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

Eosinophil localization to the basement membrane zone is autoantibody- and complement-dependent in a human cryosection model of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by antibodies (IgG and IgE) targeting cell-substrate adhesion proteins. A variety of BP models suggest that autoantibody-dependent neutrophil degranulation is essential for blister formation. However, lesional biopsies reveal a predominance of eosinophils and few neutrophils. Our goal was to evaluate the role of antibodies and complement in eosinophil localization, degranulation and split formation at the dermo-epidermal junction (DEJ) utilizing a human skin cryosection model of BP paired with a human eosinophilic cell line, 15HL-60. Expression of receptors for IgG (FcγRII), IgE (FcεRI) and complement (CR1 and CR3) was confirmed on 15HL-60 cells using flow cytometry. 15HL-60 expression of granule protein [eosinophil derived neurotoxin (EDN) and eosinophil peroxidase (EPO)] mRNA and their degranulation in vitro was confirmed using RT-PCR and ELISA, respectively. For cryosection experiments, BP or control sera or IgG and IgE antibodies purified from BP sera were utilized in combination with 15HL-60 cells ± fresh complement. Both BP serum and fresh complement were required for localization of 15-HL60 cells to the DEJ. Interestingly, eosinophil localization to the DEJ was dependent on IgG, but not IgE, and complement. However, no subepidermal split was observed. Additionally, the 15HL-60 cells did not degranulate under any experimental conditions and direct application of cell lysate to cryosections did not result in a split. Our observation that eosinophil localization to the DEJ is dependent on IgG mediated complement fixation provides additional insight into the sequence of events during the development of BP lesions.

IgE autoantibodies in bullous pemphigoid: supporting role, or leading player?

Bullous pemphigoid (BP) is a common autoimmune blistering skin disease in which two hemidesmosomal components--the transmembrane collagen XVII (BP180 or BPAG2) and the plakin family protein BP230 (BPAG1)--are targeted by autoimmunity. Of these, collagen XVII (COL17) is thought to be a major autoantigen, and vital roles of IgG autoantibodies in blister formation have been elucidated. However, BP shows distinct features, including pruritic urticarial erythema and eosinophilic infiltration, which may be independent of IgG-mediated autoimmunity. Recently, it has been revealed that sera from certain patients with BP contain IgE autoantibodies to COL17 and that IgE autoantibodies bind to peri-lesional dermal-epidermal junctions. Mouse models have demonstrated that IgE antibodies to COL17 induce erythema and eosinophilic infiltration in skin. In addition, the successful treatment of severe BP with omalizumab, a humanized monoclonal antibody targeting IgE, has been reported. These findings suggest that both IgG and IgE autoantibodies to COL17 may be involved in the BP pathogenesis. This article summarizes IgE-mediated autoimmunity to COL17 in BP.

IL-17 expression in dermatitis herpetiformis and bullous pemphigoid

Dermatitis herpetiformis (DH) and bullous pemphigoid (BP) are skin diseases associated with eosinophilic and neutrophilic infiltrations. Although cytokines are critical for the inflammatory process, there are single findings concerning concentration of IL-17 in bullous diseases. The goal of this study was to assess IL-17 expression in DH and BP patients. Skin biopsies were taken from 10 DH, 14 BP patients and from 10 healthy subjects. The localization and expression of IL-17 was studied by immunohistochemistry and the serum concentration was measured by immunoassays. Expression of IL-17 in the epidermis and in influxed cells in dermis was detected in skin biopsies. Expression of IL-17 was statistically higher in epidermis and infiltration cells in specimens from BP than from DH patients. Examined interleukin expression was detected in perilesional skin of all patients but it was much lower than in lesional skin. The expression of IL-17 was not observed in biopsies from healthy people. Serum level of IL-17 was statistically higher in BP and DH groups as compared to control group. Our results provide the evidence that IL-17 may play an essential role in activating and recruiting eosinophils and neutrophils, which ultimately contribute to the tissue damage in DH and BP.

