Periocular intralymphatic histiocytosis or localized Melkersson–Rosenthal syndrome?

We describe three cases of periocular edema with histopathologic features of intralymphatic histiocytosis without extravascular granulomas. All were elderly males with no other significant medical problems. Previous reports of periocular Melkersson–Rosenthal syndrome are identical clinically, and some reports show illustrations of intralymphatic histiocytosis histopathologically, in addition to other features typical of the syndrome. Given the lack of associated diseases or other features of the Melkersson–Rosenthal triad, some of these cases may be better defined as periocular intralymphatic histiocytosis.     

Complete Melkersson–Rosenthal syndrome with multiple cranial nerve palsies

Melkersson–Rosenthal syndrome (MRS) is an uncommon, complex neuromucocutaneous disorder characterized by recurrent orofacial oedema, facial palsy and fissured tongue. Complete MRS is uncommon. A case of complete MRS with multiple cranial nerve palsies is reported.     

Melkersson-Rosenthal Syndrome with Genitalia Involved in a 12-Year-Old Boy

Melkersson–Rosenthal syndrome (MRS) is an uncommon granulomatous disease characterized by the triad of relapsing facial paralysis, orofacial swelling, and fissured tongue. Genital swelling in MRS is rarely reported. We presented the first case of complete MRS with genital swelling in a child. Biopsy examinations of both the child''s lower lip and penis showed noncaseating granuloma and intralymphatic granuloma infiltration. No symptoms or signs of other systemic disease (Crohn''s disease or sarcoidosis) were observed after 2 years of follow-up. Genetic screening for CARD15/NOD2 in this patient showed negative, which further confirmed the diagnosis of MRS. Eleven other cases of suspected complete or incomplete MRS with genitalia involved were reviewed. Our case emphasizes the specific clinical feature of MRS with genitalia involved, which was genetically different from Crohn''s disease and could be an independent entity. Lymphatic obstruction is responsible for localized edema in MRS.     

Melkersson–Rosenthal syndrome associated with parvovirus b19 viraemia and haemophagocytic lymphohistiocytosis

We describe a 23‐year‐old patient who presented acutely with haemophagocytic lymphohistiocytosis (HL) and Melkersson–Rosenthal syndrome (MRS). MRS and HL are two unusual and complex clinical patterns that may present acutely and to our knowledge, an association between them has never been reported. The clinical investigations in this patient led to identification of parvovirus B19 (PB19) viraemia by PCR. Parvovirus infection has been reported as a cause of virus‐associated HL, but the presence of PB19 has never been sought or reported as a possible trigger for MRS. This observation suggests a possible association between PB19 and HL, and opens the possibility of its association also with acute‐onset MRS. Further investigations for the presence of PB19 in cases of MRS are warranted.     

Regulation of nickel-induced T-cell responsiveness by CD4+CD25+ cells in contact allergic patients and healthy individuals

In this study, we investigated the capacity of CD4⁺CD25⁺ regulatory T cells to suppress nickel‐specific effector T cells, both in nickel‐allergic patients and healthy controls. CD4⁺ cells isolated from allergic patients showed an increased proliferative response to nickel, whereas CD4⁺ cells from negative controls did not respond to allergen. When CD4⁺CD25⁺ cells were depleted, nickel‐specific responsiveness was strongly increased both in allergic and in non‐allergic individuals, with the most pronounced effect in allergic patients. These regulatory T cells were anergic to nickel but inhibited nickel‐specific CD4⁺CD25^– effector T cells in coculture experiments. CD4⁺CD25⁺ cells from nickel‐allergic patients showed only a limited capacity to suppress effector T‐cell responsiveness, because an increased nickel reactivity could still be detected in these cocultures. None of the isolated CD4⁺CD25⁺ cells, either isolated from healthy controls or allergic patients, produced IL‐10 in response to nickel. Overall, these results support the view that CD4⁺CD25⁺ cells can control the activation of nickel‐specific effector T cells in non‐allergic individuals, whereas this regulatory capacity is impaired in allergic patients. To investigate the presence of allergen‐specific regulatory T cells in truly naïve, non‐sensitized individuals, T‐cell reactivity should also be studied with non‐environmental contact allergens, such as para‐phenylenediamine.     

