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We describe, to our knowledge, the first case of disseminated Mycobacterium genavense infection in a patient who was seronegative for human immunodeficiency virus. The patient, a 47-year-old woman, had been previously treated with immunosuppressive drugs for 9 months to control an unclassified immunologic disorder characterized by intermittent fever and inflammatory pulmonary, hepatic, and dermal infiltrates. Antemortem and postmortem examinations revealed the presence of numerous mycobacteria in the bone marrow, spleen, kidneys, and lungs; these organisms failed to grow in vitro and were identified as M. genavense by 16S rRNA gene sequencing. This case illustrates that systemic M. genavense infections are not restricted to patients with AIDS but can also occur in otherwise immunocompromised patients. [ABSTRACT FROM PUBLISHER]

Reports on a study which assessed the significance of the apolipoprotein E genotype as a risk factor for vascular Chlamydia pneumoniae (C. pneumoniae) infection. Incidence of C. pneumoniae infection; Frequency of the e2 allele; Interpretation of results.

Wegener’s granulomatosis (WG) is an autoimmune disease of as yet unknown etiology. To date it has remained obscure what causes WG or determines disease progression. Case reports suggest that viral infections such as cytomegalovirus (CMV) reactivation may contribute to disease flares. In this study we found a skewing of the phenotype of CMV-specific CD8+tet(ramer)+ T-cells in WG. A marked proportion of these cells displayed a late differentiated “effector memory” T-cell phenotype with decreased expression of CD28 and CD62L, and heterogeneous CD27 expression, features which were also seen in CD8+tet− T-cells in WG, but not in controls. Our results might reflect profound generalized changes in the CD8+ T-cell compartment also affecting virus-specific T-cell responses in WG. [Copyright &y& Elsevier]

Direct interaction of Chlamydiae with the endoplasmic reticulum (ER) is essential in intracellular productive infection. However, little is known about the interplay between Chlamydiae and the ER under cellular stress conditions that are observed in interferon gamma (IFN-γ) induced chlamydial persistent infection. ER stress responses are centrally regulated by the unfolded protein response (UPR) under the control of the ER chaperone BiP/GRP78 to maintain cellular homeostasis. In this study, we could show that the ER directly contacted with productive and IFN-γ-induced persistent inclusions of Chlamydia pneumoniae (Cpn). BiP/GRP78 induction was observed in the early phase but not in the late phase of IFN-γ-induced persistent infection. Enhanced BiP/GRP78 expression in the early phase of IFN-γ-induced persistent Cpn infection was accompanied by phosphorylation of the eukaryotic initiation factor-2α (eIF2α) and down-regulation of the vesicle-associated membrane protein-associated protein B. Loss of BiP/GRP78 function resulted in enhanced phosphorylation of eIF2α and increased host cell apoptosis. In contrast, enhanced BiP/GRP78 expression in IFN-γ-induced persistent Cpn infection attenuated phosphorylation of eIF2α upon an exogenous ER stress inducer. In conclusion, ER-related BiP/GRP78 plays a key role to restore cells from stress conditions that are observed in the early phase of IFN-γ-induced persistent infection., (© 2015 John Wiley & Sons Ltd.)

Recently, we have reported that, in addition to macrophages, also neutrophil granulocytes can phagocytose apoptotic neutrophils. Based on this finding, we hypothesized that "cannibalistic" neutrophils at sites of acute infection/inflammation play a major role in the clearance of apoptotic neutrophils. Since at sites of infection/inflammation neutrophils are exposed to microbial constituents and proinflammatory cytokines, in the present study we analyzed the effect of TLR-ligands and cytokines on the ability of neutrophils to phagocytose apoptotic cells in vitro. We observed that exposure to ligands of TLR2 (Malp2, Pam3CSK4), TLR4 (LPS), TLR7/TLR8 (R848), and TLR9 (ODN 2006) led to increased phagocytosis of apoptotic cells by neutrophils. In addition, proinflammatory cytokines such as TNF and GM-CSF strongly enhanced the uptake of apoptotic cells by neutrophils. These results support the hypothesis that neutrophils acquire the ability to phagocytose apoptotic cells at sites of acute infection/inflammation and thereby can contribute to the resolution of inflammation.

Epidermolysis bullosa acquisita is a prototypical organ-specific autoimmune disease caused by autoantibodies against type VII collagen of the dermal-epidermal junction. Although mechanisms of autoantibody-induced blister formation were extensively characterized, the initiation of autoantibody production in autoimmune blistering diseases is still poorly defined. In the current study, we addressed the role of T cells for the production of blister-inducing autoantibodies in mice immunized with type VII collagen. To detect autoreactive type VII collagen-specific T cells, lymph node cells from immunized SJL mice were stimulated in vitro with recombinant Ag, and their proliferation was measured by radioactive thymidine incorporation and flow cytometry analysis of CFSE-labeled cells. Interestingly, using synthetic peptides of the immunogen, partly different T and B cell epitopes in mice immunized with type VII collagen were demonstrated. In contrast to wild-type mice, immunization with type VII collagen of SJL athymic nude mice lacking T cells did not induce an autoimmune response and blistering phenotype. Importantly, SJL nude mice repleted with T cells from immunized wild-type mice showed a robust and durable autoantibody production resulting in subepidermal blistering disease in the recipients. Our present results demonstrate that T cells are required for the initiation of autoimmunity against type VII collagen in experimental epidermolysis bullosa acquisita and provide a basis for developing T cell-directed immunomodulatory strategies for this and related autoimmune diseases.

