High serum values of soluble CD154, IL-2 receptor, RANKL and osteoprotegerin in Langerhans cell histiocytosis

Phase II study in children and adults under 40 years with newly diagnosed Langerhans cell histiocytosis: protocol for an LCH-19-MSMFB clinical trial in Japan

INTRODUCTION

Although the prognosis of Langerhans cell histiocytosis (LCH) is excellent, the high recurrence rate and permanent consequences, such as central diabetes insipidus and LCH-associated neurodegenerative diseases, remain to be resolved. Based on previous reports that patients with high-risk multisystem LCH show elevated levels of inflammatory molecules, we hypothesised that dexamethasone would more effectively suppress LCH-associated inflammation, especially in the central nervous system (CNS). We further hypothesised that intrathecal chemotherapy would effectively reduce CNS complications. We administer zoledronate to patients with multifocal bone LCH based on an efficacy report from a small case series.

METHODS AND ANALYSIS

This phase II study (labelled the LCH-19-MSMFB study) is designed to evaluate the significance of introducing dexamethasone and intrathecal chemotherapy for multisystem disease and zoledronate for multifocal bone disease in previously untreated, newly diagnosed children, adolescents (under 20 years) and adults under 40 years. The primary endpoint is the 3-year event-free survival rate by risk group of under 20 years and the 3-year event-free survival rate of 20 years and over.

ETHICS AND DISSEMINATION

This study was approved by the Central Review Board of the National Hospital Organisation Nagoya Medical Centre (Nagoya, Japan) on 21 January 2022 and was registered in the Japan Registry of Clinical Trials (https://jrct.niph.go.jp/en-latest-detail/jRCTs041210027). Written informed consent will be obtained from all patients and/or their guardians.

TRIAL REGISTRATION NUMBER

jRCTs041210027.

Immune microenvironment associated with the severity of Langerhans cell histiocytosis in children

The aim of this study is to investigate the clinical potential of immune microenvironment in peripheral blood for the severity and therapeutic efficacy of Langerhans cell histiocytosis (LCH). A total of 200 newly diagnosed children with LCH during 10 years was enrolled for analysis in this study. Peripheral blood samples were acquired from patients before treatment in our hospital and immune indicators were detected by a four-color flow cytometer. The levels of CD3 + CD8 + T cell, CD3 + CD4 + HLA-DR + T cell, CD3 + CD8 + HLA-DR + T cell, IL-4, IL-6, IL-10 and IFN-γ in peripheral blood were markedly elevated in LCH patients vs. healthy controls. Patients with multiple system with risk organ involvement (MS-RO + ) exhibited higher levels in IL-6, IL-10 and IFN-γ, CD3 + CD4 + HLA-DR + T cell and CD3 + CD8 + HLA-DR + T cell, compared to those in patients without risk organ involvement (RO-). Patients who responded effectively to initial chemotherapy showed significantly lower levels of IL-4, IL-10, IFN-γ, CD3 + CD4 + HLA-DR + T cell and CD3 + CD8 + HLA-DR + T cell in peripheral blood, compared to those in patients who did not respond to initial chemotherapy. Furthermore, univariate analyses were performed that the higher levels of CD3 + CD4 + HLA-DR + T cells, CD3 + CD8 + HLA-DR + T cells and IL-10 in peripheral blood were related to non-response in LCH after initial chemotherapy. Immune microenvironment in peripheral blood may be associated with the severity and treatment response of LCH. The levels of CD3 + CD4 + HLA-DR + T cells, CD3 + CD8 + HLA-DR + T cells and IL-10 may be biomarkers to predict treatment response of LCH patients.

Serum levels of soluble interleukin 2 receptor (sIL-2R), tumor necrosis factor-alpha (TNF-α), and immunoglobulin M are correlated with the disease extent in childhood Langerhans cell histiocytosis

PURPOSE

This study aimed to identify peripheral parameters associated with the severity of Langerhans cell histiocytosis (LCH) and to look for indicators associated with improvement in LCH patients with risk-organ involvement.

METHODS

This study enrolled LCH patients who were assessed as active disease-better (AD-B) after treatment. Patients were divided into the single system (SS) group, multisystem disease without risk-organ involvement (RO- MS) group, and multisystem disease with risk-organ involvement (RO + MS) group. Serum cytokines, immunoglobulins, and lymphocyte subsets were measured at admission for all three groups. Changes in these indicators after treatment were also analyzed.

