Modulation of expression of epidermal Langerhans cell properties following in situ exposure to glucocorticosteroids

Epicutaneous Administration of 17β-Estradiol Induces Langerhans Cells Depletion

BACKGROUND

Langerhans cells (LC) number and function in mouse vaginal mucosa are affected by 17β-estradiol (E₂) application; nonetheless, its effect on epidermal LC has not been studied. The purpose of this study was to evaluate the effect of topical administration of E₂ on the number, phenotype, and migratory ability of LC in mouse skin.

METHODS

Ears of adult CD1 male mice were topically treated once with several doses. Immunohistochemical staining for CD207 and TUNEL staining were performed. LC migration to lymph nodes and the effect on the expression of costimulatory molecules on cultured dendritic cells (DC) were also evaluated.

RESULTS

E₂ decreased the number of CD207+ LC in a dose-dependent manner. One hour after treatment, 1 and 10 µg/mL E₂ significantly reduced the LC number by 21% and 26%, respectively, after two hours, the reduction was 23% and 41%, respectively. After 48 hours, LC recovered, and after 96 hours of treatment, the CD207+/MHCII+ DC numbers were increased in regional lymph nodes. However, CD86 and CD40 molecules were expressed at lower levels than in positive control. The TUNEL assay did not show apoptotic cells. Furthermore, in cultured DC, E₂ promoted a decrease in CD40 and CD86 expression and an increase in CD273, CD274, MHCII, and CCR7.

CONCLUSIONS

The topical administration of E₂ induced a transitory local diminution of LC population and a tolerogenic phenotype. This decrease in epidermal LC suggests that E₂ may affect skin immune responses, inducing an inhibitory response, which should be considered when prescribing topical E₂ medications.

Duration of topical therapy in the maintenance of atopic dermatitis remission in pediatric age

BACKGROUND

Topical corticosteroids (TCS) are the first-choice treatment for atopic dermatitis (AD) flares. In literature there are clear advice about the potency, dosage and frequency of application of TCS, but there are no shared indications about duration of the treatment during a flare. The aim of the study is to demonstrate if the use of a steroid cream for less than or 5 days, could be equal or more effective than the application for more than 5 days during a flare episode, in keeping a remission state of AD.

METHODS

The study population (N.=122) was selected according to the following inclusion criteria: at least one specialist allergological and dermatological examination in the period November 2015 to February 2017, age between 1 and 11 years; mild to moderate atopic dermatitis. All patients were given a standardized telephone questionnaire, which concerns on multiple aspects: parents' self-reported perceptions of the severity of their child's condition; actual use of emollients, moisturizers and steroid creams; number of consecutive days of using of topical steroid cream during an exacerbation of AD; average number of AD exacerbations per month in the last year; total number of AD exacerbations in the last year.

RESULTS

Data from 96 patients was examined. We classified three groups of patients from data collected: group 1 (N.=40): use of TCS for ≤5 consecutive days during an exacerbation event of AD; group 2 (N.=12): use of TCS for >5 consecutive days during an exacerbation event of AD; group 3 (N.=44): nonuse of TCS or use of TCS with a different posology. We found a further subgroup in group 3 (3a, N.=27) with patients using only emollient crème in AD management. In group 1, 27 patients (67.5%) did not show a good AD control; on the contrary, 13 patients (27.5%) reported a good AD control. In group 2, 4 patients (25%) did not show a good AD control; on the contrary, 8 patients (75%) reported a good AD control. By comparing the data obtained in the presence of good AD control, the difference between the percentages obtained was found to be statistically significant (P=0.034).

CONCLUSIONS

The results obtained show that a therapeutic pattern based on the use of TCS for a duration of more than 5 consecutive days during an episode of AD exacerbation is more efficient than the proposed alternative therapeutic scheme in the maintenance of AD remission.

Langerhans cells and melanocytes share similar morphologic features under in vivo reflectance confocal microscopy: a challenge for melanoma diagnosis

BACKGROUND

Intraepidermal Langerhans cells (ILC) are difficult to differentiate from melanocytes under reflectance confocal microscopy (RCM) and their presence may simulate pagetoid spread of melanocytes on RCM images.

OBJECTIVE

We sought to correlate bright round and dendritic cells in a pagetoid pattern identified on RCM with findings of conventional histopathology and immunohistochemistry for lesions that were falsely diagnosed as melanoma by RCM.

METHODS

This retrospective study included histopathologically proven nevi, imaged by RCM, which displayed bright cells in a pagetoid pattern (BCPP) under RCM, resulting in the incorrect RCM diagnosis of melanoma. Morphological comparisons were made between RCM images of nevi showing BCPP, histopathologically proven melanomas displaying BCPP, and biopsy-proven nevi without BCPP.

RESULTS

We identified 24 nevi that were falsely diagnosed as melanoma by RCM because of the presence of BCPP. These pagetoid cells on RCM corresponded on histopathology to ILC with a high density in 23 of the 24 nevi (95%) and to melanocytes in 7 of the 24 nevi (29%). Among 6 melanomas displaying BCPP on RCM, ILC with high density were observed histopathologically in 5 of the 6 cases (83%) and pagetoid melanocytes were seen in all 6 cases (100%).

LIMITATIONS

The results cannot be generalized to clinically banal-appearing nevi.

CONCLUSIONS

Although the finding of BCPP is a useful RCM feature for the diagnosis of melanoma, it does not always imply the presence of pagetoid melanocytes but may at times represent ILC.

