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Summary Mucous membrane pemphigoid (MMP) is a pemphigoid disease with predominant mucous membrane involvement. It mainly affects the mucous membranes of the mouth, eyes, nose and pharynx, but also the larynx, trachea, esophagus, genital and perianal regions. The manifestation of the disease covers a wide spectrum from gingival erythema and single oral lesions to severe tracheal strictures that obstruct breathing and conjunctival scarring with marked visual impairment and, not infrequently, blindness. In addition to a clinical picture of predominant mucosal involvement, diagnosis is based on direct immunofluorescence of a peri‐lesional biopsy and serology. The main target antigen is BP180 (collagen XVII), and reactivity with laminin 332 is associated with malignancy in approximately 25 % of MMP patients. The treatment of MMP is challenging. On the one hand, due to the involvement of different mucous membranes, good interdisciplinary cooperation is required; on the other hand, due to the rarity of the disease, no randomized controlled clinical trials are available. The aim of this guideline is to present the clinical picture, including severity and scoring systems, and to give guidance for diagnosing and treating this complex disease. In MMP, interdisciplinary cooperation plays an essential role as well as the prompt diagnosis and initiation of adequate therapy in order to avoid irreversible damage to the mucous membranes with serious complications.

Background Current recommendations on the management of systemic sclerosis (SSc) suggest that autologous hematopoietic stem cell therapy (HSCT) can be a rescue therapy for patients with rapidly progressive SSc. Objectives To assess the safety and efficacy of HSCT for patients with SSc and to compare these with non-HSCT patients in a control cohort with adjusted risk factors. Methods A retrospective analysis of data from the multicentric German network for systemic scleroderma (DNSS) with 5000 patients with SSc. Control groups consisted of all patients with diffuse cutaneous (dc)-SSc (group A) and an adjusted high-risk cohort of male patients with Scl70-positive dc-SSc (group B). Results Eighty SSc patients received an HSCT 4.1 ± 4.8 years after SSc diagnosis. Among them, 86.3% had dc-SSc, 43.5% were males, and 71.3% were positive for Scl70 antibodies. The control group A (n=1513) showed a significant underrepresentation of these risk factors for mortality. When the survival of the control group B (n=240) was compared with the HSCT group, a lower mortality of the latter was observed instead. Within 5 years after HSCT, we observed an improvement of the mRSS from 17.6 ± 11.5 to 11.0 ± 8.5 (p=0.001) and a stabilization of the DLCO. We did not see differences in transplant-related mortality between patients who received HSCT within 3 years after SSc diagnosis or later. Conclusion Our analysis of real-life data show that the distribution of risk factors for mortality is critical when HSCT cohorts are compared with non-HSCT control groups.

ObjectivesSystemic sclerosis is a heterogeneous, multisystem disease. It can occur at any age, but most patients develop the disease between the age of 40 to 50 years. There is controversial evidence on whether/how the age at disease onset affects their clinical phenotype. We here investigate the relationship between age at disease onset and symptoms in a large cohort of SSc patients (lcSSc, dcSSc and SSc-overlap syndromes).MethodsClinical data of the registry of the German Network for Systemic Scleroderma including 3281 patients were evaluated and subdivided into three age groups at disease onset (60 years).ResultsAmong all SSc patients, 24.5% developed their first non-Raynaud phenomenon symptoms at the age 60 years), except for gastrointestinal and musculoskeletal involvement. No significant difference was found for the use of corticosteroids. However, significantly, fewer patients older than 60 years received immunosuppressive treatment.ConclusionIn this large registry, ∼25% of patients developed SSc at an age above 60 years with an increased frequency of lcSSc. In this age group, an onset of internal organ involvement was significantly accelerated across all three subsets. These findings suggest that, in the elderly cohort, more frequent follow-up examinations are required for an earlier detection of organ complications.

The vascular hypothesis of systemic sclerosis (SSc) would predict microvascular alterations should also affect anatomical regions like ocular microvasculature. The objective of this study was to evaluate retinal and choriocapillary vessel density (VD) in patients with definite SSc and very early disease of systemic sclerosis (VEDOSS) using optical coherence tomography angiography (OCTA). 22 eyes of 22 patients and 22 eyes of 22 healthy subjects were included in this study. Patients were classified into patients with definite SSc and patients with VEDOSS. VD data of the superficial OCT angiogram (OCTA-SCP), deep OCT angiogram (OCTA-DCP) and choriocapillaris (OCTA-CC) were analysed. VD in the OCTA-SCP and OCTA-CC was lower in patients with SSc (p 0.05). In VEDOSS patients, VD in the OCTA-CC was still reduced compared to controls (p 0.05). Correlation analysis revealed a positive correlation between nailfold capillaroscopy and VD of OCTA-CC (Spearman correlation coefficient (rSp) 0.456, p 0.05) and a negative correlation between skin score and VD of OCTA-SCP (p 0.05). Ocular perfusion seems to be impaired in patients with SSc and even VEDOSS. VD correlated with disease severity. OCTA could be a new useful diagnostic and predictive parameter for monitoring patients with different stages of the disease.