Evidence for pathogenicity of autoreactive T cells in autoimmune bullous diseases shown by animal disease models

Autoimmune bullous diseases (AIBDs) are characterized by blisters and erosions on the skin and/or mucous membranes, which are caused by autoantibodies directed to structural proteins of the epidermis and the epidermal basement membrane zone. This Viewpoint Essay discusses the contribution by autoreactive T cells to the pathogenesis of bullous pemphigoid, pemphigus and epidermolysis bullosa acquisita, with an emphasis on studies using active animal mouse models for these diseases. Previous studies have demonstrated that cytokines produced by autoreactive T cells, the interaction between antigen-specific T cells and B cells and the function of regulatory T cells are likely related to the pathogenesis of AIBDs. In interpreting the experimental results, the limitations of those animal models should be considered. Further understanding of the pathogenicity of autoreactive CD4(+) T cells may lead to disease-specific treatments.

Organ-specific eosinophilic disorders of the skin, lung, and gastrointestinal tract

Eosinophils are multifunctional leukocytes that increase in various tissues in patients with a variety of disorders. Locally, they can be involved in the initiation and propagation of diverse inflammatory responses. In this review the clinical association of eosinophils with diseases of the skin, lung, and gastrointestinal tract is summarized. An approach to determining the causal role of eosinophils in these diseases is presented. Recent findings concerning molecular diagnosis, cause, and treatment are discussed.

Detection of anti-BP180NC16a and anti-BP230 autoantibodies in blister fluid of patients with bullous pemphigoid: the first survey in Greece

Bullous pemphigoid (BP) is an acquired bullous disease with an increasing prevalence among elderly people worldwide, including in Greece. Blister formation in most patients with BP is caused by autoantibodies against structural components of the basement membrane zone of the skin, predominantly BP180NC16a and BP230 antigens on the hemidesmosome adhesion complex. Routine diagnostic methods such as histological examination and direct and indirect immunofluorescence are combined to determine diagnosis. In this study, an ELISA was used to measure levels of both anti-BP180NC16A and anti-BP230 autoantibodies in the blister fluid of 13 patients with newly diagnosed BP, before starting treatment. The aim of the study was to evaluate this method as a diagnostic tool in BP. Our results indicate that blister-fluid examination by ELISA can be a useful tool to diagnose bullous pemphigoid, especially in elderly patients who refuse biopsy or have poor venous access.

Ontogeny of the eotaxins in human lung

The ontogeny of the C-C chemokines eotaxin-1, eotaxin-2, and eotaxin-3 has not been fully elucidated in human lung. We explored a possible role for eotaxin in developing lung by determining the ontogeny of eotaxin-1 (CCL11), eotaxin-2 (CCL24), eotaxin-3 (CCL26), and the eotaxin receptor, CCR3. We tested discarded surgical samples of developing human lung tissue using quantitative RT-PCR (QRT-PCR) and immunostaining for expression of CCL11, CCL24, CCL26, and CCR3. We assessed possible functionality of the eotaxin-CCR3 system by treating lung explant cultures with exogenous CCL11 and analyzing the cultures for evidence of changes in proliferation and activation of ERK1/2, a signaling pathway associated with CCR3. QRT-PCR analyses of 22 developing lung tissue samples with gestational ages 10-23 wk demonstrated that eotaxin-1 mRNA is most abundant in developing lung, whereas mRNAs for eotaxin-2 and eotaxin-3 are minimally detectable. CCL11 mRNA levels correlated with gestational age (P < 0.05), and immunoreactivity was localized predominantly to airway epithelial cells. QRT-PCR analysis detected CCR3 expression in 16 of 19 developing lung samples. Supporting functional capacity in the immature lung, CCL11 treatment of lung explant cultures resulted in significantly increased (P < 0.05) cell proliferation and activation of the ERK signaling pathway, which is downstream from CCR3, suggesting that proliferation was due to activation of CCR3 receptors by CCL11. We conclude that developing lung expresses the eotaxins and functional CCR3 receptor. CCL11 may promote airway epithelial proliferation in the developing lung.

Experimental models for the autoimmune and inflammatory blistering disease, Bullous pemphigoid

Bullous pemphigoid (BP) is a subepidermal skin blistering disease characterized immunohistologically by dermal-epidermal junction (DEJ) separation, an inflammatory cell infiltrate in the upper dermis, and autoantibodies targeted toward the hemidesmosomal proteins BP230 and BP180. Development of an IgG passive transfer mouse model of BP that reproduces these key features of human BP has demonstrated that subepidermal blistering is initiated by anti-BP180 antibodies and mediated by complement activation, mast cell degranulation, neutrophil infiltration, and proteinase secretion. This model is not compatible with study of human pathogenic antibodies, as the human and murine antigenic epitopes are not cross-reactive. The development of two novel humanized mouse models for the first time has enabled study of disease mechanisms caused by BP autoantibodies, and presents an ideal in vivo system to test novel therapeutic strategies for disease management.

