Christian Vestergaard

Active participation of CCR5+CD8+ T lymphocytes in the pathogenesis of liver injury in graft-versus-host disease

We examined the molecular pathogenesis of graft-versus-host disease-associated (GVHD-associated) liver injury in mice, focusing on the role of chemokines. At the second week after cell transfer in the parent-into-F1 model of GVHD, CD8(+) T cells -- especially donor-derived CD8(+) T cells -- infiltrated the liver, causing both portal hepatitis and nonsuppurative destructive cholangitis (NSDC). These migrating cells expressed CCR5. Moreover, macrophage inflammatory protein-1alpha (MIP-1alpha), one of the ligands for CCR5, was selectively expressed on intralobular bile duct epithelial cells, endothelial cells, and infiltrating macrophages and lymphocytes. Administration of anti-CCR5 antibody dramatically reduced the infiltration of CCR5(+)CD8(+) T lymphocytes into the liver, and consequently protected against liver damage in GVHD. The levels of Fas ligand (FasL) mRNA expression in the liver were also decreased by anti-CCR5 antibody treatment. Anti-MIP-1alpha antibody treatment also reduced liver injury. These results suggest that MIP-1alpha-induced migration of CCR5-expressing CD8(+) T cells into the portal areas of the liver plays a significant role in causing liver injury in GVHD; thus, CCR5 and its ligand may be the novel target molecules of therapeutic intervention of hepatic GVHD.

Anti‐interleukin‐31‐antibodies ameliorate scratching behaviour in NC/Nga mice: a model of atopic dermatitis

Background:  Interleukin‐31 (IL‐31), a novel cytokine, is upregulated in atopic dermatitis skin lesions in humans and skin lesions in the NC/Nga mice, a murine model for atopic dermatitis.

IL-25 in Atopic Dermatitis: A Possible Link between Inflammation and Skin Barrier Dysfunction?

Atopic dermatitis (AD) is a common skin disease associated with a T(H)2 response and increased levels of T(H)2-associated cytokines and IgE. The mechanisms resulting in skewing the immune response in a T(H)2 direction in AD are not fully elucidated. However, such skewing has recently been associated with IL-25 in a murine model for allergic airway disease. The aim of this study was to investigate whether IL-25 may have a role in AD. We have identified IL-25-producing cells within the dermis of AD patients and propose that these cells are dendritic cells (DCs). This is supported by in vitro experiments that indicate that monocyte-derived DCs are capable of producing IL-25. As null mutations of filaggrin are associated with the development of an impaired skin barrier in AD, we investigated whether IL-25 affects filaggrin synthesis by keratinocytes. Using mRNA analysis, we have shown that IL-25 stimulation does indeed decrease filaggrin synthesis in cultured keratinocytes. These results suggest that IL-25 produced by DCs could have a dual role as both an inducer of the T(H)2 response and as an inhibitor of filaggrin synthesis, thereby directly affecting skin barrier function in AD patients.

Original ArticleIL-25 in Atopic Dermatitis: A Possible Link between Inflammation and Skin Barrier Dysfunction?

Atopic dermatitis (AD) is a common skin disease associated with a T(H)2 response and increased levels of T(H)2-associated cytokines and IgE. The mechanisms resulting in skewing the immune response in a T(H)2 direction in AD are not fully elucidated. However, such skewing has recently been associated with IL-25 in a murine model for allergic airway disease. The aim of this study was to investigate whether IL-25 may have a role in AD. We have identified IL-25-producing cells within the dermis of AD patients and propose that these cells are dendritic cells (DCs). This is supported by in vitro experiments that indicate that monocyte-derived DCs are capable of producing IL-25. As null mutations of filaggrin are associated with the development of an impaired skin barrier in AD, we investigated whether IL-25 affects filaggrin synthesis by keratinocytes. Using mRNA analysis, we have shown that IL-25 stimulation does indeed decrease filaggrin synthesis in cultured keratinocytes. These results suggest that IL-25 produced by DCs could have a dual role as both an inducer of the T(H)2 response and as an inhibitor of filaggrin synthesis, thereby directly affecting skin barrier function in AD patients.

Expression of CCR2 on monocytes and macrophages in chronically inflamed skin in atopic dermatitis and psoriasis

Monocytes form a significant component of the inflammatory reaction taking place in the skin of atopic dermatitis and psoriasis. Chemokines are pivotal in mediating the attraction of leucocytes to sites of inflammation. The CC-chemokine, monocyte chemotactic protein 1 (MCP-1/CCL2), is expressed by keratinocytes in both atopic dermatitis and psoriasis. MCP-1 binds to the chemokine receptor CCR2 which is known to be expressed on monocytes and macrophages. We examined the expression of CCR2 on peripheral blood monocytes from patients with psoriasis (n=8) and atopic dermatitis (n=7) and found it to be expressed on approximately 90% of the cells, whereas monocytes from healthy donors had a significantly lower CCR2 expression (p<0.05). Skin biopsies from patients suffering from atopic dermatitis and psoriasis revealed that CCR2-positive cells expressed CD163, a marker for monocytes/macrophages. However, not all CD163-positive cells expressed CCR2, which could be interpreted as a mechanism for retaining the macrophages in the skin. Furthermore, we found that keratinocytes are able to express MCP-1, when stimulated with tumour necrosis factor-alpha and/or interferon-gamma in a dose-dependent manner. Thus MCP-1 and CCR2 interaction is likely of importance for the monocyte/macrophage trafficking of inflammatory skin disorders.

Regulation of caspase 14 expression in keratinocytes by inflammatory cytokines – a possible link between reduced skin barrier function and inflammation?

