Bacterial infections in lupus: Roles in promoting immune activation and in pathogenesis of the disease

Bacterial infection in patients with juvenile systemic lupus erythematosus and fever

BACKGROUND

Juvenile Systemic Lupus Erythematosus (JSLE) is a chronic, systemic autoimmune disease characterized by an increased susceptibility to infections. Fever in these patients can result from infection, heightened lupus activity, or a combination of both. Various clinical factors and biomarkers have been proposed to differentiate between infection and disease activity, but the results remain inconclusive. The Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2 k) is used to assess lupus activity in the presence or absence of infection. This study aimed to identify factors associated with bacterial infections in JSLE patients presenting with fever.

METHODS

A case-control study, approved by the institutional ethics committee, was conducted.

RESULTS

Bacterial infection was identified in 17% of 116 patients. Factors evaluated included immunomodulator use, high-dose steroids, renal replacement therapy, erythrocyte sedimentation rate (ESR) > 20, C-reactive protein (CRP) > 60 and > 90 mg/L, ferritin > 500 ng/mL, neutrophil-to-lymphocyte ratio (NLR) > 6, platelet-to-lymphocyte ratio (PLR) > 133, procalcitonin (PCT) > 0.9 ng/mL, lymphocyte-to-C4 ratio (LC4R) > 66.7, and ESR/CRP ratio < 2. In the adjusted model, PCT > 0.9 ng/mL retained significance with p < 0.01. Nagelkerke's R2 was 0.65, and the Hosmer-Lemeshow test indicated good internal validity.

CONCLUSIONS

Bacterial infection was detected in 17% of JSLE patients with fever. Procalcitonin > 0.9 ng/mL is a critical marker for identifying bacterial infection. NLR, PLR, ESR/CRP ratio, LC4R, and ferritin require further investigation to establish definitive cut-off values for differentiating bacterial infections from other infections or disease activity. Individual patient evaluation remains the recommended approach for diagnosis.

Impact of dosing strategy on clinical outcomes of patients with lupus nephritis initially treated with lower-than-recommended-dose cyclophosphamide

AIM

Cyclophosphamide is the mainstay treatment for patients with lupus nephritis (LN); it can be prescribed at lower doses than the recommended regimen to avoid side effects. We aimed to investigate the impact of cyclophosphamide dosing strategies on treatment outcomes of patients with LN initially treated with a lower-than-recommended dose.

METHODS

We retrospectively reviewed patients with proliferative LN (class III, IV, or mixed) initially treated with lower-than-recommended-dose cyclophosphamide. Patients who received a titrated dose of cyclophosphamide ≥0.5 g/m2 were categorized into the titrate group, while those who received doses <0.5 g/m2 were categorized into the non-titrate group. The primary outcome was primary renal response (PRR) at 52 weeks.

RESULTS

Of the 78 patients included, 47 were assigned to the titrate group and 31 to the non-titrate group. The titrate group had a higher proportion of PRR achievement (23 of 47 patients [48.9 %] vs. 7 of 31 patients [22.6 %] in the non-titrate group). After adjusting for potential confounders, a baseline urinary protein-to-creatinine ratio ≥3 g/g (OR, 0.3; 95 % CI, 0.1-0.9; P = 0.030), and titrating the dose of cyclophosphamide to ≥0.5 g/m2 (OR, 4.7; 95 % CI, 1.5-15.2; P = 0.010) were independent factors for PRR. Additionally, the titrate group had a lower rate of infection (8 of 47 patients [17.0 %] vs. 12 of 31 patients [38.7 %], respectively; OR, 0.3; 95 % CI, 0.1-0.9; P = 0.036) and death associated with LN (4 of 47 patients [8.5 %] vs. 8 of 31 patients [25.8 %], respectively; OR, 0.3; 95 % CI, 0.1-0.9; P = 0.047) compared with the non-titrate group. LN flare and the need for rescue therapy did not differ between the groups.