The pathophysiology of bullous pemphigoid

Bullous pemphigoid (BP) is a blistering skin disease characterized by an autoimmune response to 2 hemidesmosomal proteins within the dermal-epidermal junction, designated BP180 and BP230. While BP230 localizes intracellularly and associates with the hemidesmosomal plaque, BP180 is a transmembrane glycoprotein with an extracellular domain. Most BP patients have autoantibodies binding to an immunodominant region of BP180, the noncollagenous 16A domain (NC16A), which is located extracellularly close to the transmembrane domain of the protein. Autoreactive T and B cell responses to BP180 have been found in patients with BP. Passive transfer of antibodies to the murine BP180 ectodomain triggers a blistering skin disease in mice that closely mimics human BP. Lesion formation in this animal model depends upon complement activation, mast cell degranulation and accumulation of neutrophils and eosinophils. Patients' autoantibodies to BP180 induce dermal-epidermal separation in cryosections of human skin when co-incubated with leukocytes. The loss of cell-matrix adhesion is mediated by proteinases released by granulocytes. The increased knowledge of the pathophysiology of BP should facilitate the development of novel therapeutic strategies for this disease.

Oral steroid improves bullous pemphigoid-like clinical manifestations in non-Herlitz junctional epidermolysis bullosa with COL17A1 mutation

Non-Herlitz junctional epidermolysis bullosa (JEB-nH), a nonlethal variant of junctional epidermolysis bullosa (JEB), is an autosomal recessive disorder characterized by separation of the dermal-epidermal junction. JEB-nH is caused by mutations in several genes and lack of the COL17A1 gene product may lead to skin fragility. A 41-year-old Japanese man with JEB-nH, featuring mutations in the gene encoding type XVII collagen, presented with great blisters over his entire body accompanied by severe itching and eosinophilia usually observed in bullous pemphigoid (BP). To our knowledge, our patient is the first with JEB-nH to be treated successfully with an oral steroid to control his skin affliction, symptoms and eosinophilia. This suggests that in the case of JEB-nH with eosinophilia caused by some secondary immune activation, oral steroids may constitute an alternate therapy to improve aggravated skin conditions and severe itching, both of which tend to show resistance to usual dermatological treatments.

Eosinophilic disorders

Eosinophilic inflammatory responses occur in association with multiple disorders. Although the initial cause and the affected organs vary among the different eosinophilic disorders, there are only 2 major pathways that mediate eosinophilia: (1) cytokine-mediated increased differentiation and survival of eosinophils (extrinsic eosinophilic disorders), and (2) mutation-mediated clonal expansion of eosinophils (intrinsic eosinophilic disorders). Independent from the original trigger, the most common cause of eosinophilia is the increased generation of IL-5-producing T cells. In some cases, tumor cells are the source of eosinophil hematopoietins. The intrinsic eosinophilic disorders are characterized by mutations in pluripotent or multipotent hematopoietic stem cells leading to chronic myeloid leukemias with eosinophils as part of the clone. Here, we propose a new classification of eosinophilic disorders on the basis of these obvious pathogenic differences between the 2 groups of patients. We then discuss many known eosinophilic disorders, which can be further subdivided by differences in T-cell activation mechanisms, origin of the cytokine-producing tumor cell, or potency of the mutated stem cell. Interestingly, many subgroups of patients originally thought to have the idiopathic hypereosinophilic syndrome can be integrated in this classification.

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.

Multiplex bead array assay for detection of 25 soluble cytokines in blister fluid of patients with complex regional pain syndrome type 1