RESULTS

From January 2015 to January 2022, a total of 46 patients were recruited in the present study, including 19 patients (41.3%) in the SS group, 16 patients (34.8%) in the RO- MS group, and 11 patients (23.9%) in the RO + MS group. Serum levels of soluble interleukin 2 receptor (sIL-2R) (> 912.5 U/mL), tumor necrosis factor-alpha (TNF-α) (> 20.3 pg/mL), and immunoglobulin M (< 1.12 g/L) were found to be effective in identifying patients in the RO + MS group. Furthermore, the levels of sIL-2R (SS vs RO + MS: P = 0.002, RO- MS vs RO + MS: P = 0.018) and CD8 + T-cell count (SS vs RO + MS: P = 0.028) significantly declined in the RO + MS group after treatment, indicating disease improvement.

CONCLUSIONS

The levels of sIL-2R and TNF-α were positively correlated with the extent of disease, while the levels of IgM were negatively correlated with the extent of disease. Additionally, the levels of sIL-2R and CD8 + T-cell count could serve as useful indicators to evaluate the treatment response in RO + MS-LCH patients.

Adult Langerhans Cell Histiocytosis and the Skeleton

Langerhans cell histiocytosis (LCH) is a rare inflammatory neoplasia in which somatic mutations in components of the MAPK/ERK pathway have been identified. Osseous involvement is evident in approximately 80% of all patients and may present as a single osteolytic lesion, as a multi-ostotic single system disease or as part of multisystem disease. Both exogenous, such as treatment with glucocorticoids, and endogenous parameters, such as anterior pituitary hormone deficiencies and inflammatory cytokines, may severely affect bone metabolism in LCH. Computed tomography (CT) or magnetic resonance imaging (MRI) are usually required to precisely assess the degree of bone involvement; 18F-fluorodeoxyglucose (FDG) positron emission tomography-CT can both detect otherwise undetectable LCH lesions and differentiate metabolically active from inactive or resolved disease, while concomitantly being useful in the assessment of treatment response. Treatment of skeletal involvement may vary depending on location, extent, size, and symptoms of the disease from close observation and follow-up in unifocal single-system disease to chemotherapy and gene-targeted treatment in cases with multisystem involvement. In any case of osseous involvement, bisphosphonates might be considered as a treatment option especially if pain relief is urgently needed. Finally, a patient-specific approach is suggested to avoid unnecessary extensive surgical interventions and/or medical overtreatment.

Plasma Signaling Factors in Patients With Langerhans Cell Histiocytosis (LCH) Correlate With Relative Frequencies of LCH Cells and T Cells Within Lesions

Langerhans cell histiocytosis (LCH) lesions contain an inflammatory infiltrate of immune cells including myeloid-derived LCH cells. Cell-signaling proteins within the lesion environment suggest that LCH cells and T cells contribute majorly to the inflammation. Foxp3+ regulatory T cells (Tregs) are enriched in lesions and blood from patients with LCH and are likely involved in LCH pathogenesis. In contrast, mucosal associated invariant T (MAIT) cells are reduced in blood from these patients and the consequence of this is unknown. Serum/plasma levels of cytokines have been associated with LCH disease extent and may play a role in the recruitment of cells to lesions. We investigated whether plasma signaling factors differed between patients with active and non-active LCH. Cell-signaling factors (38 analytes total) were measured in patient plasma and cell populations from matched lesions and/or peripheral blood were enumerated. This study aimed at understanding whether plasma factors corresponded with LCH cells and/or LCH-associated T cell subsets in patients with LCH. We identified several associations between plasma factors and lesional/circulating immune cell populations, thus highlighting new factors as potentially important in LCH pathogenesis. This study highlights plasma cell-signaling factors that are associated with LCH cells, MAIT cells or Tregs in patients, thus they are potentially important in LCH pathogenesis. Further study into these associations is needed to determine whether these factors may become suitable prognostic indicators or therapeutic targets to benefit patients.

A case of langerhans cell histiocytosis of the mandible that spontaneously regressed after biopsy in a child

In younger patients of LCH, we should consider that the effectiveness of follow-up without aggressive treatment for SS-type LCH in the oral and maxillofacial bone. However, there are very rare case in which an SS-type LCH recurred after showing a healing tendency. Regular follow-up must be performed even after healing.

