Elevated levels of eotaxin and interleukin-5 in blister fluid of bullous pemphigoid: correlation with tissue eosinophilia

BACKGROUND: Bullous pemphigoid (BP) often provokes blood and tissue eosinophilia, which suggests that some chemoattractants modulate the eosinophil infiltration in BP. Eotaxin, a CC chemokine, strongly attracts eosinophils, and interleukin (IL)-5 induces eosinophil differentiation, proliferation and colony formation in vitro. OBJECTIVES: To examine the correlation between levels of eotaxin and IL-5 and the number of lesional eosinophils, and the expression of eotaxin in BP lesions. PATIENTS/METHODS: In this study we measured eotaxin and IL-5 levels in blister fluid of BP by enzyme-linked immunosorbent assay. We also examined the expression of eotaxin in BP lesions by immunohistochemistry. RESULTS: Both eotaxin and IL-5 were detected at high levels in BP blister fluid. Blister fluid eotaxin, but not IL-5 levels, correlated significantly with the number of dermal infiltrating eosinophils. By immunohistochemistry, eotaxin was strongly expressed in epidermal keratinocytes around BP blisters. CONCLUSIONS: These findings suggest that eotaxin and IL-5 are strongly associated with the tissue eosinophilia of BP. Therapies which aim to inhibit production of eotaxin and IL-5 may improve the inflammation and blister formation in BP.     

Increased coexpression of eotaxin and interleukin 5 in bullous pemphigoid

While the presence of eosinophils in the skin lesions of bullous pemphigoid is well documented, the chemotactic factors responsible for eosinophil recruitment into the tissue still remain to be defined. In this study, eotaxin and interleukin-5 (IL-5) concentrations were determined in the blister fluid and sera of patients with bullous pemphigoid (acute and remission phase, n=6) in comparison with normal healthy controls (n=6) using the enzyme-linked immunosorbent assay (ELISA) technique. Eotaxin and IL-5 levels were increased in the blister fluid compared with the acute and remission phase sera, as well as compared with the sera of normal controls. In addition, immunoreactivity for eotaxin was predominantly found in the inflammatory cell infiltrate of lesional bullous pemphigoid biopsy specimens. In conclusion, the data provide evidence that co-operation of eotaxin and IL-5 may play an essential role in activating and recruiting eosinophils, which ultimately contribute to the tissue damage in bullous pemphigoid.     

The role of T lymphocytes and cytokines in the pathogenesis of pemphigoid gestationis

BACKGROUND: Pemphigoid gestationis (PG), also known as herpes gestationis, is a rare autoantibody-mediated bullous disease, usually associated with pregnancy and the postpartum period. However, infiltrating cells have recently been suggested to also contribute to the pathogenesis of cutaneous lesions. OBJECTIVES: To evaluate the immunophenotype of T cells infiltrating the PG lesional skin and their prevalent cutaneous cytokine expression, as well as the presence and distribution of mast cells, eosinophils and neutrophils. Methods We performed an immunohistochemical study with a large panel of monoclonal antibodies to CD3, CD4, CD8, HLA-DR, CD25, myeloperoxidase, tryptase, eosinophil cationic protein EG2, human interleukin (IL)-2, -4, -5, -8, interferon (IFN)-gamma, and granulocyte-macrophage colony-stimulating factor using the alkaline phosphatase-antialkaline phosphatase procedure on lesional skin of seven patients with PG. Skin from four subjects with pruritic urticarial papules and plaques of pregnancy and three additional healthy donors were used as controls. RESULTS: The findings indicate that there is a T-cell population with a prevalent T-helper (Th) 2 phenotype in the lesional skin of PG subjects. We also found a number of eosinophils and neutrophils with clear signs of activation. CONCLUSIONS: These data suggest that an inflammatory infiltrate is involved in the production of PG bullous lesions. In particular, we assume that the Th2 cells might be implicated in the very early stages of autoimmune response and may exercise a broad influence in blister formation in this disease.     

