Healing of cutaneous wounds requires a complex integrated network of repair mechanisms, including the action of newly recruited leukocytes. Using a skin repair model in adult humans, we investigated the role chemokines play in sequential infiltration of leukocyte subsets during wound healing. At day 1 after injury, the C-X-C chemokines IL-8 and growth-related oncogene alpha are maximally expressed in the superficial wound bed and are spatially and temporally associated with neutrophil infiltration. IL-8 and growth-related oncogene alpha profiles also correlate with keratinocyte migration and subsequently subside after wound closure at day 4. Macrophage infiltration reaches the highest levels at day 2 and is paralleled by monocyte chemoattractant protein-1 mRNA expression in both the basal layer of the proliferative epidermis at the wound margins and mononuclear cells in the wound area. Other monocyte-attracting chemokines such as monocyte chemoattractant protein-3, macrophage inflammatory protein-1alpha and -1beta, RANTES, and 1309 are undetectable. At day 4, perivascular focal lymphocyte accumulation correlates with strong focal expression of the C-X-C chemokines Mig and IP-10. Our results suggest that a dynamic set of chemokines contributes to the spatially and temporally different infiltration of leukocyte subsets and thus integrates the inflammatory and reparative processes during wound repair.

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DC vaccination could not be demonstrated to be more effective than DTIC chemotherapy in stage IV melanoma patients. The observed association of overall performance status and HLA haplotype with overall survival for patients treated by DC vaccination should be tested in future trials employing DC vaccines.

Regulation of chemokine-mediated leukocyte migration within inflammatory tissues is a complex event that cannot be mimicked and analyzed in vitro.Hapten-induced contact hypersensitivity (CHS) is a highly frequent, often occupationally related human skin disorder in industrialized countries with an enormous sociomedical impact. 1 Moreover, CHS is considered as a standard model for an antigen-specific, T-lymphocytemediated immune response. 2 This concept still holds true for the clinically nonapparent sensitization phase of CHS with antigen-processing and presentation by Langerhans cells and a consecutive T cell stimulation in the draining lymph node. However, there is increasing evidence that during the clinically visible and physically disturbing elicitation phase of CHS nonspecific hapten-induced proinflammatory effects precede or parallel the antigen-specific effect and are a conditio sine qua non for the vigorous inflammatory reactions. 2 In a mouse CHS model Grabbe and colleagues 3 demonstrated that nonspecific effects of epicutaneously applied haptens contribute to the elicitation of CHS. Proinflammatory irritative rather than antigen-specific properties of the hapten are furthermore responsible for the strict concentration-dependence of the effector phase of CHS. Therefore, it is tempting to speculate that such irritative properties of haptens promote inflammatory skin reactions via induction of proinflammatory cytokines, adhesion molecules, and chemoattractants. Accordingly, some contact allergens such as urushiol, the relevant hapten in poison ivy, and nickel sulfate have been demonstrated to directly induce inflammatory activation of keratinocytes resulting in expression of ICAM-1, interleukin (IL)-8, and/or tumor necrosis factor (TNF)-␣. 4 -6 In recent years, in particular chemokines have emerged as potent stimulators of effector cell accumulation and activation and are likely candidates to mediate leukocyte recruitment during elicitation of CHS. Since the description of IL-8 more than a decade ago, the supergene Supported by grants from the W. Sander-Stiftung (95.064.2) (to R. G.) and from the Deutsche Forschungsgemeinschaft (811/1-3) to M. G. M. G. and A. Trautmann contributed equally to this work.

Dense focal accumulation of neutrophils in the upper epidermis is a hallmark of psoriasis. Because the signals for neutrophil diapedesis and migration in vivo are not fully understood, psoriatic lesions with pronounced migration of neutrophils may serve as an important model for studying neutrophil chemotaxis. In this study, we present evidence for differential expression of the neutrophil chemotactic cytokines growth-related oncogene alpha, interleukin-8, and ENA-78 (epithelial cell derived and neutrophil-activating properties, 78 amino acids) in psoriatic lesions. In situ hybridization and immunohistochemistry of serial sections were employed to identify and microanatomically localize the cells producing these chemokines. High levels of focal interleukin-8 message were found to be expressed in the upper epidermis by keratinocytes and, most importantly, neutrophils themselves. Growth-related oncogene alpha transcripts were detected in clusters of keratinocytes of the upper epidermis at the same sites where interleukin-8 mRNA was abundant. In contrast to interleukin-8, growth-related oncogene alpha was also detected in the papillary dermis produced by vessel-associated cells. Sites of interleukin-8 and growth-related oncogene alpha mRNA expression were associated with infiltration of neutrophils. Interestingly, mRNA expression of the highly homologous chemokine ENA-78 was quiescent. In conclusion, our data indicate that growth-related oncogene alpha is an important chemoattractant for neutrophil diapedesis in vivo, whereas further migration of neutrophils and formation of micropustules appears to be influenced by the cooperative action of both growth-related oncogene alpha and interleukin-8.