Inflammatory processes are known to be involved at least in the early phase of complex regional pain syndrome type 1 (CRPS1). Blister fluid obtained from the involved extremities displayed increased amounts of proinflammatory cytokines IL-6 and TNFα compared with the noninvolved extremities. The aim of this paper is to investigate the involvement of mediators by measurement of several other cytokines using new detection techniques that enable multiple cytokine measurement in small samples. The use of a multiplex-25 bead array cytokine assay and Luminex technology enabled simultaneous measurement of representative (1) proinflammatory cytokines such as GM-CSF, IL-1β, IL-1RA, IL-6, IL-8, and TNF-α; (2) Th1/Th2 distinguishing cytokines IFN-γ, IL-2, IL-2R, IL-4, IL-5, and IL-10; (3) nonspecific acting cytokines IFN-α, IL-7, IL-12p40/p70, IL-13, IL-15, and IL-17; and (4) chemokines eotaxin, IP-10, MCP-1, MIP-1α, MIP-1β, MIG, and RANTES. Although minimal detection levels are significantly higher in the bead array system than those in common ELISA assays, in blister fluid, IL-1RA, IL-6, IL-8, TNF-α, IL-12p40/p70, MCP-1, and MIP-1β were detectable and increased in CRPS1 affected extremities. Levels of IL-6 and TNF-α simultaneously measured by ELISA (Sanquin Compact kit) and by multiplex-25 bead array assay (Biosource) were highly correlated (r = 0.85, P < .001 for IL-6 and r = 0.88, P < .001 for TNF-α). Furthermore, IP-10 and eotaxin were detectable but diminished in CRPS1, whereas detectable amounts of IL-10 were similar in involved and noninvolved extremities. Multiplex bead array assays are useful systems to establish the involvement of cytokines in inflammatory processes by measurements in blister fluids of CRPS1. Ten representative cytokines were detectable. However, detection levels and amounts measured are at least 3 times higher in the multiplex-25 array assay than in the ELISA assays used simultaneously for the measurement of cytokines.

Bullous pemphigoid associated with hypereosinophilic syndrome: simultaneous response to imatinib

Hypereosinophilic syndrome is a myeloproliferative disorder defined by unexplained, persistent hypereosinophilia with cutaneous or systemic involvement. We describe a patient with coexistence of hypereosinophilic syndrome and bullous pemphigoid. Treatment with the novel tyrosine kinase inhibitor imatinib mesylate resulted in durable remission of hypereosinophilia and skin lesions.

Increased expression of Th2-associated chemokines in bullous pemphigoid disease. Role of eosinophils in the production and release of these chemokines

Bullous pemphigoid is an inflammatory disease of the skin associated with eosinophil infiltration and the presence of high levels of Th2 cytokines in the associated blister fluid. Little is known about the contribution of chemokines in this disease. We found that eotaxin and MCP-4 mRNA and immunoreactivity were expressed in all biopsies of BP patients and were mainly localized to the epidermis and eosinophils. The expression of eotaxin and MCP-4 was enhanced in eosinophils following IL-5 treatment. Subsequent stimulation of IL-5-primed eosinophils with Ig-immune complexes, results in increase secretion of eotaxin and MCP-4 in the supernatants. Using immunostaining, these two chemokines were localized to the granules of eosinophils. BF was found to contain chemotactic activity for eosinophils, neutrophils and T cells. The chemotactic effect of BF for eosinophils was more effective when eosinophils were stimulated with IL-5 or IL-4. We also found that the levels of Th(2)-associated chemokines (eotaxin and MCP-4) in BF were significantly higher than the Th(1)-associated chemokines (MIP-1beta and IP-10). This was consistent with the increased chemotaxis of polarized Th(2) cells toward BF, when compared to Th(1)-differentiated T cells. Our results support the involvement of Th(2)-associated chemokines in the pathogenesis of BP disease.

Interleukin-4 and interleukin-13 enhance CCL26 production in a human keratinocyte cell line, HaCaT cells

Eotaxin-2/CCL24 and eotaxin-3/CCL26 are CC chemokines and their receptor, CC chemokine receptor 3 is preferentially expressed on eosinophils. It was reported that vascular endothelial cells and dermal fibroblasts produced CCL26. However, the regulation of CCL24 and CCL26 production in keratinocytes has not been well documented. We investigated the expression and production of CCL24 and CCL26 in the human keratinocyte cell line, HaCaT cells. Reverse transcription and polymerase chain reaction was performed using these cells and Enzyme-linked immunosorbent assay was carried out using supernatant of these cells. The production of CCL24 in HaCaT cells was slightly enhanced by IL-4 and that of CCL26 was strongly enhanced by IL-4 and IL-13. Furthermore, TNF-alpha generated a synergistic effect on IL-4 enhanced CCL26 production. Dexamethasone, IFN-gamma and the p38 mitogen-activated protein kinase inhibitor SB202190 inhibited IL-4 enhanced CCL26 production. IL-4 enhanced production of CCL26 was inhibited by leflunomide and JAK inhibitor 1, but not by JAK3 inhibitor, which indicates that it is mediated by JAK1-STAT6-dependent pathway. This result also strongly suggests the involvement of the type 2 IL-4 receptor in IL-4 enhanced production of CCL26. These results suggest that keratinocytes are involved in the migration of CC chemokine receptor 3 positive cells such as eosinophils in a Th2-dominant situation like atopic dermatitis.