Neutrophil granulocytes are rapidly recruited from the bloodstream to the site of acute inflammation where they die in large numbers. Because release of toxic substances from dead neutrophils can propagate the inflammatory response leading to tissue destruction, clearance of dying inflammatory neutrophils has a critical function in the resolution of the inflammatory response. Apoptotic neutrophils are phagocytosed primarily by macrophages, provided these cells are present in adequate numbers. However, macrophages are rare at sites of acute inflammation, whereas the number of neutrophils can be extremely high. In the current study, in vitro experiments with human neutrophils were carried out to investigate whether neutrophils can ingest apoptotic neutrophils. We show that naïve granulocytes isolated from venous blood have a limited capacity to phagocytose apoptotic cells. However, exposure to activating stimuli such as LPS, GM-CSF and/or IFN-gamma results in enhanced phagocytosis of apoptotic cells. The efficient uptake of apoptotic cells by neutrophils was found to depend on the presence of heat labile serum factors. Importantly, the contact to or uptake of apoptotic cells inhibited neutrophil functions such as respiratory burst and the release of the proinflammatory cytokines TNF-alpha and interferon-inducible protein-10. Contact to apoptotic cells, however, induced the secretion of IL-8 and growth-related oncogene-alpha, which was independent of NF-kappaB and p38 MAPK but involved C5a and the ERK1/2 pathway. The data suggest that activated neutrophils participate in the clearance of apoptotic cells. In addition, because apoptotic cells inhibit proinflammatory functions of neutrophils, uptake of apoptotic cells by neutrophils contributes to the resolution of inflammation.

Polymorphonuclear neutrophil granulocytes (PMN) are primary antimicrobial effector cells of the innate immune system and serve to destroy invading pathogens. Although most ingested microorganisms are killed readily inside PMN, several obligate or facultative intracellular pathogens survive even in this hostile environment. Extension of the life span of neutrophils is a general escape mechanism of pathogens residing in PMN. However, after 2-4 days, even infected neutrophils become apoptotic and are phagocytosed by macrophages. Since microbes entering macrophages via the uptake of infected apoptotic PMN may survive and multiply in macrophages, apoptotic neutrophils can serve as "Trojan horses" for certain pathogens. Interfering with activating signaling pathways appears to be another potent mechanism by which intracellular microorganisms suppress cellular activation in neutrophils. In addition to provide a short overview of the topic, the present review aims to summarize our own findings regarding the interaction between human neutrophils and intracellular pathogens as well as regarding the disease promoting role of apoptotic cells after infection with Leishmania major.

Bacterial lipopeptides represent a group of bacterial compounds able to trigger the functions of cells of the innate immune response. Whereas diacylated lipopeptides are recognized by TLR2/6 dimers, triacylated lipopeptides were shown to act via TLR2/1 dimers. Although several previous studies dealt with the effect of the TLR2/1 ligand Pam(3)CysSK(4) on neutrophil granulocytes (PMN), it is still not clear whether TLR2/6 ligand lipopeptides can directly influence PMN functions. In the present study we used highly purified human neutrophils to investigate the direct effects of the diacylated mycoplasmal macrophage activating lipopeptide-2 (MALP-2) on the function of neutrophil granulocytes. After exposure to 10 ng/ml MALP-2 neutrophils acquired activated cell shape, secreted IL-8 and MIP-1beta and their phagocytic capacity was enhanced. Analysis of cell surface activation markers confirmed the activating effect of MALP-2, the expression of CD62L was downregulated whereas CD11b was upregulated on PMN after exposure to MALP-2. The constitutive apoptosis of PMN was inhibited after exposure to MALP-2. However, MALP-2 exerted only a short-term effect on the apoptosis of resting neutrophils, a longer lasting effect was observed after transendothelial migration. MALP-2 did not directly induce the production of reactive oxygen intermediates but primed PMN for a fMLP-induced oxidative burst. The migration of neutrophils was enhanced after treatment with MALP-2. This was due, however, to a chemokinetic rather than to a chemotactic effect. Pam(3)CysSK(4) also activated PMN, but in comparison to MALP-2, at higher concentrations. These findings suggest that diacylated lipopeptides are important microbial structures recognized by and acting on neutrophil granulocytes.

