Immunohistochemical investigation of evolving inflammation in lesions of acne vulgaris

Abstract: The mechanisms involved in the development of inflammation in acne vulgaris have yet to be elucidated. Previous studies have shown that the initial cellular infiltrate in early inflammatory lesions is mononuclear, predominantly CD4 positive T cells. The aims of this study were to investigate the pattern of expression of adhesion molecules and HLA-DR in evolving acne lesions. Forty-nine patients with moderate to severe acne were biopsied following lesion mapping. Lesions were classified according to their duration of inflammation as up to 6 h, from 6 to 24 h, from 24 to 48 h and from 24 to 48 h and from 48 to 72 h. The cellular infiltrate was determined using monoclonal antibodies to CD1, CD3, CD4 and CD8. The expression of ICAM-1, E-selectin, VCAM-1 and HLA-DR was determined. Early (6 h) lesions had perivascular CD3 positive T-cell infiltrates which were predominantly CD4 positive. This was associated with vascular expression of ICAM-1, E-selectin, VCAM-1 and HLA-DR. Periductal infiltrates were present in 70% of the early lesions (up to 6 h). The cells were predominantly CD4 positive and associated with a high level of HLA-DR and ICAM-1 expression. Periductal infiltration increased with time and persisted to 72 h. ICAM-1 and HLA-DR were expressed epidermally in early and late lesions. CD1 positive cells were a minor, but consistent element in the perivascular and periductal infiltrates of early and late lesions. There was no statistically significant difference in the levels of expression of E-selectin, VCAM-1, ICAM-1 or HLA-DR for lesions of different duration. The pattern of HLA-DR and adhesion molecule expression plus the nature of the cellular infiltrate supports the hypothesis that inflammation in acne is mediated by CD4 positive T cells.     

Inflammatory events are involved in acne lesion initiation

The earliest subclinical acne "lesion" is a microcomedone, of which hyperproliferation of the follicular epithelium is a characteristic feature. Inflammatory cells have been observed at the periphery of these "lesions". This study investigated whether inflammatory events occur pre or post hyperproliferative changes. Cellular, vascular, and proliferative markers were examined by immunohistochemical techniques on biopsies of clinically normal follicles from uninvolved skin and early inflamed lesions from acne patients. Control follicles were obtained from non-acne subjects. Follicles from uninvolved skin exhibited no microcomedonal features. Proliferation in the epithelium was comparable to controls and was significantly lower than in inflamed lesions. Numbers of CD3+, CD4+ T cells were elevated in the perifollicular and papillary dermis although levels were not equivalent to those in papules. The number of macrophages was also greatly increased and similar to those in papules. There were no changes in blood vessel numbers or vascular intercellular adhesion molecule 1 expression but E-selectin expression was increased to levels found in papules and vascular adhesion molecule 1 levels were upregulated. Levels of the pro-inflammatory cytokine interleukin-1 were also upregulated perifollicularly. Moreover, aberrant integrin expression was demonstrated in the epidermis around these uninvolved follicles and inflamed lesions whereas the basement membrane was still intact. These results provide novel evidence for vascular endothelial cell activation and involvement of inflammatory responses in the very earliest stages of acne lesion development.     

Toll-like receptor 2 is highly expressed in lesions of acne inversa and colocalizes with C-type lectin receptor

BACKGROUND: Acne inversa (hidradenitis suppurativa) is a chronic inflammatory and cicatricial disorder that affects skin areas rich in apocrine glands and terminal hairs, such as perineum and axillae. The exact pathogenesis of the disease is not well understood and the mechanisms by which bacterial superinfection contributes to the disease progression are not clear. Toll-like receptors (TLRs) expressed by inflammatory cells play a crucial role in the innate immune response to bacteria. OBJECTIVES: We sought to investigate the role of TLR2 in the pathogenesis of acne inversa. METHODS: We investigated the expression of TLR2 using real-time polymerase chain reaction analysis and immunohistochemical stainings of tissue samples from patients with acne inversa. Furthermore, we phenotypically characterized the infiltrating cells and their expression of TLR2. RESULTS: Compared with normal skin, a highly increased in situ expression of TLR2 in acne inversa skin lesions was found at both the mRNA and the protein level. The most abundant cells in the dermal infiltrate of acne inversa were CD68+ macrophages, CD209+ dendritic cells (DCs) and CD3+ T cells. CD19+ B cells and CD56+ natural killer cells were found only in small numbers. Double staining with fluorescence-labelled antibodies showed that TLR2 was expressed by infiltrating macrophages (CD68+) and DCs (CD209+). Flow cytometric analysis of isolated infiltrating cells further confirmed surface expression of TLR2 by macrophages and DCs. CONCLUSIONS: These data indicate that the enhanced expression of TLR2 by infiltrating macrophages and DCs may contribute to the pathogenesis of inflammatory lesions of acne inversa.     

