Normal Langerhans Cells Research Articles

Abnormal lipid metabolism in epidermal Langerhans cells mediates psoriasis-like dermatitis.

Psoriasis is a chronic, inflammatory skin disease, frequently associated with dyslipidemia. Lipid disturbance in psoriasis affects both circulatory system and cutaneous tissue. Epidermal Langerhans cells (LCs) are tissue-resident DCs that maintain skin immune surveillance and mediate various cutaneous disorders, including psoriasis. However, the role of LCs in psoriasis development and their lipid metabolic alternation remains unclear. Here, we demonstrate that epidermal LCs of psoriasis patients enlarge with longer dendrites and possess elevated IL-23p19 mRNA and a higher level of neutral lipids when compared with normal LCs of healthy individuals. Accordantly, epidermal LCs from imiquimod-induced psoriasis-like dermatitis in mice display overmaturation, enhanced phagocytosis, and excessive secretion of IL-23. Remarkably, these altered immune properties in lesional LCs are tightly correlated with elevated neutral lipid levels. Moreover, the increased lipid content of psoriatic LCs might result from impaired autophagy of lipids. Bulk RNA-Seq analysis identifies dysregulated genes involved in lipid metabolism, autophagy, and immunofunctions in murine LCs. Overall, our data suggest that dysregulated lipid metabolism influences LC immunofunction, which contributes to the development of psoriasis, and therapeutic manipulation of this metabolic process might provide an effective measurement for psoriasis.

Langerhans Cell Histiocytosis in Adults: Treatment Opportunities of Today

Langerhans cell histiocytosis (LCH) is an extremely rare disease associated with tissue infiltration by pathological cells which are phenotypically similar to normal Langerhans cells. Standard therapy of LCH in adults has not been developed so far, due to the lack of sufficient evidence base for different treatment methods. In clinical practice, cytostatic treatment is applied along with new approaches using signaling pathway inhibitors involved in LCH pathogenesis. This literature review covers currently existing methods of LCH therapy in adults and their feasibility in clinical practice.

PENGARUH MEDIA TERKONDISI SEL PUNCA MESENSIMAL TERHADAP EKSPRESI GEN TRANSCRIPTION FACTOR 7-LIKE 2 (TCF7L2) TIKUS MODEL DIABETES MELITUS TIPE 2

Diabetes mellitus type 2 is the most common type of diabetes. This study was conducted to determine the effect of Mesenchymal Stem Cell-Conditioned Medium (MSC-CM) in Homeostatic Model Assessment of β-cell function (HOMA-β) value, normal Langerhans cells, and Transcription Factor 7-Like 2 (TCF7L2) gene expression in type 2 diabetic rats model. As many as 27 male Sprague Dawley rats were divided into 3 study research groups: normal control (9 normal rats), diabetic control (9 type 2 diabetic rats, induced by 60 mg/kg BW Streptozotocin and 120 mg/kg BW Nicotinamide i.p.), and treatment (9 type 2 diabetic rats treatment with 0.1 ml/200g BW MSC-CM i.p.). On day 30 after therapy, the expression of TCF7L2 gene was performed with real time-quantitative PCR (RT-qPCR). The HOMA-β value were calculated based on Fasting Insulins (FINs) levels and Fasting Blood Glucose (FBG) levels data from other research team members. Based on results, MSC-CM increases the HOMA-β value and amount of normal Langerhans cells of treatment group that indicates amelioration effect of MSC-CM, but there was no significant difference in TCF7L2 gene expression level between diabetic control and treatment group.