Itraconazole therapy in pityriasis versicolor

An infectivity inhibition micromethod was used to detect interferon (IFN) in sera and suction blister fluids from 35 patients with untreated psoriasis vulgaris. IFN (greater than or equal to 16 units/ml) was detected in 56% of the sera (median 25 units/ml), in 77% of the suction blister fluids from lesional skin (median 35 units/ml) and 33% of the blister fluids from unaffected skin (median 10 units/ml). IFN levels were significantly higher in blister fluids from lesional skin than from unaffected skin (P less than 0.05) indicating local IFN production. Results of characterization experiments indicated the presence of both acid stable and acid labile IFN-alpha as well as IFN-gamma in sera and blister fluids. After Goeckerman therapy, IFN was detected in 91% of the sera (median 89 units/ml), in 90% of the blister fluids from lesional skin (median 50.5 units/ml) and in 72% of the blister fluids from unaffected skin (median 26.5 units/ml). The IFN levels in sera were significantly higher than in blister fluids from both lesional skin (P = 0.05), and unaffected skin (P = 0.001). Furthermore, after Goeckerman therapy the IFN levels in blister fluids from unaffected skin and in sera were significantly higher than those in untreated patients (P = 0.01 and P = 0.0001) respectively. The results indicate that UVB radiation induces systemic IFN production.     

Characterization of skin cytokines in bullous pemphigoid and pemphigus vulgaris

The purpose of this study was to determine cytokine and cell marker expression in perilesional skin biopsies from patients with the autoimmune blistering diseases bullous pemphigoid (BP, n = 21) and pemphigus vulgaris (PV, n = 7). Immunohistochemistry and in situ hybridization were used to detect T helper (Th)1 [interleukin (IL)-2, interferon (IFN)-gamma] and Th2 (IL-4, IL-5, IL-13) protein and mRNA. Perilesional skin biopsies from patients with BP were characterized by the deposition of IL-4, IL-13 and IL-5. In patients with BP, IL-4 and IL-13 localized to mononuclear cells within the dermal infiltrate while IL-5 was predominately expressed at the dermal-epidermal junction. BP skin sections also expressed vascular cell adhesion molecule 1 on endothelial cells, not seen in patients with PV. PV biopsies were remarkable for a mixed Th1/Th2 pattern of cytokine expression, including the presence of IL-2, IFN-gamma and IL-4 and the absence of IL-5 and IL-13. In situ hybridization detected mRNA for IL-4 and IL-5 in the cellular infiltrate of BP patients, and IL-2 in a patient with PV. In vitro binding assays demonstrated that normal human eosinophils, activated by coculture in IL-5, bound preferentially to BP skin sections that contained detectable in vivo bound IL-5. The predominance of Th2 cytokines in BP, in association with increased binding of eosinophils in vitro, suggests that Th2 cytokines are relevant in the recruitment and adhesion of eosinophils within the dermal infiltrates of patients with BP, and may play a part in the pathogenesis of blister formation.     

CCL18 is expressed in patients with bullous pemphigoid and parallels disease course

