Cerebellar peduncle damage in Langerhans cell histiocytosis-associated neurodegenerative disease revealed by diffusion tensor imaging.

PURPOSE: To confirm the hypothesis that brain white matter damage is involved in the pathogenesis and disease progression of Langerhans cell histiocytosis (LCH)-associated neurodegenerative disease (ND), we aimed to analyze pediatric patients with LCH using diffusion tensor imaging (DTI). METHODS: We enrolled 33 patients with LCH and obtained 33 DTI datasets. Using DTI-based tractography, fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD) were measured in the cerebral and cerebellar white matter tracts. The participants were divided into three groups-non-ND, ND without clinical symptoms (r-ND), and ND with clinical symptoms (c-ND)-according to their clinical status during the examination with DTI. We compared the DTI parameters in white matter tracts were compared among the three groups. RESULTS: In the order of non-ND, r-ND, and c-ND groups, the FA in superior cerebellar peduncle (SCP) and middle cerebellar peduncle (MCP) significantly decreased, the ADC, AD, and RD of MCP, and the RD of SCP were significantly elevated (FA-SCP; p < 0.001, FA-MCP; p = 0.026, ADC-MCP; p < 0.001, AD-MCP; p = 0.002, RD-MCP; p = 0.003, and RD-SCP; p = 0.018). Furthermore, in the simple linear regression analysis, the FA, ADC, AD, and RD values in the MCP and the FA value in the SCP were significantly influenced by the presence of neurological symptoms and ND findings on MRI (all p < 0.001). CONCLUSION: In LCH-ND, we identified microstructural damage in the SCP and MCP. DTI parameters in these tracts may help monitor LCH-ND; therefore, future studies are required to validate these results in a large cohort.

High Plasma Presepsin Levels in Children With Hemophagocytic Lymphohistiocytosis.

Presepsin is reported as a novel diagnostic and prognostic biomarker for sepsis, and its optimal cutoff value is reported to be 600 to 650 pg/mL. Three children were diagnosed with hemophagocytic lymphohistiocytosis (HLH). The cause of HLH was unknown in cases 1 and 2, while Epstein-Barr virus infection was the cause in case 3. The plasma presepsin levels at the diagnosis were 1020, 1080, and 3160 pg/mL in cases 1, 2, and 3, respectively. In case 1, the plasma level of presepsin decreased to 164 pg/mL on day 19 of her sickness, when symptoms improved. Follow-up plasma presepsin levels were missing for cases 2 and 3. No microbiological pathogens were detected in the blood cultures of any of the patients. Our cases suggest that plasma presepsin levels can be elevated in childhood HLH.

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.

New biomarker paves the way for a clinical trial for neurodegeneration in Langerhans cell histiocytosis.

Neurodegeneration in Langerhans cell histiocytosis (ND-LCH) is a major clinical issue requiring urgent resolution. Sveijer et al. showed that plasma neurofilament light protein is a promising biomarker for screening patients with ND-LCH and determining the therapeutic effect of a mitogen-activated protein kinase inhibitor. Therefore, this can be a powerful tool for conducting clinical trials for ND-LCH. Commentary on: Sveijer M, von Bahr Greenwood T, Jädersten M, Kvedaraite E, Zetterberg H, Blennow K, et al. Screening for neurodegeneration in Langerhans cell histiocytosis with neurofilament light in plasma. Br J Haematol. 2022;198:722-729.

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.

Severe hypoglycemia in propranolol treatment for infantile hemangiomas.

BACKGROUND: Infantile hemangioma (IH), formerly termed strawberry hemangioma, is a benign vascular tumor caused by capillary endothelial cell proliferation. The tumor regresses after 1 year of age, but sequelae occur in approximately half of the patients without systemic treatment. Propranolol (PPL) is currently the first-line therapeutic agent in Japan as well as in Western countries. It is not commonly known that PPL may induce severe hypoglycemia, in addition to cardiovascular and respiratory side effects. METHODS: We retrospectively analyzed patients with severe PPL-induced hypoglycemia in the 3 years since the launch of Hemangiol®, a PPL preparation specific for IH, in Japan in 2016. RESULTS: The incidence of severe hypoglycemia and of hypoglycemic convulsions following PPL treatment was estimated to be 0.54% and 0.35%, respectively. The incidence of hypoglycemic convulsions appeared to be higher in Japan than in Western countries. Severe hypoglycemia was common in infants aged >1 year, when PPL was used for ≥6 months. Severe hypoglycemia often develops from 05:00 a.m. to 09:00 a.m. and is frequently associated with prolonged periods of fasting, poor feeding, or poor physical conditions. CONCLUSION: To avoid the risk of hypoglycemia, the treatment should be initiated by 6 months of age during the proliferative phase at the latest, and should not be extended indiscriminately beyond 1 year of age. Guardians should be advised not to administer PPL on an empty stomach, in the presence of poor feeding, or who are in poor physical condition, not to prolong fasting after PPL administration, and to monitor the child's condition immediately after he or she wakes up.