453 The role of purinergic signaling in development of irritant dermatitis of acrodermatitis enteropathica

Purinergic signaling is crucial to maintain homeostasis of inflammation. We previously elucidated that disruption of the homeostasis of skin inflammation by Zn deficiency-mediated ablation of Langerhans cells (LCs) that expressed CD39 (E-NTPDase1) was causative for development of dermatitis in acrodermatitis enteropathica. ATP was hydrolyzed into AMP by E-NTPDases (Entpd), E-NPPs (Enpp), and tissue non-specific alkaline phosphatases (TNAP). It has been well known that LCs express Entpd1 (CD39) and keratinocytes (KCs) do not express it in both mice and humans. However, the expression of other ATP-hydrolyzing molecules such as Entpd 2-3, Enpp 1-3, and TNAP in LCs and KCs is not addressed so far. The purpose of this study is 1. to determine the expression of these ATP-hydrolyzing molecules in LCs and KCs of both mice and humans by qPCR, and 2. to examine the alteration of expression of these ATP-hydrolyzing molecules under Zn deficient condition by qPCR. Normal murine KCs expressed Entpd2, Enpp1, and low levels of Enpp2 and TNAP, whereas normal human epidermal KCs (NHEKs) expressed Entpd2, Entpd3, and Enpp1. Normal murine LCs expressed Entpd1 (CD39), Entpd2, and low level of Enpp1, whereas normal human LCs expressed Entpd1 (CD39), and low levels of Enpp2 and Enpp3. KCs from Zn-deficient diet mice showed increased expression of Entpd2 and Enpp1, and loss of expression of Enpp2 and TNAP. Finally, we examined the impact of LCs in ATP hydrolysis. ATP hydrolysis activity was determined by measuring released phosphate. ATP hydrolysis activity was impaired up to 82% in LC-depleted murine epidermis compared with LC-existing murine epidermis. These data suggested that the expression of ATP-hydrolyzing molecules in LCs and KCs were different between mice and humans. Additionally, Zn deficiency altered the expression of ATP-hydrolyzing molecules in KCs. Lastly, Entpd1 (CD39)- and Entpd2-expressing LCs assumed about 80% of ATP hydrolysis, whereas Entpd2- and Enpp1-expressing KCs assumed the remaining 20% ATP hydrolysis in murine epidermis.

Langerhans cell homeostasis and activation is altered in hyperplastic human papillomavirus type 16 E7 expressing epidermis.

It has previously been shown that expression of human papillomavirus type 16 (HPV) E7 in epidermis causes hyperplasia and chronic inflammation, characteristics of pre-malignant lesions. Importantly, E7-expressing epidermis is strongly immune suppressed and is not rejected when transplanted onto immune competent mice. Professional antigen presenting cells are considered essential for initiation of the adaptive immune response that results in graft rejection. Langerhans cells (LC) are the only antigen presenting cells located in normal epidermis and altered phenotype and function of these cells may contribute to the immune suppressive microenvironment. Here, we show that LC are atypically activated as a direct result of E7 expression in the epidermis, and independent of the presence of lymphocytes. The number of LC was significantly increased and the LC are functionally impaired, both in migration and in antigen uptake. However when the LC were extracted from K14E7 skin and matured in vitro they were functionally competent to present and cross-present antigen, and to activate T cells. The ability of the LC to present and cross-present antigen following maturation supports retention of full functional capacity when removed from the hyperplastic skin microenvironment. As such, opportunities are afforded for the development of therapies to restore normal LC function in hyperplastic skin.

English

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder in which pathological Langerhans cells (LCs) accumulate in a variety of organs. This report describes a boy with Langerhans' cell histiocytosis who presented with primarily soft tissue swellings, without pain. A high index of suspicion is required to reach to a diagnosis of langerhans cell histiocytosis to prevent delay in proper management of this disease. INTRODUCTION: The childhood histiocytoses, although individually rare, varies widely in its clinical expression. These disorders are grouped together because they have in common a prominent proliferation or accumulation of cells of the monocyte-macrophage system of bone marrow origin. (1) A systematic classification of the childhood histiocytoses is based on histopathologic findings. The name Langerhans cell histiocytosis (LCH) has been applied to the class I histiocytoses. The normal Langerhans cell is an antigen-presenting cell of the skin. The hallmark of LCH in all forms is the presence of a clonal proliferation of cells of the monocyte lineage containing the characteristic electron microscopic findings of a Langerhans cell. This is the Birbeck granule, a tennis racket-shaped bilamellar granule that, when seen in the cytoplasm of lesional cells in LCH, is diagnostic of the disease. (1) CASE REPORT: A 4 year old male child presented to our pediatric outpatient department of mamata medical college with the chief complaint of multiple swellings over the forehead for the last one year. The child was apparently normal one year back when his parents noticed multiple small swellings which were gradually progressing in size. The child is a product of non-consanguineous marriage, full term, normal vaginal delivery and has a younger sister who is doing well. On examination there were three swellings over the forehead, which were subcutaneous, nontender margins ill-defined and with underlying bony defects in center of the swellings. Bilateral exophthalmos was present There was no organomegaly, generalized lymphadenopathy, skin manifestations or ear discharge.