Background IgA vasculitis (IgAV) encompasses a systemic form involving kidneys, gut, skin, or joints, and a skin-limited form. One characteristic feature of systemic IgAV is deposition of galactose-deficient IgA1 (GD-IgA1) in kidneys (as in IgA nephropathy). The relevance of GD-IgA1 for cutaneous vasculitis is unknown. Objective We investigated whether GD-IgA1 is deposited perivascularly in systemic and also skin-limited IgAV and whether its serum levels differ between both forms. Methods In a case-control study, deposition of GD-IgA1 was analyzed immunohistochemically by KM55 antibody in skin biopsy specimens from 12 patients with skin-limited IgAV and 4 with systemic IgAV. GD-IgA1 levels were compared by enzyme-linked immunosorbent assay in sera from 15 patients each with skin-limited and systemic IgAV and from 11 healthy individuals. Results All biopsy samples from systemic IgAV, and also from skin-limited IgAV, revealed perivascular GD-IgA1 deposition. The average GD-IgA1 concentration in serum was significantly higher in systemic IgAV than in skin-limited IgAV, despite overlap between the groups. Limitations Although high GD-IgA1 levels may be predictive of systemic IgAV, patient numbers were too low to determine cutoff values for systemic versus skin-limited IgAV. Conclusion Perivascular GD-IgA1 deposition is a prerequisite for systemic and skin-limited IgAV; however, high GD-IgA1 levels in some patients with systemic IgAV suggest a dose-dependent effect of GD-IgA1 in IgAV.

Bullous pemphigoid (BP) is the most common autoimmune skin blistering disease characterized by autoimmunity against the hemidesmosomal proteins BP180, type XVII collagen, and BP230. To elucidate the genetic basis of susceptibility to BP, we performed the first genome-wide association study (GWAS) in Germans. This GWAS was combined with HLA locus targeted sequencing in an additional independent BP cohort. The strongest association with BP in Germans tested in this study was observed in the two HLA loci, HLA-DQA1*05:05 and HLA-DRB1*07:01. Further studies with increased sample sizes and complex studies integrating multiple pathogenic drivers will be conducted. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-01863-9.

Antinuclear antibodies (ANA) are a common diagnostic finding in patients with systemic autoimmune diseases. In patients with typical clinical symptoms, the determination of ANA is of both diagnostic and prognostic importance. However, if ANA were determined due to unspecific symptoms, the interpretation of ANA findings can be problematic. In these cases, misjudgements with severe consequences for the patients are possible. Many systemic autoimmune diseases have prominent early skin involvement and the dermatologist can be the first physician that such a patient sees. Therefore, knowledge of ANA diagnostics is important for dermatologists. Basic principles of autoantibody diagnostics, guidance for the interpretation of laboratory results and new developments are discussed in this overview.Antinukleäre Antikörper (ANA) sind ein typischer Laborbefund bei systemischen Autoimmunerkrankungen. Bei konkretem Verdacht auf diese Erkrankungen ist die Bestimmung der ANA sowohl diagnostisch als auch prognostisch wichtig. In der Praxis werden ANA allerdings oft aufgrund unspezifischer Symptome bestimmt, sodass die Interpretation eines positiven ANA-Nachweises häufig zu Problemen führt. Hier kann es zu Fehleinschätzungen mit schwerwiegenden Folgen für die Patienten kommen. Viele Kollagenosen manifestieren sich früh an der Haut. Entsprechende Patienten wenden sich daher entweder direkt an den Hautarzt oder werden von hausärztlichen oder rheumatologischen Kollegen zur dermatologischen Mitbeurteilung vorgestellt. Kenntnisse der ANA-Labordiagnostik sind aus diesem Grund für den Dermatologen wichtig. Daher werden in diesem Überblick grundlegende Prinzipien der Autoantikörperdiagnostik, Interpretationshilfen und aktuelle Neuerungen in der Diagnostik aus dermatologischer Perspektive zusammengefasst.

Background and objectives Erysipelas, caused by beta-hemolytic streptococci, and limited cellulitis, frequently caused by Staphylococcus aureus or other bacteria, are skin and soft tissue infections characterized by typical clinical signs. However, despite the therapeutical relevance they are often not differentiated (e.g in clinical trials). Erysipelas are efficiently treated with penicillin, while limited cellulitis is treated with more wide-spectrum antibiotics. This study investigates whether parameters such as CRP, blood counts or novel parameters like immature granulocytes could serve as biomarkers to distinguish between these entities. Patients and methods For this retrospective analysis 163 patients were included. We compared laboratory markers in patients with erysipelas (n = 68) to those with limited cellulitis (n = 41) of the leg. Both erysipelas and limited cellulitis were defined clinically, with an additional aspect for erysipelas being a prompt response to penicillin. Results Erysipelas were characterized by higher levels of inflammation. CRP and leukocyte counts are the best parameters to discriminate between both infections. A CRP value ≥ 3.27 mg/dl indicated the diagnosis of erysipelas with 75 % sensitivity and 73.2 % specificity. Conclusions Our results support the thesis that erysipelas and limited cellulitis are distinct infections as defined in the German guidelines and that an assessment of CRP and leukocytes is useful for differential diagnosis.