CONCLUSION

For patients with LN initially treated with lower-than-recommended-dose cyclophosphamide, titration of the cyclophosphamide dose ≥0.5 g/m2 was beneficial on renal response, while reducing infection leading to hospitalization and LN-associated death.

Comparison of Clinical and Laboratory Characteristics in Lupus Nephritis vs. Non-Lupus Nephritis Patients-A Comprehensive Retrospective Analysis Based on 921 Patients

Background: Lupus nephritis (LN) is an inflammation of the kidneys that is related to systemic lupus erythematosus (SLE). This study aimed to evaluate the differences in clinical and laboratory characteristics between LN and non-LN SLE patients. Methods: We conducted a retrospective analysis of medical records collected from SLE patients treated at the University Hospital in Kraków, Poland, from 2012 to 2022. All patients met the 2019 European League Against Rheumatism and the American College of Rheumatology (EULAR/ACR) criteria for SLE. Results: Among 921 SLE patients, LN was documented in 331 (35.94%). LN patients were younger at SLE diagnosis (29 vs. 37 years; p < 0.001) and had a male proportion that was 2.09 times higher than the non-LN group (16.62% vs. 7.97%; p < 0.001). They were more often diagnosed with serositis and hematological or neurological involvement (p < 0.001 for all). Hypertension and hypercholesterolemia occurred more frequently in these patients (p < 0.001 for both). LN patients exhibited a higher frequency of anti-dsDNA, anti-histone, and anti-nucleosome antibodies (p < 0.001 for all). Conversely, the non-LN group had a 1.24-fold (95% CI: 1.03-1.50; p = 0.021) increase in the odds ratio of having positive anti-cardiolipin IgM antibody results. LN patients were more frequently treated with immunosuppressants. The risk factors for experiencing at least three LN flares included female sex, younger age at the onset of LN or SLE, LN occurring later than SLE onset, the presence of anti-nucleosome or anti-dsDNA antibodies, and certain SLE manifestations such as myalgia, arthritis, proteinuria > 3.5 g/day, and pathological urinary casts in the urine sediment. Conclusions: LN patients differ from non-LN patients in the age of SLE diagnosis, treatment modalities, and autoantibody profile and have more frequent, severe manifestations of SLE. However, we still need more prospective studies to understand the diversity of LN and its progression in SLE patients.

The prevalence of neutropenia and association with infections in patients with systemic lupus erythematosus: a Swedish single-center study conducted over 14 years

Hematologic abnormalities are common manifestations of SLE, although neutropenia is observed less frequently and is not included in the classification criteria. Nonetheless, neutropenia is a risk factor for infections, especially those caused by bacteria or fungi. We aimed to evaluate the impact of neutropenia in SLE through a systematic investigation of all infections in a large cohort of well-characterized patients, focusing on neutropenia, lymphopenia, and hypocomplementemia. Longitudinal clinical and laboratory parameters obtained at visits to the Rheumatology Unit, Linköping University Hospital, and linked data on all forms of healthcare utilization for all the subjects included in our regional SLE register during 2008-2022 were assessed. Data regarding confirmed infections were retrieved from the medical records. Overall, 333 patients were included and monitored during 3,088 visits to a rheumatologist during the study period. In total, 918 infections were identified, and 94 occasions of neutropenia (ANC < 1.5 × 109/L) were detected in 40 subjects (12%). Thirty neutropenic episodes in 15 patients occurred in association with infections, of which 13 (43%) required in-hospital care, 4 (13%) needed intensive care, and 1 (3%) resulted in death. Bayesian analysis showed that patients with ≥ 1 occasion of neutropenia were more likely to experience one or more infections (OR = 2.05; probability of association [POA] = 96%). Both invasiveness (OR = 7.08; POA = 98%) and severity (OR = 2.85; POA = 96%) of the infections were significantly associated with the present neutropenia. Infections are common among Swedish SLE patients, 12% of whom show neutropenia over time. Importantly, neutropenia is linked to both the invasiveness and severity of infections. Awareness of the risks of severe infections in neutropenic patients is crucial to tailor therapies to prevent severe illness and death.