Where does the antigen of cutaneous sarcoidosis come from?

Background: The antigen pathway of cutaneous sarcoidosis remains obscure. We have investigated topographic involvement of inflammatory cells and lymphatic vessels. Methods: Eleven cutaneous biopsies from eight patients were studied, along with controls from other granulomatous disorders and various skin lesions. Markers for lymphocytes, dendritic cells (DCs), and lymphatic vessel endothelial cells were detected using immunohistochemistry. Results: S100⁺ and CD1a⁺ immature DCs (Langerhans cells) occurred more frequently within the epidermis, whereas S100⁺, fascin⁺, or CD83⁺ maturing DCs occurred more frequently beneath the epithelium in cutaneous sarcoidosis cases than in controls (e.g. CD83, cutaneous sarcoidosis vs. other granulomatous disorders: r = 0.557, p = 0.011). Fascin⁺ and CD83⁺ mature DCs were often closely attached to CD3⁺ T‐lymphocytes around dermal granulomas. D2‐40⁺ lymphatic vessels were often found surrounding dermal granulomas, especially those located in the deeper dermis, in contrast to fascin⁺ blood vessels. Conclusions: Antigen‐capturing by immature DCs seems to take place initially in the epidermis, followed by maturation of DCs. These mature DCs may present the processed antigen to T‐lymphocytes that cause dermal granulomas either in the interstitium of the upper dermis, or in or around lymphatic vessels of the lower dermis. Environmental antigen could be verified by skin test. Kurata A, Terado Y, Izumi M, Fujioka Y, and Franke FE. Where does the antigen of cutaneous sarcoidosis come from?     

Evaluation of activatory and inhibitory natural killer cell receptors in non-segmental vitiligo: a flow cytometric study

Background Recent observations established the role of altered cellular immunity and autoimmune hypothesis in the pathogenesis of vitiligo. There have been several reports discussing T‐cell and natural killer (NK) cell populations, but NK cell receptors were not evaluated in vitiligo. Objective The purpose of this investigation was to assess the role of T and NK cells as well as activatory and inhibitory NK cell receptor alterations in the pathogenesis of vitiligo and whether any aberrations were correlated with clinical findings of the disease. Patients/methods Fifty‐three patients with non‐segmental vitiligo and 45 age‐ and sex‐matched healthy controls were enrolled in the study. The percentages of lymphocytes, granulocytes, monocytes and CD3, CD4, CD8, CD14, CD16, CD56, CD45, CD45RA, CD54RO, CD28, CD80, CD94, CD158a, KIR3DL‐1 receptors as well as CD94, CD158a, KIR3DL‐1 receptors on CD16⁺ cells were detected by using flow cytometry. The patient and control groups were compared in terms of the results of flow cytometric analysis, and the results were assessed regarding the type and activity of vitiligo. Results The percentages of CD16⁺CD56⁺, CD3⁺CD16⁺CD56⁺, CD8⁺ and CD45RO⁺ cells were significantly increased in vitiligo group compared with the controls. No difference was detected between the patients and control groups in percentages of CD3⁺, CD4⁺, CD3^?CD16⁺CD56⁺, CD28⁺, CD45⁺, CD45RA⁺, CD94⁺, CD158a⁺ and KIR3DL‐1⁺ cells. The percentage of CD16⁺CD158a⁺ cells was significantly decreased in a randomized selected group of vitiligo patients. There were no differences in percentage expression of studied cell surface antigens between patients in the active or stable period. CD3⁺ cells were significantly increased in generalized form, and CD45RO⁺ cells were significantly increased in acral/acrofacial form when compared with the other types of vitiligo. Conclusions These results indicate further evidence for T and NK cell abnormalities in non‐segmental vitiligo. The present data show that NK cell activation may be responsible in the pathogenesis of vitiligo in conformity with decreased inhibitory and increased activatory NK cell receptors.     

