Langerin-mediated internalization of a modified peptide routes antigens to early endosomes and enhances cross-presentation by human Langerhans cells

The potential of the skin immune system to generate immune responses is well established, and the skin is actively exploited as a vaccination site. Human skin contains several antigen-presenting cell subsets with specialized functions. In particular, the capacity to cross-present exogenous antigens to CD8^＋ T cells is of interest for the design of effective immunotherapies against viruses or cancer. Here, we show that primary human Langerhans cells （LCs） were able to cross-present a synthetic long peptide （SLP） to CD8^＋ T cells. In addition, modification of this SLP using antibodies against the receptor langerin, but not dectin-1, further enhanced the cross-presenting capacity of LCs through routing of internalized antigens to less proteolytic early endosome antigen 1 ^＋ early endosomes. The potency of LCs to enhance CD8^＋ T-cell responses could be further increased through activation of LCs with the toll-like receptor 3 ligand polyinosinic：polycytidylic acid （phC）. Altogether, the data provide evidence that human LCs are able to cross-present antigens after langerin-mediated internalization. Furthermore, the potential for antigen modification to target LCs specifically provides a rationale for generating effective anti-tumor or anti-viral cytotoxic T lymphocyte responses.

Langerhans cell histiocytosis misdiagnosed as thyroid malignancy: A case report

BACKGROUND The incidence of Langerhans cell histiocytosis(LCH) is low, and involvement of the thyroid is even rarer, which results in high missed diagnosis or misdiagnosis rates.CASE SUMMARY We report a young woman with a thyroid nodule. Thyroid malignancy was suggested by fine needle aspiration, but she was eventually diagnosed with multisystem LCH, thus avoiding thyroidectomy.CONCLUSION The clinical manifestations of LCH involving the thyroid are atypical, and the diagnosis depends on pathology. Surgery is the main method for treating primary thyroid LCH, while chemotherapy is the main treatment method for multisystem LCH.

Adult localized Langerhans cell histiocytosis:A case report

BACKGROUND Langerhans cell histiocytosis(LCH)is a rare clonal proliferative disease of Langerhans cells with unknown pathogenesis.An increasing number of clinicians recognize that LCH has a wide clinical spectrum and a highly varied course.Adults rarely develop LCH.Here,we report a case of adult localized LCH.CASE SUMMARY A 32-year-old woman presented with plaques and ulcers on the vulva and crissum,accompanied by pain that persisted for more than one year.Physical examination revealed a red-infiltrating plaque with ulcerations and exudates in the vulva and crissum.Pathological examination revealed a diffuse infiltration of lymphocytes,eosinophilic granulocytes,and histiocytoid cells in the superficial dermis.Proliferative histiocytoid cells showed mild atypia,partly with kidneyshaped nuclei.Immunohistochemical examination showed that the histiocytoid cells were positive for S100 protein and CD1 and weakly positive for CD68(20%+),with a Ki-67 index of 30%.Laboratory tests did not reveal any other systemic damage.The patient was diagnosed with adult localized LCH and was prescribed oral prednisone(20 mg)once daily.The skin lesions gradually improved and are still being followed-up.CONCLUSION Adult localized LCH is rare and must be differentiated from other common conditions.

Langerhans cell histiocytosis masquerading as acute appendicitis: Case report and review

Langerhans cell histiocytosis(LCH) is a rare syndrome characterized by unifocal,multifocal unisystem,or disseminated/multi-system disease that commonly involves the bone,skin,lymph nodes,pituitary,or sometimes lung(almost exclusively in smokers) causing a variety of symptoms from rashes and bone lesions to diabetes insipidus or pulmonary infiltrates.We present a previously unreported case of gastrointestinal LCH as well as a novel characteristic lesion affecting the colon of a young woman who presented with signs and symptoms mimicking acute on chronic appendicitis.Immunohistochemical analysis of appendectomy specimen and nodular specimens on colonoscopy demonstrated S-100,CD1a,and langerin reactivity.The patient underwent systemic chemotherapy with cytarabine and demonstrated excellent response to therapy.