Microbial-influenced pesticide removal co-occurs with antibiotic resistance gene variation in soil-earthworm-maize system

Within human-influenced landscapes, pesticides cooccur with a variety of antibiotic stressors. However, the relationship between pesticides removal process and antibiotic resistance gene variation are not well understood. This study explored pesticide (topramezone, TPZ) and antibiotic (polymyxin E, PME) co-contamination using liquid chromatography-tandem mass spectrometry (LC-MS/MS), bacterial-16 S rRNA sequencing and high-throughput quantitative polymerase chain reaction (HT-qPCR) in a soil-earthworm-maize system. After incubating soil for 28 days with TPZ and PME (10 mg kg-1 dry weight), earthworm weight-gain, mortality rates, and maize plant weight-gain only differed slightly, but height-gain significantly decreased. PME significantly increased TPZ-removal in the soil. Accumulation of TPZ in earthworm's tissues may pose potential risks in the food chain. Combined pollution altered the microbial community structure and increased the abundance of functional microorganisms involved in aromatic compound degradation. Furthermore, maize rhizosphere can raise resistance genes, however earthworms can reduce resistance genes. Co-contamination increased absolute abundance of mobile genetic elements (MGEs) in bulk-soil samples, antibiotic resistance genes (ARGs) in skin samples and number of ARGs in bulk-soil samples, while decreased absolute abundance of transposase gene in bulk-soil samples and number of ARGs in rhizosphere-soil samples. Potential hosts harbouring ARGs may be associated with the antagonistic effect during resistance and detoxification of TPZ and PMB co-occurrence. These findings provide insights into the mechanism underlining pesticide removal regarding occurrence of ARGs in maize agroecosystem.

A Catastrophic Biodiversity Loss in the Environment Is Being Replicated on the Skin Microbiome: Is This a Major Contributor to the Chronic Disease Epidemic?

There has been a catastrophic loss of biodiversity in ecosystems across the world. A similar crisis has been observed in the human gut microbiome, which has been linked to "all human diseases affecting westernized countries". This is of great importance because chronic diseases are the leading cause of death worldwide and make up 90% of America's healthcare costs. Disease development is complex and multifactorial, but there is one part of the body's interlinked ecosystem that is often overlooked in discussions about whole-body health, and that is the skin microbiome. This is despite it being a crucial part of the immune, endocrine, and nervous systems and being continuously exposed to environmental stressors. Here we show that a parallel biodiversity loss of 30-84% has occurred on the skin of people in the developed world compared to our ancestors. Research has shown that dysbiosis of the skin microbiome has been linked to many common skin diseases and, more recently, that it could even play an active role in the development of a growing number of whole-body health problems, such as food allergies, asthma, cardiovascular diseases, and Parkinson's, traditionally thought unrelated to the skin. Damaged skin is now known to induce systemic inflammation, which is involved in many chronic diseases. We highlight that biodiversity loss is not only a common finding in dysbiotic ecosystems but also a type of dysbiosis. As a result, we make the case that biodiversity loss in the skin microbiome is a major contributor to the chronic disease epidemic. The link between biodiversity loss and dysbiosis forms the basis of this paper's focus on the subject. The key to understanding why biodiversity loss creates an unhealthy system could be highlighted by complex physics. We introduce entropy to help understand why biodiversity has been linked with ecosystem health and stability. Meanwhile, we also introduce ecosystems as being governed by "non-linear physics" principles-including chaos theory-which suggests that every individual part of any system is intrinsically linked and implies any disruption to a small part of the system (skin) could have a significant and unknown effect on overall system health (whole-body health). Recognizing the link between ecosystem health and human health allows us to understand how crucial it could be to maintain biodiversity across systems everywhere, from the macro-environment we inhabit right down to our body's microbiome. Further, in-depth research is needed so we can aid in the treatment of chronic diseases and potentially change how we think about our health. With millions of people currently suffering, research to help mitigate the crisis is of vital importance.