Transdermal rivastigmine: management of cutaneous adverse events and review of the literature

Alzheimer's disease is a chronic neurodegenerative disorder resulting in part from the degeneration of cholinergic neurons in the brain. Rivastigmine, a cholinesterase inhibitor, is commonly used as a treatment for dementia due to its ability to moderate cholinergic neurotransmission; however, treatment with oral rivastigmine can lead to gastrointestinal adverse effects such as nausea and vomiting. Transdermal administration of rivastigmine can minimize these adverse effects by providing continuous delivery of the medication, while maintaining the effectiveness of the oral treatment. While the transdermal form of rivastigmine has been found to have fewer systemic adverse effects compared with the oral form, cutaneous reactions, such as contact dermatitis, can lead to discontinuation of the drug in its transdermal form. Lack of patient compliance with regard to applying the patch to the designated site, applying the patch for the correct length of time or rotating patch application sites increases the risk of cutaneous adverse reactions. This article outlines the diagnosis and management of irritant contact dermatitis and allergic contact dermatitis secondary to transdermal rivastigmine. The large majority of reactions to transdermal patches are of an irritant type, which can be diagnosed clinically by the presence of a pruritic, erythematous, eczematous plaque strictly confined to the borders of the patch. In contrast, an allergic reaction can be differentiated by the presence of vesicles and/or oedema, erythema beyond the boundaries of the transdermal patch and lack of improvement of the lesion 48 hours after removal of the offending treatment. By encouraging the patient to follow a regular rotation schedule for the patch, and using lipid-based emollients for irritant dermatitis and pre- and post-treatment topical corticosteroids for allergic dermatitis, cutaneous reactions can often be alleviated and patients can continue with their medication regimen. Other simple changes to a patient's treatment routine, including minimizing the use of harsh soaps, avoiding recently shaven or damaged areas of skin and carefully removing the patch after use, can help to further decrease the risk of dermatitis development.

Corticosteroids But Not Pimecrolimus Affect Viability, Maturation and Immune Function of Murine Epidermal Langerhans Cells

Given the importance of dendritic cells in the immune response, we investigated the effect of corticosteroids (CS) on the integrity, survival, and function of murine Langerhans cells (LC) in comparison with pimecrolimus, a novel anti-inflammatory drug for the topical treatment of atopic dermatitis. BALB/c mice were treated twice on one day with ethanolic solutions of the compounds. At 24-72 h after the last application, we observed fragmented DNA, caspase-3 activity, and an upregulation of CD95 expression in LC from mice treated with CS but not in LC of pimecrolimus- or vehicle-treated animals. CS-epidermal cell (EC) supernatants but not pimecrolimus-EC supernatants contained significantly lower amounts of soluble factors (GM-CSF, TNF-alpha, IL-1alpha) required for LC survival and maturation than EC supernatants from vehicle-treated mice. With regard to LC maturation, CS but not pimecrolimus inhibited the expression of CD25, CD205, and costimulatory molecules. In line with this, LC from pimecrolimus-treated mice were similar to LC from vehicle-treated mice in their capacity to stimulate antigen-presenting function and migration, whereas LC from CS-treated mice were greatly impaired in these abilities. In summary, our data show for the first time that CS but not pimecrolimus induce apoptosis in LC in situ, implying that the prolonged use of CS could have adverse effects on the skin immune system.

Influence of immunosuppressive drugs on dendritic cells

Immunosuppressive drugs used to control allograft rejection and in efforts to promote transplant tolerance are well recognized for their abilities to inhibit lymphocyte activation and proliferation. In recent years, evidence has accumulated that these diversely acting agents (anti-proliferative drugs, calcineurin inhibitors, rapamycin, deoxyspergualin and glucocorticoids) also affect the development and functional immunobiology of dendritic cells, in vitro and in vivo. Here we review the influence of immunosuppressive drugs on the differentiation and function of these important antigen-presenting cells. We also consider how these effects influence immune reactivity and tolerance induction, implications for furthermore understanding of dendritic cell biology and prospects for improving the outcome of organ transplantation and therapy of other immune-mediated disorders by impacting dendritic cell function.

Functional modulation of dendritic cells to suppress adaptive immune responses

In recent years, dendritic cells (DCs) have entered the center court of immune regulation. Dependent on their ontogeny, state of differentiation, and maturation and thereby a variable expression of membrane-bound and soluble molecules, DCs can induce immunostimulatory as well as immunoregulatory responses. This dual function has made them potential targets in vaccine development in cancer and infections as well as for the prevention and treatment of allograft rejection and autoimmune diseases. The present review is focused on the effect of immune-modulatory factors, such as cytokines and immunosuppressive drugs, and on the survival, differentiation, migration, and maturation of DC human subsets. A better understanding of DC immunobiology may lead to the development of specific therapies to prevent or dampen immune responses.

Downregulation of class II molecules on epidermal Langerhans cells in Lyme borreliosis

BACKGROUND

Borrelia burgdorferi can be isolated from the skin of patients with acrodermatitis chronica atrophicans (ACA), a late-stage manifestation of Lyme borreliosis; despite a marked T-cell infiltrate in lesional skin and high antibody titres in patients' sera.

OBJECTIVES

To determine whether antigen-presenting Langerhans cells (LCs), which reportedly show signs of injury in erythema chronicum migrans (ECM), the early stage of disease, are altered in ACA.

PATIENTS/METHODS

We studied the immunophenotype of cutaneous leucocytes on cryostat sections of lesional skin from both ECM and ACA patients.

RESULTS

The total number of CD1a+ cells evaluated by semiautomatic image analysis was lower in ECM (594 +/- 263 cells mm(-2) epidermis) than in ACA (835 +/- 317 cells mm(-2) epidermis). HLA-DR expression was remarkably downregulated on CD1a+ LCs to 29% in ECM and 18% in ACA, whereas in normal skin, most of the epidermal CD1a+ dendritic cells were HLA-DR+. The inflammatory infiltrate was mainly composed of CD68+ macrophages and CD45RO+ memory T cells, with a predominance of CD4+ helper T cells.

CONCLUSIONS

It is conceivable that the downregulation of major histocompatibility complex class II molecules on LC in both the early and late skin manifestations of Lyme borreliosis is indicative of a poorly effective anti-B. burgdorferi immune response and thus at least partly responsible for the insufficient elimination of this micro-organism from ACA skin.