IntroductionEndothelial cells, strategically located between blood and tissue compartments, play an important role for initiation and regulation of inflammatory events. Targeted by cytokines, such as tumor necrosis factor (TNF)-␣ or interleukin (IL)-1, or by bacterial lipopolysaccharides, they sequentially express adhesion molecules that mediate rolling, adhesion, and transmigration of blood leukocytes from the vessel lumen to the underlying tissue. Moreover, endothelial cells represent a cytokine source that allows them to communicate with other cells and organs. One important cytokine produced by endothelial cells is monocyte chemoattractant protein-1 (MCP-1), a member of the C-C subfamily of chemokines. It exhibits chemoattractive activity on monocytes and T lymphocytes (see Mantovani et al 1 and Baggiolini et al 2 for a review). MCP-1 expression by endothelial cells contributes to the establishment of a chemokine gradient that facilitates subset-specific recruitment of leukocytes to sites of inflammatory challenge. 3 Under flow conditions, MCP-1 triggers firm adhesion of rolling monocytes to E-selectin-expressing vascular endothelium, 4 thus contributing to recruitment of monocytes from the vascular compartment. Experimental models with mice lacking MCP-1 or its receptor, CCR2, or employing neutralizing antibodies against MCP-1 have established the prominent role of this chemokine in the pathogenesis of inflammatory disorders. [5][6][7][8] Induced expression of MCP-1 is strongly dependent on activation of the transcription factor NF-B, whereas basal transcription is regulated by SP-1. 9,10 Exposure of cells to TNF␣ results in the sequential activation of NF-B-inducing kinases (NIKs) and IB kinases ␣ and ␤ (IKK␣/␤). IKKs promote the critical step in which IB␣ phosphorylation finally leads to IB␣ degradation and p50/p65 translocation to the nucleus. Data from IKK knock-out mice suggest that the ␤ isoform of IKKs is the main mediator of pro-inflammatory signaling (see Karin 11 for a review). The transcriptional activity of nuclear NF-B factors is further modulated by protein modification and/or cofactor recruitment. 12,13 Thus, additional signaling events are required. Indeed several pathways have been shown to interfere with NF-B activation: Phosphatidylcholine-specific phospholipase C (PC-PLC), a component of the acidic sphingomyelin pathway, may promote the generation of ceramide upon TNF␣ stimulation and has been implicated in activation of NF-B. 14 Furthermore, members of the mitogen-activated protein (MAP) kinase family such as p38 were shown to be involved in TNF␣-mediated gene expression during inflammatory activation of 21 Recent studies demonstrate that activation of p38 even inhibits TNF␣-induced NF-B activation under certain conditions. 22 Thus, the cross-talk between the p38 MAP kinase cascade and the NF-B-activating pathway may occur at different levels, depending on the extracellular stimuli, the individual gene, and the cell type. We have recently demonstrated that p38 significantly contributes...

The abundance of macrophages in localized cutaneous leishmaniasis (LCL) and diffuse cutaneous leishmaniasis (DCL) lesions and differences in the composition of T cell subsets indicate involvement of cell-specific chemotaxis processes. The expression of macrophage chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1 alpha and -1 beta, RANTES (regulated on activation, normal T cell expressed and secreted), I-309, and interleukin-8 were investigated in lesions of patients with LCL or DCL. In LCL, high levels of MCP-1 and moderate levels of MIP-1 alpha were detected. In DCL, MCP-1 expression was significantly lower and MIP-1 alpha expression was predominant. All other chemokines investigated were minimally expressed or absent. These findings suggest that MCP-1 and MIP-alpha are responsible for the recruitment of macrophages and T cells in cutaneous leishmaniasis. The results show that self-healing LCL is associated with higher levels of MCP-1, which may stimulate macrophage microbicidal mechanisms, and nonhealing DCL is associated with higher levels of MIP-alpha.

Bullous pemphigoid is an inflammatory subepidermal blistering disease that is associated with auto- antibodies to the keratinocyte surface protein, BP180. In addition to the binding of autoantibodies, the infiltration of inflammatory cells is necessary for blister formation. Cytokines, including interleukin-6 and interleukin-8, have been implicated in the disease process of both human and experimental murine bullous pemphigoid. This study was aimed at testing the hypothesis that the binding of anti-BP180 antibodies to their target antigen triggers a signal transduction event that results in the secretion of these pro-inflammatory cytokines. Consistent with this hypothesis, treatment of cultured normal human epidermal keratinocytes with bullous pemphigoid IgG, but not control IgG, led to increased levels of interleukin-6 and interleukin-8, but not interleukin-1alpha, interleukin-1beta, tumor necrosis factor-alpha, interleukin-10, or monocyte chemoattractant protein-1, in the culture medium. This effect was concentration- and time-dependent and was abolished by depleting the bullous pemphigoid IgG of reactivity to two distinct epitopes on the BP180 NC16A domain. Upregulation of interleukin-6 and interleukin-8 was found at both protein and mRNA levels. In addition, bullous pemphigoid IgG did not induce the release of interleukin-6 and interleukin-8 from BP180-deficient keratinocytes obtained from a patient with generalized atrophic benign epidermolysis bullosa. These data indicate that bullous pemphigoid-associated autoantibodies to the human BP180 ectodomain trigger a signal transducing event that leads to expression and secretion of interleukin-6 and interleukin-8 from human keratinocytes.