Background The autoimmune skin disease bullous pemphigoid (BP) is characterized by subepidermal blister formation and a strong dermal infiltrate of mononuclear cells and eosinophils as well as a T‐helper (Th) 2‐dominated cytokine milieu. CCL18 is a chemokine, with unknown receptor counterpart, frequently associated with inflammatory Th2‐type responses. Objectives The study was performed to investigate an association of CCL18 with BP. Methods CCL18 was determined by enzyme‐linked immunosorbent assay in serum and blister fluid of patients with BP, pemphigus vulgaris and healthy individuals. In vitro chemotaxis assays were performed to demonstrate migration of peripheral blood mononuclear cells to BP blister fluid. Immunohistology and immunofluorescence staining were used to evaluate CCL18 expression in skin. Results We have found that the levels of CCL18 in sera from patients with BP are 84% higher than those normally observed in healthy individuals. In addition, blister fluid of patients with BP is extremely rich in CCL18, reaching concentrations which are fivefold and sevenfold higher than those found in the sera of patients with BP and healthy individuals, respectively. Using immunofluorescence techniques we identified Langerhans cells, antigen‐presenting cells of the dermis and eosinophils as producers of CCL18 in BP skin. We studied the possibility of using CCL18 expression as a biomarker linked to BP by monitoring the serum levels of CCL18 and the disease course of nine patients with BP over a maximum period of 54 months. In this study, CCL18 levels correlated with the disease course in most of the patients. Conclusions Our data implicate CCL18 as a functionally relevant chemokine in BP, mediating recruitment of blood mononuclear cells into the hallmark infiltrated skin lesion. The high correlation of CCL18 expression and BP disease suggests that blood levels of this chemokine can be used as an easy method to monitor disease progression and/or efficacy of therapeutic interventions.     

Infiltrating cells and related cytokines in lesional skin of patients with chronic idiopathic urticaria and positive autologous serum skin test

Abstract:  In approximately one-third of patients with chronic idiopathic urticaria (CIU), autoantibodies against the high-affinity IgE receptor and/or against IgE can be detected and a wheal-and-flare response can be provoked by the intradermal injection of autologous serum (ASST). In this study we aimed to further characterize the inflammatory response observed in the subgroup of CIU patients with positive ASST and serum-evoked histamine-release in vitro from basophils in comparison with unaffected skin and healthy donors. An immunohistochemical analysis of infiltrating cells (CD4, MPO, EG1, EG2, tryptase), cytokines (IL-4, IL-5, IFN-γ), chemokines and chemokine receptors (IL-8, CCR3, CXCR3), and adhesion molecules (ICAM-1, VCAM-1, ELAM-1) was performed on seven selected patients (four males and three females; median age: 45 years; range: 22–57) and five healthy donors. Cytokine evaluation was also performed in five psoriatic patients to obtain an additional control .
In spontaneous wheals we observed an increased number of CD4+ T lymphocytes when compared with the controls, and an increased number of neutrophils and eosinophils, whereas mast cells did not show a significant variation. A significant expression for IL-4 and IL-5 could only be observed in lesional skin, while IFN-γ showed a slight expression in the same site. Chemokine receptors CCR3 and CXCR3 did not show a defined polarized response in either lesional or unaffected skin. An increased expression of all cellular adhesion molecules (CAMs) studied was detected in spontaneous wheals. The lack of a significant difference in the expression of tryptase + mast cells, T lymphocytes, IL-8, CXCR3 and CCR3, a few CAMs between the lesional and unaffected skin of CIU patients suggests a wide immunological activation that involves not only lesional tissues, but possibly extends to the whole of the skin's immune system.     

Serum chemokine profile in patients with bullous pemphigoid

BACKGROUND: Bullous pemphigoid (BP) is an autoimmune inflammatory disease causing blister formation at the dermoepidermal junction. Cutaneous infiltration of activated CD4+ T cells and eosinophils is an early event in blister formation during the disease process, suggesting that the trafficking of circulating leucocytes through the sites of inflammation is crucial in the pathogenesis of the disease. While the accumulated evidence suggests that some cytokines are involved in the pathogenesis, there have been few reports about serum chemokine profiles in patients with BP. OBJECTIVES: To determine serum profiles of various chemokines and their clinical association in patients with BP. METHODS: Concentrations of 10 chemokines - interferon (IFN)-gamma-inducible protein-10 (IP-10), monokine induced by IFN-gamma (MIG), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, RANTES, eotaxin, monocyte chemoattractant protein (MCP)-1, MCP-2, MCP-3 and growth-regulated oncogene-alpha- were measured in serum samples from 38 patients with BP, 16 with pemphigus vulgaris (PV) and 17 normal controls using a sandwich immunoassay-based multiplex protein array system. RESULTS: While there was no significant increase in any serum chemokine levels in patients with PV, serum levels of IP-10 and MCP-1 were significantly increased in patients with BP compared with healthy controls. Furthermore, serum levels of IP-10, MIG, MCP-1 and eotaxin in patients with BP increased significantly with disease severity as determined by the area affected. CONCLUSIONS: These observations suggest that an elaborately orchestrated network of chemokines, especially MCP-1 and IP-10, contributes to the pathomechanism of BP.     