Heterogeneous reactivity of murine epidermal Langerhans cells after application of FITC: a histochemical evaluation

To elucidate the detailed kinetics of epidermal Langerhans cells after topical contact sensitizer stimulation, we examined ATPase or Ia positive epidermal cells of BALB/c mice in a time-spaced manner after the topical application of fluorescein isothiocyanate (FITC). We also performed double labeling of Langerhans cells in epidermal sheets with ATPase activity and Ia antigen or costimulatory molecules (B7-1 and B7-2) after the same stimulation. Observations showed that the density of ATPase positive cells and Ia positive cells decreased following a different time course; the former reached a nadir (77.4% of control) at 4 h but the latter reached a minimum (82.8% of control) at 16 h after the application of FITC. A double labeling technique revealed an increase in Ia single positive cells at 4 h as opposed to that of ATPase single positive cells at 16 h after application. Both costimulatory molecules were expressed on the dendritic processes of many Langerhans cells as a dotty pattern at 4 h after application; B7 positive and ATPase negative areas were observed at this time. On electron microscopic observation, a few activated Langerhans cells found in the dermis at 4 h after application had distinctive profiles compared with residual Langerhans cells in the epidermis. These findings suggest that there is a heterogeneity of reactivity to FITC in epidermal Langerhans cells, and that only a small portion of them migrates from the epidermis during sensitization. The findings also indicate the importance of the interaction between the Langerhans cell and its surrounding microenvironment in the epidermis for its activation. In addition, the results indicate that the enzymatic and the phenotypic markers do not definitively reflect the presence (or absence) of Langerhans cells.

Glucocorticoid-mediated regulation of thymic dendritic cell function

The possible effects of glucocorticoids (GC) on the biology of thymic dendritic cells (DC) have been analyzed. Both DC and GC seem to be involved in intrathymic T cell selection but possible relationships, if any, between them remain currently unknown. For the first time, we have proved the expression of GC receptors in thymic DC. Moreover, our data demonstrate that in vitro dexamethasone (Dex) treatment barely affects the viability of mature thymic DC, which are largely resistant to its apoptotic effect. Dex-treated thymic DC also show a slightly reduced surface expression of some adhesion and co-stimulatory molecules in correlation with diminished allostimulatory properties. Furthermore, the production of both IL-1beta and tumor necrosis factor (TNF)-alpha, but not that of IL-6 and IL-10, diminished in the mixed leukocyte reaction established with Dex-treated thymic DC. However, the addition of recombinant rat IL-1beta and TNF-alpha, alone or in combination, did not recover the allostimulatory capacity. Taken together, these results support certain GC-mediated regulation of the activity of thymic DC which could be relevant for the biology of the thymus gland.

Progressor but not regressor skin tumours inhibit Langerhans' cell migration from epidermis to local lymph nodes

Langerhans' cells (LC) are found in high numbers infiltrating skin tumours, the functional significance of which remains unknown. To study the mechanism by which tumours increase the number of LC we developed a procedure whereby supernatant from cultured T7 tumour cells applied topically increases the number of LC. Tumour factors increased the number of resident epidermal LC and did not attract LC precursors into parental murine skin grafted onto F1 hybrids. There was no evidence for increased LC division in response to the tumour-derived factors. LC migration from the epidermis to local lymph nodes, induced by topical fluorescein isothiocyanate (FITC), was inhibited by the tumour supernatant. To examine the functional significance of this, FITC-induced migration of LC from the epidermis overlying progressor tumours, which evade immunological destruction, and regressor tumours, which are immunologically destroyed, was examined. The progressor tumour T7 growing subcutaneously in syngeneic mice inhibited FITC-induced migration of LC from overlying epidermis. Furthermore, two progressor, but not two regressor murine skin tumour lines growing in BALB/c nu/nu mice inhibited LC migration from the epidermis. Our results demonstrate that progressor skin tumours produce factor(s) which inhibit LC migration from the epidermis to lymph nodes, leading to LC accumulation. Inhibition of LC migration by tumour-derived factors may enable tumours to evade the activation of protective immunity as regressor tumours do not interfere with the normal trafficking of LC.

Modulation of MHC class II+ Langerhans cell numbers in corticosteroid treated epidermis by GM-CSF in combination with TNF-alpha

It is important to understand how dendritic cells (DC) are recruited, maintained and stimulated to migrate from tissues to lymph nodes. This is because DC are potent initiators of primary immune responses and candidates for vaccine development. Identification of factors which could lead to increased numbers of DC in tissues could affect immune responses by modulating their interaction with antigen which penetrates the tissue. To identify cytokines which could increase DC in tissues we tested the ability of GM-CSF, TNF-alpha and IL-6 to partially prevent steroid depletion of Langerhans cells (LC) from the epidermis. Cytokines diluted in serum-containing medium were compared with cytokines diluted in albumin-containing, serum-free medium in order to determine a minimum combination of cytokines required to increase LC and the effect of serum on the LC-increasing activity of cytokines. In the presence of serum, GM-CSF or TNF-alpha could increase LC frequency compared to the control; but in the absence of serum neither of these cytokines were effective unless they were combined with each other. In the presence of serum the combination of GM-CSF with TNF-alpha was ineffective. The data support the hypotheses that GM-CSF and TNF-alpha are both important in regulating LC numbers in the epidermis in vivo. Serum may modulate how each of these cytokines, separately or in combination, affect LC frequency in the epidermis - GM-CSF and TNF-alpha separately probably interact with other factors present in serum to increase LC frequency, whereas in combination it is possible that these separate effects are cancelled in the presence of serum. TNF-alpha and GM-CSF together, in the absence of serum, form one combination of a minimum number of cytokines which can regulate LC frequency in the epidermis; and IL-6 alone, or in combination with GM-CSF, does not increase LC frequency.