The lesional skin of linear IgA bullous dermatosis expresses growth-regulated peptide (GRO)-alpha

The patient was a 62-year-old man with erythema with tense vesiculobullae and erosions on the bilateral elbows, right knee, and one buttock. A skin biopsy specimen revealed subepidermal blister formation with a predominant infiltration of neutrophils and papillary neutrophilic microabscesses. Direct immunofluorescence study showed linear deposition of IgA and weak deposition of IgG at the basement membrane zone of the lesional skin, and indirect immunofluorescence study showed linear deposition of IgA at the epidermal side of the 1M NaCl-separated normal skin. He was diagnosed with linear IgA bullous dermatosis. Immunohistochemical study revealed that the lesional and perilesional keratinocytes expressed growth-regulated peptide (GRO) -alpha, a potent chemoattractant for neutrophils. This suggests that GRO-alpha plays a role in the infiltration of neutrophils into the lesional skin and in bulla formation in linear IgA bullous dermatosis.

Interleukin-16 expression and release in bullous pemphigoid

Cutaneous infiltration of activated CD4(+) T cells and eosinophils is an early event in blister formation during bullous pemphigoid (BP), suggesting that the trafficking of circulating leucocytes through the sites of inflammation, their activation and cytokine release is crucial in the pathogenesis of the disease. IL-16 is a major chemotactic factor able to recruit CD4(+) cells in the skin during inflammation and to induce the expression of functional high-affinity interleukin (IL)-2 receptors, thus contributing to cellular activation and proliferation. We performed a study in order to evaluate the presence of IL-16 in skin samples and sera and blister fluids of patients affected with BP in active phase of the disease (n = 39), compared with healthy donors studied as control group. Ten patients were also evaluated before and after steroid therapy. Our results demonstrated that IL-16 was expressed strongly by keratinocytes and by dermal infiltrating CD4(+) T lymphocytes in lesional skin of BP patients. High levels of IL-16 were detected in sera and blisters of BP, significantly higher in respect to healthy donors. When patients were investigated for the presence of eosinophil cationic protein (ECP) and soluble CD30 (sCD30) to reveal signs of eosinophils and Th2-cells activation, we found a positive correlation between IL-16 serum levels and both ECP and sCD30, suggesting that IL-16 is involved in Th2 lymphocytes and eosinophils recruitment during BP.

Tissue Eosinophilia in Pemphigoid Gestationis: Association with Eotaxin and Upregulated Activation Markers on Transmigrated Eosinophils

PROBLEM

We studied chemotactic cytokines and activation of skin-homed eosinophils in pemphigoid gestationis, a rare autoimmune bullous disease of late pregnancy.

METHOD OF STUDY

Eotaxin and interleukin (IL)-5 were analysed in patients' blister fluid and serum by enzyme-linked immunosorbent assay. Lesional tissue was investigated for eotaxin deposition by immunohistochemistry. Adhesion molecules and activation markers on tissue eosinophils were analysed by immunofluorescence staining.

RESULTS

Eotaxin was elevated in serum of two pemphigoid gestationis patients compared with nine healthy pregnant women. Blister fluid contained even higher amounts of eotaxin and in addition IL-5. Eotaxin was mainly expressed in subepidermal tissue in close proximity to eosinophils that expressed high levels of adhesion molecules (CD11b, CD11c, CD18 and CD49d) and the activation marker HLA-DR.

CONCLUSIONS

High local levels of eotaxin and IL-5 as present in the blister fluid correspond to the high state of activation of the infiltrated eosinophils.