Imatinib mesylate (Glivec; Novartis AG, Basel, Switzerland) is a tyrosine kinase inhibitor which is used in the treatment of oncologic diseases like chronic myeloid leukemia and gastrointestinal stroma tumor (GIST). Among cutaneous side effects, bullous reactions are rare. The authors describe the case of a 66-year-old woman developing blistering and skin fragility on her hands, foot, lower legs, and back after intake of imatinib for treatment of GIST. Biopsy showed vacuolar alteration at the dermoepidermal junction (DEJ) associated with a few lymphocytes and a subepidermal blister. The upper papillary dermis below the vacuolar alteration and below the blister showed hyalinization and loss of elastic microfibrils. Direct immunofluorescence was negative for deposits of immunoglobulins. Immunofluorescence on cryosections revealed loss of laminin and collagen IV in vacuoles at the DEJ. Electron microscopy showed dissolution of lamina lucida and lamina densa of the basement membrane below as well as next to the vacuoles and blister. In conclusion, the authors present the first patient with GIST with blistering and skin fragility due to imatinib therapy. As a pathophysiological explanation the authors propose loss of laminin and collagen IV at the DEJ leading to basement membrane instability and blistering. This case also suggests additional features reminiscent of lichen sclerosus induced by imatinib, a drug which is actually known for its antifibrotic effects.

Clinical differentiation between herpes zoster and bacterial superficial skin and soft tissue infections of the face can be difficult. In addition, diagnosis can be complicated by bacterial superinfection of lesional herpes zoster. The aim of this study was to determine whether inflammatory parameters, such as C-reactive protein (CRP) and blood counts, might be reliable biomarkers to distinguish between skin and soft tissue infections and herpes zoster when the face is infected. The study data (multivariate analysis and area under the curve) identified CRP (0.880) and leukocytes (0.730) together as the parameters that best discriminate between skin and soft tissue infections and herpes zoster. A CRP threshold ≥ 2.05 mg/dl indicated a diagnosis of skin and soft tissue infection with a sensitivity of 80% and specificity of 83.8%. For leukocytes ≥ 7.3×109/l, diagnosis of skin and soft tissue infection had a sensitivity of 75% and specificity of 67.6%. Thus, when differential diagnosis is difficult, CRP and leukocytes should be determined, while parameters such as neutrophils or immature granulocytes do not add diagnostic value.

The early inflammatory skin micromilieu affects resistance in experimental infection with Leishmania major. We pursue the concept that macrophages, which take up parasites during early infection, exert decisive influence on the inflammatory micromilieu after infection. In order to analyze their distinctive potential, we identified differentially regulated genes of murine granuloma macrophages (GMΦ) from resistant and susceptible mice after their infection with metacyclic Leishmania major. We found induction of several cytokines in GMΦ from both strains and a stronger upregulation of the transcription factor aryl hydrocarbon receptor (AhR) in GMΦ from resistant mice. Using both an AhR agonist and antagonist we demonstrated that AhR is involved in Leishmania-induced production of TNF in macrophages. In vivo, single local injection of an AhR agonist in early lesions of susceptible mice caused an increased induction of Tnf and other cytokines in the skin. Importantly, local agonist treatment led to a reduction of disease severity, reduced parasite loads and a weaker Th2 response. Our results demonstrate that local activation of AhR has a beneficial effect in experimental leishmaniasis.

Uncontrolled inflammation is a leading cause of many clinically relevant diseases. Current therapeutic strategies focus mainly on immunosuppression rather than on the mechanisms of inflammatory resolution. Glucocorticoids (GCs) are still the most widely used anti-inflammatory drugs. GCs affect most immune cells but there is growing evidence for cell type specific mechanisms. Different subtypes of monocytes and macrophages play a pivotal role both in generation as well as resolution of inflammation. Activation of these cells by microbial products or endogenous danger signals results in production of pro-inflammatory mediators and initiation of an inflammatory response. GCs efficiently inhibit these processes by down-regulating pro-inflammatory mediators from macrophages and monocytes. On the other hand, GCs act on “naïve” monocytes and macrophages and induce anti-inflammatory mediators and differentiation of anti-inflammatory phenotypes. GC-induced anti-inflammatory monocytes have an increased ability to migrate toward inflammatory stimuli. They remove endo- and exogenous danger signals by an increased phagocytic capacity, produce anti-inflammatory mediators and limit T-cell activation. Thus, GCs limit amplification of inflammation by repressing pro-inflammatory macrophage activation and additionally induce anti-inflammatory monocyte and macrophage populations actively promoting resolution of inflammation. Further investigation of these mechanisms should lead to the development of novel therapeutic strategies to modulate undesirable inflammation with fewer side effects via induction of inflammatory resolution rather than non-specific immunosuppression.