Steroids inhibit uptake and/or processing but not presentation of antigen by airway dendritic cells

Recent studies from our laboratory indicate that local and (particularly) systemic steroids can modulate the traffic of dendritic cells (DC) through resting and inflamed airway epithelial tissues. The present report focuses upon the T-cell activating properties of DC, which are controlled by granulocyte-macrophage colony-stimulating factor (GM-CSF) signals, and in particular the question of whether the DC-stimulating effects of GM-CSF are susceptible to regulation by steroids. We present evidence that while dexamethasone inhibited GM-CSF-dependent uptake and/or processing of exogenous antigen by DC, it was ineffective in blocking the presentation of preprocessed self antigen to alloreactive T cells in a one-way mixed lymphocyte reaction (MLR). Associated GM-CSF-induced up-regulation of major histocompatability complex (MHC) class II and CTLA4 ligand expression by DC were also unaffected by dexamethasone phosphate (DX), reinforcing the view that the inhibitory effects of steroids on the T-cell activating functions of DC are restricted to steps upstream from presentation of processed antigen to the T-cell receptor (TCR). These findings have potentially important implications in relation to the use of topical steroids in the treatment of atopic asthma, a disease in which local T-cell activation in airway tissue is a key pathogenic factor, and which furthermore is characterized by intense production of GM-CSF within the airway epithelium.

Effects of topical testosterone propionate on the positive nickel patch test

In a group of nickel sensitized women, we investigated the effects of topical application of testosterone propionate on the epidermic density of CD1 + dendritic cells and on the response to patch tests performed with scaled nickel concentrations. In a significant number of examined subjects, treatment with testosterone propionate induced an increase of the minimum eliciting dose of nickel and an evident reduction of CD1 + dendritic cell epidermic density. In those subjects in which the minimum eliciting dose resulted unmodified, the epidermic density of CD1 + dendritic cells also did not undergo significant variations following treatment with testosterone propionate. This parallelism between the behaviour of the responses to patch tests and the epidermic density of CD1 + dendritic cells induces us to think it possible that testosterone propionate is able to increase the tolerance to contact with allergen by interfering with the activity of Langerhans cells. The possible mechanisms of testosterone action on Langerhans cells remain to be elucidated.

Effect of coadministration of corticosteroids on the development of contact sensitization

BACKGROUND

Transdermal administration of drugs can increase patient compliance and reduce side effects, but it can also cause contact sensitization. Corticosteroids frequently are used to suppress the local immune response; however, their use as a pretreatment for transdermal system application sites is not practical.

OBJECTIVE

Our purpose was to determine the feasibility of suppressing contact sensitization by delivering a corticosteroid with the transdermal delivery systems.

METHODS

Materials were applied continuously for 3 weeks to the same (protocol SS) or different (protocol AS) skin sites. Skin flux and appearance of sensitization were determined.

RESULTS

Coadministration of hydrocortisone reduced the incidence of sensitization by d-chlorpheniramine and benzoyl peroxide from 45% to 7.5% and from 20% to 2.3%, respectively, under protocol SS. Under protocol AS, sensitization by d-chlorpheniramine was reduced from 15% to 1%. Frequent exposure to the sensitizer plus corticosteroid induced tolerance to the sensitizer.

CONCLUSION

Sensitization by moderately immunogenic drugs after any length of exposure may be reduced to acceptable levels by the coadministration of hydrocortisone.

Modulation of Ia+ Langerhans cell numbers in vivo by cultured epidermis derived supernatants and by GM-CSF

This paper demonstrates that epidermal cells in culture produce an activity which can increase the frequency of Ia+ epidermal Langerhans cells (LC). This was achieved by treating mice topically with a mixture containing supernatant derived from primary culture of murine epidermis (ES) and a synthetic corticosteroid, triamcinolone acetonide (TAC). The presence of the supernatant in the mixture partially protected the Ia+ LC from depletion by the steroid. The Ia+ LC frequency increasing activity was measured as the difference between the Ia+ LC frequency due to treatment with steroid mixed with supernatant and the Ia+ LC frequency due to treatment with steroid mixed with negative control medium. The mean frequency of Ia+ LC in epidermis treated with TAC mixed with ES was 606(SD 43) cells/mm2, as compared with 486 (SD 68) cells/mm2 in the epidermis treated with TAC mixed with control medium. The activity appeared to be caused by (a) proteinaceous factor(s). A fraction of ES which was retained above a > or = 10 KDa molecular weight cut-off membrane was capable of partially protecting Ia+ LC frequency from TAC depletion. Supernatants from cultured lymph nodes, dermis as well as the squamous cell carcinoma lines T7 and T79, but not the human osteosarcoma cell-line 143B, also contained similar activities. We demonstrate that GM-CSF also increased the number of Ia+ epidermal LC when applied topically to mouse skin in this system. Therefore, using this Ia+ LC frequency modulation system, we propose that GM-CSF is one example of a cytokine which may be involved in the regulation of Ia+ LC numbers in epidermis and that epidermal cells produce factors which can increase the number of Ia+ LC.

Histochemical, immunohistochemical and ultrastructural studies on the action of glucocorticoids on epidermal Langerhans cells (ELC) of murine skin

We studied the influence of the glucocorticosteroids dexamethasone and prednisolone on epidermal Langerhans cells (ELC) in the ear skin of BALB/c mice. ELC were detected by HLA II-antigen-expression and ATPase staining. The number of ELC was counted by normal light and immunofluorescence microscopy. Both, dexamethasone and prednisolone decreased the number of ELC and the intensity of the reaction for HLA II and ATPase significantly. In the electron microscope, ELC were identified by their light cytoplasm, the lobulated nucleus and typical Birbeck Granula (BG). After systemic application of dexamethasone or prednisolone the ultrastructure was changed with respect to a loss of typical BG and occurrence of numerous small vacuoles without electron dense content instead of BG.

Epidermal Langerhans cells in the terrestrial turtle, Kinosternum integrum

In mammalian epidermis, Langerhans cells (LC) are the only antigen-presenting dendritic cells that possess the ectoenzyme adenosine triphosphase (ATPase) and constitutively express class II molecules encoded by the major histocompatibility complex. Recently, we demonstrated the presence of LC in chicken epidermis. The aim of the present study is to demonstrate the presence of LC-like cells in turtle Kinosternum integrum, epidermis by light and ultrastructural ATPase histochemistry. ATPase-positive dendritic cells were observed in epidermal sheets whose maximum mean number was 192 cells/mm2. Electron microscopy for ATPase stained sections showed an electrondense precipitate in the plasma membrane of dendritic clear cells located among basal and suprabasal keratinocytes, ultrastructurally similar to LC. In serial sections, some dendritic cells showed LC (Birbeck) granules. The present study demonstrates for the first time ATPase-positive dendritic cells, morphologically similar to LC, in reptilian epidermis.