[Elucidated pathogenesis and therapeutic prospects in Langerhans cell histiocytosis].

Langerhans cell histiocytosis (LCH) is characterized by immature dendritic cell proliferation, which is currently classified as an inflammatory myeloid neoplasm. Clinical features and outcomes vary from spontaneously regressing isolated bone disease to fatal liver, spleen, or hematopoietic system (risk organ) involvement-positive multisystem disease. LCH cells have the only mutation in the mitogen-activated protein kinase (MAPK) signaling pathway gene, represented by the BRAF V600E mutation, which is the driver mutation. The type of disease depends on the stage of hematopoietic cell differentiation at which the mutation occurs. LCH cells acquire anti-apoptosis and senescence-associated secretory phenotype by oncogene-induced senescence, with migration failure to lymph nodes. These cause LCH cell accumulation and various inflammatory cell recruitment in the lesion, resulting in severe inflammation. Tissue damage in LCH is due to this inflammation, not the LCH cell proliferation. Patients with a risk of organ involvement without the initial treatment response may be rescued by allogeneic hematopoietic stem cell transplantation after reducing the disease activity with MAPK inhibitors. Intravenous zoledronic acid and intrathecal cytarabine injections have been introduced into the ongoing clinical trial in Japan to reduce bone recurrence and prevent neurodegeneration as sequelae.

Successful living donor liver transplantation for liver failure due to maternal T cell engraftment following cord blood transplantation in X-linked severe combined immunodeficiency disease: Case report.

Maternal T cells from perinatal transplacental passage have been identified in up to 40% of patients with severe combined immunodeficiency (SCID). Although engrafted maternal T cells sometimes injure newborn tissue, liver failure due to maternal T cells has not been reported. We rescued a boy with X-linked SCID who developed liver failure due to engrafted maternal T cell invasion following living donor liver transplantation (LDLT) following unrelated umbilical cord blood transplantation (UCBT). After developing respiratory failure 3 weeks postpartum, he was diagnosed with X-linked SCID. Pathological findings showed maternal T cells engrafted in his liver and hepatic fibrosis gradually progressed. He underwent UCBT at 6 months, but hepatic function did not recover and liver failure progressed. Therefore, he underwent LDLT using an S2 monosegment graft at age 1.3 years. The patient had a leak at the Roux-en-Y anastomosis, which was repaired. Despite occasional episodes of pneumonia and otitis media, he is generally doing well 6 years after LDLT with continued immunosuppression agents. In conclusion, the combination of hematopoietic stem cell transplantation (HSCT) and liver transplantation may be efficacious, and HSCT should precede liver transplantation for children with X-linked SCID and liver failure.

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.

Impact of immunophenotypic characteristics on genetic subgrouping in childhood acute lymphoblastic leukemia: Tokyo Children's Cancer Study Group (TCCSG) study L04-16.