Immune Microenvironment in Langerhans Cell Histiocytosis: Potential Prognostic Indicators

In this study, the immune microenvironment in Langerhans cell histiocytosis (LCH) was characterized to determine if immune indices are predictive of severity. Serum samples from 54 treatment-naïve patients were analyzed quantitatively for inflammatory cytokines and immunoglobulins before and after the induction of chemotherapy. The initial serum sIL-2R, TNF-α, and IL-10 of untreated LCH patients with risk organ involvement (RO+) were significantly higher than those with single-system (SS) involvement. LCH patients with hematologic involvement exhibited a significantly higher sIL-2R, TNF-α, IL-10, and IL-1β expression, as compared to the group without involvement. sIL-2R, TNF-α, and IL-10 were increased in patients with liver or spleen involvement. Th cells have decreased in the liver+ and spleen+ group, and Ts cells were significantly decreased in non-response group after induction chemotherapy. The serum level of immune indices represents, to some extent, the severity of the disease. Pertinent laboratory inspections can be used to improve risk stratification and guide immunotherapy.

Immunohistochemical characterization of immune cell infiltration in paediatric and adult Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia commonly affecting children with frequent somatic mutations in MAPK pathway genes including BRAF^V600E and MAP2K1. Some studies suggest that LCH cells can recruit and modulate inflammatory cells, which could provide reciprocal survival signals. To characterize the immune profile of infiltrating inflammatory cells, and to clarify their participation in LCH pathogenesis, a detailed immunohistochemical analysis was performed. Fifteen (10 children, 5 adults) LCH cases were assessed through macrophage (CD68 and CD163), mature dendritic cell (mDC; CD83 and CD208), regulatory T cell (Treg; CD4, CD25 and FOXP3) and cytotoxic lymphocyte (CL; CD56, CD57, perforin and granzyme B) immunomarkers. Moreover, lymphocytic and LCH markers were also analysed. All cases were S100, CD1a, CD207 and CD4-positive. Bcl-2 and cyclin D1 expression was observed in 13 of 15 cases. In the immune microenvironment, M2-polarized macrophages and Tregs were the predominant cell populations, followed by significantly (P < .005) smaller levels of mDCs and CLs. Additionally, the number of CD3 + cells was significantly higher than that of CD20 + cells. In the CD3 + cell population, there were a significantly higher number of CD4 + cells than CD8 + cells. While there were no differences when comparing the paediatric and adult populations, FOXP3 + cells were significantly higher in patients with multisystem involvement and treated with chemotherapy, than single-site cases and those without chemotherapy. Our results suggest that M2-polarized macrophages and Treg infiltration can promote LCH development and survival, probably through pro-tumoral, immunosuppressive and/or cytokine-mediated mechanisms. This work highlights the need for further exploration of immune-targeted therapy for LCH.

Langerhans cell histiocytosis in adults is associated with a high prevalence of hematologic and solid malignancies

Background

Langerhans cell histiocytosis (LCH) is a rare disorder of histiocyte proliferation. Previous case studies suggest a higher prevalence of hematologic and solid malignancies among LCH patients, possibly due to treatment with tumorigenic agents such as etoposide. We report the first large, single‐institution experience of adult LCH patients with additional malignancies to study the characteristics of these patients.

Methods

We identified 132 consecutive patients >18 years of age with histologically confirmed LCH at our center between 1990 and 2015. Demographics and detailed oncologic history were recorded to identify patients with additional malignancies.

Results

Of 132 adult LCH patients, 42 (32%) patients had an additional malignancy. There were 53 malignancies among the 42 patients, with 31 (58%) preceding LCH diagnosis, 11 concurrent (≤3 months; 21%) with LCH diagnosis, and 11 (21%) after. Median age was 54 years (range 28‐89) with a median follow‐up of 3.7 years (0.1‐22.2) for this cohort. OS at 3 years was 98% in patients with LCH alone and 82% among patients with additional malignancies, with 30 (71%) alive at last follow‐up. Solid tumors, lymphomas, and other hematologic malignancies were observed as follows: 39 (74%), 9 (17%), and 5 (9%).

Conclusion

Our cohort of adult LCH patients demonstrates an unusually high number of additional malignancies. Our study includes predominantly malignancies diagnosed preceding or concurrent with LCH, suggesting a cause of malignancy independent of LCH treatment. Further exploration of the biology of this rare disease may elucidate the mechanism of frequent additional malignancies.

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.