Regulators of immunological responses in the cornea and the anterior chamber of the eye

Although the eye is considered to be immunologically privileged, this privilege is not absolute. This is well demonstrated by, for example, the fate of corneal transplantations. Clinical studies in man and experimental studies in animals have shown that survival of a corneal transplant depends on the local condition of the cornea and the anterior chamber of the eye. The presence of neovascularisation or Langerhans cells in the recipient cornea endangers the graft, while the intracorneal production of immunosuppressive factors may inhibit the development of rejection. The balance between suppressive and stimulatory factors determines whether a local immune response will develop.

In-vivo administration of interleukin 1 both enhances and suppresses contact sensitivity in the mouse

The in-vivo effects of systemic administration of recombinant human interleukin 1 beta (rIL-1 beta) were studied in the mouse contact-sensitivity model. rIL-1 beta in a single dose of 20 micrograms injected intraperitoneally 72-48 h before or 2-24 h after sensitization suppressed contact sensitivity. Given before challenge rIL-1 beta modulated the response in a biphasic way with an enhancement at 48 h and a suppression at 2 h before challenge. Only microgram doses of rIL-1 beta could enhance the contact sensitivity at 48 h, while microgram doses of rIL-1 beta at 2 h before challenge suppressed and nanogram doses enhanced the response. Treatment with indomethacin could only abrogate the effects of nanogram doses of rIL-1 beta. Measurements of the thickness of unchallenged control ears revealed that rIL-1 beta by itself could cause a small but significant increase in thickness depending on the dose and the time of administration.

Basement membrane changes in psoriatic patients on long-term topical corticosteroid therapy

It has been observed that the beneficial anti-inflammatory effects of topical steroids in psoriasis are counteracted by increasing instability of the disease, with rebound phenomena associated with the cessation of these drugs. We report the occurrence of multi-layered fragmentation and disorganization of the basal laminae in active, untreated psoriatic lesions, resolving and uninvolved, inadvertently steroid-treated psoriatic skin, as well as in a variety of non-psoriatic dermatoses treated with fluorinated topical steroids for prolonged periods. These changes, which were associated with a moderate to severe loss of dermal collagen, were not found in untreated and treated psoriatic controls, with or without concomitant alpha 1-antitrypsin deficiency, who had not received steroids, suggesting that they were probably the consequence of prolonged fluorinated steroid use. This conclusion is supported by the observation that the largest number of layers (10-15) of fragmented basal laminae was noted in the patients who had received fluorinated steroids for 6 years or more, while those on 4 years or less of fluorinated steroid therapy exhibited only three to seven layers of fragmented basal laminae. In psoriatic lesions, the fragmentation of the basal lamina was associated with the presence of basal keratinocyte herniations (BKH), the frequency of which has been shown to parallel clinical psoriatic activity. The persistence of these electron-microscopic markers of psoriatic activity (i.e. BKH) in psoriatic plaques treated with prolonged fluorinated steroids suggests that loss of integrity of the basement membrane, as indicated by the presence of multi-layered fragmentation of the basal lamina, may account for the instability of the psoriatic lesions treated with prolonged topical fluorinated steroids.

Human epidermal Langerhans cells undergo profound morphologic and phenotypical changes during in vitro culture

Morphology, phenotype, and enzyme activity of highly enriched (80%) unlabeled human epidermal Langerhans cells (LC) have been studied, with emphasis on changes during a short-term culture of three days in vitro. All freshly isolated LC contained Birbeck granules and expressed high levels of CD1a, CD1c, and MHC class II molecules HLA-DR, -DP, and -DQ. They have a weak to moderate expression of RFD1, C3biR, Fc gamma R, p 150/95, MHC class I molecules HLA-ABC, and of the adhesion molecules LFA-3 and ICAM-1, whereas no expression of LFA-1 and several monocyte/macrophage markers were detected. Human LC undergo profound changes during in vitro culture. Birbeck granules, C3biR, Fc gamma R, and p 150/95 were completely lost and the expression of CD1a and CD1c was markedly decreased or lost. Expression of molecules that have essential functions in antigen presentation remained present at the same level (MHC class II molecules and ICAM-1) or was markedly enhanced (LFA-3 and MHC class I). Highly remarkable was the dramatically enhanced expression of interdigitating cell marker RFD1. The monocyte/macrophage markers initially absent remained absent and the enzyme activity initially present (including ATPase and nonspecific esterase) remained present. In conclusion, the results in this report stress rapid alterations of human LC during in vitro culture, resulting in transformation into cells that have phenotypical characteristics of potent antigen presenting cells that resemble interdigitating cells.

A study of systemic and topical effects of topical steroid application through the comparison of two application schedules

We compared two application schedules of a topical steroid, BV (Betamethasone valerate). The schedules were once daily and twice a week on juvenile Wistar rats treated for four weeks. Steroid actions were assessed topically (skin thickness and epidermal Langerhans cell density) and systemically (body weight and internal organ wet weights). The results revealed some rather severe systemic effects caused by frequent steroid application. And we also found a uniquely weak BV effect with Langerhans cells compared to obvious systemic effects on rats. We came to the conclusion that frequent steroid application to the young should be avoided.

