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

Advances in our understanding of genetic markers and targeted therapies for pediatric LCH

INTRODUCTION

Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm, encompassing a diverse clinical spectrum ranging from localized bone or skin lesions to a multisystemic life-threatening condition. Over the past decade, there has been an expansion in understanding the molecular biology of LCH, which translated into innovative targeted therapeutic approaches.

AREAS COVERED

In this article, we will review the molecular alterations observed in pediatric LCH and the relationship between these molecular changes and the clinical phenotype, as well as targeted therapies in LCH.

EXPERT OPINION

Mitogen-activated protein kinase (MAPK) pathway mutation is a hallmark of LCH and is identified in 80% of the cases. Notably, BRAFV600E mutation is seen in ~50-60% of the cases, ~30% has other MAPK pathway mutations, while 15-20% have no detected mutations. While the first line therapeutic approach is vinblastine and prednisone, targeted therapies - specifically BRAF/MEK inhibitors - emerged as a promising second-line salvage strategy, particularly when a mutation is identified. Most patients respond to BRAF/MEK inhibitors but at least 75% reactivate after stopping, however, most patients respond again when restarting inhibitors.

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.

Validation of a Novel Cuproptosis-Related Prognostic Gene Marker and Differential Expression Associated with Lung Adenocarcinoma

BACKGROUND

Cuproptosis induction is seen as a promising alternative for immunotherapies and targeted therapies in breast cancer. The objective of this research was to examine the prognostic and biological importance of cuproptosis-related genes (CRGs) in lung adenocarcinoma (LUAD).

METHODS

The following methods were used: GSE10072 dataset and TCGA database analysis, differential expression analysis of CRGs, and biological function (BP) and signaling pathway enrichment analysis, prognostic analysis and clinical analysis of CRGs, construction of the prognostic signature and RNA modified genes and miRNA analysis of CRGs in LUAD, immunoinfiltration analysis and immunohistochemical staining of DβH, UBE2D3, SOD1, UBE2D1 and LOXL2.

RESULTS

AOC1, ATOX1, CCL8, CCS, COX11, CP, LOXL2, MAP2K2, PDK1, SCO2, SOD1, UBE2D1, UBE2D3 and VEGFA showed significantly higher expression, while ATP7B, DβH, PDE3B, SLC31A2, UBE2D2, UBE2D4 and ULK2 showed lower expression in LUAD tissues than normal tissues. We also found that ATP7B (4%), AOC1 (3%) PDE3B (2%), DβH (2%), CP (1%), ULK2 (1%), PDK1 (1%), LOXL2 (1%) and UBE2D3 (1%) showed higher mutation frequencies. The univariate Cox analysis was used to identify CRGs that have prognostic value. It identified 21 genes that showed significant prognostic value, containing DβH, UBE2D3, SOD1, UBE2D1 and LOXL2. Patients with DβH up-expression have a longer survival time and patients with UBE2D3, SOD1, UBE2D1 and LOXL2 down-expression also have a longer survival time. hsa-miR-29c-3p, hsa-miR-29a-3p, hsa-miR-181c-5p, hsa-miR-1245a, etc., play an important role in the miRNA regulatory network, and in LUAD, miR-29a, miR-29c and miR-181c high expression survival was longer, and miR-1245a low expression survival was longer. We also performed an analysis to examine the relationships between DβH, LOXL2, SOD1, UBE2D1 and UBE2D3 and immune infiltration in LUAD, including B cells, CD8+ T cells, CD4+ T cells, macrophages, neutrophils and DCs.

CONCLUSION

DβH, UBE2D3, SOD1, UBE2D1, and LOXL2 are potential candidates implicated in LUAD and can be further explored for their application as diagnostic, prognostic, and therapeutic biomarkers for LUAD.

Resolution of blood eosinophilia and limited mouth opening after short-term follow-up in a pediatric Langerhans cell histiocytosis case

Introduction

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia that often affects children, presenting a broad clinical spectrum.