Bone metabolism in Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare disease of not well-defined etiology that involves immune cell activation and frequently affects the skeleton. Bone involvement in LCH usually presents in the form of osteolytic lesions along with low bone mineral density. Various molecules involved in bone metabolism are implicated in the pathogenesis of LCH or may be affected during the course of the disease, including interleukins (ILs), tumor necrosis factor α, receptor activator of NF-κB (RANK) and its soluble ligand RANKL, osteoprotegerin (OPG), periostin and sclerostin. Among them IL-17A, periostin and RANKL have been proposed as potential serum biomarkers for LCH, particularly as the interaction between RANK, RANKL and OPG not only regulates bone homeostasis through its effects on the osteoclasts but also affects the activation and survival of immune cells. Significant changes in circulating and lesional RANKL levels have been observed in LCH patients irrespective of bone involvement. Standard LCH management includes local or systematic administration of corticosteroids and chemotherapy. Given the implication of RANK, RANKL and OPG in the pathogenesis of the disease and the osteolytic nature of bone lesions, agents aiming at inhibiting the RANKL pathway and/or osteoclastic activation, such as bisphosphonates and denosumab, may have a role in the therapeutic approach of LCH although further clinical investigation is warranted.

Fever and Skin Involvement at Diagnosis Predicting the Intractable Langerhans Cell Histiocytosis: 40 Case-Series in a Single Center

Langerhans cell histiocytosis (LCH) occurs as a clonal disease with enigmatic immune responses. LCH patients occasionally present with fever, although the significance remains elusive. We investigated the predicting factors for developing intractable disease of refractory and/or reactivated LCH. In total, 40 pediatric LCH patients managed in Kyushu University from 1998 to 2014 were enrolled. The medical records were analyzed retrospectively. Sixteen patients suffered from multisystem (MS) LCH involving risk organs (ROs) (n=4) or not (n=12). In total, 24 patients had single-system LCH affecting bone (multi n=8, single n=13), skin (n=2), or lymph node lesions (n=1). Eight patients had the intractable disease of 7 MS or 1 multibone LCH. Two patients died from MS LCH with or without RO involvement. Ten patients showed persistent fever (>38°C) at onset. Intractable cases had fever, RO and skin involvement, leukocytosis, coagulopathy, microcytic anemia, higher levels of soluble interleukin-2 receptor and C-reactive protein, more frequently at diagnosis. Multivariate analysis indicated that fever and skin lesions at diagnosis were independently associated with the intractability (odds ratio: fever, 35.5; 95% confidence interval, 3.0-1229.1; skin lesions, 24.6; 95% confidence interval, 1.9-868.7). Initial fever and skin involvement might predict the development of intractable and fatal-risk LCH even without the RO involvement.

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.

Insights into the pathogenesis of Langerhans cell histiocytosis: the development of targeted therapies

More than a century after its first description, Langerhans cell histiocytosis (LCH) still remains an intriguing disease. Considerable progress in understanding its biology has been achieved recently. Description of the V600E BRAF mutation in samples of LCH tissue in 2010 was followed by description of additional mutations, all leading to constitutive ERK activation. Current experimental data suggest that LCH is a myeloid neoplasia with inflammatory properties, yet the exact pathophysiology remains poorly understood. Disease management paradigms have changed over time, closely reflecting the evolving view of the nature of the disease. The international Histiocyte Society have conducted three prospective clinical studies on multisystem LCH since the early 1990s. The standard frontline therapy for patients with multisystem LCH based on the cumulative knowledge of those trials consists of 6–12 weeks of initial therapy (daily oral steroids and weekly vinblastine injections), followed by pulses of prednisolone/vinblastine every 3 weeks, for a total treatment duration of 12 months. A currently ongoing study (LCH-IV) with a complex design (five interventional and two observational strata) targets further reduction of mortality and morbidity by tailoring treatment intensity depending on expected risk, as well as by exploring treatment regimens for special locations. Current knowledge on LCH pathobiology opens opportunities for improvement in the patient outcome. The activating BRAF and MAP2K1 mutations collectively accounting for about 75% of the LCH population as well as the resulting constitutive activation of downstream ERK offer an opportunity for targeted treatment. Related issues (eg, finding most effective and less toxic drugs or combinations, appropriate dosage, and optimal treatment duration) must be addressed in controlled prospective trials. Additional mechanisms, such as the interactions of the mutated dendritic cell clone with other inflammatory cells and key cytokines and chemokines, still remain attractive targets for therapeutic intervention, particularly in patients with localized, less aggressive disease.