Immunohistochemical study of normal skin of HIV-1-infected patients shows no evidence of infection of epidermal Langerhans cells by HIV

Langerhans cells (LC) are dendritic epidermal antigen-presenting cells expressing the surface molecule CD4, which renders them theoretical cellular targets for direct infection by the human immunodeficiency virus (HIV). To date, somewhat conflicting results have been reported concerning the in vivo infection of LC by HIV as well as the numerical alteration of these cells in the course of HIV infection. In the present work we studied clinically normal skin of a group of 44 HIV-1-seropositive patients classified according to the Centers for Disease Control (CDC) stages II (n = 14), III (n = 9), and IV (n = 21). Monoclonal antibodies (MAb) to HIV p18, p24, and gp120 and to HLA-DR and CD1a antigens (specific for LC) were applied on frozen skin sections using an amplification biotin-streptavidin-fluorescein technique. The MAb to HIV p18 cross-reacted with a cytoplasmic antigen of epidermal basal keratinocytes also present on HIV-seronegative skin specimens. No other reactivity was observed with any of the three anti-HIV MAb. The quantitative study showed that no significant correlations could be established between the number of LC (evaluated independently by HLA-DR and CD1a antigens) and the number of peripheral blood CD4+ve lymphocytes or the CDC disease stage. These results cast some doubt on the previously reported in vivo infection and numerical decrease in LC in HIV infection. The precise involvement of LC in HIV infection awaits further investigation.

ATPase and morphologic changes in Langerhans cells induced by epicutaneous application of a sensitizing dose of DNFB

We have previously described an ATPase Langerhans cell (LC) staining technique allowing progression from light to electron microscope observation. Using this technique we have studied, following epicutaneous application of a sensitizing dose of a hapten, 2,4-dinitro-1-fluorobenzene (DNFB), the fate of the epidermal LC located in the sensitization zone. We wanted to know, under the light microscope, if the density and/or morphology of the LC are modified by such a treatment and, under the electron microscope, what are the ultrastructural changes accompanying the possible light microscope modifications. Under the light microscope, the observation of LC during the 5 d necessary for the development of contact sensitivity to DNFB shows that their number drops in the course of the first 24 h to normalize again 3 d later. Under the electron microscope, observations over the first 24 h revealed that LC remained in the epidermis, but were ATPase-negative. The disappearance of the membrane ATPase activity took place while the LC presented an increased number of coated pits, coated vesicles, endosomes, and lysosome organelles which characterize, at the ultrastructural level, the process of receptor-mediated endocytosis (RME). Following RME, many Birbeck granules (BG) appeared in the cytoplasm. Thus, epicutaneous application of DNFB leads to an endocytic activation of LC. However, the ligand(s) and/or the cell-surface components, which probably internalize during the RME process, remain unknown.

CD-1 (T6), HLA-DR-expressing cells, presumably Langerhans cells, in nasal mucosa

In the skin, epidermal Langerhans cells (LC) constitute a major population of antigen-presenting cells. These cells are characterized by the expression of both CD-1 (T6) and HLA-DR on the cell membrane. We wanted to know whether similar CD-1/HLA-DR-positive cells occur in the nasal mucosa of patients with an isolated grass pollen allergy and in non-allergic controls. CD-1/HLA-DR-positive dendritic cells were found in columnar and cuboidal epithelium and the lamina propria of the nasal mucosa. These CD-1/HLA-DR-positive cells presumably correspond with LC in the skin. We also found significantly more CD-1-positive cells in nasal biopsy samples of allergic than in those of the non-allergic controls. In the allergic patients some of the CD-1-positive cells were found to be surface IgE-positive, possibly due to passive adherence of IgE to Fc receptors.

Direct effects of glucocorticosteroids on epidermal Langerhans cells

To determine the direct effects of glucocorticosteroids on epidermal Langerhans cells (LC), we treated isolated LC with dexamethasone (DEX) in vitro, and investigated Ia expression by LC using immunofluorescence microscopy and FACS analysis. We found that DEX directly decreased the number of Ia+ LC in a dose- and time-dependent manner. Pulse incubation with DEX also inhibited the immunostimulatory function of LC in vitro. FACS analysis demonstrated that LC detected in DEX-treated culture expressed a similar amount of Ia antigen and Fc receptor on the cell surface as LC cultured with the solvent control, suggesting that LC may be composed of a heterogeneous population in terms of sensitivity to DEX, and DEX may completely abolish the expression of surface molecules on a subpopulation of LC or may be cytolytic to this sensitive population.

Flow cytometrically-sorted residual HLA-DR+T6+ Langerhans cells in topical steroid-treated human skin express normal amounts of HLA-DR and CD1a/T6 antigens and exhibit normal alloantigen-presenting capacity

Topical corticosteroids decrease the number of HLA-DR+T6+ Langerhans cells (LCs) and the antigen-presenting capacity of epidermal cells (ECs). We have investigated the properties of residual HLA-DR+T6+ LCs in steroid-treated human skin. Flow cytometric analysis revealed that clobetasol propionate 0.05% applied twice daily for 7 d reduced the percentage of HLA-DR+T6+ LCs in EC suspensions to 46% of control (from a mean percentage +/- sem of 2.49 +/- 0.30 in control skin to 1.15 +/- 0.22 in steroid-treated skin), but did not significantly alter the relative amounts of HLA-DR and CD1a/T6 antigens per individual HLA-DR+T6+ cell. HLA-DR+T6- and HLA-DR-T6+ cells were not detected in either group. Steroid therapy significantly decreased the allostimulatory capacity of unsorted ECs. By contrast, in parallel experiments in which the same EC suspensions were greatly enriched (85% to 90%) for HLA-DR+T6+ LCs by flow cytometric sorting, the allostimulatory capacity of purified LCs from steroid-treated skin was not significantly different from control. Residual HLA-DR+T6+ LCs, which preserve their antigenic markers and alloantigen-presenting function, may be relatively unaffected because they have only recently immigrated into the epidermis, or they may represent a subgroup of steroid-resistant LCs. Alternatively, given the dose response relationship between topical steroid potency and decrease in HLA-DR+T6+ LC numbers, the apparent steroid resistance of residual HLA-DR+T6+ LCs may reflect heterogenity in the density of expression of LC steroid receptors.