Particularités des complications infectieuses au cours de lupus érythémateux systémique

AIM

To describe characteristics of systemic lupus erythematosus (SLE) patients with infectious complications and to determine frequency, clinical and microbiological features and outcomes of reported infections.

METHODS

This is a descriptive, retrospective study conducted over an 11-year period at the Internal Medicine Department La Rabta Hospital Tunis, collecting medical records of SLE patients who had experienced infectious complications.

RESULTS

Fifty-six patients were included, consisting of 52 females and 4 males (gender ratio M/F= 0.07). The mean age at SLE diagnosis was 35±13.8 years. The mean duration of the disease was 4.8±3.1 years. A total of seventy-eight infections were documented. Infection revealed the disease in 12 patients (21%) and occurred after an average delay of 36 months [1-156 months] of SLE diagnosis. Forty-three patients (74%) were receiving corticosteroid therapy, associated in 37.5% of cases with immunosuppressive treatment. Urinary and pleuro-pulmonary infections were most common infectious sites. An infectious agent was identified in 59 cases (76%). Bacterial infections were the most common (76%), dominated by the enterobacteria pathogen agent. Viral infections (n=12) were mainly caused by varicella-zoster virus and cytomegalovirus. Five patients required intensive care. Twenty patients experienced a lupus flare during the infectious episode. The outcome was favorable in 52 (93%) patients. Three patients died, two due to septic shock caused by pulmonary infection in two cases and cutaneous infection in one patient. One patient died from a probable pulmonary embolism.

CONCLUSION

Infectious complications are responsible for significant morbidity and mortality during SLE. Hence the importance of early diagnosis and adequate management.

Gut microbiota and transcriptome response of earthworms (Metaphire guillelmi) to polymyxin B exposure

Polymyxin B (PMB) has received widespread attention for its use as a last-line therapy against multidrug-resistant bacterial infection. However, the consequences of unintended PMB exposure on organisms in the surrounding environment remain inconclusive. Therefore, this study investigated the effects of soil PMB residue on the gut microbiota and transcriptome of earthworms (Metaphire guillelmi). The results indicated that the tested doses of PMB (0.01-100 mg/kg soil) did not significantly affect the richness and Shannon's diversity index of the earthworm gut microbiota, but PMB altered its community structure and taxonomic composition. Moreover, PMB significantly affected Lysobacter, Aeromonas, and Sphingomonas in the soil microbiota, whereas Pseudomonas was significantly impacted the earthworm gut microbiota. Furthermore, active bacteria responded more significantly to PMB than the total microbial community. Bacterial genera such as Acinetobacter and Bacillus were highly correlated with differential expression of some genes, including up-regulated genes associated with folate biosynthesis, sulphur metabolism, and the IL-17 signalling pathway, and downregulated genes involved in vitamin digestion and absorption, salivary secretion, other types of O-glycan biosynthesis, and the NOD-like receptor signalling pathway. These results suggest that adaptation to PMB stress by earthworms involves changes in energy metabolism, their immune and digestive systems, as well as glycan biosynthesis. The study findings help elucidate the relationship between earthworms and their microbiota, while providing a reference for understanding the environmental risks of PMB.

Tsokos G. Infections in Patients with Systemic Lupus Erythematosus: The Contribution of Primary Immune Defects Versus Treatment-Induced Immunosuppression

Patients with systemic lupus erythematosus experience high rates of infections. The use of immunosuppressive drugs to treat the disease, along with the fact that both the innate and adaptive branches of the immune system are compromised, account for the development of infections. In this communication, we briefly discuss the aberrant function of the immune system in patients with systemic lupus erythematosus and review the occurrence of infections that have been reported in clinical trials conducted to develop new therapeutics. Understanding the immune dysfunction in patients with systemic lupus erythematosus and the appearance of infections while trying to control the disease using immunosuppressive or immunomodulatory drugs should help limit infections and mitigate the associated morbidity and mortality.