Langerhans Cell Histiocytosis of the Orbit: Spectrum of Disease and Risk of Central Nervous System Sequelae in Unifocal Cases

PURPOSE

To describe the spectrum of disease extent and clinical response in Langerhans cell histiocytosis (LCH) presenting with orbital involvement and to determine if unifocal orbital disease increases the risk for central nervous system sequelae (CNS-LCH).

METHODS

Retrospective chart review of patients with orbital LCH representing a range of severity treated at the Children's Hospital of Wisconsin from 2003 to 2011; analysis of current international treatment protocols; literature review.

RESULTS

Six patients presenting with orbital LCH are described: 1 with unifocal orbital disease completely responsive to local measures; 1 with multifocal bone disease completely responsive to local intervention; 1 with unifocal orbital disease incompletely responsive to surgical intervention, and requiring systemic chemotherapy; and 3 with multisystem disease at presentation. Literature review identified 806 cases of CNS-LCH. Orbital involvement could be determined in 11 cases. Of these, 6 had multisystem disease and 3 had multifocal bone disease; 1 presented with unifocal orbital disease but progressed to multifocal bone involvement; 1 had insufficient clinical information to distinguish unifocal from multisite presentation. No cases of CNS-LCH directly resulted from isolated unifocal orbital disease.

CONCLUSIONS

Initial treatment of orbital LCH should depend on disease extent at diagnosis. Unifocal cases that completely respond to biopsy, curettage, and/or corticosteroid instillation may be managed with initial oncologic staging and careful long-term observation, with default to chemotherapy for local recurrence or multisite progression. There is currently little evidence that unifocal orbital disease increases the risk for CNS-LCH and therefore warrants prophylactic systemic chemotherapy in all patients.

Bisphosphonates in Langerhans Cell Histiocytosis: An International Retrospective Case Series

Background

Bone is the most common organ of involvement in patients with Langerhans cell histiocytosis (LCH), which is often painful and associated with significant morbidity from pathological fractures. Current first-line treatments include chemotherapy and steroids that are effective but often associated with adverse effects, whereas the disease may reactivate despite an initial response to first-line agents. Bisphosphonates are osteoclast inhibitors that have shown to be helpful in treating bone lesions of LCH. To date, there are no large international studies to describe their role in treating bone lesions of LCH.

Method

We conducted a multicenter retrospective review of 13 patients with histologically proven LCH, who had received bisphosphonates either at diagnosis or at disease reactivation.

Results

Ten patients (77%) had a single system bone disease, and 3 (23%) had bone lesions as part of multisystem disease. Median follow-up time post-bisphosphonate therapy was 4.6 years (range, 0.8 to 8.2 years). Treatment with bisphosphonates was associated with significant pain relief in almost all patients. Twelve (92%) achieved resolution of active bone lesions, and 10 out of them had no active disease for a median of 3.5 years (range, 0.8 to 5 years). One patient did not respond. No major adverse effects were reported in this series.

Conclusion

Bisphosphonates are well-tolerated drugs that can significantly improve bone pain and induce remission in active bone LCH. Future prospective studies evaluating the role of bisphosphonates in LCH are warranted.

Langerhans cell histiocytosis with seborrheic eczema of the scalp and extensive calvarial involvement

INTRODUCTION

Langerhans cell histiocytosis (LCH) is a multisystem disorder of unknown etiology and characterized by accumulation of histiocytes in various tissues.

CASE REPORT

A 3-year-old, previously healthy girl presented with progressive flattening of the parietal convexity for 6 months and seborrheic eczema of the scalp. At presentation, the patient showed no neurological deficit. The eczemas were extensively distributed over the scalp, but not found in any other site of the body. Blood examination revealed a marked increase in soluble interleukin-2 receptor levels. Neuroimages revealed multiple calvarial defects that were replaced by well-demarcated, enhancing extracerebral masses. A biopsy surgery confirmed the diagnosis as LCH.

CONCLUSION

LCH may cause progressive calvarial defects. If seborrheic eczemas are concurrent, they may suggest prompt histological verification and treatments be initiated.

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.

Recent advances in Langerhans cell histiocytosis

The purpose of this review is to provide an updated overview of the pathogenesis and treatment of Langerhans cell histiocytosis (LCH). The pathogenesis of LCH remains obscure and the optimal treatment for LCH has not been established, although incremental progress has been made. Proinflammatory cytokines and chemokines are known to play a role in LCH, which suggests that LCH is an immune disorder. However, the oncogenic BRAF mutation is also detected in more than half of LCH patients, which suggests that LCH is a neoplastic disorder. Remaining major issues in the treatment of LCH are how to rescue patients who have risk-organ involvement but do not respond to first-line therapy, the optimal treatment for the orphan disease of multifocal adult LCH, and how to reduce and treat central nervous system-related consequences, such as central diabetes insipidus and neurodegeneration. More research is needed to better understand the pathogenesis of this disease and to resolve the treatment issues.