Class II antigen expression of epidermal Langerhans cells in renal allograft recipients

This study was designed to investigate the influence of systemic immunosuppressive therapy on the HLA-DR expression of epidermal Langerhans cells. Fifteen renal allograft recipients immunosuppressed with cyclosporin A and steroids were studied. Skin biopsies were taken from the upper arm prior to transplantation and at different intervals during the post-transplantation period. The epidermis was separated from the dermis, and the epidermal sheet was subjected to immunohistochemistry in order to make the HLA-DR antigens on the Langerhans cells visible. Following 2 days of immunosuppression, the number of Langerhans cells expressing HLA-DR antigens started to decrease and after 1 week, only 60% of the initial number of positive cells were detected. The number of positive cells remained low throughout the experimental period. It is suggested that systemic immunosuppressive therapy will suppress the expression of HLA-DR antigens on epidermal Langerhans cells, something which may mirror a systemic effect on other antigen-presenting cells.

Relative lack of systemic effects of mometasone furoate on Langerhans cells of mice after topical administration as compared with other glucocorticosteroids

The effects of topically applied mometasone furoate were compared with those of other glucocorticosteroids, in particular fluocinolone acetonide, in assays of murine epidermal Ia+ Langerhans cell density. No evidence of systemic effects, as determined by a decline in the density of Ia+ LC in distant sites, was detected after local topical applications (5 times a week) of mometasone furoate 0.001% for periods of up to 3 weeks. Other steroids, even in such very low concentrations, and mometasone furoate in higher concentrations, produced systemic effects on Ia+ LC when used for longer than 5 d. The recovery time of Ia+ Langerhans cells is significantly shorter after application of mometasone furoate than after fluocinolone acetonide. However, with both compounds, recovery occurred more rapidly after 3 weeks than after a 1- or 2-week interval of compound administration.

Photoimmunology: the mechanisms involved in immune modulation by UV radiation

Ultraviolet radiation (UVR) may be the most prevalent agent that man encounters in his environment. As a result, certain biological adaptations take advantage of the beneficial effects of UVR exposure, e.g. the photoactivation steps involved in vitamin D metabolism. In this regard, UVR plays an important role in maintaining our good health; however, it must be noted that UVR is potentially the most harmful naturally occurring agent in our environment. Thus, it appears that several mechanisms have evolved to protect us against the detrimental effects of UVR overexposure. Although epidermal melaninization or "tanning" may be the most obvious example of these processes, we would argue that adoptive mechanisms within the immune system also provide protection against UVR-induced skin damage. It is now known that UVR affects the distribution and functional activities of various immunocompetent cells within the skin, as well as modifying the production of inflammatory and hematopoietically active cytokines. This review will focus on the known mechanisms involved in the immune modulatory effects of UVR and how adoptive immune responses to UVR-induced skin damage contribute to specific pathological processes.

Effects of topical corticosteroid therapy on Langerhans cell antigen presenting function in human skin

We have investigated the mechanisms by which topical corticosteroids modulate cutaneous immune reactions in man. Volunteers applied clobetasone butyrate 0.05% (Eumovate; EV), betamethasone valerate 0.1% (Betnovate; BV), clobetasol propionate 0.05% (Dermovate; DV), and control vehicles twice daily to forearm skin for 7 days. Steroid therapy significantly decreased the number of HLA-DR/T6 (CD1a) positive Langerhans cells (LCs) per mm2 in suction blister-derived epidermal sheets, expressed as a mean percentage of controls, as follows: EV 69.2%; BV 67.3%; DV 37.8%. LC antigen presenting capacity was determined in the allogeneic and autologous epidermal cell-lymphocyte reactions. The LC-dependent allostimulatory capacity of epidermal cells, expressed as a mean percentage of controls, was also significantly reduced by steroid therapy: EV 45.1%; BV 41.9%; DV 23.4%. Following therapy with clobetasol propionate 0.05%, the capacity of epidermal cells to present tetanus toxoid to, and to augment concanavalin A mediated lymphocyte stimulation of, autologous lymphocytes was reduced to 33.6% and 19.7% respectively of controls. Depression of epidermal cell allostimulatory capacity was not the result of a steroid-induced decrease in the production of epidermal cell-derived thymocyte activating factor (ETAF)/interleukin 1 by keratinocytes, since it could not be reversed by addition of exogenous interleukin 1. Indomethacin, added to block any potential prostaglandin synthesis during the culture period, did not restore the allostimulatory capacity of epidermal cells from steroid-treated sites. Addition of epidermal cells from DV-treated sites depressed the capacity of control epidermal cells to stimulate lymphocytes in the allogeneic epidermal-lymphocyte reaction. Our results demonstrate that the anti-inflammatory action of topical corticosteroids in man is associated not only with a reduction in the number of HLA-DR/T6 positive LCs, but also with a marked decrease in Langerhans cell-dependent T lymphocyte activation. The effects of the different steroids on both of these parameters correlated with their potency as determined in the standard occlusive vasoconstrictor assay. Topical corticosteroids are widely used for the treatment of inflammatory skin disorders, and inhibit not only the elicitation phase, but also the induction phase, of allergic contact dermatitis reactions.(ABSTRACT TRUNCATED AT 400 WORDS)

Glucocorticoid effects on contact hypersensitivity and on the cutaneous response to ultraviolet light in the mouse