Immunophenotyping was performed in 1044 consecutive childhood acute lymphoblastic leukemia (ALL) patients enrolled in the Tokyo Children's Cancer Study Group L04-16 trial, revealing novel findings associated with genetic abnormalities. In addition to TCF3-PBX1 and MEF2D fusions, the CD10(+) subtype of KMT2A-MLLT3-positive ALL frequently exhibited the cytoplasmic-µ(+) pre-B ALL immunophenotype. Although ETV6-RUNX1 was significantly correlated with myeloid antigen expression, more than half of patients expressed neither CD33 nor CD13, while the CD27(+) /CD44(-) immunophenotype was maintained. Expression of CD117 and CD56 in B-cell precursor-ALL was limited to certain subtypes including ETV6-RUNX1 and KMT2A-MLLT3. Besides BCR-ABL1, CRLF2, hyperdiploidy, and hypodiploidy, CD66c was also expressed in Ph-like kinase fusion-, PAX5 fusion-, and DUX4 fusion-positive ALL, but not in MEF2D fusion-positive ALL, indicating constant selectivity of CD66c expression. In T-ALL, SIL-TAL1-positive patients were likely to exhibit a more mature immunophenotype. Expression of CD21 and CD10 was not rare in T-ALL, while lack of CD28 was an additional feature of early T-cell precursor-ALL. Considering the immunophenotype as a prognostic maker, MEF2D fusion-positive ALL with CD5 expression may be associated with a poorer prognosis in comparison with those lacking CD5 expression. In cases with characteristic marker expression, the presence of certain fusion transcripts could be predicted accurately.

Prevalence of germline GATA2 and SAMD9/9L variants in paediatric haematological disorders with monosomy 7.

Monosomy 7 (-7) occurs in various types of paediatric myeloid disorders and has a poor prognosis. Recent studies have demonstrated that patients with germline gain-of-function SAMD9/9L variants and loss-of-function GATA2 variants are prone to developing myelodysplastic syndrome (MDS) associated with -7. However, the prevalence of the genetic variants among paediatric haematologic disorders with -7 is unknown. The present study screened germline variants of GATA2 and SAMD9/9L in 25 patients with various types of paediatric haematological disorders associated with -7. The diagnoses of the 25 patients included MDS (n = 10), acute myeloid leukaemia (AML) and myeloid sarcomas (n = 9), juvenile myelomonocytic leukaemia (n = 3) and other disorders (n = 3). Seven patients with a germline pathogenic GATA2 variant were found. For SAMD9/9L screening, next-generation sequencing was used to detect low-abundance variants and found four novel germline variants. Functional analysis revealed that three out of the four variants showed growth-restricting capacity in vitro and thus, were judged to be pathogenic. Cases with GATA2 mutation tended to be older, compared to those with SAMD9/9L mutations. In conclusion, GATA2 and SAMD9/9L were sequenced in 25 patients with paediatric haematologic disorders associated with -7, and 40% of them were found to have some pathogenic germline variants in the three genes.

Long-term outcomes of children with extracutaneous juvenile xanthogranulomas in Japan.

BACKGROUND: Juvenile xanthogranuloma (JXG) is the most common non-Langerhans cell histiocytosis in children. The mortality and morbidity of JXG with extracutaneous lesions remain unclear. METHODS: Data of patients aged < 18 years who were diagnosed with JXG between 2001 and 2010 were retrospectively collected through a nationwide survey. RESULTS: Twenty patients (11 male and nine female) had extracutaneous lesions. The median observation time was 10 years (range, 0-17). Six patients presented with symptoms at birth. The median age at diagnosis was 8.5 months (range, 0 month-13 years). Fifteen patients underwent treatment for JXG, including chemotherapy (n = 11), and five did not receive treatment. All patients except one survived; 17 were disease-free and two survived with disease. One newborn-onset patient with liver, spleen, and bone marrow involvement died of the disease. Permanent sequelae included central diabetes insipidus, growth hormone deficiency, and panhypopituitarism detected at diagnosis in three, one, and two patients, respectively. Four patients had visual impairment (optic nerve compression and intraocular invasion in two each), three had epilepsy, one had mental retardation, and one had a skin scar. Eight patients who had intracranial lesions were older at diagnosis, and had a higher frequency of disease-related comorbidities and permanent sequelae than those without intracranial involvement. CONCLUSIONS: Patients with extracutaneous JXG had good outcomes, although those with intracranial lesions had serious permanent sequelae. Effective and safe treatment regimens for patients with intracranial JXG need to be developed.

[Organ-based Tube-current Modulation Applied on Different MDCT Scanners: Reduction in the Radiation Dose to the Eye Lens at Head CT].