International audience; Many pathogens, ranging from viruses to multicellular parasites, promote expansion of MDSCs, which are myeloid cells that exhibit immunosuppressive features. The roles of MDSCs in infection depend on the class and virulence mechanisms of the pathogen, the stage of the disease, and the pathology associated with the infection. This work compiles evidence supported by functional assays on the roles of different subsets of MDSCs in acute and chronic infections, including pathogen-associated malignancies, and discusses strategies to modulate MDSC dynamics to benefit the host.

Raynaud's phenomenon (RP) is a painful vasospasm of small arteries, localised in fingers and toes. Typically these body parts turn white (ischemia), then blue (deoxygenation) and then red (reperfusion). Two different types of RP exist: the common primary RP without underlying disease and the rare secondary RP, mostly associated with rheumatoid diseases such as systemic sclerosis. Thus, the dermatologist has to be aware of this condition. In this article the clinical criteria, differential diagnoses, diagnostic considerations and treatment options are discussed.

Objective.Vasculopathy is a key factor in the pathophysiology of systemic sclerosis (SSc) and the main cause for Raynaud phenomenon (RP), digital ulcers (DU), and/or pulmonary arterial hypertension (PAH). It is so far unknown how patients with SSc are treated with vasoactive agents in daily practice. To determine to which extent patients with SSc were treated with different vasoactive agents, we used data from the German Network for Systemic Scleroderma registry.Methods.The data of 3248 patients with SSc were analyzed.Results.Patients were treated with vasoactive drugs in 61.1% of cases (1984/3248). Of these, 47.6% received calcium channel inhibitors, followed by 34.2% treated with angiotensin-converting enzyme (ACE) inhibitors, 21.1% treated with intravenous (IV) prostanoids, 10.1% with pentoxifylline, 8.8% with angiotensin 1 receptor antagonists (AT1RA), 8.7% with endothelin 1 receptor antagonists (ET1RA), 4.1% with phosphodiesterase type 5 (PDE5) inhibitors, and 5.3% with others. Patients with RP received vasoactive therapy in 63.3% of cases, with DU in 70.1%, and with PAH in 78.2% of cases. Logistic regression analysis revealed that patients with PAH were significantly more often treated with PDE5 inhibitors and ET1RA, and those with DU with ET1RA and IV prostanoids. In addition, 41.8% of patients were treated with ACE inhibitors and/or AT1RA. Patients registered after 2009 received significantly more often ET1RA, AT1RA, and IV prostanoids compared with patients registered prior to 2005.Conclusion.These data clearly indicate that many patients with SSc do not yet receive sufficient vasoactive therapy. Further, in recent years, a marked change of treatment regimens can be observed.

ObjectiveTo report 3 patients with relapsing-remitting multiple sclerosis (RRMS) showing vitiligo after treatment with alemtuzumab.MethodsRetrospective case series including flow cytometric analyses and T-cell receptor (TCR) sequencing of peripheral blood mononuclear cells.ResultsWe describe 3 cases of alemtuzumab-treated patients with RRMS developing vitiligo 52, 18, and 14 months after alemtuzumab initiation. Histopathology shows loss of epidermal pigmentation with absence of melanocytes and interface dermatitis with CD8+ T-cell infiltration. Also compatible with pathophysiologic concepts of vitiligo, peripheral blood mononuclear cells of one patient showed high proportions of CD8+ T cells with an activated (human leukocyte antigen–DR+), memory (CD45RO+), and type 1 cytokine (interferon-γ + tumor necrosis factor–α) phenotype at vitiligo onset compared to a control cohort of alemtuzumab-treated patients with RRMS (n = 30). Of note, analysis of CD8 TCR repertoire in this patient revealed a highly increased clonality and reduced repertoire diversity compared to healthy controls and treatment-naive patients with RRMS. We observed a predominance of single clones at baseline in this patient and alemtuzumab treatment did not substantially affect the proportions of most abundant clones over time.ConclusionThe 3 cases represent a detailed description of vitiligo as a T-cell-mediated secondary autoimmune disease following alemtuzumab treatment. The prevailing concept of unleashed B-cell responses might therefore not cover all facets of alemtuzumab-related secondary autoimmunity. Mechanistic studies, especially on TCR repertoire, might help clarify the underlying mechanisms.

