between MS-LCH and SS-LCH patients were targeted. RESULTS: One new candidate biomarker, m/z 3145 was selected and identified after obtaining a MS/MS fragmentation pattern using liquid chromatography-MS/MS. This peak was identified as a proteolytic fragment derived from inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4, [PDB: Q14624]). CONCLUSIONS: Peptidomics of LCH have revealed that the level of acute-phase ITIH4 distinguishes MS-LCH-RO (-) from SS-LCH-RO (-). Acute-phase proteins serve non-specific, physiological immune functions within the innate immune system. LCH may be a reactive disorder with both underlying neoplastic potential of antigen presenting cells harboring BRAF mutations and hyper-immunity of other inflammatory cells against MCPyV infection. Among LCH-RO (-), MCPyV-DNA sequences were present in both MS-LCH tissues and SS-LCH tissues without significant differences. ITIH4 may show that LCH activity or LCH subtypes correlates with the systemic or localized reactions of MCPyV infection.

Interleukin-1 loop model for pathogenesis of Langerhans cell histiocytosis.

We propose Langerhans cell histiocytosis (LCH) is an inflammatory process that is prolonged by mutations. We hypothesize that Merkel cell polyomavirus (MCPyV) infection triggers an interleukin-1 (IL-1) activation loop that underlies the pathogenesis of LCH. Langerhans cells (LCs) are antigen presenting cells in the skin. When LCs encounter exogenous antigens, they migrate from the epidermis into draining lymphoid tissues to initiate T-cell activity. It has been proposed that LC migration-related factors, including E-cadherin, matrix metalloproteinase, and Notch ligand induce LCH activity. We found that the tyrosine phosphatase SHP-1, which binds IL-1 receptor-associated kinase 1, is expressed at a significantly higher level in LCH affecting multiple organ systems (MS-LCH) than in LCH affecting a single organ system (SS-LCH). IL-1 stimulates T helper 17 cells and their signature cytokine IL-17 had been a matter of controversy. We detected higher levels of IL-17A receptor expression in MS-LCH than in SS-LCH and proposed an IL-17 endocrine model that could settle the controversy. IL-1 is the first cytokine secreted in response to sensitizers and promotes LC migration from sentinel tissues. Myeloid differentiation primary response 88 (MyD88), downstream of the IL-1 receptor, has functions in both RAS signaling and inflammation, leading to human cell transformation. In 2010, an activating mutation in the B-rapidly accelerated fibrosarcoma gene (BRAF) V600E was found in LCH. This BRAF mutation induces phosphorylation of the extracellular signal-regulated kinase (ERK) that may play an important role with MyD88 in LCH pathogenesis. However, phosphorylated ERK (pERK) is rapidly dephosphorylated by dual specificity phosphatase 6 (DUSP6), and limited proliferation is predicted in BRAF mutant cells. MyD88 binds pERK via its D-domain, thereby preventing pERK-DUSP6 interaction and maintaining ERK in an active, phosphorylated state. We detected MCPyV-DNA in the peripheral blood cells of two out of three patients with LCH in high-risk organs but not in those of patients with LCH in non-high-risk organs (0/12; P = .029). MCPyV infection can trigger precursor LCH cells with BRAF mutation to produce IL-1; the IL-1 loop is amplified in all LCH subclasses. Our model indicates both BRAF mutation and IL-1 loop regulation as potential therapeutic targets.

Sporadic Epstein syndrome with macrothrombocytopenia, sensorineural hearing loss and renal failure.

We report here a sporadic case of Epstein syndrome, one of the MYH9 disorders. A Japanese boy was first noted to have thrombocytopenia at 3 years of age. Blood smear showed giant platelets but no Döhle-like bodies in the neutrophils. He had no family history of thrombocytopenia, hearing loss, and/or renal failure. Thrombocytopenia took a chronic course and platelet count fluctuated in the range 18 000-46 000/µL, not responding to i.v. immunoglobulin or prednisolone treatment. The patient had episodes of gross nasal bleeding at 7 and 18 years of age. Mild hearing loss was suspected at 6, and proteinuria was first noted at 14 years of age. At the development of renal failure at 24 years of age, he was identified to have de novo R702H MYH9 mutation. This case illustrates the importance of suspecting MYH9 disorder even in cases of chronic macrothrombocytopenia without family history.

High serum osteopontin levels in pediatric patients with high risk Langerhans cell histiocytosis.

Osteopontin (OPN) acts as an osteoclast activator, a proinflammatory cytokine, and a chemokine attracting histiocytes/monocytes and is abundantly expressed in Langerhans cell histiocytosis (LCH). We investigated whether serum OPN levels are related to disease types in LCH. Fifty-eight newly diagnosed LCH patients were studied; eight with risk organ (liver, spleen and/or hematopoietic) involvements positive multisystem (MS+) disease, 27 with risk organ involvement negative multisystem (MS-) disease and 23 with single system (SS) disease. Pediatric patients with non-inflammatory disease (n=27) were used as controls. All of patients with MS+ disease were younger than 3 years. Serum OPN levels and 44 kinds of humoral factors were measured by ELISA and Bio-Plex suspension array system, respectively. In the patients younger than 3 years, the median serum OPN level (interquartile range) was 240.3 ng/ml (137.6-456.0) in MS+ (n=8); 92.7 ng/ml (62.0-213.8) in MS- (n=14) and 72.5 ng/ml (55.6-94.0) in SS (n=9) and 74.4 ng/ml (42.2-100.0) in control (n=12). The OPN values were significantly higher in the MS+ group than the MS-, SS and control groups (p=0.044, p=0.001 and p=0.002, respectively), but not different between the MS-, SS and control groups. In the patients older than 3 years, the median level of serum OPN (IQR) was 56.2 ng/ml (22.9-77.5) in MS- (n=13), 58.9 ng/ml (31.0-78.7) in SS (n=14) and 41.9 (28.9-54.1) in control (n=15). These values did not differ significantly between each group. The serum OPN levels were positively correlated with the serum IL-6, CCL2, IL-18, IL-8 and IL-2 receptor concentration. OPN may be involved in risk organ dissemination and poor prognosis of LCH through the function as inflammatory cytokine/chemokine.