High level of thymus and activation-regulated chemokine in blister fluid and sera of patients with bullous pemphigoid

BACKGROUND: Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by eosinophilia and high serum IgE levels. The accumulated evidence suggests that various cytokines are involved in the lesional skin of patients with BP. Recently, thymus and activation-regulated chemokine (TARC/CCL17), a CC chemokine, was identified as a selective chemoattractant for CC chemokine receptor 4 (CCR4)-expressing cells. OBJECTIVE: In this study, we examined the involvement of TARC in patients with BP. METHODS: We determined the fluid and serum TARC levels in patients with BP by enzyme-linked immunosorbent assay and compared the serum TARC levels with the eosinophil numbers in peripheral blood. We also compared the serum TARC levels in five patients with BP before and after they were treated. Moreover, we examined TARC, CCR4 and CXC chemokine receptor 3 (CXCR3) expression in the lesional skin of patients with BP by immunohistochemical procedures. Furthermore, we measured CCR4 positivity in CD4+ CD45RO+ cells of peripheral blood mononuclear cells (PBMCs) in patients with BP and healthy control subjects. RESULTS: The fluid TARC levels in patients with BP were significantly higher than those in blisters from burn patients or suction blisters of healthy control subjects. The serum TARC levels in patients with BP were also significantly higher than those in pemphigus vulgaris (PV) patients and healthy control subjects, and decreased after the treatment. The serum TARC levels in patients with BP significantly correlated with the eosinophil numbers in peripheral blood (r = 0.72, P < 0.002). Immunohistochemistry showed a strong reactivity of TARC in the epidermal keratinocytes (KCs) of BP. Moreover, both CCR4 and CXCR3 were expressed on the dermal infiltrating CD4+ T cells mainly beneath the bullae of patients with BP. Fluorescence-activated cell sorting analysis showed a higher percentage of CCR4 positivity in CD4+ CD45RO+ cells of PBMCs in patients with BP than that in healthy control subjects, while there was no significant difference of CXCR3 positivity in CD4+ CD45RO+ cells of PBMCs between patients with BP and healthy control subjects. CONCLUSIONS: These findings strongly suggest that TARC may be one of the important chemokines that are involved in the pathogenesis of BP.     

大疱性类天疱疮患者血清及疱液嗜酸性粒细胞阳离子蛋白水平检测

【摘要】 目的 探讨血清及疱液嗜酸性粒细胞阳离子蛋白（ECP）水平与大疱性类天疱疮（BP）的关系。方法 选择2012年1月至2019年10月在北京协和医院皮肤科就诊的初发BP患者40例、健康人40例进行血清ECP检测；选择同一时期就诊的33例初发BP患者、41例非免疫性疱病患者进行疱液ECP检测。用酶联免疫吸附实验检测血清和疱液ECP含量，同时对1例BP和1例接触性皮炎患者皮损部位病理切片进行ECP免疫组化染色。符合正态分布的两组间数据比较采用t检验或t′检验，计数资料的比较采用χ2检验。采用Pearson相关系数分析BP患者血清ECP与外周血嗜酸性粒细胞之间的关系。结果 BP组血清ECP含量为（116.9 ± 19.3） ng/L，健康对照组为（93.3 ± 15.9） ng/L，差异有统计学意义（t = 5.96，P＜0.001）。BP组疱液ECP含量为（665.8 ± 189.0） ng/L，非免疫性疱病组为（547.5 ± 240.6） ng/L，差异有统计学意义（t = 2.31，P = 0.02）。免疫组化结果显示，BP患者ECP阳性细胞胞质棕黄色颗粒明显多于接触性皮炎患者。BP患者血清ECP与外周血嗜酸性粒细胞比例之间无统计学相关性（r = -0.15，P = 0.35）。结论 BP患者血液、疱液ECP水平明显升高，且疱液ECP水平远远高于血清ECP水平，提示ECP可能参与BP的发病过程。     