Toxicity and Impact of Silica Nanoparticles on the Configuration of Gut Microbiota in Immunodeficient Mice

Nanoparticles (NPs), having exceptional physicochemical and electrical characteristics with lower toxicity, have evolved as dynamic drug delivery carriers in living organisms. Potentially, the intragastric gavage of silica nanoparticles (SiNPs) affects gut microbiota profiles in immunodeficient mice. In this study, the impact of SiNPs of variable size and dosage was investigated in cyclophosphamide (Cy)-induced immunodeficient mice, specifically on their immune functions and gut microbiota, through physicochemical and metagenomic analysis. SiNPs of different sizes and doses were gavaged to Cy-induced immunodeficient mice for 12 days at an interval of 24 h to investigate their effects on immunological functions and the gut microbiome of mice. Our results showed that SiNPs had no significant toxicological effects on the cellular and hematological activities of immunodeficient mice. Furthermore, after the administration of different levels of SiNPs, no immune dysfunction was found in the immunosuppressed mice groups. However, gut-microbial studies and comparisons of characteristic bacterial diversity and compositions demonstrated that SiNPs significantly affect the abundance of different bacterial communities. LEfSe analysis revealed that SiNPs significantly increased the abundance of Lactobacillus, Sphingomonas, Sutterella, Akkermansia, and Prevotella, and potentially reduced Ruminococcus and Allobaculum. Thus, SiNPs significantly regulate and modify the configuration of the gut microbiota in immunodeficient mice. These dynamic variations in the intestinal bacterial community, abundance, and diversity provide new insight into the regulation and administration of silica-based NPs. This would be helpful for the further demonstration of the mechanism of action and prediction of the potential effects of SiNPs.

Serious Infection Rates Among Patients with Select Autoimmune Conditions: A Claims-Based Retrospective Cohort Study from Taiwan and the USA

INTRODUCTION

Serious infections are an important concern for patients with autoimmune conditions. We sought to estimate serious infection rates among patients with select autoimmune conditions relative to the general population in Taiwan and the USA.

METHODS

This retrospective cohort study estimated setting-specific standardized serious infection incidence rates and ratios among patients with systemic lupus erythematosus, including extra-renal lupus and lupus nephritis, rheumatoid arthritis and primary membranous nephropathy, compared with the general population using insurance claims for hospitalizations between 2000 and 2013. Multivariable Cox proportional hazard models were used to estimate adjusted hazard ratios for serious infections, adjusting for age, sex, index year, prior serious infection, comorbidities and medications.

RESULTS

In Taiwan, serious infection rates were 22.7, 28.7, 70.6, 43.4 and 215.3 per 1000 person-years among the general population and among cohorts of patients with primary membranous nephropathy, rheumatoid arthritis, extra-renal lupus and lupus nephritis, respectively. In the USA, serious infection rates were 2.6, 9.0, 15.6, 21.0 and 63.3 per 1000 person-years among the general population and among cohorts of patients with primary membranous nephropathy, rheumatoid arthritis, extra-renal lupus and lupus nephritis, respectively. Patients had significantly higher serious infection rates than the general population in both settings, largely driven by bacterial, respiratory, urinary tract and opportunistic infections. Patients with lupus nephritis had the highest burden of serious infections relative to the general population, with 7- to 25-fold higher adjusted hazard ratios in Taiwan and the USA, respectively.

CONCLUSION

This study identified a significant excess serious infection burden among patients with targeted autoimmune conditions compared with the general populations in Taiwan and the USA.