Human and murine studies showed that GM-CSF exerts beneficial effects in intestinal inflammation. To explore whether GM-CSF mediates its effects via monocytes, we analyzed effects of GM-CSF on monocytes in vitro and assessed the immunomodulatory potential of GM-CSF–activated monocytes (GMaMs) in vivo. We used microarray technology and functional assays to characterize GMaMs in vitro and used a mouse model of colitis to study GMaM functions in vivo. GM-CSF activates monocytes to increase adherence, migration, chemotaxis, and oxidative burst in vitro, and primes monocyte response to secondary microbial stimuli. In addition, GMaMs accelerate epithelial healing in vitro. Most important, in a mouse model of experimental T cell–induced colitis, GMaMs show therapeutic activity and protect mice from colitis. This is accompanied by increased production of IL-4, IL-10, and IL-13, and decreased production of IFN-γ in lamina propria mononuclear cells in vivo. Confirming this finding, GMaMs attract T cells and shape their differentiation toward Th2 by upregulating IL-4, IL-10, and IL-13 in T cells in vitro. Beneficial effects of GM-CSF in Crohn’s disease may possibly be mediated through reprogramming of monocytes to simultaneously improved bacterial clearance and induction of wound healing, as well as regulation of adaptive immunity to limit excessive inflammation.

Antiphospholipid antibody syndrome (APS) is a systemic autoimmune disease characterized by arterial and/or venous thrombosis, recurrent abortions and detection of antiphospholipid antibodies. In fulminant cases, involvement of multiple organs can lead to significant morbidity and even fatal outcomes, so that a rapid, interdisciplinary treatment is needed. Here, we describe the case of a 39-year-old woman with a severe hard-to-treat APS with arterial occlusion and progressive skin necrosis, who was successfully treated with a combination therapy with plasmapheresis and rituximab. The treatment led to complete remission of the skin lesions for over a year. Clinical response correlated with a long-lasting reduction of antiphospholipid antibodies and B-cell depletion. This case demonstrates the use of antiphospholipid antibodies for monitoring APS-activity and shows that this severe vascular disease requires rigorous therapeutic approaches.

The protozoan parasite Leishmania (Viannia) braziliensis is one of the main causes of cutaneous and mucocutaneous leishmaniasis in South America. Here, we describe three cases of L. (V.) braziliensis infection which were acquired during travelling in Bolivia, Peru or Paraguay and illustrate the phenotypic heterogeneity and therapeutic complexity of the disease. Two patients presented with unusual clinical manifestations, i.e. with prominent regional lymphadenopathy ("bubonic leishmaniasis") and with simultaneously emerged skin and mucosal lesions, respectively. Both patients insufficiently responded to oral treatment with miltefosine; resolution of the lesions was only achieved after a course of intravenous liposomal amphotericin B.

Background: Atopic dermatitis (AD) is a chronic disease characterized by periods of remission and relapse. Therapeutic objectives for AD should be to quickly reduce disease symptoms by targeting pathophysiological pathways, and to provide long-term management by reducing recurrences. Objective: Calcineurin inhibitors currently appear to be one of the most promising alternative systemic and topical compounds to treat AD. This review focuses on new developments of topical calcineurin inhibitors, therapeutic regimens including long-term management, and prophylaxis of AD. Methods: The published clinical studies that present data on treatment of AD with calcineurin inhibitors were assessed. Results/conclusion: Topical calcineurin inhibitors such as tacrolimus and pimecrolimus provide an effective treatment for AD. They are useful for long-term management and prophylaxis of AD. Safety concerns with regard to increased risk for lymphomas or skin cancer could not be confirmed but will remain under careful observa...

Phagocyte-derived S100 proteins are endogenous activators of innate immune responses. S100A12 binds to the receptor for advanced glycation end-products, while complexes of S100A8/S100A9 (myeloid-related proteins, MRP8/14; calprotectin) are ligands of toll-like receptor 4. These S100 proteins can be detected in stool. In the present study we analyse the release of S100A12 and MRP8/14 from intestinal tissue. Specimens from patients with Crohn’s disease (CD; n = 30), ulcerative colitis (UC; n = 30), irritable bowel syndrome (IBS; n = 30) or without inflammation (n = 30) were obtained during endoscopy. After 24 h culture, S100A12 and MRP8/14 were analysed in supernatants. Endoscopic, histological, laboratory and clinical disease activity measures were documented. We found an increased spontaneous release of S100A12 from tissue in inflammatory bowel disease (IBD). The release of S100A12 into the supernatants was 28-fold enhanced in inflamed tissue when compared to non-inflamed tissue (mean 46.9 vs. 1.7 ng/ml, p < 0.0001). In active CD, release of S100A12 and MRP8/14 was strongly dependent on localization, with little release from sites of active ileal inflammation compared to colonic inflammation. This difference was more pronounced for S100A12 than for MRP8/14. S100A12 and MRP8/14 provoked up-regulation of adhesion molecules and chemokines on human intestinal microvascular endothelial cells (HIMECs) isolated from normal colonic tissue. The direct release of phagocyte-derived S100 proteins from inflamed tissues may reflect secretion from infiltrating neutrophils (S100A12) and also monocytes or epithelial cells (MRP8/14). Via activation of pattern recognition receptors, these proteins promote inflammation in intestinal tissue. The enhanced mucosal release can explain the correlation of fecal markers with disease activity in IBD. Copyright  2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Lymph nodes (LNs) are important sentinel organs where antigen-presenting cells interact with T cells to induce adaptive immune responses. In cutaneous infection of mice withLeishmania major, resistance depends on the induction of a T-helper-cell-1 (Th1)-mediated cellular immune response in draining, peripheral LNs. We investigated whether draining, peripheral LNs are absolutely required for resistance againstL. majorinfection. We investigated the course of experimental leishmaniasis in wild-type (wt) mice lacking peripheral LNs (pLNs), which we generated by in utero blockade of membrane-bound lymphotoxin, and in mice lacking pLNs or all LNs due to genetic deletion of lymphotoxin ligands or receptors. wt mice of the resistant C57BL/6 strain without local skin-draining LNs were still able to generate specific T-cell responses, but this yielded Th2 cells. This switch to a Th2 response resulted in severe systemic infection. We also confirmed these results with mice lacking pLNs due to genetic depletion of lymphotoxin-β. The complete absence of LNs due to a genetic depletion of the lymphotoxin-β receptor also resulted in a marked deterioration of disease and a Th2 response. Thus, in the absence of pLNs, anL. major-specific Th2 response is induced in the remaining secondary lymphoid organs, such as the spleen and non-skin-draining LNs. This indicates a critical requirement for pLNs to induce protective Th1 immunity and suggests that whether Th1 or Th2 priming to the same antigen occurs depends on the site of the primary antigen recognition.