Methods

Here, we report a 13-year-old male Salvadorian patient who was referred presenting a nodular swelling at the mandibular angle region, mildly symptomatic, few weeks ago, which relevantly was associated with limited mouth opening. Intraoral examination was unremarkable. Imaginological exams revealed an osteolytic lesion affecting the vestibular cortex at the right mandibular angle. The blood test results were normal, except for eosinophilia (21%; absolute eosinophil count 4 × 109/L). After an incisional biopsy, microscopical and immunohistochemical analyses were consistent with LCH diagnosis, which corresponded to a single system-single site category. After a few weeks, the mandibular movements were re-established, and complete resolution of blood eosinophilia was observed.

Conclusion

LCH with blood eosinophilia is rarely reported. To our knowledge, 3 cases have been previously published.

Detection of Immune Microenvironment Changes and Immune-Related Regulators in Langerhans Cell Histiocytosis Bone Metastasis

The inflammation/immune response pathway is considered a key contributor to the development of Langerhans cell histiocytosis (LCH) bone metastasis. However, the dynamic changes in the immune microenvironment of LCH bone metastasis and critical regulators are still unclear. Expression profiling by arrays of GSE16395, GSE35340, and GSE122476 was applied to detect the immune microenvironment changes in the development of LCH bone metastasis. The single-cell high-throughput sequencing of GSE133704, involved in LCH bone lesions, was analyzed. The online database Metascape and gene set variation analysis (GSVA) algorithms were used to detect the gene function of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The protein-protein interaction (PPI) network of hub regulators was constructed by the STRING database. In these results, key immune cells, such as Tem cells, NK T cells, CD8(+) T cells, and Th1 cells, were identified in LCH bone metastasis. These genes, which include LAG3, TSPAN5, LPAR5, VEGFA, CXCL16, CD74, and MARCKS, may significantly correlate with the cellular infiltration of B cells, aDCs, pDCs, cytotoxic cells, T cells, CD8+ T cells, T helper cells, and Tcm cells. In conclusion, our study constructed an atlas of the immune microenvironment of LCH bone metastasis. Genes including LAG3, TSPAN5, LPAR5, VEGFA, CXCL16, CD74, and MARCKS may be involved in the development of LCH bone metastasis. The hub gene-immune cell interactive map may be a potential prognostic biomarker for the progression of LCH bone metastasis and synergetic targets for immunotherapy in LCH patients.

Signaling pathways, microenvironment, and targeted treatments in Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid malignancy in the "L-group" histiocytosis. Mitogen-activated protein kinase (MAPK) pathway activating mutations are detectable in nearly all LCH lesions. However, the pathogenic roles of MAPK pathway activation in the development of histiocytosis are still elusive. This review will summarize research concerning the landscape and pathogenic roles of MAPK pathway mutations and related treatment opportunities in Langerhans cell histiocytosis. Video abstract.

Cuproptosis-related modification patterns depict the tumor microenvironment, precision immunotherapy, and prognosis of kidney renal clear cell carcinoma

Background

Due to the different infiltration abundance of immune cells in tumor, the efficacy of immunotherapy varies widely among individuals. Recently, growing evidence suggested that cuproptosis has impact on cancer immunity profoundly. However, the comprehensive roles of cuproptosis-related genes in tumor microenvironment (TME) and in response to immunotherapy are still unclear.

Methods

Based on 43 cuproptosis-related genes, we employed unsupervised clustering to identify cuproptosis-related patterns and single-sample gene set enrichment analysis algorithm to build a cuproptosis signature for individual patient's immune cell infiltration and efficacy of immune checkpoint blockade (ICB) evaluation. Then, the cuproptosis-related genes were narrowed down using univariate Cox regression model and least absolute shrinkage and selection operator algorithm. Finally, a cuproptosis risk score was built by random survival forest based on these narrowed-down genes.

Results

Two distinct cuproptosis-related patterns were developed, with cuproptosis cluster 1 showing better prognosis and higher enrichment of immune-related pathways and infiltration of immune cells. For individual evaluation, the cuproptosis signature that we built could be used not only for predicting immune cell infiltration in TME but also for evaluating an individual's sensitivity to ICBs. Patients with higher cuproptosis signature scores exhibited more activated cancer immune processes, higher immune cell infiltration, and better curative efficacy of ICBs. Furthermore, a robust cuproptosis risk score indicated that patients with higher risk scores showed worse survival outcomes, which could be validated in internal and external validation cohorts. Ultimately, a nomogram which combined the risk score with the prognostic clinical factors was developed, and it showed excellent prediction accuracy for survival outcomes.