Bullous pemphigoid: using animal models to study the immunopathology

Bullous pemphigoid was first described by Lever in 1953 as a subepidermal blistering disease. Its immunohistological features include dermal-epidermal junction separation, an inflammatory cell infiltrate in the upper dermis, and basement membrane zone-bound autoantibodies. These autoantibodies show a linear staining at the dermal-epidermal junction, activate complement, and recognize two major hemidesmosomal antigens, BP230 (BPAG1) and BP180 (BPAG2 or type XVII collagen). An IgG passive transfer mouse model of BP was developed by administering rabbit antimurine BP180 antibodies to neonatal mice. This model recapitulates the key features of human bullous pemphigus. Using this in vivo model system, several key cellular and molecular events leading to the bullous pemphigus disease phenotype were identified, including IgG binding, complement activation, mast cell degranulation, and neutrophil infiltration and activation. Proteinases and reactive oxygen species released by neutrophils work together to damage the basement membrane zone, causing dermal-epidermal junction separation. Recent experimental data from human bullous pemphigus studies suggest that human bullous pemphigus and its mouse IgG passive transfer model counterpart may well share not only common immunohistological features but also pathological mechanisms underlying the development of this antibody-mediated disease.

Dermal endothelial cells express eotaxin in hypereosinophilic syndrome

We describe a patient with hypereosinophilic syndrome, who had severe cutaneous eruptions. Immunohistochemical study revealed that dermal endothelial cells in the lesional skin of this patient expressed eotaxin, which indicates eotaxin plays a part in inducing eosinophil migration into cutaneous tissue in hypereosinophilic syndrome.

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.

Th1, Th2 and Th3 cytokines in the pathogenesis of bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune bullous skin disease mediated by autoantibodies against hemidesmosomal proteins. In addition to humoral immunity, the contribute of infiltrating T-helper (Th) autoreactive lymphocytes and their related cytokines to the pathomechanism of blistering is now growing in interest. To investigate T-cell activation markers and the presence of inflammatory and fibrogenic cytokines (i.e. IL2, IL-4, IL-5, IFN-gamma, TGF-beta) in BP lesional skin, we performed an immunohistochemical study and an in situ hybridization procedure on five BP patients, comparing them with two psoriatic patients and four healthy subjects. Our aim was to expand suitable information about tissutal expression of cytokines, secondly to further investigate the role of TGF-beta (a Th3-like or T-regulatory (T-reg) cytokine) in a non-scarring disorder like BP, in order to highlight its pleiotropic activity. The immunohistochemical analysis revealed a moderate to strong staining for IL-4 and IL-5 with a prevalent perivascular localization in the upper dermis. The staining for IFN-gamma showed a moderate/focal expression on the dermal perivascular infiltrate. IL-2 protein was observed in four cases. While no positive staining for IL-4 mRNA was detected in all BP subjects with in situ hybridization, IL-5 mRNA was documented in four BP specimens. A focal nuclear staining for IFN-gamma was observed in the epidermal layers and on the cellular infiltrate of lesional skin. In all BP cases, a moderate/diffuse positivity for TGF-beta(1) mRNA was documented in both cytoplasm and nucleus of the infiltrating perivascular cells of lesional and perilesional skin. Our results suggest a balance between Th1, Th2 and Th3 activity, with quantitatively different impact of the various cytokines on the pathomechanism of blistering, depending on the reciprocal network. The supposed participation of each cytokine analyzed in the pathogenesis of BP is discussed. The newest data obtained consist of TGF-beta detection in a non-scarring disease like PB, that had never been documented before, and in the confirmation of a mixed cytokine pattern in the fully developed phase of the disease.

Elevated serum eotaxin levels in patients with inflammatory bowel disease

OBJECTIVE

Eotaxin is a recently characterized chemokine with potent and selective chemotactic activity for eosinophils. Previous studies indicating that eosinophils accumulate and become activated in inflammatory bowel disease (IBD) led us to hypothesize that eotaxin is potentially involved in the pathophysiology of IBD and, therefore, that eotaxin would be increased in the serum of patients with IBD. The objective of this study was to test those assumptions.

METHODS

We investigated 72 patients with IBD, 35 with ulcerative colitis, and 37 with Crohn's disease. A total of 27 patients had active and 45 inactive disease; 26 were receiving corticosteroids. Eotaxin serum levels were determined by solid phase sandwich ELISA. Lymphocytes, monocytes, and granulocyte subpopulations were determined in fresh blood samples with an automated autoanalyzer.