Erdheim-Chester disease: characteristics and management

Erdheim-Chester disease is a rare CD68(+), CD1a(-) non-Langerhans cell histiocytosis with multiorgan involvement. The etiology of Erdheim-Chester disease is unclear; there are no known associated infectious or hereditary genetic abnormalities. However, somatic BRAF mutations have recently been identified in these patients. Historically, the literature regarding the management of Erdheim-Chester disease consisted of case reports and small case series with anecdotal therapeutic responses to agents including, but not limited to, cytotoxic chemotherapy, bone marrow transplantation, cladribine, corticosteroids, IFN-α, the BCR-ABL/KIT inhibitor imatinib mesylate, the IL-1 receptor antagonist anakinra, the TNF-inhibitor infliximab, and recently the BRAF inhibitor vemurafenib. We performed a search of the literature using PubMed with the terms Erdheim Chester disease, without date limitations, including case reports, case series, original articles, and previous review articles. In the absence of large-scale studies, experience-based management prevails. The present review details our approach to the management of patients with Erdheim-Chester disease.

Bisphosphonates regulate cell proliferation, apoptosis and pro-osteoclastic expression in MG-63 human osteosarcoma cells

Bisphosphonates are well established in the management of cancer-induced skeletal complications. Recent studies suggest that nitrogen-containing bisphosphonates (N-BPs) promote the apoptosis of cancer cells as well as osteoclasts in bone metastatic sites. To investigate whether N-BPs exhibit a direct antitumor effect on osteoclasts, the current study investigated the effects of zoledronic acid (ZOL) on MG-63 cells in vitro. MG-63 cells were treated with ZOL. The inhibitory effect of ZOL on the growth of MG-63 cells was measured by MTT assay. ZOL-induced apoptosis of the MG-63 cells was examined by Hoechst 33258 staining, electron microscopy, Annexin V-FITC and propidium iodide staining. Reverse-transcription polymerase chain reaction (RT-PCR) and western blotting analysis were employed to assess the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL). The MTT assay showed that ZOL induced a distinct dose- and time-dependent reduction of cell viability with an IC(50) value of 52.37±1.0 μM for 72 h. Flow cytometric analysis further revealed that the cell apoptosis was induced by arrest of the cell cycle in the G(1) phase. RT-PCR and western blot analysis demonstrated that ZOL upregulated OPG expression. These results suggest that ZOL has direct effects on osteosarcoma cell growth and apoptosis. Increased OPG expression is an indirect effect, possibly via changes in the local microenvironment.

Reduced bone mineral density in adult patients with Langerhans cell histiocytosis

This retrospective study evaluated bone mineral density (BMD) and bone turnover in adults with LCH. Twenty-five adult patients and 25 matched controls were evaluated with BMD measurement and indices of bone metabolism. A BMD value below the expected range for age (Z-score ≤ - 2.0) was found in 20% of patients; in particular, all postmenopausal women and men over 50-years had either osteoporosis or osteopenia. Patients with active disease had significantly lower Z-scores compared to patients with inactive disease and controls. Reduced bone turnover was found in all 14 patients treated with chemotherapy. No fractures due to osteoporosis were identified during 305.15 patient-years of follow-up.

Spontaneous regression of pulmonary involvement after smoking reduction and removal of and radiation therapy for Langerhans cell histiocytosis of the sphenoid bone: which comes first, the chicken or the egg?

Isolated pulmonary Langerhans cell histiocytosis (LCH) in adults is known to regress spontaneously after smoking cessation alone, but little is known about whether this rationale could also apply in cases of multisystem pulmonary LCH. In particular, pediatric patients with multisystem LCH including involvement in "risk organs" such as lungs often benefit from systemic chemotherapy. Here, we present a 37-year-old man with spontaneous regression of pulmonary lesions in multisystem LCH, achieved solely by smoking reduction following local treatment of bone lesions.