IL-34 and CSF-1: similarities and differences

Colony-stimulating factor-1 (CSF-1) is widely expressed and considered to regulate the development, maintenance, and function of mononuclear phagocyte lineage cells such as monocytes, macrophages, dendritic cells (DCs), Langerhans cells (LCs), microglia, and osteoclasts. Interleukin-34 (IL-34) was recently identified as an alternative ligand for the CSF-1 receptor (CSF-1R) through functional proteomics experiments. It is well established that the phenotype of CSF-1R-deficient (CSF-1R⁻/⁻) mice is more severe than that of mice bearing a spontaneous null mutation in CSF-1 (CSF-1(op/op)). CSF-1R⁻/⁻ mice are severely depleted of macrophages and completely lack LCs, microglia, and osteoclasts during their lifetime. In contrast, CSF-1(op/op) mice exhibit late-onset macrophage development and osteoclastogenesis, whereas they show modestly reduced numbers of microglia and a relatively normal LC development. In contrast, IL-34-deficient (IL-34⁻/⁻) mice show a marked reduction of LCs and a decrease in microglia. IL-34 and CSF-1 display different spatiotemporal expression patterns and have distinct biological functions. In this review, we focus on the functional similarities and differences between IL-34 and CSF-1 in vivo.

In vivoconfocal microscopic evaluation of corneal Langerhans cell density, and distribution and evaluation of dry eye in rheumatoid arthritis

Corneal Langerhans cells (LCs) offer the opportunity to gain insight into the activity of the innate immunity. We examined the density and the distribution of LCs and compared the results with dry-eye parameters in rheumatoid arthritis (RA). Fifty-two RA patients with various degrees of disease activity and 24 healthy subjects were enrolled. Peripheral and central LC number and morphology were assessed with invivo laser confocal microscopy. In addition, ocular surface disease index (OSDI), lid parallel conjunctival folds, Schirmer test, and tear break-up time (TBUT) were evaluated. The prevalence of central and peripheral LC, and the central LC morphology values (LCM) were higher than normal in RA. Within the RA group, LC prevalence and morphology were not affected by disease activity. However, patients on anti-TNF or glucocorticosteroid (GCS) therapy exhibited normal LCM, and normal central and peripheral LC density. OSDI was higher and TBUT was lower than normal in RA. The alteration of LC in RA suggests an active inflammatory process in the cornea, which may reflect an increased activation state of the innate immune system-even in inactive stages of RA and without ocular symptoms. The results also indicate ocular effects of GCS therapy in RA.

Deletion of microRNA miR-223 increases Langerhans cell cross-presentation

Langerhans cells (LCs) are skin-residential dendritic cells that regulate skin immunity. MicroRNAs (miRNAs) are key regulators in the control of biological functions in a variety of cell types. Deletion of all miRNAs interrupts the homeostasis and function of epidermal LCs. However, the roles of individual miRNAs in regulating LC development and function are still completely unknown. MiRNA miR-223 is especially expressed in the myeloid compartment. Here, we reported that miR-223 is highly expressed in freshly isolated epidermal LCs, and tested whether miR-223 regulates LC development and function using miR-223 knockout (KO) mice. We found that the number, maturation, migration and phagocytic capacity of LCs were comparable between miR-223KO and wild-type mice. However, lack of miR-223 significantly increases LCs-mediated antigen-specific CD8+ T cell proliferation in vivo and in vitro, while LCs from KO and WT mice showed comparable stimulation for antigen-specific CD4+ T cells. Our data suggest that miR-223 negatively regulates LC cross-presentation, but may not be required for normal LC homeostasis and development.