Possible role of superantigens in inducing autoimmunity in pemphigus patients

The diagnostic and pathological relevance of anti‐desmoglein autoantibodies in common forms of pemphigus has been well established, and T cells have been shown to play a role in the onset and progression of these diseases. The role of superantigens in provoking polyclonal activation of T cells with many different fine specificities, possibly including autoreactive T cells and T‐cell mediated autoantibody response, is unknown. Further, abnormal T‐cell function may lead to opportunistic infections particularly with Candida. The response of T cells of pemphigus patients to recall antigens of these opportunists is not clear. The aim of this study was to investigate the in vitro response of T lymphocytes from pemphigus patients to common bacterial superantigens such as streptococcal pyrogenic exotoxin A and staphylococcal enterotoxin B, and recall antigens such as Candida antigen. Changes in CD3⁺CD4⁺ and CD3⁺CD8⁺ T‐cell sub‐populations and expression of naive/memory markers (CD45RA⁺/RO⁺) on different T cells were analyzed by flow cytometry. Significant elevation in CD3⁺CD4⁺ and expression of the memory (CD45RO⁺) markers on these cells was observed both in pemphigus vulgaris and pemphigus foliaceus patients, as compared to healthy controls, upon stimulation with streptococcal pyrogenic exotoxin A and staphylococcal enterotoxin B. However, only memory T cells (CD45RO⁺) were significantly increased upon Candida antigen stimulation. Our study suggests that CD4⁺ memory T lymphocytes may modulate the pathogenic autoantibody response in pemphigus patients, and also emphasizes the possibility that the superantigen‐reactive T cells participate in the triggering of autoimmunity in pemphigus.     

Immunohistochemical characterization of non‐epithelial cells in spiradenoma

Spiradenoma is unique with respect to the presence of a large number of non‐epithelial cells, including S100 protein⁺ cells, most of which are presumably Langerhans cells, in the parenchyma as shown in the published work. However, the characterization of these non‐epithelial cells to date is insufficient. Immunohistochemistry of CD1a, CD3, CD4, CD8, CD56, CD68, intercellular adhesion molecule‐1 (ICAM‐1), and HLA‐DR, as well as double‐immunofluorescence labeling of S100 protein/CD1a and CD1a/CD3, was performed using paraffin‐embedded specimens from five cases of spiradenoma retrospectively. Non‐epithelial cells evenly distributed throughout the parenchyma of spiradenoma primarily consisted of CD1a⁺ Langerhans cells and CD3⁺ T cells. ICAM‐1 was expressed by epithelial cells and non‐epithelial cells in the parenchyma. HLA‐DR on the epithelial cells was limited to the focal area. In double‐immunofluorescence labeling, approximately one‐half of Langerhans cells were spatially related to T cells in the parenchyma, suggesting their functional interaction.     

Inflammatory features of melasma lesions in Asian skin

Melasma is triggered by various factors including ultraviolet radiation and estrogen; however, its pathogenesis is unclear. To investigate the inflammatory features of melasma lesions as triggers for this disorder, 197 women with melasma who attended Asan Medical Center and Kangskin Clinic, Seoul, from June 2011 to October 2011 completed a questionnaire concerning triggering or aggravating factors. These cases were divided into “non‐inflammatory” and “inflammatory” groups. Skin biopsies and immunostaining for CD68, CD117, and leukocyte common antigen (LCA) were performed in the lesional and peri‐lesional skin of ten cases in the non‐inflammatory group and nine cases in the inflammatory group. Among the 197 subjects (mean age, 41.5 years; mean age of melasma onset, 33.8 years), 50 patients (25.4%) were categorized into the inflammatory group. This group comprised cases that had inflammatory symptoms and events that triggered the melasma lesions. The lesional dermis contained more CD68⁺ melanophages, CD117⁺ mast cells, and LCA⁺ leukocytes in the inflammatory group than in the non‐inflammatory group. Inflammatory clinical features and an increased number of inflammatory cells in the lesion may be involved in the development of melasma in Asian skin.     