Lesional Th17 cells and regulatory T cells in bullous pemphigoid

Th17 cells play crucial roles in the pathogenesis of autoimmune diseases. We previously reported that Th17 cells are recruited to the lesional skin in pemphigus vulgaris (PV) and pemphigus foliaceus (PF). The aim of this study was to evaluate lesional Th17 cells and Treg cells in bullous pemphigoid (BP). Correlations between these cells and disease severity of BP were also evaluated. Immunohistochemical studies showed that both IL-17+ and Foxp3+ cells were present in higher numbers in BP lesions, compared with control skin. IL-17/CD4 ratio in BP was significantly higher than that in PF. Foxp3/CD4 ratio in BP was significantly less than that in either PV or PF. There were no obvious correlations between these cells and disease severity of BP. This study suggests that, compared with pemphigus, BP shows more Th17 cell-related inflammation and less Treg-related regulation.     

Tacrolimus decreases the expression of eotaxin, CCR3, RANTES and interleukin-5 in atopic dermatitis

Background There is a lack of studies on the effect of tacrolimus on eosinophils and related molecules including eotaxin, CCR3, RANTES and interleukin (IL)‐5. Objectives To investigate the effects of tacrolimus on in vivo eosinophil counts and on the related molecules eotaxin, CCR3, RANTES and IL‐5 in patients with atopic dermatitis (AD). Methods Lesional skin specimens and sera were obtained from 15 patients with AD and from 15 normal controls. For 8 weeks, the patients with AD applied 0·03% tacrolimus ointment to all affected areas twice daily. Blood sampling and skin biopsies were then repeated. We evaluated serum eotaxin and IL‐5 levels, and tissue eotaxin, CCR3, RANTES and IL‐5 levels. Additionally, tissue levels of eotaxin and CCR3 mRNA were measured. Results After treatment with topical tacrolimus twice daily for 8 weeks, significant decreases were found in serum IL‐5 levels, immunoreactive cell counts of eotaxin, IL‐5, CCR3 and RANTES in AD skin, and tissue eosinophil counts. However, the change in the serum eosinophil count was not statistically significant, and mRNA levels of eotaxin and CCR3 were not decreased significantly after treatment. Conclusions Topical tacrolimus reduces the number of eosinophils in tissue and suppresses the expression of eotaxin, CCR3, RANTES and IL‐5 related to proliferation, recruitment, activation and survival of eosinophils.     

Role of cell-mediated immune reaction in blister formation of bullous pemphigoid.

In patients with bullous pemphigoid (BP), early lesions appear as exudative erythematous patches. Histologically, the inflammatory infiltrate is composed mainly of mononuclear cells (MNCs) in the erythematous lesion, although eosinophils and neutrophils are also present. The MNCs are predominantly helper/inducer T cells even in the bullous lesions. Some of the MNCs infiltrated were stained in cytoplasm by antihuman gamma-interferon (IFN-gamma) monoclonal antibody (MoAb) immunohistologically. These infiltrates are considered to produce IFN-gamma. In the bullous fluids of early BP lesions, high levels of IFN-gamma are detected by radioimmunoassay using antihuman IFN-gamma MoAb. The results suggest that infiltrating lymphocytes are stimulated immunologically in BP bullous lesions. Cell-mediated immune reaction as well as autoantibody to the basement membrane zone may also play an important role in blister formation in BP.     