Multisystem Langerhans cell histiocytosis in children: current treatment and future directions

Langerhans cell histiocytosis (LCH) is a rare (about 3-5 cases per million children aged 0-14 years), non-malignant disease characterized by proliferation and accumulation of clonal dendritic cells, extreme clinical heterogeneity, and an unpredictable course. Three large-scale, international, prospective therapeutic studies (LCH-I to III) for multisystem LCH (MS-LCH) have been conducted by the Histiocyte Society since 1991. The cumulative lessons from these studies are summarized in this review. Patients with MS-LCH represent a heterogeneous group with respect to disease severity and outcome, therefore treatment stratification and risk-tailored treatment are mandatory. The risk for mortality can be predicted based on involvement of 'risk organs' (e.g. hematopoietic system, liver, and/or spleen) at diagnosis and on response to initial therapy (assessed after 6-12 weeks of treatment). Thus, patients without involvement of risk organs (low-risk group) are not at risk for mortality but need systemic therapy in order to control the disease activity and avoid reactivations and permanent consequences. Patients with risk organ involvement (risk group) are at risk for mortality, and lack of therapy response defines a subgroup with a particularly dismal prognosis (high-risk group). Those patients in the risk group who respond to therapy and survive are at risk for reactivations and permanent consequences. The LCH-I study compared the efficacy of vinblastine and etoposide, and concluded that they are equivalent single-agent treatments for children with MS-LCH. However, the results of this trial were inferior with respect to response rate at week 6, disease reactivation rate, and sequelae, when compared with historical trials using more intensive regimens. The combination of prednisolone and vinblastine was established as a standard first-line treatment through the LCH-II and LCH-III studies. The regimen consists of one to two 6-week courses (continuous oral corticosteroids 40 mg/m2/day for 4 weeks, tapered over 2 weeks plus weekly vinblastine intravenous push) of initial therapy, followed by a continuation phase (three weekly pulses of oral prednisolone 40 mg/m2/day for 5 days plus a vinblastine injection). The addition of a third drug to the standard combination (etoposide in LCH-II and methotrexate in LCH-III) failed to significantly improve survival in the risk group. The remaining mortality in the risk group is about 20%, and up to 40% in the high-risk group. Concerning low-risk MS-LCH, comparison of results of the LCH-II study with historical data suggested that the remaining reactivation rate of about 50% (and possibly permanent consequences) could be reduced by prolongation of the total treatment duration. To study this hypothesis, in the low-risk group of the LCH-III study standard maintenance therapy was randomly given for a total treatment duration of 6 and 12 months. Unpublished preliminary data from this recently closed trial suggested that prolongation of the treatment duration may significantly improve reactivation-free survival. In summary, several studies have shown that systemic therapy is indicated for all patients with MS-LCH. A standard two-drug regimen consisting of an initial 'intensive' phase for 6-12 weeks, followed by a less intensive 'maintenance phase' for a total treatment duration of at least 12 months is recommended for patients treated outside of clinical trials. Non-responders, particularly those with progressive disease in risk organs, are eligible for experimental salvage approaches. Remaining questions will be addressed in the upcoming LCH-IV trial, which is in the process of intensive preparation.

Nationwide survey of bisphosphonate therapy for children with reactivated Langerhans cell histiocytosis in Japan

BACKGROUND

Several studies have suggested that Langerhans cell histiocytosis (LCH) is responsive to treatment with bisphosphonates (BPs). However the efficacy and safety of BPs therapy for childhood LCH is unknown.

PROCEDURE

Data on children with LCH who had received BPs therapy were collected retrospectively from hospitals participating in the Japanese Pediatric Leukemia/Lymphoma Study Group.

RESULTS

Twenty-one children with histologically proven LCH were identified. Of these, the case histories of 16 children who had been treated with pamidronate (PAM) for disease reactivation were analyzed in detail. The median post-PAM therapy follow-up period was 2.8 years (range: 0.9-9.3 years). The median age at commencement of PAM therapy was 9.4 years (range: 2.3-15.0 years). All children had one or more bone lesions but none had risk organ (RO) involvement. In the majority of the children, six courses of PAM were administered at a dose of 1.0 mg/kg/course at 4-week intervals. In 12 of the 16 children, all active lesions including lesions of the skin (n = 3) and soft tissues (n = 3) resolved. Of these children, eight children had no active disease for a median of 3.3 years post-PAM therapy (range: 1.8-9.3 years). Progression-free survival (PFS) was 56.3 ± 12.4% at 3 years. PFS was significantly higher in children with a first reactivation compared with children experiencing a second or subsequent reactivation.

CONCLUSIONS

PAM may be an effective treatment for reactivated LCH with bone lesions. A prospective trial of the efficacy of PAM in recurrent pediatric LCH is warranted.