Solitary Langerhans cell histiocytosis of frontal lobe: a case report and literature review

The brain parenchymal Langerhans cell histiocytosis （LCH） without systemic disease or lytic skull lesions is extremely rare. We report a 23-year-old male presenting with new onset 1 hour seizure with loss of consciousness 20 days prior to admission, and recurrent seizure 2 weeks later. Brain magnetic resonance imaging （MRI） showed an irregularly mass with enhancement involving the right frontal lobe. Microscopically, the lesion was characterized by sheets of Langerhans cells in addition to reactive inflammatory elements. Immunohistochemically, Langerhans cells were positive for Langerin, CDla and S-100 protein. The patient received no chemotherapy or radiotherapy after surgery. After 24 months of follow-up, no recurrence or other systemic lesions were observed. Although there is no standard treatment for solitary cerebral LCH, the prognosis generally appears to be good.

A NEW LOOK AT LANGERHANS CELL HISTIOCYTOSIS: REVIEW OF A SERIES OF 55 CASES

Objective: Langerhans cell histiocytosis (LCH) has been well described only in children. We analyzed the characteristics, reactivation, and outcome of LCH in a cohort of 55 patients across all ages. Methods: We reviewed the records of all patients with LCH treated at a single institute between Jan. 1974 and May 1998. Results: The 55 patients were 2 to 67 years of age (median, 31 years) at the time of diagnosis, and 85.5% were male. Forty patients (72.7%) had single-system LCH; Fifteen (27.3%) had multisystem disease. The head and neck was the most frequent tumor site (63.6%). LCH was not found in organs at risk of involvement (liver, spleen, bone marrow, and lungs). The frequency of bony invasion (23.6% overall) differed significantly according to age ≤15 years (66.7%) vs. age >15 years (11.6%) (P=0.0005). At a median follow-up of 12 years, no patient died of LCH. The 5, 10-year survival estimates were 100%. The 5, 10-year disease-free survival estimates were 70.9% and 58.4%. The 5-year disease-free survival estimate was 58.3% for age ≤ 15 years vs. 74.4% for age >15 years (P=0.83) and 75% for single-system disease vs. 60% for multisystem disease (P=0.13). LCH was reactivated in 43.6% of patients, with a median of 14 months (range, 2-180 months). Three patients with recurrent disease experienced spontaneous remission. At the time of the most recent follow-up, 23.6% of survivors had active disease. Conclusion: LCH is not found exclusively in children and adolescents. The frequency of bone invasion is inversely related to age. Reactivation is very common regardless of the type of treatment, but the prognosis is generally good.

Langerhans cell histiocytosis involving only the thymus in an adult: A case report

BACKGROUND Langerhans cell histiocytosis(LCH)is a rare disease of unknown etiology.LCH involving the thymus is mainly seen in pediatric patients and is extremely rare in adults.In this report,we describe a rare case of LCH originating from the thymus in an adult.CASE SUMMARY A 56-year-old man was admitted in April 2022 with complaints of intermittent dizziness since 2020,which had worsened in the previous 10 d.The physical chest examination was negative,and there was a history of hypertension for>2 years.Chest computed tomography showed a nodular soft tissue density shadow in the anterior mediastinum measuring approximately 13 mm×9 mm×8 mm.Postoperative pathological findings confirmed the diagnosis of LCH.CONCLUSION It is challenging to differentiate LCH involving the thymus from thymoma in imaging features.Pathological biopsy remains the gold standard when an anterior mediastinal occupying lesion is found.

Multisystem involvement Langerhans cell histiocytosis in an adult:A case report

BACKGROUND Langerhans cell histiocytosis(LCH)is a rare condition wherein Langerhans cells proliferate abnormally,adversely impacting organs including lymph nodes,bones,skin,lungs,and pituitary gland.The LCH disease course varies widely among patients from a self-limiting condition to one that progresses rapidly and culminates in death.It is uncommon for multisystem LCH to be observed in adults.Herein we describe a woman suffering from multi-system LCH involvement.CASE SUMMARY A 37-year old Chinese woman was admitted to the hospital in June 2019 suffering from dyspnea that had progressed over the course of 5 years.Her medical history included:central diabetes insipidus(DI)that had been treated via radiotherapy,desmopressin acetate,and bromocriptine;bilateral pneumothorax with two surgeries having been performed to remove bullae;and autoimmune hepatitis that had been unsuccessfully treated using a combination of methylprednisolone and mycophenolate mofetil.A chest computed tomography(CT)scan revealed the presence of multiple pulmonary cysts of varying sizes.We re-analyzed right pulmonary bullae samples that had been removed in 2014,performed a systematic 18 F-FDG PET/CT analysis,and convened a multidisciplinary medical team to diagnose and treat this patient.As a result,we were able to eventually diagnose this patient with LCH that was not associated with BRAF-V600 E mutations.CONCLUSION We hope to emphasize the importance of systemic evaluation and of cooperation between multidisciplinary physicians with the goal of improving awareness and detection of this orphan disease.