A single exposure to 254 nm ultraviolet irradiation (UV) can systemically suppress experimental sensitization to the simple allergen 2,4-dinitro, 1-chlorobenzene (DNCB) in the mouse. We show here that topical application at the site of irradiation of the 21-oic acid methyl ester derivative of the synthetic glucocorticoid triamcinolone acetonide (TAme) prevents UV suppression of sensitization. That is, mice painted with TAme at the site of UV exposure developed normal contact hypersensitivity (CH); mice exposed to UV only, like mice treated with the parent compound triamcinolone acetonide (TA), failed to be sensitized by DNCB applied to a distal site. TAme is inactivated rapidly by plasma esterases, so its effect is thought to be confined to the skin. Apparently, TAme blocked the cutaneous signal(s) for systemic suppression of CH. Histologically, irradiated skin exhibited mild inflammation and hyperproliferation, but these effects were greatly exaggerated and prolonged in the UV + TAme-treated skin, independent of sensitization at the distal site. The infiltrate consisted mostly of neutrophils and lacked the round cells characteristic of cell-mediated immunity. Apparently, normal immune suppression by UV prevented this vigorous reaction to irradiated skin. Applied together with DNCB. TAme blocked sensitization. It also prevented response to challenge by DNCB in previously sensitized animals. However, unlike the parent compound triamcinolone acetonide (TA), Budesonide or Beclomethasone diproprionate, each of which can penetrate the epidermis in active form, TAme had no effect on sensitization when applied at a distal site. Likewise, TAme did not affect plasma B (17-desoxycortisol) levels, whereas the other three compounds reduced plasma B tenfold, as expected of compounds causing adrenal-pituitary suppression. The results as a whole show that glucocorticoids can specifically inhibit cutaneous steps in induction of cell-mediated immunity or its suppression, and can, at the site of challenge, prevent its expression in CH.

Epidermal Langerhans cell density in patients with pulmonary malignancies and chronic obstructive pulmonary disease

To evaluate the relationship between ELC density and pulmonary malignancies, as reported in previous investigations, we examined the nonsun-exposed epidermis of 18 patients with pulmonary cancer (CA) not receiving immunosuppressive therapy, 20 patients with chronic obstructive pulmonary disease (COPD-S), and 10 patients with COPD receiving glucocorticosteroid (GCS) therapy (COPD + S). The ELC density was not significantly different between lung tumor patients (1024 +/- 167) and COPD-S (1072 +/- 200, p less than 0.4) control patients, and we found no significant correlation between ELC density and tumor cell type, presence or absence of metastases, tumor stage, or present smoking status. Although we did detect that systemic GCS therapy significantly reduced the ELC density in COPD + S patients (910 +/- 211, p less than 0.05); use of inhaled or chronic low dose (less than or equal to 20 mg daily) GCS did not appear to significantly alter ELC density. In addition, anergy to epicutaneous dinitrochlorobenzene in CA and COPD + S patients positively correlated with a reduction in ELC density, suggesting a possible functional deficit arising from the numerical change. Further investigation is needed to elucidate whether factor(s) other than a reduction in ELC density are involved in the anergic state.

Age-associated changes in Langerhans cells of murine oral epithelium and epidermis

Oral mucosa and skin of older individuals are immunologically less responsive to a range of allergens, but it is not known whether this is due to changes in the number of Langerhans cells or to impaired cell function. EDTA-separated epithelial sheets from the cheek and palate mucosa, and from ear aN< footpad skin of three-month-old and 24-month-old C57BL/6NNia mice were stained for ATPase, beta-glucuronidase activity and Iab-surface antigen to demonstrate Langerhans cells. The general distribution of such cells was unchanged with age, but those in epithelia from the old mice were more varied in shape, with irregular celL bodies and more elongated dendritic processes. The numerical density of Langerhans cells in old mice was reduced by 30-59 per cent compared with that in young mice.

HLA-D region antigen expression by human epidermal Langerhans cells

We have systematically examined HLA-D region antigen expression by normal human epidermal Langerhans cells with an improved double label indirect immunofluorescence technique in order to better understand the immunologic potential of this human interstitial dendritic cell type. The results of this study which differ somewhat from earlier observations strongly suggest that 100% of OKT-6-positive epidermal Langerhans cells constitutively express HLA-DQ and HLA-DP as well as HLA-DR molecules. Since HLA-DQ expression has been positively correlated with the ability to present nominal antigen, our findings would suggest the possibility that epidermal Langerhans cells, like other members of the human dendritic cell series, might be more efficient than monocytes at nominal antigen presentation since only about 50% of peripheral blood monocytes express HLA-DQ molecules.

Defined in situ enumeration of T6 and HLA-DR expressing epidermal Langerhans cells: morphologic and methodologic aspects

An essential prerequisite for the in situ enumeration of epidermal Langerhans cells (LCs) is the unequivocal identification of the desired cell type. We have examined over 250 cryostat sections of normal human skin to analyze morphologic and methodologic problems underlying the quantification of epidermal LCs, defined by anti-T6 (OKT6) and anti-HLA-DR (OKIal) immunoperoxidase staining. Our findings show that OKT6 reactivity of dendritic processes in cross-sectioned epidermis yields microscopic images which are not easy to analyze objectively. The morphology that we find leads us to categorize dendritic cells into 3 arbitrary types of T6+ LC profiles. In addition we describe criteria for the assessment of OKT6 staining patterns relating to the dendritic state of epidermal LCs. Preliminary quantitative data on this issue are discussed in relation to: epidermal thickness; the thickness of skin tissue sections; and the discrepancy between the number of T6+ and HLA-DR+ LCs. We hope that the principles outlined in this report may serve to overcome potential methodologic problems with quantitation of T6+ epidermal LCs in skin sections.

Immunopathology of cutaneous human lupus erythematosus defined by murine monoclonal antibodies

Skin biopsy specimens obtained from involved skin from sixteen patients with systemic and discoid lupus erythematosus were studied. Murine monoclonal antibodies with a biotin-avidin-horseradish peroxidase staining system were used. The findings consisted of a marked reduction in the number of epidermal Langerhans cells defined by surface antigens, reduced HLA-DR (Ia-like) antigens on the surface of dermal capillary endothelium, and mononuclear cell infiltrates characterized by a predominance of helper T lymphocytes and an increase in the number of mononuclear phagocytic cells. B lymphocytes were rarely identified. The number of T lymphocytes within the dermis correlated inversely with both the number of HLA-DR-positive epidermal Langerhans cells (p less than 0.01) and the HLA-DR staining of dermal capillary endothelium (p less than 0.01). These findings suggest that a T lymphocyte-mediated immune response associated with a reduction in Langerhans cells and capillary endothelium HLA-DR antigens is involved in the inflammatory process of lupus erythematosus skin.