RESULTS

Serum eotaxin levels were significantly higher in patients with Crohn's disease and in those with ulcerative colitis than in the control subjects (p < 0.0001). Patients with inactive Crohn's disease had significantly higher levels of eotaxin than patients with inactive ulcerative colitis (p < 0.05). We did not find significant differences for activity or inactivity of disease, nor for treatment with prednisone. A negative correlation (p < 0.05) was found between eotaxin serum level and eosinophil counts in peripheral blood in patients with Crohn's disease.

CONCLUSIONS

There is an increased expression of eotaxin in IBD patients, suggesting that eotaxin may be involved in the pathogenesis of IBD. This increase is more accentuated in Crohn's disease and negatively correlates with the eosinophil number in peripheral blood. Our data support the increasing evidence that eosinophil are functionally involved in the pathophysiology of IBD.

Expression of eotaxin, an eosinophil-selective chemokine, parallels eosinophil accumulation in the vesiculobullous stage of incontinentia pigmenti

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis primarily affecting female children. The initial vesiculobullous stage of IP is characterized clinically by inflammatory papules, blisters, and pustules, and histopathologically by acanthosis, keratinocyte necrosis, epidermal spongiosis and massive epidermal eosinophil infiltration. The cause of this multisystem disease is attributed to the mutations of an X-linked regulatory gene, termed nuclear factor-kappaB essential modulator (NEMO). The exact mechanism of epidermal eosinophil accumulation has not yet been determined. We explored the possible role of an eosinophil-selective, nuclear factor-kappaB-activated chemokine, eotaxin, in the accumulation of eosinophils in the initial stage of the disease. Monoclonal antibody (6H9) specific for human eotaxin strongly labelled the suprabasal epidermis of IP skin, paralleling the upper epidermal accumulation of eosinophils, but did not label the epidermis of normal skin or lesional skin from patients with other inflammatory skin diseases not characterized by prominent eosinophil accumulation, namely dermatitis herpetiformis and selected cases of atopic dermatitis lacking significant numbers of eosinophils. In addition, endothelial cells in lesional skin of IP also exhibited strong expression of eotaxin, which correlated with perivascular and intravascular eosinophil infiltration. We also examined the in vitro effects on epidermally derived eotaxin of several cytokines that were nuclear factor-kappaB-activated and/or known to induce eotaxin expression. In normal human keratinocytes, proinflammatory cytokines either independently (IL-1alpha) or synergistically (tumour necrosis factor-alpha (TNF-alpha)/ interferon-gamma (IFN-gamma) and TNF-alpha/IL-4) up-regulated eotaxin expression. These studies suggest that release of cytokines during the initial inflammatory stage of IP induces epidermal expression of eotaxin, which may play a role in the epidermal accumulation of eosinophils.

Immunologic and histopathologic characterization of an active disease mouse model for pemphigus vulgaris

Pemphigus vulgaris is an autoimmune blistering disease of the skin and mucous membranes that is caused by anti-desmoglein 3 IgG autoantibodies. Recently, we generated an active disease mouse model for pemphigus vulgaris by adoptive transfer of splenocytes from immunized desmoglein 3-/- mice to Rag2-/- mice. In this study, we performed immunologic and histopathologic studies using this pemphigus vulgaris model in mice and compared the gross and microscopic phenotypes of pemphigus vulgaris model mice and desmoglein 3-/- mice. Pemphigus vulgaris model mice showed strong in vivo IgG, and weak IgA deposition on keratinocyte cell surfaces in stratified squamous epithelia, and produced circulating anti-desmoglein 3 IgG antibodies without apparent cross-reactivity to desmoglein 1, in enzyme-linked immunosorbent assays. The predominant IgG subclass was IgG1. Pemphigus vulgaris model mice and desmoglein 3-/- mice were almost indistinguishable in terms of both gross and microscopic findings. Both types of mice showed suprabasilar acantholysis in the stratified squamous epithelia, including the oral mucous membranes and traumatized skin around the snout or paws; however, some pemphigus vulgaris model mice demonstrated a more severe phenotype than desmoglein 3-/- mice. The esophagus and forestomach were affected in some pemphigus vulgaris model mice, but not in desmoglein 3-/- mice. Furthermore, eosinophilic spongiosis, which is found in early pemphigus vulgaris lesions in patients, was observed in pemphigus vulgaris model mice but not in desmoglein 3-/- mice. Pemphigus vulgaris model mice reflect several of the histopathologic and immunologic features seen in pemphigus vulgaris patients, and provide a valuable tool to investigate the pathophysiologic mechanisms of pemphigus vulgaris.