CCR4 is expressed on infiltrating cells in lesional skin of early mycosis fungoides and atopic dermatitis

CCR4 is expressed on tumor cells of mycosis fungoides (MF) and Sézary syndrome (SS). In MF, most infiltrating cells in patches and plaques express CXCR3, while tumor cells express CCR4 in advanced stages. Poteligeo Test IHC (CCR4 staining kit) is a newly developed staining kit that can examine the presence of CCR4 expressed on tumor cells of adult T‐cell leukemia/lymphoma, peripheral T‐cell lymphoma and cutaneous T‐cell lymphoma before treatment of anti‐CCR4 antibody using paraffin‐embedded samples. In this study, we analyzed CCR4 expression in lesional skin of MF, SS, atopic dermatitis (AD) and psoriasis with this new kit. CCR4 was expressed on infiltrating cells in lesional skin of patch, plaque, tumor MF and SS, and the number of positive cells increased as the disease progressed. Immunohistochemistry with frozen sections also showed some positive cells scattered in the dermis, although the quality was not high enough to quantify positive cells. There were significant positive correlations between CCR4⁺ cells and serum lactate dehydrogenase levels. Interestingly, CCR4⁺ cells were also detected in AD skin, whose number was larger than that in psoriatic skin. Previous studies showed only scattered CCR4⁺ cells in skin samples by standard immunohistochemical staining. The new, sensitive CCR4 staining kit has revealed that CCR4 is expressed on infiltrating cells in lesional skin of early MF and AD as well as advanced MF and SS. These cells can be therapeutic targets for patients who are resistant to standard treatments.     

In vitro propagation of tissue-infiltrating lymphoid cells from lesional skin by culture in IL 2-containing medium

Using an in vitro culture system, we have propagated lymphoid cells infiltrating the tissues of allergic contact dermatitis and several inflammatory dermatoses, and those drawn from the blister observed at the sites of allergic contact dermatitis. Approximately 10(7) cells were eventually obtained after 3 weeks from 3 mm punch-biopsied tissues by their culture in human IL 2-containing medium. Studies by flow-cytometrical analysis demonstrated that the proliferated cells were composed of 32-88% Leu-1-bearing (Leu-1+) cells, 70-90% Leu-2a-bearing (Leu-2a+) cells, 10-40% Leu-3a-bearing (Leu-3a+) cells, 70-90% HLA-DR-bearing (HLA-DR+) cells, and less than 10% Tac (IL 2 receptor)-bearing (Tac+) cells. Only the cultured cells derived from lesional tissue of pityriasis rosea and those from the blister content of contact dermatitis showed low percentage of T cell phenotype-bearing cells. These results suggest that the described method has opened a new system that enables us to culture possible effector lymphoid cells actually infiltrating various lesional skin.     

Paradoxical increase in skin inflammation in the absence of CCR4

The chemokine receptors are seven transmembrane, G-protein-coupled surface receptors that play key roles in the migration and localization of leukocytes to the skin during physiologic and inflammatory states. Their ligands, chemokines, are small secreted proteins that initiate leukocyte chemoattraction. Recent data indicate that known subsets of T helper (Th) cells express signature chemokine receptors (e.g., CXCR3, CCR3/4, and CCR6) that help to define individual subsets such as Th1, Th2, and Th17 cells, respectively, although there is some degree of overlap among these T-cell subsets. In this issue, Lehtim?ki et al. use an oxazolone-induced contact hypersensitivity (CHS) model to show that T cells (as well as neutrophils and eosinophils) from CCR4(-/-) mice accumulate just as (if not more) efficiently in inflamed skin as compared with the same population of leukocytes from wild-type (WT) mice. Although somewhat unexpected, their results can be explained if CCR4 attracts both proinflammatory and suppressive T cells into skin in addition to serving functions that are partially redundant with those of CCR10. Finally, we discuss other possible roles for CCR4 in the homing of T cells to skin.     