The obligate intracellular pathogen Leishmania major survives and multiplies in professional phagocytes. The evasion strategy to circumvent killing by host phagocytes and establish a productive infection is poorly understood. Here we report that the virulent inoculum of Leishmania promastigotes contains a high ratio of annexin A5-binding apoptotic parasites. This subpopulation of parasites is characterized by a round body shape, a swollen kinetoplast, nuclear condensation, and a lack of multiplication and represents dying or already dead parasites. After depleting the apoptotic parasites from a virulent population, Leishmania do not survive in phagocytes in vitro and lose their disease-inducing ability in vivo. TGF-beta induced by apoptotic parasites is likely to mediate the silencing of phagocytes and lead to survival of infectious Leishmania populations. The data demonstrate that apoptotic promastigotes, in an altruistic way, enable the intracellular survival of the viable parasites.

Introduction: Dynasilan is a fluoroalkylsilan that is able to interact with surface active centres on intraocular lenses (IOL), offering a new way for surface modification of different IOL materials. The purpose of this in vitro study was to investigate the influence of this new surface modification on the adherence of two typical endophthalmitis causing bacteria (Staphylococcus epidermidis, Propionibacterium acnes)., Materials and Methods: In a pilot experiment, the effect of Dynasilan coating on the adherence of S. epidermidis was tested on glass slides. Forty-two Dynasilan-modified and 42 unmodified IOL (14 PMMA, 14 silicone and 14 hydrogel) were incubated at 37 degrees C in brain heart infusion broth (10(8) CFU/ml) with either S. epidermidis for 24 h or with P. acnes for 1 h. Subsequently, the adherent bacteria were resuspended using ultrasonification at 35 kHz for 3x45 s. After dilution series and incubation at 37 degrees C on Petri dishes for 24 h and 3 days, respectively, the colonies were counted., Results: In the pilot experiment, a markedly lower number of adherent S. epidermidis was observed on Dynasilan-modified glass slides. Of all IOL materials incubated with S. epidermidis, those modified with Dynasilan showed a lower mean number of adherent bacteria (mean 1.37x10(7); SD 2.37x10(7)) than those untreated (2.43x10(7); SD 3.04x10(7)). IOLs incubated with P. acnes showed a significantly lower mean number of adherent bacteria of 2.51x10(4) (SD 2.71x10(4)) on Dynasilan-modified IOLs versus 6.27x10(4) (SD 7.70x10(4)) on untreated IOLs., Conclusion: The presented in vitro results indicate that Dynasilan surface modification is able to reduce the adherence of S. epidermidis and P. acnes on all IOL materials tested. Further studies regarding the stability of this modification and its biocompatibility must be performed.

Background: Polymorphonuclear neutrophil granulocytes (PMN) are phagocytes of the first line of antimicrobial defense. Previously we demonstrated that lipoteichoic acid (LTA) from Staphylococcus aureus (S. aureus) directly activates neutrophil granulocytes. Others have reported that exposure of S. aureus to beta-lactam antibiotics leads to LTA release. In the present study we addressed the question whether exposure of S. aureus to beta-lactam antibiotics or antibiotics of other groups results in the generation of PMN-stimulating activity and whether this activity can be attributed to LTA., Methods: S. aureus were exposed to flucloxacillin, a beta-lactam antibiotic or to the protein synthesis-inhibitors erythromycin and gentamicin, or to ciprofloxacin, a gyrase inhibitor. Supernatants of the antibiotic-treated bacteria were assayed for their LTA content and for their effect on PMN functions., Results: We observed that exposure of S. aureus to flucloxacillin and, to a lesser degree to ciprofloxacin, but not to erythromycin or gentamicin led to LTA release. Co-incubation of neutrophil granulocytes with LTA-containing supernatants led to PMN activation as assed by morphological changes, release of IL-8, delay of spontaneous apoptosis and enhanced phagocytic activity. Depletion of LTA from the supernatants markedly reduced their PMN-activating capacity., Conclusion: The findings suggest that, via the activation of PMN, antibiotic-induced LTA release from S. aureus leads to enhanced antimicrobial activity of the innate immune defense mechanisms.

Single-nucleotide polymorphisms (SNPs) are targets to discriminate intraspecies diversity of bacteria and to correlate a genotype with a potential pathotype. Quantification of polygenotypic populations supports this task for in vitro and in vivo applications. We present a novel assay capable of quantifying mixtures of two genotypes differing by only one SNP.

A 59-year-old female patient with a history of malignant lymphoma presented with symptoms of septicaemia. The skin of the extremities showed bullous, necrotizing plaques. Blood culture revealed Vibrio vulnificus as the causative organism. The infection was most likely acquired while swimming in the unusually warm Baltic Sea through inadvertent swallowing of sea water. The disease is rare in Europe. It is discussed in view of its typical clinical and histological picture.

Polymorphonuclear neutrophil granulocytes (PMNs) possess numerous effector mechanisms to kill ingested pathogens as the first line of defence. However, several microorganisms evade intracellular killing in neutrophils, survive and retain infectivity. There is increasing evidence that several pathogens even multiply within neutrophils. Taking Leishmania major as a prototypic intracellular pathogen, we suggest an evasion strategy that includes the manipulation of PMNs in such a way that the pathogens are able to use the granulocytes as host cells. The ability to survive and maintain infectivity in PMNs subsequently enables these organisms to establish productive infection. These organisms can use granulocytes as Trojan horses before they enter their definitive host cells, the macrophages.