Reduction of skin-homing cytotoxic T cells (CD8+ -CLA+) in patients with vitiligo

Background: Vitiligo is a frequently acquired, hereditary disease, characterized by achromic macules due to the absence of melanocytes. In contrast with earlier studies, in which the main pathogenic role was attributed to anti‐melanocyte antibodies, recent papers have emphasized a role for CD8⁺ cytotoxic T lymphocytes in melanocyte destruction. Fifteen percent of peripheral T cell express cutaneous lymphocyte‐associated antigen (CLA), responsible for skin‐homing T cell. Phototherapy is used to treat patients with generalized vitiligo and it has been shown to interfere with CLA⁺ T cells in other skin diseases. Objective: To describe peripheral blood T cell subpopulations' frequency and ability to express the skin‐homing molecule (CLA) in patients with non‐segmental vitiligo, before and after photochemotherapy (PUVA). Patients and Methods: Twenty‐two patients with generalized and active spreading vitiligo were submitted to 30 PUVA‐8MOP sessions. Lymphocyte immunophenotyping was performed by flow cytometry using anti‐CD3, anti‐CD8 and anti‐CLA monoclonal antibodies. Fifteen healthy volunteers, sex‐ and age‐matched, were included as a control group. Results: CD8⁺–CLA⁺ T cells were significantly reduced in number in untreated vitiligo patients (P=0.008) when compared with control individuals, albeit with a more intense CLA expression (P=0.028). These findings were not altered after PUVA. No significant difference was noticed in CD4/CD8 ratios nor in CD4–CLA⁺ T cell numbers between vitiligo patients and controls, both before and after PUVA. Conclusions: CD8–CLA⁺ T cells are reduced in peripheral blood of patients with non‐segmental vitiligo. This finding may be related to the previously reported increase of CD8⁺ cells in both lesions and perilesional skin of these patients.     

Characterization of human skin-derived CD1a-positive lymph cells

Abstract The phenotype and function of CD1a⁺ lymph cells is of considerable interest. By means of microsurgical lymph cannulation human lymph derived from normal skin was sampled. Cells were isolated and processed for immunocytochemistry, electron microscopy, flow cytometry and functional assays. The majority of the cells, (62%), were T cells. The other cells comprised CD1a⁺ cells (7%), monocytes/macrophages (8%), and B cells (1%); the remainder were erythrocytes or uncharacterized cells. The CD1a⁺ cells reacted with antibodies against protein S-100, HLA-DR, the Lag antigen, CD4, CD11a, CD11b, CD18, CD25, CD40, CD54, CD80 and CD86. Interestingly, a small prolow portion the of CD1a⁺ cells (about 5%) reacted with an antibody to CD14. The CD1a⁺ cells did not react with an antibody against human follicular dendritic cells nor were they CD19-, CD23-, E-cadherin- or factor XIIIa-positive. Both allogenic and antigen-specific T cell proliferation stimulated by antigen-presenting lymph cells were strongly inhibited by adding anti-CD80 and anti-CD86 antibodies. By electron microscopy Birbeck granules were detected in only 22% of the CD1a⁺ lymph cells and these cells exhibited an extensive ruffling of the surface. These findings demonstrate that CD1a⁺ lymph cells, which do not express the dermal dendritic cell marker factor XIIIa, resemble dendritic cells formerly designated as ‘veiled’ as well as lymphoid dendritic cells, suggesting that after migration to the regional lymphoid organs, Langerhans cells form a more differentiated population of dendritic cells specialized in sensitizing T lymphocytes. Our results add further support to the view that resident Langerhans cells may be precursors of lymphoid dendritic cells acquiring the final phenotype in the microenvironment of the lymph node. Received: 30 July 1998 / Received after revision: 30 September 1998 / Accepted: 19 October 1998     