Macrophages are increased in cervical epithelium of women with cervicitis

BACKGROUND: Sexually transmitted diseases (STIs) are major causes of morbidity in women. The mechanisms involved in establishment of genital mucosal infection are poorly defined. OBJECTIVE: To investigate changes in cervical epithelial (CE) CD45+ cell subpopulations in women with microscopic evidence of cervicitis (n=9) and those without (n=12). METHODS: CE samples were obtained using cytobrush including matched venous blood. CE and peripheral blood (PB) mononuclear cells were analysed by flow cytometry for CD3+, CD4+, CD8+, CD14+,CD19+, and HLA-DR+ expression. RESULTS: Women with cervicitis had increased CE macrophages compared with those without (p<0.05). MHC class II+ cells were predominant in all cervical samples. Considerably fewer B lymphocytes were found in cervical samples in both groups of women. No changes were observed in cervical T lymphocyte subsets. However, a relative CD8+ lymphocytosis in PB was noted in women with cervicitis. CONCLUSION: The increased numbers of CE macrophages in women with cervicitis may have important implications for pathogenesis of STIs including human immunodeficiency virus infection.     

T lymphocytes in lesional skin of patients with dermatitis herpetiformis

Ten patients with dermatitis herpetiformis had biopsies taken from involved skin.Monoclonal antibodies and the avidin-biotin peroxidase staining technique were used to stain for T cells and Langerhans cells in skin sections. A significant increase in the number of CD3-positive T cells was observed in the upper dermis of involved compared with uninvolved skin (P<0.0005). Most of the T cells in involved skin were CD45RO-positive memory cells; CD4-positive T cells exceeded the number of CD8-positive T cells by a ratio of 4:1. In addition, CD1a-positive dendritic cells were observed within the clumps of T cells in involved dermis in nine of the 10 patients, but were absent from the dermis of uninvolved skin. Double immunofluorescent staining demonstrated that approximately 20–40% of the CD3-positive T cells were activated, and expressed the HLA-DR antigen. These findings suggest that activated T cells are involved in the pathogenesis of dermatitis herpetiformis skin lesions.     

Immunohistology of skin pathergy reaction in Behçet's disease

Summary The immunophenotypic characteristics of the skin pathergy reaction (SPR) at 48 h in Behçet's disease (BD) were investigated in 12 patients with BD and in five controls. The findings in 11 positive and one negative SPR lesions of patients with BD were evaluated in comparison with those of normal adjacent skin and with the negative pathergy biopsies from the controls. Positive SPR biopsies showed variable epidermal thickening and cell vacuolization, as well as subcorneal pustule formation. In the SPR dermis, a variable dense focal mononuclear cell (MNC) infiltrate was seen around vessels and skin appendages, extending into the deep dermis. The MNC infiltrate was predominantly composed of T lymphocytes and monocytes/macrophages. The majority of the T lymphocytes were CD4⁺, and almost all expressed CD45RO. Approximately half of the infiltrating cells strongly expressed HLA-DR. Neutrophils constituted less than 5% of the infiltrating cells, but were present as clusters of elastase-positive cells at the needle-prick sites. Vessels within the lesion showed marked congestion and endothelial swelling. The endothelial cells expressed ICAM-1 strongly, and E-selectin moderately. VCAM-1 was not expressed on endothelial cells. The basal and mid-epidermal layers of keratinocytes expressed HLA-DR and ICAM-1 strongly, particularly so in areas close to the dermal MNC infiltrates. In negative pathergy biopsies, there were increased numbers of neutrophils and a few small clusters of macrophages and T lymphocytes only at the needle-prick site, and the endothelial cells of vessels close to these areas expressed E-selectin weakly. The immunohistological findings of the SPR appear to indicate an augmented antigen-independent non-specific induction phase of the inflammatory response. Absence of VCAM-1 expression by endothelial cells suggests that direct epidermal injury is the cause of the cutaneous inflammation.     