Abstract:  Caspase 14 is a unique member of the cysteinyl aspartate‐specific proteinase family. Its expression is confined primarily to cornified epithelium such as the skin. Caspase 14 has been associated with the processing of filaggrin monomers and the development of natural moisturising factors of the skin, and thus, it could be speculated that caspase 14 dysregulation is implicated in the development of an impaired skin barrier function. We have investigated the regulation of caspase 14 transcription in cultured primary keratinocytes following stimulation with a number of factors present in inflamed skin, including TH1‐ and TH2‐associated cytokines in addition to LPS and peptidoglycan. In particular, we found that TH2‐associated cytokines reduced the caspase 14 mRNA level significantly. Furthermore, we found that the expression of caspase 14 was reduced in skin biopsies from patients with atopic dermatitis (AD), psoriasis and contact dermatitis, further supporting a role for this kinase in inflammatory skin conditions. Hence, the regulation of caspase 14 levels provides a possible link between impaired skin barrier function and inflammatory reactions in skin diseases such as AD and may offer an explanation to the skin barrier dysfunction in inflamed skin lesions.

Increased Prevalence of Coronary Artery Disease in Severe Psoriasis and Severe Atopic Dermatitis

BACKGROUND Psoriasis and atopic dermatitis (AD) are immuno-inflammatory diseases that can result in lifelong systemic inflammation. Unlike AD, psoriasis has been associated with cardiovascular disease. The aim of this study was to examine the prevalence, severity, and subtype of coronary artery disease (CAD) in psoriasis and AD patients without known cardiovascular disease. METHODS Consecutively enrolled patients (psoriasis n = 58, AD n = 31) and retrospectively matched controls (n = 33) were examined using cardiac computed tomography angiography (CCTA) and assessed using an 18-segment model of the coronary tree. RESULTS The prevalence of a coronary artery calcium score >0 was 29.8% in psoriasis and 45.2% in AD, vs 15.2% in controls (P = .09 and P = .01, respectively). More patients with psoriasis had a coronary artery calcium score ≥100 (psoriasis 19.3%, controls 2.9%; P = .02). CCTA showed the presence of plaques in 38.2% of psoriasis patients and 48.1% of AD patients, vs 21.2% of controls (P = .08 and P = .03, respectively). Psoriasis was associated with an increased prevalence of significant coronary stenosis (stenosis >70%) (psoriasis 14.6%, controls 0%; P = .02) and 3-vessel coronary affection or left main artery disease (psoriasis 20%, controls 3%; P = .02), whereas AD was associated with mild (AD 40.7%, controls 9.1%; P = .005) single-vessel affection. CONCLUSIONS These findings suggest that psoriasis and AD are associated with an increased prevalence of CAD. Patients with psoriasis have an increased prevalence of severe CAD.

Expression of MDC/CCL22 and its receptor CCR4 in rheumatoid arthritis, psoriatic arthritis and osteoarthritis

The pathogenesis of rheumatoid arthritis (RA) and psoriatic arthritis (PsA) involves an abnormal chemokine regulation. The chemokine receptor CCR4 is necessary for T cell migration to the skin. We, therefore, studied if CCR4 and its ligand macrophage-derived chemokine (MDC/CCL22) could participate in spreading the disease between skin and joints by examining RA, PsA and osteoarthritis (OA) patients. In synovial fluid from RA and PsA patients we observed a significantly higher MDC/CCL22 level compared to OA patients. Additionally, the MDC/CCL22 protein was found to be elevated in RA and PsA plasma compared to OA and healthy volunteers. Flow cytometry revealed that most CD4(+)CCR4(+) lymphocytes also co-expressed CD45RO. Neither the MDC/CCL22 level nor the expression of CCR4 correlated to CRP. Immunohistochemistry of the RA and OA synovial membrane demonstrated CCR4 to be expressed by mononuclear cells and endothelial cells. Our results show that MDC/CCL22 is present within the synovial membrane of RA and OA patients and in high amount in the synovial fluid of patients with RA and PsA. This will enable migration of CCR4 expressing memory cells supporting that MDC/CCR4 could play a role in attracting skin specific memory T cells to the joints.

TSLP, IL-31, IL-33 and sST2 are new biomarkers in endophenotypic profiling of adult and childhood atopic dermatitis.

Recent years have seen growing interest in identifying new biomarkers in atopic dermatitis (AD) that could serve as indicators of disease severity and predictors of treatment response.

Kinetics and differential expression of the skin-related chemokines CCL27 and CCL17 in psoriasis, atopic dermatitis and allergic contact dermatitis

Abstract:  CCL27 and CCL17 are chemokines believed to be involved in the process of establishing the inflammatory infiltrate, characteristic for the various inflammatory skin diseases. The skin‐specific CCL27 binds the chemokine receptor‐10 (CCR10), and CCL17 is a chemokine receptor‐4 (CCR4) ligand. The purpose of our study was to characterize the expression of CCL27 and CCL17 in the inflammatory skin diseases: psoriasis, atopic dermatitis (AD) and acute allergic contact dermatitis (ACD) induced in nickel‐sensitive individuals. Surprisingly, our studies revealed a markedly decreased CCL27 mRNA and protein expression in psoriatic lesions compared with non‐lesional psoriatic skin. A minor CCL17 mRNA increase was measured in lesional psoriatic skin. No alterations were found in AD. In ACD, we found a pronounced (90‐fold) raise in CCL17 mRNA and a 50‐fold increase in CCL17 protein compared with normal skin. A kinetic ACD study of CCL17 expression showed the highest mean value 24 h after hapten application. Furthermore, we found the mRNA levels of CCR10 and CCR4 paralleling the results of their corresponding ligands. Overall, our principal findings were a distinct decrease in CCL27 in lesional psoriatic skin and a marked upregulation of CCL17 in ACD. These findings underscore the differential cutaneous T‐cell recruitment in different inflammatory diseases.