Detection of CD4+ CD25+ FOXP3+ regulatory T cells in peripheral blood of patients with chronic autoimmune urticaria

Background/Objectives: Compelling evidence indicates a significant role for a population of CD4⁺ T regulatory cells in suppressing immune responses and in maintaining immunological homeostasis. This study aims to investigate the potential role of CD4⁺CD25^HIGHFOXP3⁺ T regulatory cells in patients with chronic autoimmune urticaria and to define the characteristics of CD4⁺CD25^HIGHFOXP3⁺ cells in chronic urticaria. Methods: We used flow cytometry to assess the expression of CD4⁺CD25^HIGHFOXP3⁺ cells in the peripheral blood mononuclear cells of patients with chronic autoimmune urticaria. Results: In this study, we found that patients with chronic autoimmune urticaria have a significantly reduced frequency of CD4⁺CD25^HIGHFOXP3⁺ cells (1.39 ± 0.27% vs 2.09 ± 0.34%; P = 0.001) in their peripheral blood, accompanied by a decreased intensity of FOXP3 expression (50.13 ± 9.79 vs 68.19 ± 6.40; P < 0.001). Notably, although patients with chronic idiopathic urticaria had a reduced frequency of CD4⁺CD25^HIGHFOXP3⁺ cells (1.85 ± 0.46% vs 3.64 ± 0.48%; P < 0.001), their FOXP3 expression levels did not differ from those in healthy controls. Conclusions: Patients with chronic autoimmune urticaria displayed a reduced percentage of CD4⁺CD25⁺FOXP3⁺ regulatory T cells. The results imply CD4⁺CD25⁺FOXP3⁺ regulatory T cells may contribute to the autoimmune pathological process of chronic autoimmune urticaria.     

The predominant drug-specific T-cell population may switch from cytotoxic T cells to regulatory T cells during the course of anticonvulsant-induced hypersensitivity

Background

Delayed hypersensitivity is responsible for severe cutaneous adverse drug reactions (cADRs), especially in Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis, and drug-induced hypersensitivity syndrome (DIHS) (also known as drug rash with eosinophilia and systemic symptoms [DRESS] syndrome). The drug-induced lymphocyte stimulation test (DLST), or lymphocyte transformation test (LTT), is used to identify the culprit drug in severe cADR cases.

Objective

The aim of this study was to examine the immune reactions in cADR patients through the identification of the drug-specific proliferating cells by flow cytometric DLST (FCM-DLST).

Methods

The peripheral blood mononuclear cells of 16 anticonvulsant-induced cADR patients were investigated by conventional DLST and a FCM-DLST protocol in which CFSE dilution and BrdU incorporation were combined. FCM-DLST allowed for the identification of the drug-specific proliferating cells in six cases. Three of these cases were DIHS cases, whereas there was one case of SJS, one case of maculopapular rash (MP), and one case of erythema multiforme (EM) among the six cases.

Results

In FCM-DLST, drug-specific proliferating T cells were detected as CFSE^low BrdU^high cells. These cells corresponded to the cells incorporating ³H-thymidine in conventional DLST. Although CD4⁺ T-cell proliferation dominated the observed proliferation in most of the cases (in the recovery stage of the three DIHS cases, the MP case, and the EM case), drug-specific CD8⁺ cytotoxic T lymphocytes (CTLs) were detected, especially in the acute stages of the SJS case and one of the DIHS cases. There was a dramatic switch in the predominant drug-specific proliferating T-cell population in the course of one of the cases of DIHS in which CD8⁺ CTLs were predominant initially, whereas CD4⁺ T cells were predominant later. Moreover, drug-specific CD4⁺ CD25⁺ Foxp3⁺ regulatory T cells (Tregs) proliferated during the recovery stage in one DIHS case.