Conclusion

Distinct cuproptosis-related patterns have significant differences on prognosis and immune cell infiltration in kidney renal clear cell carcinoma (KIRC). Cuproptosis signature and risk score are able to provide guidance for precision therapy and accurate prognosis prediction for patients with KIRC.

Neutralizing Anti-IL-17A Antibody Demonstrates Preclinical Activity Enhanced by Vinblastine in Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterised by the accumulation into granulomas of apoptosis-resistant pathological dendritic cells (LCH-DCs). LCH outcome ranges from self-resolving to fatal. Having previously shown that, (i) monocyte-derived DCs (Mo-DCs) from LCH patients differentiate into abnormal and pro-inflammatory IL-17A-producing DCs, and (ii) recombinant IL-17A induces survival and chemoresistance of healthy Mo-DCs, we investigated the link between IL-17A and resistance to apoptosis of LCH-DCs. In LCH granulomas, we uncovered the strong expression of BCL2A1 (alias BFL1), an anti-apoptotic BCL2 family member. In vitro, intracellular IL-17A expression was correlated with BCL2A1 expression and survival of Mo-DCs from LCH patients. Based on the chemotherapeutic drugs routinely used as first or second line LCH therapy, we treated these cells with vinblastine, or cytarabine and cladribine. Our preclinical results indicate that high doses of these drugs decreased the expression of Mcl-1, the main anti-apoptotic BCL2 family member for myeloid cells, and killed Mo-DCs from LCH patients ex vivo, without affecting BCL2A1 expression. Conversely, neutralizing anti-IL-17A antibodies decreased BCL2A1 expression, the downregulation of which lowered the survival rate of Mo-DCs from LCH patients. Interestingly, the in vitro combination of low-dose vinblastine with neutralizing anti-IL-17A antibodies killed Mo-DCs from LCH patients. In conclusion, we show that BCL2A1 expression induced by IL-17A links the inflammatory environment to the unusual pro-survival gene activation in LCH-DCs. Finally, these preclinical data support that targeting both Mcl-1 and BCL2A1 with low-dose vinblastine and anti-IL-17A biotherapy may represent a synergistic combination for managing recurrent or severe forms of LCH.

Characterization of PD-1/PD-L1 immune checkpoint expression in the pathogenesis of musculoskeletal Langerhans cell histiocytosis: A retrospective study

Recent data suggest that programmed cell death -1 (PD-1) and programmed cell death ligand-1 (PD-L1) are involved in the pathogenesis of Langerhans cell histiocytoma (LCH); however, their contributions are not well established. Also, the involvement of PD-1/PD-L1 molecules in musculoskeletal LCH remains particularly unclear. The current study aims to characterize the involvement of PD-1/PD-L1 immune checkpoint system in the pathogenesis of musculoskeletal LCH. PD-1/PD-L1 expression was evaluated in 6 patients, 3 men and 3 women with a mean age of 13.5 years, with musculoskeletal LCH who were treated at Kindai University Hospital and Osaka Women's and Children's Hospital between November 2005 and December 2020. The median follow-up period for all patients with musculoskeletal LCH was 41 months. We surveyed symptoms, number of lesions, treatment modality, and outcomes. Immunostaining for CD4, CD8, PD-1, and PD-L1 was also performed on pathological specimens obtained by biopsy. Multiple lesions were observed in 5 cases, and a single lesion was observed in 1 case. The chief complaint in 5 cases was pain. Four patients underwent spontaneous regression. The other 2 patients received chemotherapy. The outcomes included continuous disease-free (n = 5) and alive with the disease (n = 1). The CD4-, CD8-, PD-1-, and PD-L1-positive rates among all specimens were 100%, 100%, 16.6%, and 83.3%, respectively. The CD4/PD-L1, CD8/PD-L1, and PD-1/PD-L1 positive rates in all the specimens were 83.3%, 83.3%, and 16.6%, respectively. We believe that the PD-1/PD-L1 immune checkpoint molecules may play some role in the microenvironment of musculoskeletal LCH.

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.