Liver Transplantation in an Adult With Sclerosing Cholangitis due to Multisystem Langerhans Cell Histiocytosis

To the Editor: Langerhans cell histiocytosis (LCH) is a rare hematopoietic disorder characterized by proliferation of CD1a+ dendritic cells. An association between LCH and sclerosing cholangitis (SC) has rarely been reported in adults with only four cases of liver transplantation for LCH associated SC in the literature (1). We have recently managed such a patient with SC secondary to LCH who eventually required liver transplantation, and feel the case adds to the evidence that liver transplantation can be efficacious in treating some rare diseases, such as LCH, and that posttransplant immunosuppression can prevent recurrence. Furthermore, it highlights the ethical implications of using valuable organs when evidence for transplant is scarce. The patient was diagnosed with SC in 2006, aged 39, following previous gallstone pancreatitis and chronically abnormal liver function with intermittent pruritis. He was then independently diagnosed with LCH in 2007 after a symptomatic scapula mass was biopsied. His SC progressed despite repeated biliary duct dilatations and by 2008 he was being considered for liver transplant with a Model for End-stage Liver Disease (MELD) score of 15. Pretransplant liver biopsy revealed immunostaining diagnostic of LCH (Figure 1). He underwent successful orthotopic liver transplantation in March 2009 and was immunosuppressed postoperatively with tacrolimus and prednisolone. Due to subsequent hyperglycemia this was changed to cyclosporine and mycofenolate mofetil. At present, he is well with normalized liver function and no signs of transplant rejection in two subsequent liver biopsies. Liver biopsy: (A) portion of a segmental bile duct (BD) infiltrated by Langerhans cells (arrows), CD1a [panel (B)] and S100 immunoreactive [panel (D)]. High-power view of mass of Langerhans cells with eosinophils (Eos) [panel (C)]. Liver transplantation has been shown to be the only successful treatment of end-stage biliary cirrhosis in patients with LCH (1). Chemotherapy in this group may actually cause deterioration in liver function. Our decision to transplant was precipitated by the patient's liver failure and rising MELD score. A recent study of 1130 patients demonstrated survival benefit at 1 year posttransplant once a patient's MELD score reached 15 irrespective of pathogenesis (2). In rare diseases where evidence of efficacy is limited to a few case reports, deterioration in liver function may therefore best guide a decision to consider transplantation. Due to the systemic nature of LCH, there is the additional concern of disease recurrence posttransplant. Reassuringly, only one recurrence within an adult graft has previously been described (3). Immunosuppression posttransplant could reduce recurrence rates and this may suggest an immune mechanism in the pathogenesis of LCH. In liver transplantation secondary to LCH the ideal immunosuppressant would prevent graft rejection and LCH recurrence. There is currently no convincing evidence which agent most effectively achieves this. Cyclosporine has been the most extensively documented immunosuppressant used to treat LCH. However evidence of its efficacy is mainly in the form of case series and these have demonstrated widely varying results (4, 5). To our knowledge there is no literature on the use of other immunosuppressants such as mycophenolate mofetil, mammalian target of rapamycin (mTOR) inhibitors or calcineurin inhibitors as anti-LCH agents. Of note Jorden et al. have shown that pathological Langerhans cells aberrantly express CD52, whereas normal Langerhans cells do not (6). Therefore alemtuzumab, an anti-CD52 monoclonal antibody previously shown to be efficacious in preventing graft rejection (7), may also have activity against LCH. The immunological mechanisms involved in this disease, although as yet poorly understood, provide the opportunity for posttransplant immunosuppression to have a dual role in preventing graft rejection and disease recurrence. The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.

Tyrosine phosphatase SHP-1 is expressed higher in multisystem than in single-system Langerhans cell histiocytosis by immunohistochemistry

Langerhans cell histiocytosis (LCH) is a proliferative disorder of Langerhans cell (LC)-like CD1a-positive cell (LCH cell) with unknown causes. LCH consists of two subtypes: single-system LCH (LCH-SS) with favorable prognosis and multisystem LCH (LCH-MS) with poor prognosis. LCH has been indicated as a neoplastic disorder from monoclonal characteristics of LCH cells. This study aimed to investigate an expression of tyrosine phosphatase SHP-1 in LCH, since its expression levels were variously reported in many tumors, overexpression in ovarian cancers (a candidate oncoprotein), and downregulation by methylation in gastric cancers, prostate cancers, malignant lymphomas, and leukemias (a putative tumor suppressor). By immunohistochemistry (IHC), the SHP-1 expression in LCs and LCH cells was compared in LCH (two subtypes: LCH-SS = 21, LCH-MS = 12), dermatopathic lymphadenopathy (DLA) (n = 9) and normal epidermal LCs (n = 3) near LCH lesion. IHC results were analyzed semiquantitatively using a Photoshop software. The mean intensity score (IS) of DLA, LCH-SS, LCH-MS, and LCs were 47, 100, 139, and 167 (in arbitrary unit), respectively. The IS had significant differences among LCH-SS, LCH-MS, and DLA (p < 0.01). SHP-1 is expressed significantly higher in LCH-MS than in LCH-SS. SHP-1 can be a progression marker of LCH. SHP-1 is also useful for differential diagnosis between LCH in lymph nodes and DLA.