PURPOSE: Organ-based tube current modulation (OB-TCM) techniques, which are provided by three vendors, reduces the radiation dose to the lens of the eyes by decreasing the tube current, when the X-ray tube passes over the anterior surface of critical organs. However, the characteristics of dose modulation of these techniques are different. The purpose of this study was to understand the performance characteristics of OB-TCM technique of each computed tomography (CT) vendor at head CT. METHODS: We used three CT scanners (SOMATOM Definition Flash; Siemens Healthcare, Revolution CT; GE Healthcare, and Aquilion ONE Genesis Edition; Canon Medical Systems). We measured the radiation dose to the lens surface as evaluation of radiation dose reduction and measured the image noise as index of image quality. We measured the radiation dose rate in the air for analysis of the characteristics of dose modulation in each OB-TCM. RESULTS: When applying OB-TCM, the radiation doses for the lens surface were decreased by 28%, 22%, and 25% for Siemens, GE, and Canon CT scanners, respectively, and the image noise level was increased by 5.6%, 8.5%, and 15.1% for Siemens, GE, and Canon CT scanners, respectively. The characteristics of dose modulation in each OB-TCM were also confirmed by measured the radiation dose rate. CONCLUSION: We confirmed that each OB-TCM has different influence on image quality and radiation doses for lens surface, due to the different characteristics of dose modulation for each CT vendor.

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.

National survey of Japanese patients with mevalonate kinase deficiency reveals distinctive genetic and clinical characteristics.

OBJECTIVES: Mevalonate kinase deficiency (MKD), a rare autosomal recessive autoinflammatory syndrome, is caused by disease-causing variants of the mevalonate kinase (MVK) gene. A national survey was undertaken to investigate clinical and genetic features of MKD patients in Japan. METHODS: The survey identified ten patients with MKD. Clinical information and laboratory data were collected from medical records and by direct interviews with patients, their families, and their attending physicians. Genetic analysis and measurement of MVK activity and urinary excretion of mevalonic acid were performed. RESULTS: None of the 10 patients harbored MVK disease-causing variants that are common in European patients. However, overall symptoms were in line with previous European reports. Continuous fever was observed in half of the patients. Elevated transaminase was observed in four of the 10 patients, two of whom fulfilled the diagnostic criteria for hemophagocytic lymphohistiocytosis. About half of the patients responded to temporary administration of glucocorticoids and NSAIDs; the others required biologics such as anti-IL-1 drugs. CONCLUSION: This is the first national survey of MKD patients in a non-European country. Although clinical symptoms were similar to those reported in Europe, the incidence of continuous fever and elevated transaminase was higher, probably due to differences in disease-causing variants.

Dysregulation of Epstein-Barr Virus Infection in Hypomorphic ZAP70 Mutation.

Background: Some patients with genetic defects develop Epstein-Barr virus (EBV)-associated lymphoproliferative disorder (LPD)/lymphoma as the main feature. Hypomophic mutations can cause different clinical and laboratory manifestations from null mutations in the same genes. Methods: We sought to describe the clinical and immunologic phenotype of a 21-month-old boy with EBV-associated LPD who was in good health until then. A genetic and immunologic analysis was performed. Results: Whole-exome sequencing identified a novel compound heterozygous mutation of ZAP70 c.703-1G>A and c.1674G>A. A small amount of the normal transcript was observed. Unlike ZAP70 deficiency, which has been previously described as severe combined immunodeficiency with nonfunctional CD4+ T cells and absent CD8+ T cells, the patient had slightly low numbers of CD8+ T cells and a small amount of functional T cells. EBV-specific CD8+ T cells and invariant natural killer T (iNKT) cells were absent. The T-cell receptor repertoire, determined using next generation sequencing, was significantly restricted. Conclusions: Our patient showed that a hypomorphic mutation of ZAP70 can lead to EBV-associated LPD and that EBV-specific CD8+ T cells and iNKT cells are critically involved in immune response against EBV infection.

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.

Rhinocerebral Mucormycosis With Temporal Artery Thrombosis in an Adolescent Following HLA-haploidentical Stem Cell Transplantation.

Rhinocerebral mucormycosis (RCM) can lead to internal carotid artery thrombosis. Here, we report the first case of RCM with temporal artery thrombosis following HLA-haploidentical stem cell transplantation in an adolescent presenting with low-grade fever, right mandibular pain, and right jaw claudication. This case suggests that RCM can cause temporal artery thrombosis and should be considered as a differential diagnosis in severely immunocompromised patients with maxillary sinusitis presenting with jaw claudication.

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.