Conclusions

FCM-DLST revealed that the cell proliferation detected by conventional DLST is a heterogeneous proliferation of both CD8⁺ CTLs and CD4⁺ T cells that likely includes Tregs. However, the number of cADR cases in this study was limited, which limits the conclusions that can be drawn from it.     

Role of macrophage infiltration in successful repigmentation in a new periphery‐spreading vitiligo lesion in a male Japanese patient

Vitiligo is an acquired disorder in which depigmented macules result from mostly autoimmune loss of melanocytes. The initiating process in vitiligo has still been uncertain. Here, we report the case of a 19‐year‐old man with undetermined/unclassified vitiligo with a new periphery‐spreading vitiligo lesion on the right dorsal hand after rigorous sun exposure. Histopathological evaluation showed noticeable infiltration of CD68⁺ macrophages, moderate infiltration of CD3⁺ T cells, little infiltration of CD8⁺ T cells and CD11c⁺ myeloid dendritic cells, HMB45/CD11c double‐positive cells, and Melan‐A/MART1⁺ deposits in the dermis. We surmised that melanocyte‐derived deposits were mostly phagocytosed by CD68⁺ macrophages and were faintly phagocytosed by CD11c⁺ myeloid dendritic cells, referring distribution of CD68⁺ mononuclear cells and melanocyte biomarkers. Complete repigmentation was achieved following topical application of hydrocortisone butyrate propionate 0.1% ointment. We summarize that prompt clearance of debris by macrophages would be essential to an excellent prognosis of complete repigmentation.     

Melkersson‐Rosenthal Syndrome

A 13 year‐old boy presented with a six‐month history of severe lip swelling. His past medical history was significant for eczema, multiple episodes of urticaria, and two episodes of anaphylaxis. Physical exam revealed severe cheilitis and labial angioedema. The cranial nerves were intact, and there was no evidence of a fissured tongue. A lip biopsy showed noncaseating granulomas throughout the dermis, with extension into the underlying skeletal muscle. Other features included dilated lymphatic channels, some closely approximating the granulomas, and a mild perivascular lymphoplasmacytic infiltrate. The epidermis was acanthotic with parakeratosis and focal acantholysis. Methenamine silver and acid‐fast stains were negative. A laboratory work‐up revealed an increased total eosinophil count, an increased serum IgE level, and a low complement C1q level. All other complement levels were normal. The patient also had an unremarkable chest x‐ray and a normal angiotensin converting enzyme level. This case represents the monosymptomatic form of Melkersson‐Rosenthal syndrome (MRS), also known as cheilitis granulomatosa Meischer. MRS is classically known as a triad of granulomatous cheilitis, facial nerve palsy, and fissured tongue. The onset of granulomatous cheilitis typically precedes the other symptoms, and when present alone, it is known as the monosymptomatic form of MRS.     

Phenotypic determination of T-lymphocytes responding to chemotactic stimulation from fMLP,IL-8, human IL-10, and epidermal lymphocyte chemotactic factor

Summary Human T lymphocytes were collected after they had migrated towards N-formyl-methionyl-leukyl-phenylalanine (fMLP), rIL-8, human IL-10 (hIL-10), and epidermal lymphocyte chemotactic factor (ELCF). They were stained for determination of their phenotype by FACS analysis using anti-CD4, -CD8, -CD18, -CD45R0 and OPD4 antibodies. Human IL-10 increased the percentage of CD8⁺ T lymphocytes in the migrating cell population by 152% compared with cells migrating towards the medium and decreased the number of CD4⁺ T lymphocytes by 79%. ELCF increased the number of CD4⁺ T lymphocytes by 18%, and the number of CD45R0⁺ T lymphocytes by 52%, while the number of CD8⁺ T lymphocytes was decreased by 20%. rIL-8 increased the number of CD4⁺ T lymphocytes and decreased the CD8⁺ T lymphocytes. The distribution of the different subpopulations of T lymphocytes was not changed significantly by fMLP. The observed changes in the phenotypes did not occur when incubating T lymphocytes with the chemotaxins. Our observations demonstrate that individual chemotactic factors will attract specific subsets of T lymphocytes. They may help to explain the predominance of memory T lymphocytes (CD4R0⁺, CD4⁺) in allergic contact dermatitis and certain other skin diseases. They also confirm the results of a recent study, that showed hIL-10 to be selectively chemotactic for CD8⁺ T lymphocytes.     