Toll Receptors and Langerhans Cell Histiocytosis.

AbstractAbstract 3793 Introduction:Langerhans cell histiocytosis is a clonal proliferative disease of antigen presenting cells. Clinically, it is associated with aberrant secretion of cytokines from both Langerhans cells (LCs) themselves and immune cells associated with the disease. Toll-like receptors (TLRs) are membranous and cytoplasmic proteins involved in pattern-based recognition of bacterial and viral products. Activation of TLRs results in production of pro-inflammatory cytokines, modulation of the immune response, and maturation of LCs. TLRs activate signal transduction pathways involving IRFs (interferon regulatory factors), NFkB (Nuclear Factor-k-B) and MAPK (mitogen activated protein kinases).In this study, we have examined LCH samples for their expression of TLRs and downstream effector proteins. Methods:We examined archived samples from 42 LCH patients. Paraffin embedded samples were sectioned and stained for immunohistochemistry (IHC) using antibodies directed against TLR1-9; IRF3, 7 and 8; MEK1/2 and ERK1/2. RNA was isolated from the same samples using laser-capture microdissection, and the expression of TLR receptors, effectors and downstream targets was analyzed using qRT-PCR. These data were compared with gene expression data published in Gene Expression Omnibus using data set GSE16395. Results:IHC results showed upregulation in pathologic LCs compared to normal LCs of TLR 1, 3, 5, 7, 8 and 9, but not TLR 4 and 6. Moreover, upregulation of downstream pathways involving MEK1/2 and ERK1/2 and IRF8 in was also observed in pathologic LCs. Gene expression analysis showed up-regulation of the effectors of TLRs including CASP8, MAP3K7, and PPARA as well as genes in the NFKB pathway (CCL2, NFKb1, NFKB2, NFKBIL1, NFRKB, and REL), the JNK/p-38 pathway (ELK1, c-FOS, MAP3K1 and MAP3K8), and the interferon regulatory factor pathway (CXCL10, IRF7, IRF8 and TBK1). Comparison with the gene expression data base confirmed the results obtained from qRT-PCR for the gene expression of TLRs, their effectors, and downstream. Conclusion:Upregulation of TLRs and the pathways they control occurs commonly in LCH. Therapies directed toward inhibition of TLRs and their downstream targets may provide a means of modulating the adverse inflammatory aspects of LCH. Disclosures:No relevant conflicts of interest to declare.

Immunohistochemical and ultrastructural features of Langerhans cells in condyloma acuminatum

There are few studies on the abnormal morphology of Langerhans cells (LCs) in condyloma acuminatum (CA) lesions and the essence of the abnormal morphology of LCs in CA lesions is still not well elucidated. The aim of this study was to further investigate the morphological features of LCs in CA lesions. CD1a(+) LCs in 13 CA lesions and in 13 normal controls were labeled using immunohistochemistry and examined by light microscopy. Ultrastructural investigation on LCs in six CA lesions and in six normal controls was performed by electron microscopy. Compared with those in normal controls, most CD1a(+) LCs in CA lesions exhibited dysplastic dendrities and abnormal distribution. The number of CD1a(+) LCs in CA lesions (26.31 +/- 18.84) was statistically lower (p < 0.001) than that in normal controls (72.00 +/- 27.40). Electron microscopy showed that the number of Birbeck granules within lesional LCs (4.00 +/- 2.94) was significantly decreased (p < 0.001) than that within normal LCs (10.80 +/- 4.78). The ultrastructures of most lesional LCs displayed degenerative changes. The morphology of most LCs in CA lesions shows degenerative changes, which suggest that these LCs have been functionally impaired.