Glucocorticoids (GC) are still the most widely used immunosuppressive agents in clinical medicine. Surprisingly, little is known about the mechanisms of GC action on monocytes, although these cells exert pro- and anti-inflammatory effects. We have shown recently that GC induce a specific monocyte phenotype with anti-inflammatory properties in humans. We now investigated whether this also applies for the murine system and how this subset would relate to recently defined murine subtypes. After treatment with dexamethasone for 48 h, monocytes up-regulated scavenger receptor CD163 and Gr-1, down-regulated CX3CR1, and shared with human GC-treated monocytes functional features such as low adhesiveness but high migratory capacity. They specifically up-regulated anti-inflammatory IL-10, but not TGF-β, and in contrast to their human counterparts, they down-regulated IL-6. Although GC-induced monocytes down-regulated CX3CR1, a distinctive marker for classical/proinflammatory human and murine monocytes (CX3CR1loCCR2+Ly6Chi), they differed from this physiologically occurring subset, as they remained Ly6Cmed and unactivated (CD62 ligand++). In addition to their immunosuppressive effects, they were CD11b+Gr-1+ and expressed the IL-4Rα chain (CD124), a recently described, signature molecule of tumor-induced myeloid-derived suppressor cells (MDSC). We therefore generated murine MDSC in B16 melanoma-bearing mice and indeed found parallel up-regulation of CD11b+Gr-1+ and CD124 on GC-induced monocytes and MDSC. These data allow us to speculate that the GC-induced subtype shares with inflammatory monocytes the ability to migrate quickly into inflamed tissue, where they, however, exert anti-inflammatory effects and that similarities between GC-induced monocytes and MDSC may be involved in progression of some tumors observed in patients chronically treated with GC.

Aging has been associated with a decline in immunocompetence and resistance to infections, partially due to dysregulated NO production by macrophages and deficits in mounting Th2 cell responses. We wondered if these alterations would reverse the immune response in experimental leishmaniasis. Bone-marrow-derived macrophages from 2- and 18-month-old (senescent) C57BL/6 or BALB/c mice showed no marked difference in leishmanicidal functions. In vivo infections of resistant C57BL/6 mice withLeishmania majorrevealed no difference between senescent and young mice. However, among susceptible BALB/c mice, senescent animals showed less foot-pad swelling than young mice, and 40 to 60% of them even showed healing of ulcers, reduced parasite dissemination, and a Th1 cell response. These changes were associated with a spontaneous release of interleukin-12 (IL-12) by macrophages from aged but not from young mice. Since exogenous microbial stimulation can influence immune responses during aging, we also infected senescent mice who were raised under specific-pathogen-free (SPF) conditions. They showed neither resistance nor a Th1 response, but their macrophages still spontaneously released IL-12. A microbiological analysis showed that conventionally kept mice, but not SPF mice, had experienced infection with murine hepatitis virus (MHV), an infection associated with a Th1-like response. We conclude that for the reversal of the immune response, senescence is the premier requirement but needs to be completed by another mandatory event such as microbial stimulation. One of the age-related, but not environment-related, factors is the spontaneous release of IL-12 by macrophages, while confrontation with MHV presents an environment-related difference, with both having the potential to support a Th1 response.