Distinct compartmentalization of immune cells and mediators characterizes bullous pemphigoid disease

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by recruitment of leucocytes into skin and release of damaging enzymes, resulting in epidermal detachment and blister formation. To better understand the role of leukotriene B4 (LTB4) and other inflammatory factors in BP pathophysiology, we conducted microscopic and immunohistochemical analyses of preserved skin biopsy sections and conducted flow cytometry and ELISA analyses of matched blood and blister fluid from BP patients. Neutrophils predominated in BP blister fluid, which also contained monocytes/macrophages and T cells, but few to no eosinophils and B cells. In contrast, BP skin histology showed a different pattern, with abundant neutrophils but eosinophils being the predominant immune cell type. LTB4 pathway and neutrophil activation markers were prevalent in BP skin lesions and strongly associated with perivascular neutrophils. Blister fluid neutrophils, monocytes/macrophages and eosinophils all exhibited increased surface expression of leukotriene A4 hydrolase and neutrophil elastase (P = .002 for both). Blister fluid was also enriched in interleukins (IL)-1α, IL-1β, IL-8, IL-10, IL-18, monocyte colony-stimulating factor (M-CSF) and vascular endothelial growth factor (VEGF). Our findings suggest differential leucocyte recruitment from blood into dermis and from dermis into blister, which correlates with disease activity, and presents potential new treatment opportunities for BP.     

Immune complexes in pemphigus and bullous pemphigoid

28 serum and 10 blister fluid specimens obtained from 28 pemphigus vulgaris (PV) patients were assayed for immune complexes using the polyethylene glycol (PEG)assay. 11% of sera and 30% of the blister fluids have elevated levels of immune complexes. Anti-intercellular cement substance (ICS) antibody could not be detected in PEG precipitates, but was present in the supernatants from the serum. However, anti-ICS antibody was found in 70 of the precipitated complexes from the blister fluid. 18 serum and 31 blister fluid specimens obtained from 18 bullous pemphigoid (BP) patients were assayed for immune complexes using the PEG assay. 17% of sera and 31% of the blister fluids have elevated levels of immune complexes. Antibasement membrane zone (BMZ) antibody could not be detected in the PEG precipitates, but was present in the supernatants obtained from the sera. Anti-BMZ antibody was found in 57% of the precipitated complexes from the blister fluids. This data further supports the hypothesis that the majority of the complexes in PV and BP are formed in situ.     

Characterization of skin blister fluids from children with Epstein–Barr virus‐associated lymphoproliferative disease

Epstein–Barr virus (EBV)‐associated T‐ or natural killer (NK)‐cell lymphoproliferative disease (LPD) is a heterogeneous group of disorders characterized by chronic proliferation of EBV‐infected lymphocytes. Patients may present with severe skin manifestations, including hypersensitivity to mosquito bites (HMB) and hydroa vacciniforme (HV)‐like eruption, which are characterized by blister formation and necrotic ulceration. Skin biopsy specimens show inflammatory reactions comprising EBV‐infected lymphocytes. However, blister fluids have not been fully assessed in patients with this disease. Blister fluids were collected from three patients with EBV‐associated LPD: two with HMB and one with HV. Immunophenotyping of blister lymphocytes and measurement of tumor necrosis factor (TNF)‐α in blister fluids were performed. The patients with HMB and HV exhibited markedly increased percentages of NK and γδ T cells, respectively, in both peripheral blood and blister fluids. These NK and γδ T cells strongly expressed the activation marker human leukocyte antigen‐DR and were considered to be cellular targets of EBV infections. TNF‐α was highly elevated in all blister fluids. Severe local skin reactions of EBV‐associated LPD may be associated with infiltrating EBV‐infected lymphocytes and a high TNF‐α concentration in blister fluids.