S179D prolactin diminishes the effects of UV light on epidermal gamma delta T cells

Epidermal gamma delta T cells (γδT) and Langerhans cells (LC) are immune cells altered by exposure to ultraviolet radiation (UVB), a powerful stressor resulting in immune suppression. Prolactin (PRL) has been characterized as an immunomodulator, particularly during stress. In this study, we have asked whether separate administration of the 2 major forms of prolactin, unmodified and phosphorylated, to groups of 15 mice (3 experiments, each with 5 mice per treatment group) affected the number and morphology of these epidermal immune cells under control conditions, and following UV-irradiation. Under control conditions, both PRLs reduced the number of γδT, but a molecular mimic of phosphorylated PRL (S179D PRL) was more effective, resulting in a 30% reduction. In the irradiated group, however, S179D PRL was protective against a UV-induced reduction in γδT number and change in morphology (halved the reduction and normalized the morphology). In addition, S179D PRL, but not unmodified (U-PRL), maintained a normal LC:γδT ratio and sustained the dendritic morphology of LC after UV exposure. These findings suggest that S179D PRL may have an overall protective effect, countering UV-induced cellular alterations in the epidermis.

Index of Suspicion in the Nursery

Index of Suspicion in the Nursery

Expression of haptoglobin in human keratinocytes and Langerhans cells

Epidermal Langerhans cells (LCs) play an important role in cutaneous immunological reactions. Freshly obtained or intraepidermal LCs are incapable of activating autologous naive T cells. However, when they are cultured for 2-3 days, LCs are able to activate autologous T cells. It has been proposed that haptoglobin (Hp) is the inhibitor that prevents LC functional transformation in the skin. Abundant Hp has been found in the cytoplasm of epidermal LCs. However, the source of Hp in LCs has not been addressed. To determine the expression of Hp in epidermal cells, and to provide evidence that there is a functional relationship between LCs and keratinocytes (KCs) through Hp. Normal human epidermal cells and HaCaT cells were used for detection of Hp mRNA by in situ hybridization and reverse transcription-polymerase chain reaction, and Hp protein by immunohistochemical staining, immunofluorescence counterstaining and Western blotting. Hp mRNA was expressed in normal human KCs and HaCaT cells, but not in normal human epidermal LCs. Hp protein was detected by immunohistochemical staining and immunofluorescence counterstaining in CD1a+ epidermal dendritic cells (LCs), but not in KCs. Hp protein was weakly expressed by HaCaT cells. Hp mRNA is present in normal human KCs and HaCaT cells, suggesting that they have the potential to synthesize Hp protein. Normal human epidermal LCs are unable to synthesize Hp protein by themselves, although they have abundant Hp protein in their cytoplasm. It is likely that LCs acquire Hp through an exogenous pathway.

Anti-CD52 antibody, alemtuzumab, binds to Langerhans cells in Langerhans cell histiocytosis.

The humanized anti-CD52 monoclonal antibody, alemtuzumab (or Campath-1H), has been shown to potently deplete lymphocytes in human patients. It has been used to successfully treat graft versus host disease and chronic lymphocytic leukemia (CLL). CD52 is expressed on normal lymphocytes, monocytes, and some dendritic cell subsets. However, normal Langerhans cells (LC's) in the skin do not bind alemtuzumab. We sought to determine whether the pathologic LC's of Langerhans cell histiocytosis (LCH) express CD52 and thus could be targeted by this antibody. Immunohistochemistry was performed on both frozen and fixed/paraffin-embedded tissue specimens using either Campath-1G (the parental rat isotype) or Campath-1H (the humanized version of Campath in clinical use). Both Campath-1H and Campath-1G were found to bind to the pathologic LC's in LCH, but not the normal LC's of skin. Specific staining was demonstrated in all (13 of 13) LCH specimens examined, though staining was somewhat variable among specimens, and tended to be weaker in paraffin-embedded specimens. Expression of CD52 by the pathologic LC's seen in LCH suggests that alemtuzumab may represent a new, targeted therapy for this disease. Such therapy is particularly needed for patients with refractory, high-risk disease. Further investigation of the possible clinical use of this antibody in these patients is warranted.