Role of the chemokine receptor CCR4 and its ligand thymus- and activation-regulated chemokine/CCL17 for lymphocyte recruitment in cutaneous lupus erythematosus

Skin-infiltrating T lymphocytes are thought to play a major role in the pathogenesis of cutaneous lupus erythematosus (CLE). In this study, we investigated the role of the chemokine receptor 4 (CCR4) and its ligand thymus- and activation-regulated chemokine (TARC/CCL17) for the recruitment of T cells in inflamed skin of patients with CLE. We found significant numbers of CCR4+ T lymphocytes in the skin of all patients with CLE. Interestingly, a subset of patients with disseminated scarring skin involvement were characterized by both lesional and circulating CD8+ T cells expressing CCR4. Destruction of epidermal and adnexal structures was histomorphologically associated with CCR4+ cytotoxic T cells invading basal layers of the epidermis where keratinocytes showed apoptotic death. The CCR4 ligand TARC/CCL17 was strongly expressed in skin lesions and elevated in the serum of CLE patients. The functional relevance of lymphocytic CCR4 expression could be confirmed by TARC/CCL17-specific in vitro migration assays. Our investigations suggest that CCR4 and TARC/CCL17 play a role in the pathophysiology of CLE. In particular, cytotoxic CD8+ T cells expressing CCR4 appear to be involved in scarring subtypes of CLE.     

A clinical evaluation of acne scarring and its incidence

Despite scarring being a recognized sequel of acne, the actual extent and incidence of residual scarring remains unknown. One hundred and eighty-five acne patients were included in this study (101 females, 84 males). Patients were selected from acne clinics and their acne scarring was examined. The scarring was quantified according to a lesion count and allocated a score. The type and extent of scarring was correlated to the age and sex of the patient, the site of the acne, the previous acne grade according to the Leeds Technique,¹ acne type (noted in clinic at the original referral time) and duration of acne, before adequate therapeutic measures had been instituted. Results indicate that facial scarring affects both sexes equally and occurs to some degree in 95% of cases. Total scarring on the trunk was significantly greater in males, as was hypertrophic and keloid scarring in these sites (P <0.05). There were significant correlations between the initial acne grade and the overall severity of scarring in all sites and in both sexes (P<0.01). Superficial inflamed papular acne lesions as well as nodular lesions were capable of producing scars, A time delay up to 3 years between acne onset and adequate treatment related to the ultimate degree of scarring in both sexes and in all three sites. This emphasizes the need for earlier adequate therapy in an attempt to minimize the subsequent scarring caused by acne.     

The development of manifest psoriatic lesions is linked with the invasion of CD8+ T cells and CD11c+ macrophages into the epidermis

Koebner response was studied in 35 psoriatic patients. Two punch biopsies per patient were taken from non-lesional psoriatic skin before, and 6 h, 2 days, 7 days, 14 days and 21 days after, tape stripping. Alterations in the numbers of CD1+ Langerhans cells, CD4+ and CD8+ T cells and CD11c+ macrophages were mapped morphometrically. Results were compared with lesional and non-lesional psoriatic skin, and control skin. Nine of 35 patients were Koebner-positive. No statistically significant differences were noted between non-lesional psoriatic and control skin. CD4+ T cells increased in number 2 days after trauma in both the epidermis and the dermis, whereas epidermal CD8+ T cells and CD11c+ macrophages increased only in the Koebner-positive lesional skin after 7 days. The changes in lesions induced by tapestripping resembled those seen in lesional psoriatic skin (mature plaques). The number of CD1+ cells increased in mature psoriatic lesions only. It seems possible that trauma per se stimulates the accumulation of CD4+ T cells at the site of injury, but the development of manifest psoriatic lesions correlates with invasion of CD8+ T cells and CD11c+ macrophages into the epidermis.     