Distinguishing between erythema multiforme major and Stevens-Johnson syndrome/toxic epidermal necrolysis immunopathologically

The early clinical presentations of Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are similar to that of erythema multiforme major (EMM). Cytotoxic molecules, especially granulysin, are expressed in the skin lesions of SJS/TEN and cause extensive keratinocyte death. It is postulated that the function of regulatory T cells (Treg) in SJS/TEN is inadequate. This study examined whether an immunohistological examination of cytotoxic molecules and the immunophenotype of Treg is useful for discriminating SJS from EMM in the early period. Over the past 9 years, the lesional skin of 14 patients with SJS/TEN and 16 patients with EMM was biopsied. Double immunofluorescence labeling of CD8 and granulysin, perforin, or granzyme B was performed, and immunohistochemical analyses of granulysin, perforin, granzyme B, CD1a, CD3, CD4, CD8, CD68 and Foxp3 were conducted using a highly sensitive indirect immunoperoxidase technique. The number of cells positive for each antibody per five high‐power fields was counted. The proportions of granulysin⁺ cells/CD8⁺ cells (P = 0.012) and perforin⁺ cells/CD8⁺ cells (P = 0.037) in SJS/TEN were significantly higher than in EMM. The number of Foxp3⁺ cells/five high‐power fields in SJS/TEN was significantly lower than in EMM (P = 0.004). Similarly, the number of CD4⁺ cells/five high‐power fields in SJS/TEN was significantly lower than in EMM (P = 0.0017). These data suggest that these panels of antibodies for labeling cytotoxic molecules, CD4 and Treg are useful for discriminating early SJS/TEN and EMM with a skin biopsy.     

Antigen-presenting capacity in normal human dermis is mainly, subserved by CDla+ cells

A proposed role for antigen-presenting dermal dendrocytes in the pathogenesis of many dermal inflammatory skin diseases remains speculative. We therefore sought to determine the phenotype and functional characteristics of antigen-presenting cells isolated from normal human dermis. Normal adult human skin was incubated overnight with dispase at 4°C, the epidermis was removed, and the residual dermal preparation was then minced and digested with a mixture of hyaluronidase, collagenase, and DNAase at 37°C, prior to filtration through mesh. Dermal cell suspensions thus obtained were stained using specific monoclonal antibodies, and analysed by fluorescence micro- scopy or flow cytometry. Mean values were as follows: CD45⁺ leucocytes 39%, HLA-DR⁺ cells 39%, Ulex europaeus agglutinin I⁺ endothelial cells 26%, CD1a⁺ cells 3.9%, CD11b⁺ cells 16%, CDllc⁺ cells 6%. Mitomycin C-treated crude dermal cell suspensions induced allostimulation of peripheral blood mononuclear cells in a 7-day culture, as assessed by ³H-TdR incorporation. Depletion of CDla⁺ Langerhans-like cells from the dermal cell preparation, by 95, 74 and 90% in three separate experiments using immunomagnetic beads, reduced ³H-TdR incorporation at optimal responder-to- stimulator cell ratios by 90, 64, and 87%, respectively. Our findings suggest that, in normal human dermis, the great majority of the alloantigen-presenting capacity resides in the CDla⁺ Langerhans cell-like dendritic antigen-presenting cell population, and not to any great extent in either CDla^? macrophage-like cells, or HLA-DR⁺ endothelial cells. The relationship of the CDla⁺ dermal antigen presenting cells to the Langerhans cell lineage remains to be determined.