Hepatic Langerhans cell histiocytosis:A review

Hepatic Langerhans cell histiocytosis(LCH)is characterized by proliferation and accumulation of Langerhans cells in the liver,causing liver dysfunction or forming a mass lesion.The liver can be involved in isolation,or be affected along with other organs.A common clinical hepatic presentation is cholestasis with pruritis,fatigue and direct hyperbilirubinemia.In late stages,there may be hypoalbuminemia.Liver biopsy may be required for the diagnosis of hepatic LCH.Histologic finding may be diverse,including lobular Langerhans cell infiltrate with mixed inflammatory background,primary biliary cholangitis-like pattern,sclerosing cholangitis-like pattern,and even cirrhosis at later stages.Because of its non-specific injury patterns with broad differential diagnosis,establishing a diagnosis of hepatic LCH can be challenging.Hepatic LCH can easily be missed unless this diagnosis is considered at the time of biopsy interpretation.A definitive diagnosis relies on positive staining with CD1a and S100 antigen.Liver involvement is a high risk feature in LCH.The overall prognosis of hepatic LCH is poor.Treating at an early stage may improve the outcome.Systemic chemotherapy is the mainstay of treatment and liver transplantation may be offered.New molecular markers involved in pathogenesis of LCH are being explored with a potential for targeted therapy.However,further studies are needed to improve outcome.

Current perspectives on the role of liver transplantation for Langerhans cell histiocytosis:A narrative review

Langerhans cell histiocytosis(LCH)is a malignant disease of the histiocytes involving various organ systems.The spectrum of liver involvement in LCH ranges from mild transaminitis to end-stage liver disease.The hallmark of hepatic LCH is secondary sclerosing cholangitis,which manifests due to a progressive destruction of the biliary tree by malignant histiocytes.Chemotherapy remains the mainstay of treatment for active LCH.Early recognition,diagnosis and a systematic approach to the management of LCH can ameliorate the disease process.Nonetheless,the liver involvement in these patients may progress despite the LCH being in remission.Liver transplantation(LT)remains central in the management of such patients.Various facets of the management of LCH,especially those with liver involvement remain unclear.Furthermore,aspects of LT in LCH with regards to the indication,timing and post-LT management,including immunosuppression and adjuvant therapy,remain undefined.This review summarises the current evidence and discusses the practical aspects of the role of LT in the management of LCH.

Langerhans cell histiocytosis presenting as an isolated brain tumour:A case report

Langerhans cell histiocytosis(LCH)is a rare proliferative histiocyte disorder.It can affect any organ or system,especially the bone,skin,lung,and central nervous system(CNS).In the CNS,the hypothalamic-pituitary is predominantly affected,whereas the brain parenchyma is rarely affected.LCH occurring in the brain parenchyma can be easily confused with glioblastoma or brain metastases.Thus,multimodal imaging is useful for the differential diagnosis of these intracerebral lesions and detection of lesions in the other organs.CASE SUMMARY A 47-year-old man presented with a headache for one week and sudden syncope.Brain computed tomography(CT)and magnetic resonance imaging showed an irregularly shaped nodule with heterogeneous enhancement.On^(18)F-fluorodeoxyglucose(^(18)F-FDG)positron emission tomography/CT,a nodule with^(18)F-FDG uptake and multiple cysts in the upper lobes of both lungs were noted,which was also confirmed by high-resolution CT.Thus,the patient underwent surgical resection of the brain lesion for further examination.Postoperative pathology confirmed LCH.The patient received chemotherapy after surgery.No recurrence was observed in the brain at the 12-mo follow-up.CONCLUSION Multimodal imaging is useful for evaluating the systemic condition of LCH,developing treatment plans,and designing post-treatment strategies.

Two smoking-related lesions in the same pulmonary lobe of squamous cell carcinoma and pulmonary Langerhans cell histiocytosis:A case report

BACKGROUND Pulmonary Langerhans cell histiocytosis(PLCH)is a rare cystic lung disease usually affecting young adults.It is predicted that PLCH is a lung tumor precursor associated with dysfunction of the myeloid dendritic cells in the lung.CASE SUMMARY A 70-year-old male patient presented with chronic cough and sputum.He had symptoms for 5 years and described shortness of breath on exertion for the previous 3 years.He had a 60 packs/year smoking history.Computerized tomography of the thorax revealed an 11-mm nodule in the right lung lower lobe superior segment and a 7-mm nodule in the right lung lower lobe poster basal segment.Those two nodules were resected by means of right thoracoscopic surgery.Pathological evaluation revealed a squamous cell carcinoma and PLCH.CONCLUSION Coexistent squamous cell carcinoma and PLCH suggest possible association between PLCH and lung cancer.