Intermediate or chronic cutaneous leishmaniasis: leukocyte immunophenotypes and cytokine characterisation of the lesion

The American cutaneous forms of leishmaniasis include immune-responder individuals with localised cutaneous leishmaniasis (LCL) and non-responder individuals with diffuse cutaneous leishmaniasis (DCL). Patients with intermediate or chronic cutaneous leishmaniasis (ICL) have increased morbidity due to the length of their illness, atypical forms and areas of compromise. In the present study, we evaluated the expression of the leukocyte antigens (CD4, CD8, CLA: cutaneous lymphocyte antigen, CD69, CD83 and CD1a) and cytokines (IFN-gamma, IL-4, IL-10 and TGF-beta 1) in the lesions of patients with ICL (n = 18) using an immunocytochemical procedure. ICL results were compared with the information for LCL (n = 19) and DCL (n = 4). The numbers of CD4+ and CD8+ T cells in ICL were similar to those of LCL lesions, but significantly different (P < or = 0.05) from DCL lesions. LCL lesions have about half the numbers of early activated CD69+ cells as ICL, but most are CLA+ skin homing memory T cells, whereas ICL lesions have the highest number of CD69+ T cells, but about one-third of these cells expressed CLA. This suggests that the granuloma of ICL patients contains many activated T cells that are unprimed to cutaneous-launched antigens, thus contributing to an aberrant immune response. In contrast, DCL granulomas presented the lowest numbers of activated CD69+ and CLA+ cells, associated with the characteristic tolerogenic state of these patients. The immunolocalisation of cytokines showed a mixed cytokine pattern in ICL lesions with many positive cells for IL-10, TGF-beta 1, IL-4 and IFN-gamma, with a preponderance of the first two, and different from the prevalent Th1 and Th2 responses associated with LCL and DCL lesions, respectively. CD1a+ Langerhans cells were decreased (P < or = 0.05) in both ICL (271 +/- 15 cells/mm2) and DCL (245 +/- 19 cells/mm2) as compared to LCL (527 +/- 54 cells/mm2) epidermis. The percentage of IL-10+ epidermal Langerhans cells in ICL (33.69), from the total CD1a+ population, was higher than in LCL (17.45). In addition, fewer CD83+ primed Langerhans cells were present in ICL epidermis. The diminished participation of epidermal Langerhans cells, causing a defective signalling by the epidermis, in ICL lesions may account for the tissue-damaging state observed in these patients.     

Immunocytochemical analysis of early focal cellular infiltrates in experimental oral contact hypersensitivity.

The cellular infiltrates of early contact hypersensitivity reactions to 2,4-dinitrofluorobenzene (DNFB) in rat oral mucosa were phenotypically characterized using serial frozen tissue sections and monoclonal antibodies. CD2+CD45RB- lymphocytes and ED1+RT1B/D+ monocytes/macrophages appeared in focal collections at the epithelium-connective tissue interface 2-6 h after challenge with DNFB. These foci also contained CD4+, CD5+, CD8+, TCR alpha beta+ cells. CD45RB+ "naive" T cells were difficult to detect at 2-6 h but appeared in significant numbers at 24 h post-challenge. At this stage, the number of all the other phenotypes also was increased. CD2+ cells were approximately twice as many as CD5+ or TCR alpha beta+ respectively, indicating that TCR gamma delta+ lymphocytes might be involved. An additional observation was the presence of increased numbers of CD2+ lymphocytes in the oral mucosa of sensitized but not challenged animals. Our findings indicate that the oral mucosa of skin DNFB pre-sensitized animals may be "contact hypersensitivity conditioned" by migration-prone memory T cells, and that these cells may rapidly interact with locally resident epithelial Langerhans' cells following antigen restimulation, creating the very initial antigen-specific part of experimental oral contact hypersensitivity.     