Glucocorticoids (GC) are the most widely used immunosuppressive agents in clinical medicine. Recently we showed that GC enhance survival of human monocytes and induce a specific anti-inflammatory monocyte subtype which actively induces resolution of inflammation. We now investigated if cytokines IL-4, IL-6 and IL-10, which, like GC, have mostly anti-inflammatory effects on macrophages, would have GC-like effects also on monocytes. Human monocytes were stimulated with either cytokine, GC or combination thereof, and resulting effects on apoptosis, adherence, migration, phagocytosis, ROS production and cell surface phenotype were determined. We found that IL-4, IL-6, and IL-10 had either less or different effects on various anti-inflammatory functions of monocytes compared to GC. As such, IL-4 and IL-6 alone did not delay apoptosis while IL-10 even enhanced it. However, IL-6 or IL-10 increased GC-mediated protection from apoptosis when applied together with GC. Thus, the potential of GC to induce anti-inflammatory human monocytes is unique and not mimicked by the investigated cytokines. However, IL-6 and IL-10 amplify GC-induced anti-inflammatory and pro-resolution mechanisms by enhancing survival of GC-induced monocytes and thus sustaining their function. This combined effect of GC and cytokines could be important for the physiological switch from amplification towards resolution phase of inflammation.

Active resolution of inflammation is a previously unrecognized process essential for tissue homeostasis. Monocytes play a pivotal role in the generation as well as resolution of inflammation. Glucocorticoids (GCs) are widely used anti-inflammatory agents. We demonstrate that GCs exhibit antiapoptotic effects in monocytes resulting in differentiation to an anti-inflammatory phenotype. The molecular basis of this novel antiapoptotic effect is a prolonged activation of the extracellular signal regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway resulting in inhibition of caspase activities and expression of antiapoptotic genes via activation of c-Myc. We identified up-regulation and activation of A3 adenosine receptor (A3AR) as the initial trigger of this antiapoptotic pathway. In summary, we deciphered a novel molecular pathway promoting survival of anti-inflammatory monocytes. Specific activation of A3AR or its downstream signaling pathways may thus be a novel strategy to modulate inflammation in autoimmune disorders with fewer side effects via induction of inflammatory resolution rather than immunosuppression.

S100A8 and S100A9 are novel members of the group of damage–associated molecular pattern molecules (DAMP) which are early amplifiers of innate immune responses to tissue damage or danger signals. The innate immune system is crucial for initiation and amplification of inflammatory responses. During this process, phagocytes are activated by PAMPs that are recognized by PRRs. Phagocytes are also activated by endogenous danger signals called alarmins or DAMPs via partly specific, partly common PRRs. Two members of the S100 protein family, S100A8 and S100A9, have been identified recently as important endogenous DAMPs. The complex of S100A8 and S100A9 (also called calprotectin) is actively secreted during the stress response of phagocytes. The association of inflammation and S100A8/S100A9 was discovered more than 20 years ago, but only now are the molecular mechanisms involved in danger signaling by extracellular S100A8/S100A9 beginning to emerge. Taking advantage of mice lacking the functional S100A8/S100A9 complex, these molecules have been identified as endogenous activators of TLR4 and have been shown to promote lethal, endotoxin–induced shock. Importantly, S100A8/S100A9 is not only involved in promoting the inflammatory response in infections but was also identified as a potent amplifier of inflammation in autoimmunity as well as in cancer development and tumor spread. This proinflammatory action of S100A8/S100A9 involves autocrine and paracrine mechanisms in phagocytes, endothelium, and other cells. As a net result, extravasation of leukocytes into inflamed tissues and their subsequent activation are increased. Thus, S100A8/S100A9 plays a pivotal role during amplification of inflammation and represents a promising new therapeutic target.

Giant cell arteritis (GCA) is a systemic vasculitis associated with severe complications such as loss of vision and, rarely, scalp necrosis. We present a patient with GCA who had bilateral scalp necrosis and an erythrocyte sedimentation rate of only 21 mm after the first hour. Therapy with systemic steroids, which were slowly tapered over 1 year, led to secondary wound healing without recurrence. As there are no systematic reviews on the occurrence of scalp necrosis in patients with GCA, we performed a literature research and meta-analysis and discovered 78 cases published between 1946 and 2007. Analysis of the data revealed that GCA with scalp necrosis is associated with a higher incidence of vision loss (32%) and other visual defects (37.3%) than GCA without scalp necrosis (visual disturbances in up to 20%). GCA with scalp necrosis is also associated with an increased mortality (standard mortality ratio [SMR], 4.2) in contrast to GCA without scalp necrosis, which has no significantly higher mortality than age-matched controls (SMR 0.8-1.034). In patients with scalp necrosis, the diagnosis of GCA was made about 1 month later than in patients without scalp necrosis, and scalp necrosis was never reported to occur after onset of therapy with glucocorticoids. Thus, for reasons beyond potential loss of vision, physicians should be alert for symptoms of GCA as only timely diagnosis and immediate therapy may prevent serious complications and increased mortality.