Pulmonary Langerhans cell histiocytosis and multiple system involvement:A case report

BACKGROUND Pulmonary Langerhans cell histiocytosis(PLCH)is a relatively rare type of lung disease,common in middle-aged smoking men.It is characterized by proliferation and infiltration of Langerhans cells,and the formation of multiple parabronchial mesenchymal nodules in lung tissue,and may lead to organ dysfunction.There are no typical symptoms and signs,and it is easily misdiagnosed or missed,and therefore deserves clinical attention and further discussion.CASE SUMMARY We describe the case of a nonsmoking 46-year-old man with PLCH diagnosed based on clinical manifestations of fever and dry cough,with a history of hypothyroidism and diabetes insipidus for 9 years.Computed tomography(CT)-and CT-guided puncture examinations revealed no abnormalities,and he ultimately underwent thoracoscopic biopsy to confirm the diagnosis.The pathological diagnosis was PLCH.Thyroid function was maintained by medication.Pituitary magnetic resonance imaging showed that the pituitary stalk had become thinner.CONCLUSION LCH often involves multiple systems.Moreover,the pathogenesis is not clear,clinical manifestations lack specificity,and diagnosis requires special attention.Diagnosis of PLCH can significantly benefit from comprehensive multidisciplinary analysis.

Chronic lymphocytic leukemia/small lymphocytic lymphoma complicated with skin Langerhans cell sarcoma:A case report

BACKGROUND Langerhans cell sarcoma(LCS)is a rare malignancy with poor prognosis.LCS and chronic lymphocytic leukemia(CLL)/small lymphocytic lymphoma(SLL)can occur in the same diseased tissues,such as lymph nodes or skin.CASE SUMMARY A 48-year-old female Han Chinese patient was admitted for generalized lymph node enlargement for 6 years and abdominal distension for 1 wk.She was diagnosed with small B-cell lymphoma(stage IV)/CLL(Benet stage B)and received chemotherapy.She started oral ibrutinib in February 2019.She was hospitalized on June 11,2019,and a 1.5 cm×1.5 cm dark-red nodule with ulceration scalp lesion was found.Biopsy revealed LCS but without CLL/SLL.She was diagnosed with CLL/SLL(Binet stage C,Rai stage IV)accompanied by secondary histiocytic sarcomas and skin LCS and received cyclophosphamide,doxorubicin,vincristine,dexamethasone,and etoposide but developed severe cytopenia.She ultimately refused treatments and discharged spontaneously.She died on September 12,2019.The literature review showed that in patients with CLL/SLL,skin lesions of LCS are accompanied by CLL/SLL.This patient was different from the previously reported cases of skin LCS in patients with CLL/SLL.CONCLUSION In this patient,the skin lesion of LCS showed no concomitant CLL/SLL.

Adult Langerhans cell histiocytosis and immunomodulatory drugs:Review and analysis of thirty-four case reports

Langerhans cell histiocytosis(LCH)is a rare neoplastic disease in dendritic cells.LCH is classified as either a single-system(SS)or multisystem(MS)disease.There is not a standard first-line treatment for LCH in adults.We analyzed the efficacy and safety of immunomodulatory drugs(IMiDs)by searching PubMed/MEDLINE for case reports previously published.The clinical response(nonactive disease or active disease that regressed)was 94%in SS and 53%in MS.IMiDs should only be considered for adults with cutaneous SS involvement;in MS,they should be used only for patients not eligible for more aggressive treatments.

Thymic langerhans cell histiocytosis in children:A case report

Langerhans cell histiocytosis has long been described as a rare systemic disorder involving the proliferation of Langerhans cells with formation of granuloma. The disease may be localised or diffuse. Typical forms of the disease involving the bone, the skin or the pituitary gland have been well described whereas others, such as thymic histiocytosis, are still poorly understood. Here, we report a case of isolated Langerhans cell histiocytosis of the thymus in an infant with non-specific symptoms. We provide a description of the disease and discuss patient management.