CD1a and CD1c cell sorting yields a homogeneous population of immature human Langerhans cells

There is increasing evidence that ex vivo generated Langerhans cells (LCs) cannot fully substitute for their physiological counterparts in normal epidermis when studying the immunobiology of this prototype of a tissue-residing immature dendritic cell (DC). Here, we present CD1-based magnetic-activated cell-sorting (MACS) protocols for the effective isolation of human epidermal LCs. CD1c selection yielded a homogeneous population of pure and viable HLA-DR +/CD1a + DCs, with the ultrastructural features, surface antigen expression and cytokine profile, characteristic of epidermis-resident immature LCs. The immature state and functional integrity were established by allogeneic mixed lymphocyte reactions showing a weak stimulatory capacity of freshly isolated cells and upregulation upon stimulation. Characterizing the cells in more detail, we could demonstrate for the first time that normal human LCs express CXCR4, CD40 ligand (CD40L), and Fas and Fas ligand (FasL). The observed constitutive transcription of TGF-β suggests that the viability and immature state of epidermal LCs are maintained not only by the TGF-β production from the microenvironment, but also in an autocrine or paracrine manner. LPS and IFN-ω stimulated the expression of the inflammatory cytokines TNF-α and IL-1β, and there was secretion of IL-12p70 after CD40 ligation. Remarkably, the CD1-sorted LCs showed no loss of their Birbeck granules and CD1a expression upon culturing and no spontaneous phenotypic and functional maturation into potent antigen-presenting cells (APCs). We conclude that human epidermal LCs obtained by the CD1c cell-sorting protocol are optimal candidates with which to elucidate the properties and capabilities of immature cells and to develop immunotherapeutic vaccines.

Langerhans cell histiocytosis of the female genital tract: a literature review.

Langerhans cell histiocytosis (LCH) is a rare malignant disease involving the accumulation of a monoclonal proliferation of cells in various organs, that phenotypically resemble Langerhans cells (LC). LCH is not merely a hyperplasia of LC, as it typically affects organs that are outside of their normal physiologic distribution. Normal Langerhans cells are bone marrow-derived dendritic cells that populate the epidermis and are distinguished by the presence of Birbeck granules and cell surface protein CD1a. LC act as sentinels; they recognize, internalize, and process antigens encountered in the skin. Upon encountering an antigen, LC become activated with subsequent maturation and induction of their migratory capacity. Langerhans cells in patients with LCH are aberrant and profoundly differ from normal LC. The clinical spectrum of LCH is quite diverse; multiple organs can be affected. "Pure" genital Langerhans cell histiocytosis is a rare presentation, with only 12 previously reported cases. Due to the rarity of this disease, treatment of genital LCH is still very diverse. No modality is proven to be superior in improving patient outcome, and relapses frequently occur after surgery. Dramatic responses of cutaneous and ano-genital lesions to thalidomide and interferons have been reported. We advocate the use of immuno-modulating agents in LCH of the female genital tract first, rather than surgery.

Sinus histiocytosis with massive lymphadenopathy and Langerhans cell histiocytosis express the cellular adhesion molecule CD31.

Context.-We investigated expression of the adhesion molecule CD31 in sinus histiocytosis with massive lymphadenopathy (SHML) and Langerhans cell histiocytosis (LCH) because (1) SHML and LCH cells express a variety of cellular adhesion molecules and (2) SHML has been characterized as a reactive histiocytic proliferation, and tissue macrophages (histiocytes) are known to express CD31. Objective.-The purpose of this study was to determine whether SHML and LCH cells express CD31 and whether dual staining with CD31 and S100 facilitates diagnosis of these disease states. Methods.-Formalin-fixed, paraffin-embedded archival tissues were immunohistochemically stained via the labeled streptavidin-biotin method using antibodies against CD31 and S100 protein after heat-induced epitope retrieval. Archival tissues included SHML (n = 2), LCH (n = 10), malignant melanoma (n = 5), sinus hyperplasia (n = 4), granulomas (n = 4), granular cell tumor (n = 6), and normal skin (n = 4). Results.-Normal Langerhans cells in the epidermis were CD31(-)/S100(+); neoplastic Langerhans cells in LCH were CD31(+)/S100(+). Histiocytes in granulomas and in sinus hyperplasia were CD31(+)/S100(-); abnormal histiocytes in SHML were CD31(+)/S100(+). S100(+) tumors (malignant melanoma and granular cell tumor) were CD31(-). Conclusions.-The spectrum of cell types that express CD31 is expanded to include SHML and LCH. We speculate that up-regulation of CD31 in neoplastic Langerhans cells contributes to the migratory capability of LCH cells. CD31 may be a useful nonlysosomal marker of macrophages and their neoplastic counterparts (true histiocytic sarcomas). An immunohistochemical staining panel that includes CD31 and S100 facilitates the diagnosis of SHML and LCH.