Cell-specific gene expression in Langerhans cell histiocytosis lesions reveals a distinct profile compared with epidermal Langerhans cells

Langerhans cell histiocytosis (LCH) is a rare disease characterized by heterogeneous lesions containing CD207(+) Langerhans cells (LCs) and lymphocytes that can arise in almost any tissue and cause significant morbidity and mortality. After decades of research, the cause of LCH remains speculative. A prevailing model suggests that LCH arises from malignant transformation and metastasis of epidermal LCs. In this study, CD207(+) cells and CD3(+) T cells were isolated from LCH lesions to determine cell-specific gene expression. Compared with control epidermal CD207(+) cells, the LCH CD207(+) cells yielded 2113 differentially expressed genes (false discovery rate < 0.01). Surprisingly, the expression of many genes previously associated with LCH, including cell-cycle regulators, proinflammatory cytokines, and chemokines, were not significantly different from control LCs in our study. However, several novel genes whose products activate and recruit T cells to sites of inflammation, including SPP1 (osteopontin), were highly overexpressed in LCH CD207(+) cells. Furthermore, several genes associated with immature myeloid dendritic cells were overexpressed in LCH CD207(+) cells. Compared with the peripheral CD3(+) cells from LCH patients, the LCH lesion CD3(+) cells yielded only 162 differentially regulated genes (false discovery rate < 0.01), and the expression profile of the LCH lesion CD3(+) cells was consistent with an activated regulatory T cell phenotype with increased expression of FOXP3, CTLA4, and SPP1. Results from this study support a model of LCH pathogenesis in which lesions do not arise from epidermal LCs but from accumulation of bone marrow-derived immature myeloid dendritic cells that recruit activated lymphocytes.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a poorly understood proliferative disease, with different patterns of clinical presentation. Currently it is classified according to the number and type of system involved and the degree of organ dysfunction. The aetiology of the disease remains uncertain, and in some cases the disease is polyclonal, suggesting a reactive condition. Many cytokines have been implicated in the pathogenesis of LCH. Different therapeutic approaches can be considered depending on the affected organ, including surgery, radiotherapy and chemotherapy. Long-term organ dysfunction may remain, despite disease control and/or eradication, making indefinite supportive treatment mandatory. Here we present a literature review on all of the aspects of the disease, treatment approaches and existing protocols, and finally an adult clinical case.

Serum soluble interleukin 2 receptor alpha in human cancer of adults and children: a review

Cancer growth and development is associated with the stimulation of the innate immune system, including enhanced interleukin 2 receptor (IL-2R) expression in immune cells and its shedding into the circulation in a soluble form of sIL-2Ralpha. In most haematological malignancies, including different types of leukaemias and lymphomas, sIL-2Ralpha has been found to be released directly from the surface of neoplastic cells thus reflecting the tumour bulk, turnover and activity. Several studies have proved that not only lymphoid cancer cells, but also some non-lymphoid cancer cells, express IL-2R on their surface. They include malignant melanoma and carcinomas of the kidney, head and neck, oesophagus and lung. It is suggested that in most malignant solid tumours, elevated levels of sIL-2Ralpha are likely to be the product of normal peripheral mononuclear cells activated in response to the neoplasm's growth or that they are released from activated lymphoid cells infiltrating neoplastic tissues. This latter hypothesis has been proved by discovering the high expression of CD25 on the cell surface of most of these cells. Although the precise source and biological role of sIL-2Ralpha has not been clarified definitively, pretreatment serum levels of sIL-2Ralpha have been shown to reflect the activity, advancement and biological aggressiveness of many types of cancer in adults and children as well as to correlate with prognosis and overall survival. The possibility of enriching the diagnostic tools of oncologists with a new biochemical marker of activity of neoplasms resulted in numerous studies and reports concerning the clinical usefulness of sIL-2Ralpha measurements in adult and, less frequently, in paediatric malignancies. This article presents the actual knowledge concerning the structure, source and biological function of sIL-2Ralpha in patients with haematological and non-haematological malignancies. The authors review the published data on clinical applicability of soluble IL-2Ralpha determination in terms of diagnostics, prognosis and treatment monitoring of particular types of malignant disorders both in adults and in children. They also provide an insight into the clinical usefulness of sLL-2Ralpha-blocking antibodies in patients with cancer, and in those who reject organ transplants, develop graft-versus-host disease after allogeneic bone marrow transplantation and are affected with autoimmune disorders.