Peripheral T-Cell Activation in Non-Segmental Vitiligo

Vitiligo is a hypopigmentary dermatosis of probable autoimmune origin. Previously reported aberrations in peripheral blood mononuclear cells (PBMC), especially T cells and T cell subsets, have been inconsistent. Lymphocyte subpopulations were examined using flow cytometry and monoclonal antibodies against CD4, CD8, CD20, CD25, CD45RA, and HLA-DR in 34 patients with non-segmental vitiligo. Twelve patients had not received any previous treatment and 22 had previously received at least one course of PUVA therapy that was discontinued at least four months prior to our study. Compared to matched controls, we found significant increases in CD25 and HLA-DR in vitiligo patients (p=0.000). An inverse correlation was observed between HLA-DR and patient status with regard to treatment (p=0.001). These results suggest a role for T cells in the pathogenesis of vitiligo and imply that previous PUVA therapy may be reflected by an alteration in circulating DR + ve cells.     

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.     

Scarring skin lesions of discoid lupus erythematosus are characterized by high numbers of skin-homing cytotoxic lymphocytes associated with strong expression of the type I interferon-induced protein MxA

BACKGROUND: Infiltrating T lymphocytes are considered to play a major pathological role in skin lesions of cutaneous lupus erythematosus (CLE), a cutaneous autoimmune disease of unknown aetiology. Earlier histological studies revealed that the inflammatory infiltrate in CLE skin lesions is predominantly composed of T lymphocytes, with a slight predominance of CD4+ over CD8+ T cells, but failed to explain the development of scarring skin lesions, characteristic for chronic discoid lupus erythematosus (CDLE). Because recent investigations have highlighted the relevance of cytotoxic lymphocytes in autoimmune tissue destruction, we hypothesized that the scarring CDLE lesions might be caused by cytotoxic T lymphocytes. OBJECTIVES: To analyse skin biopsies of 15 patients with CLE [10 female, five male; localized CDLE (lCDLE), n = 5; disseminated CDLE (dCDLE), n = 5, subacute CLE (SCLE), n = 5] and five control biopsies taken from healthy controls and to characterize the inflammatory infiltrate. Methods We used immunohistochemistry, including staining for the cytotoxic molecule granzyme B, the skin-homing molecule cutaneous lymphocyte antigen (CLA) and the protein MxA, which is specifically induced by type I interferons (IFNs). RESULTS: We found a strong coexpression of granzyme B and CLA on lesional lymphocytes of patients with scarring lCDLE and dCDLE, which was significantly enhanced when compared with nonscarring SCLE and healthy controls. The increased expression of granzyme B was closely associated with the lesional expression of the type I IFN-induced protein MxA. CONCLUSIONS: Our results provide evidence that type I IFNs and potentially autoreactive cytotoxic lymphocytes targeting adnexal structures are highly associated with scarring lupus erythematosus lesions and might be responsible for their scarring character.     

Heterogeneity within tissue-specific macrophage and dendritic cell populations during cutaneous inflammation in atopic dermatitis

BACKGROUND: Macrophages and dendritic cells may play a role in chronicity of atopic dermatitis (AD); however, so far only limited data are documented on the distribution of these cells in the skin during cutaneous inflammation. OBJECTIVES: To gain better insight into the presence and distribution of macrophage and dendritic cell (sub)populations in acutely and chronically inflamed skin of AD patients. METHODS: Chronic inflammatory reactions were studied in lesional AD skin biopsies; the atopy patch test was used as a model for the initiation of AD lesions, representing acute inflammation. To determine the number and phenotype of different dermal macrophage and dendritic cell populations immunohistochemistry and digital imaging were used. RESULTS: There was an increase in macrophage numbers in acutely and chronically inflamed AD skin, whereas absolute dendritic cell numbers were unchanged, compared with non-lesional AD skin. Furthermore, phenotypically heterogeneous and overlapping macrophage and dendritic cell populations were present in inflamed AD skin. The classic macrophage marker CD68 and prototypic dendritic cell marker CD1a could bind to the same cell subpopulation in the dermis of inflamed AD skin. Mannose receptors were expressed mainly by macrophages in inflamed AD skin. CONCLUSIONS: In this study we observed changes in macrophage number and phenotype during cutaneous inflammation in AD. Dendritic cell numbers did not change; however, phenotypically dendritic cell and macrophage subpopulations showed increasing overlap during inflammation in AD skin. We show for the first time that within tissue-specific macrophage populations further subpopulations are present, and that monocyte-derived cells may express markers for both dendritic cells and macrophages. Our results point to the existence of a heterogeneous pool of macrophage/dendritic cell-like cells, from which subpopulations of dermal macrophages and dendritic cells arise.     