中耳朗格汉斯细胞组织细胞增生症1例

朗格汉斯细胞组织细胞增生症(Langerhanscell histiocytosis,LCH)是罕见的炎性髓样恶性肿瘤,发病率低。约50%~80%的儿童LCH位于头颈部,其中约15%~60%的患儿涉及颞骨,常出现与乳突炎、中耳炎、外耳道炎等疾病相似的临床表现,如乳突肿胀、耳痛等[1],因此本病可能会被延迟诊断,导致患者无法得到及时治疗。本文报道1例以“左耳痛伴耳后肿胀”为主诉的患儿,术前诊断为“急性乳突炎”,术后病理确诊为LCH。

Gut and liver involvement in pediatric hematolymphoid malignancies

Hematolymphoid malignancies are common neoplasms in childhood.The involvement of the gastrointestinal(GI)tract,liver,biliary system,pancreas,and peritoneum are closely interlinked and commonly encountered.In leukemias,lymphomas,and Langerhans cell histiocytosis(LCH),the manifestations result from infiltration,compression,overwhelmed immune system,and chemotherapyinduced drug toxicities.In acute leukemias,major manifestations are infiltrative hepatitis,drug induced gastritis,neutropenic typhlitis and chemotherapy related pancreatitis.Chronic leukemias are rare.Additional presentation in lymphomas is cholestasis due to infiltration or biliary obstruction by lymph nodal masses.Presence of ascites needs a thorough workup for the underlying pathophysiology that may modify the therapy and affect the outcome.Uncommon hematolymphoid malignancies are primary hepatic,hepatosplenic,and GI lymphomas which have strict definitions.In advanced diseases with extensive spread,it may be impossible to distinguish these diseases from the primary site of origin.LCH produces biliary strictures that mimic as sclerosing cholangitis.Liver infiltration is associated with poor liver recovery even after chemotherapy.The heterogeneity of gut and liver manifestations in hematolymphoid malignancies has a clinical impact on their management.Though chemotherapy is the mainstay of therapy in all hematolymphoid malignancies,debulking surgery and radiotherapy have an adjuvant role in specific clinical scenarios.Rare situations presenting as liver failure or end-stage liver disease require liver transplantation.At their initial presentation to a primary care physician,given the ambiguity in clinical manifestations and the prognostic difference with time-bound management,it is vital to recognize them early for optimal outcomes.Pooled data from robust registries across the world is required for better understanding of these complications.

Clinical Research of Pulmonary Langerhans Cell Histiocytosis in Children

Background： Pulmonary Langerhans cell histiocytosis （PLCH） is an interstitial primary pulmonary disease, characterized by Langerhans cell proliferation. It is easily misdiagnosed in children. This study aimed to characterize the clinical manifestations and features of PLCH by retrospective analysis. Meihods： A retrospective analysis was performed in 117 PLCH patients out of 338 LCH patients who were admitted in our center from November 2006 to October 2013. Variables between two groups were compared by Mann-Whitney U-test and Chi-square test. Kaplan-Meier curves were constructed to compare the survival rates and Cox regression to evaluate the effect of risk factors. Results： The median age of PLCH group was significantly lower than that ofnon-PkCH group （ 18.63 months vs. 43.4 months, P 〈 0.001 ）. All PLCH children had other organ involvement and only 11 cases （9.4%） had respiratory symptoms. The most common radiologic finding was cystic lesions （29 cases, 24.8%）. Pulmonary thnction abnormalities were dominated by obstructive ventilatory dysfunction （63 cases, 82.9%）. The 5-year overall survival （OS） of PECH children was 93.6% ± 2.3% and the event-free survival （EFS） was 55.7% ± 5.2%. Among the 38 cases with progressed or relapsed disease, five cases （13.2%） were due to progression or recurrence of lung damage. The 5-year OS of PECH children with ＂risk organ＂ involvement was significantly lower than those without ＂risk organ＂ involvement （86.0% ± 4.9% vs. 100%,X^2 = 8.793, P= 0.003）. The difference of EFS between two groups was also significant （43.7% ± 7.7% vs. 66.3% ± 6.5%,X^2 = 5.399, P = 0.020）. The ＂＇risk organ＂ involvement had a significant impact on survival （hazard ratio = 1.9, P = 0.039）. Conclusions： PLCH mainly occurs in young children, and only a small percentage of patients have respiratory symptoms. They generally have other organ involvement. Most of PLCH children have a good prognosis and most lung lesions could have improved or stabilized. Management of＂risk organ＂ involvement is the key point to improving EFS.