We have previously reported that 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3) can selectively suppress key functions of interferon-gamma (IFN-gamma) activated macrophages. To further explore this mechanism for its relevance in vivo, we investigated an infection model that crucially depends on the function of IFN-gamma activated macrophages, the infection with the intracellular protozoan Leishmania major. 1Alpha,25(OH)2D3 treatment of L. major infected macrophages demonstrated a vitamin D receptor (Vdr) dependent inhibition of macrophage killing activity. Further analysis showed that this was a result of decreased production of nitric oxide by 1alpha,25(OH)2D3-treated macrophages due to Vdr-dependent up-regulation of arginase 1 expression, which overrides NO production by Nos2. When analyzing the course of infection in vivo, we found that Vdr-knockout (Vdr-KO) mice were more resistant to L. major infection than their wild-type littermates. This result is in agreement with an inhibitory influence of 1alpha,25(OH)2D3 on the macrophage mediated host defense. Further investigation showed that Vdr-KO mice developed an unaltered T helper cell type 1 (Th1) response on infection as indicated by normal production of IFN-gamma by CD4+ and CD8+ T cells. Therefore, we propose that the absence of 1alpha,25(OH)2D3-mediated inhibition of macrophage microbicidal activity in Vdr-KO mice results in increased resistance to Leishmania infection.

Monocytes and macrophages may either promote or down-regulate inflammatory reactions depending on their state of activation. The effects of glucocorticoids (GCs), the most widely used immunosuppressive drugs, on monocytes are currently not well defined. By analyzing the GC-induced expression pattern in human monocytes by microarray technology, we identified for the first time GC-dependent regulation of 133 genes, including anti-inflammatory molecules such as adenosine A3 receptor, CD1d, and IL-1 receptor II. The results were independently confirmed by real-time polymerase chain reaction (PCR) and flow cytometry. Functional clustering of GC-regulated genes indicated induction of monocytic properties such as phagocytosis and motility as well as repression of adhesion, apoptosis, and oxidative burst. These predictions were confirmed by independent functional assays. GCs up-regulate fMLP receptors and specifically promote chemotaxis to this chemoattractant. Furthermore, GCs promote survival of an anti-inflammatory monocytic phenotype in inflammatory reactions, probably by inhibition of apoptosis because of oxidative stress. GCs limit tissue damage because of induction of antioxidative properties and high capacity for phagocytosis of proinflammatory agents. Thus, GC treatment did not cause a global suppression of monocytic effector functions but results in differentiation of a specific anti-inflammatory phenotype which seems to be actively involved in resolution of inflammatory reactions.

The intent of this study was to identify genes of which expression during acute rejection is associated with progression to chronic allograft nephropathy using gene expression profiling. Ten patients who had graft loss through chronic allograft nephropathy (progression [PR] group) and 18 patients who had stable graft function over time (nonprogression [NP] group) were studied. Rejection severity and extent of infiltrating leukocytes in acute rejection biopsies were similar for both groups. Microarray analysis and real-time PCR validation showed that surfactant protein-C (SP-C), S100 calcium-binding protein A8 (S100A8), S100A9, and beta-globin levels distinguished the two groups. Relationship between expression of B cell markers and prognosis was also examined. Location in the graft of the protein and mRNA expression of candidate genes was investigated. The prognostic value of mRNA transcripts was tested in an independent cohort of 43 rejection biopsies. mRNA and protein expression of S100A8 and S100A9 in infiltrating cells was significantly higher in the NP group compared with the PR group. Expression of SP-C was four-fold higher in the PR group and was detected in glomeruli. No association between B cell clusters and outcome was found. In the second group of acute rejection biopsies, SP-C mRNA levels predicted renal function course beyond 6 mo in multivariate analysis. Relatively high expression of S100A8 and S100A9 during acute rejection is associated with a favorable prognosis, and high SP-C expression is associated with an unfavorable prognosis. Messenger RNA transcripts complement the biopsy in the prediction of graft function deterioration.

Systemic lupus erythematosus T cells display decreased amounts of TCR ζ mRNA that results in part from limited binding of the transcriptional enhancer Elf-1 to the TCR ζ promoter. We have identified a new cis-binding site for the cAMP response element (CRE) modulator (CREM) on the TCR ζ promoter, centered on the −390 nucleotide. Transfection of T cells with an antisense CREM α plasmid reduced the binding of CREM to the TCR ζ promoter, as shown by chromatin and reporter chromatin immunoprecipitation assays, and enhanced the production of TCR ζ mRNA and protein. Mutagenesis of the −390 CRE site prevented the binding of CREM to the TCR ζ promoter. The mechanism of CREM-mediated repression appears to be chromatin dependent, because antisense CREM promotes the acetylation of histones on the TCR ζ promoter. Finally, we established an enhanced binding of CREM to the TCR ζ-chain promoter in systemic lupus erythematosus cells compared with control T cells. Our studies demonstrate that CREM α binds to the TCR ζ promoter and repress its activity.