Comparative immunophenotypic study of lichen sclerosus: epidermotropic CD57+ lymphocytes are numerous--implications for pathogenesis

To characterize the immunophenotype of inflammatory cells in lichen sclerosus (LS), we performed a comparative case control study using one- and two-color immunohistochemistry and the nitro blue tetrazolium (NBT) reaction. Study material consisted of 100 biopsies from patients with LS or from 12 control groups consisting of inflammatory, scarring, and depigmenting cutaneous disorders. In addition, fresh tissue was sampled from four vulvectomy specimens for NBT testing. The typical inflammatory infiltrate of LS contained numerous epidermotropic CD3+, CD8+, CD57+ cells, increased intraepidermal HLA-DR+ cells, and a dermal infiltrate rich in CD8+, CD57+, HLA-DR+, and CD68+ inflammatory cells. Comparing LS to the 12 control groups, epidermotropic CD57+ lymphocytes independently predicted LS (P = 0.006, logistic regression, multivariate analysis). Among the 12 control groups, only specimens of the inflammatory stage of morphea exhibited numerous dermal CD57+ lymphocytes. Two-color immunohistochemistry confirmed the CD3+/CD8+CD57+ and CD3+/ CD8+/CD57+HLA-DR+ epidermotropic and dermal lymphocytic phenotypes and the dermal macrophage CD68+HLA-DR+ phenotype. In LS, the NBT reaction revealed evidence of superoxide production associated with CD68+HLA-DR+ cells. Expansion of CD8+CD57+lymphocytes is associated with viral infections, autoimmune disease, malignancies, and transplantation and is suspected to be the result of chronic excessive antigen challenge. In these pathologic states, CD8+CD57+ lymphocytes (as terminally differentiated, antigen-specific T cells) participate in the suppression of cytolytic activity to limit tissue damage. In LS, activated macrophages and lymphocytes indicate persistent antigen-driven inflammation. LS's numerous CD8+CD57+ lymphocytes may be either the mediators or the consequence of its hallmark sclerosis.     

Combined 0.1% retinaldehyde/ 6% glycolic acid cream in prophylaxis and treatment of acne scarring

BACKGROUND: Acne often results in permanent, badly tolerated, difficult to treat scars. OBJECTIVE: To evaluate the efficacy and safety of a 0.1% retinaldehyde/6% glycolic acid (RALGA) cream at preventing and treating acne scarring in patients previously treated for moderate acne. METHODS: A double-blind vehicle-controlled study was conducted in 145 patients randomized to apply RALGAor vehicle cream every evening for 3 months. Global scarring score and patient's assessment of global efficacy, then residual acne lesions, quality of life and tolerance were evaluated at inclusion and each month until study completion. RESULTS: Global scarring score, number of inflammatory lesions and comedones significantly improved in each group from day 28 (p<0.0001). Number of inflammatory lesions were significantly decreased only in the RALGA group. RALGA cream was more efficient than vehicle on scarring after 3 months in compliant patients (p=0.007) due to erythema and hyperpigmentation improvement. CONCLUSION: RALGA cream is efficient at preventing and treating acne scarring in patients with moderate acne.     

Immunoregulatory effector cells in drug-induced toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a rare drug-induced disease for which the pathomechanism remains poorly understood. The effector cells of epidermal injury in TEN were studied by taking skin biopsies of early lesions in 23 TEN patients and by performing immunohistochemical tests using antibodies to factor XIIIa (type I dendrocytes), L1-protein (mainly Mac 387+ monocytes and macrophages), UCLHI (mainly CD45R0+ T-memory lymphocytes), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFalpha). Computerized image analysis was used to evaluate the cell density relative to each immunolabeling. A statistical analysis of cellular counts revealed a numeric relation between the cell types in skin with TEN. Factor XIIIa+ dendrocytes were abundant and plump in the dermis, although Mac 387+ macrophages were the most numerous inflammatory cells in the epidermis. Their numbers greatly exceeded those of CD45R0+ T lymphocytes and cells showing immunoreactivity for either IL-6 or TNFalpha. In the epidermis, IL-6+ cells were significantly less numerous than TNFalpha+ cells. No quantitative difference was found between IL-6+ and CD45R0+ cell populations. Correlations were observed between either the numbers of TNFalpha+ cells or Mac 387+ macrophages and CD45R0+ lymphocytes. In the dermis, a significant correlation was also present between the numbers of Mac 387+ and factor XIIIa+ cells. These findings highlight the complex interactions between the inflammatory cells that mediate epidermal damage in skin with TEN. The high density of factor XIIIa+ dendrocytes and Mac 387+ macrophages in lesional skin assigns these cellular populations a prominent role in the pathomechanism of TEN. Despite a lower cell density, CD45RO+ T-memory lymphocytes likely participate in TNFalpha- and IL-6-regulated processes in the epidermis of TEN. TNFalpha seems to be a major cytokine involved in TEN, although a less prominent role can be ascribed to IL-6.     

Profiles of activated T lymphocytes in peripheral blood of Kuwaiti psoriasis vulgaris patients

We have previously reported unexpected immunological features of psoriasis among Kuwaitis, suggesting novel patterns of immune reactivity contributing to the disease. To better define this phenomenon, we herein describe profiles of major populations and immunologically activated subsets of peripheral blood lymphocytes in a cohort of Kuwaiti psoriasis vulgaris patients. Whole venous blood from fifteen psoriatic and twenty eight normal, healthy subjects was analyzed by 2-color flow cytometry for levels of major lymphocyte species and their immunologically activated subsets. When compared to normal subjects, psoriatic blood contained lower cell densities of CD2+, CD8+ (p=0.002 respectively) and B lymphocytes (CD19+) (p=0.003), with a trend toward a lower CD4+ density (p=0.072). Within each major lymphocyte population, activated lymphocytes were present at higher percentages in psoriatic than in healthy blood. These included CD4+ HLA-DR+ (p=0.002), CD4+CD25+ (p=0.043), CD4+CD54+ (p=0.005), CD8+CD25+ (p=0.015), CD8+ HLA-DR+ (p=0.046) and CD3+CD16+CD56+ (p=0.023) Additionally, psoriatic patients were found to have an expanded ratio of memory to naive T cells (CD45RO+CD45RA+) relative to control subjects; this was expected on the basis of increased immune activation. Our findings are consistent with a picture of psoriasis as a disease mediated by activated lymphocytes.     

活化抗原CD69、HLA-DR在寻常性银屑病外周血单一核细胞和皮损中的表达

目的 探讨活化抗原CD69和HLA-DR在寻常性银屑病患者外周血CD3+T淋巴细胞和皮损中的表达变化。 方法 流式细胞仪检测20例寻常性银屑病患者和20例健康对照外周血CD3+T细胞中CD69和HLA-DR的表达,同时采用免疫组化的方法检测15例寻常性银屑病患者和10例健康对照皮损组织中HLA-DR的表达并进行对比。两组统计学分析采用双侧t检验。 结果 CD69和HLA-DR在寻常性银屑病患者外周血CD3+T细胞中的表达率分别为（4.70 ± 1.90）%、（8.97 ± 1.79）%,比健康对照组［（1.56 ± 0.95）%、（3.02 ± 1.15）%］明显升高（均P < 0.01）。Pearson相关性分析发现,CD3+HLA-DR+细胞百分比与银屑病皮损和严重程度评分指数（PASI）评分呈正相关（r = 0.5626,P < 0.05）。与健康对照组比较,寻常性银屑病患者皮损真皮中HLA-DR表达升高,但表皮中HLA-DR表达降低（均P < 0.05）,HLA-DR在健康人主要分布在血管周围,而在寻常性银屑病患者则广泛表达于真皮组织。 结论 寻常性银屑病患者外周血CD3+T淋巴细胞及皮损中的炎症细胞存在异常活化,外周血CD3+HLA-DR+细胞与疾病严重程度存在相关性。