Benzo[a]pyrene Exposure Reduces Cell-Type Diversity and Stimulates Sex-Biased Damage Pathways in End Organs of Lupus-Prone Mice

Studies indicate that genetic factors only account for approximately thirty percent of all autoimmune diseases, while the rest of autoimmune pathogenesis is attributed to environmental factors including toxic chemicals. To understand if and how environmental pollutants trigger autoimmunity, we investigated the effect of benzo[a]pyrene (BaP) exposure on the development of autoimmune phenotypes in the lupus-prone MRL strain. The exposure of MRL mice to BaP over the course of 8 weeks before lupus onset resulted in total body weight loss in males, while marginal changes in anti-dsDNA levels occurred. Multi-organ analyses of BaP-treated and control MRL mice suggested that the kidney is a major organ directly affected by the metabolism of benzene-containing compounds, with increased expression of BaP-target genes including Cyp4b1 and Hao2. Intriguingly, spatial transcriptomic data showed that BaP caused a drastic reduction in cell-type diversity in both the kidneys and spleen of MRL mice. Further analysis of the molecular pathways affected suggested a sex-biased effect of BaP treatment, with the upregulated expression of angiogenesis genes in the lungs and an increased deposition of C3 in the kidneys of male mice. While SLE is more common in women, the disease is more severe in male patients, with an increased risk of disease progression to renal failure and lung cancer. Our results reveal sex-biased molecular pathways stimulated by BaP which may help explain the increased likelihood of end organ damage in males with lupus.

Lipidome modulation by dietary omega-3 polyunsaturated fatty acid supplementation or selective soluble epoxide hydrolase inhibition suppresses rough LPS-accelerated glomerulonephritis in lupus-prone mice

Introduction

Lipopolysaccharide (LPS)-accelerated autoimmune glomerulonephritis (GN) in NZBWF1 mice is a preclinical model potentially applicable for investigating lipidome-modulating interventions against lupus. LPS can be expressed as one of two chemotypes: smooth LPS (S-LPS) or rough LPS (R-LPS) which is devoid of O-antigen polysaccharide sidechain. Since these chemotypes differentially affect toll-like receptor 4 (TLR4)-mediated immune cell responses, these differences may influence GN induction.

Methods

We initially compared the effects of subchronic intraperitoneal (i.p.) injection for 5 wk with 1) Salmonella S-LPS, 2) Salmonella R-LPS, or 3) saline vehicle (VEH) (Study 1) in female NZBWF1 mice. Based on the efficacy of R-LPS in inducing GN, we next used it to compare the impact of two lipidome-modulating interventions, ω-3 polyunsaturated fatty acid (PUFA) supplementation and soluble epoxide hydrolase (sEH) inhibition, on GN (Study 2). Specifically, effects of consuming ω-3 docosahexaenoic acid (DHA) (10 g/kg diet) and/or the sEH inhibitor 1-(4-trifluoro-methoxy-phenyl)-3-(1-propionylpiperidin-4-yl) urea (TPPU) (22.5 mg/kg diet ≈ 3 mg/kg/day) on R-LPS triggering were compared.

Results

In Study 1, R-LPS induced robust elevations in blood urea nitrogen, proteinuria, and hematuria that were not evident in VEH- or S-LPS-treated mice. R-LPS-treated mice further exhibited kidney histopathology including robust hypertrophy, hyperplasia, thickened membranes, lymphocytic accumulation containing B and T cells, and glomerular IgG deposition consistent with GN that was not evident in VEH- or SLPS-treated groups. R-LPS but not S-LPS induced spleen enlargement with lymphoid hyperplasia and inflammatory cell recruitment in the liver. In Study 2, resultant blood fatty acid profiles and epoxy fatty acid concentrations reflected the anticipated DHA- and TPPU-mediated lipidome changes, respectively. The relative rank order of R-LPS-induced GN severity among groups fed experimental diets based on proteinuria, hematuria, histopathologic scoring, and glomerular IgG deposition was: VEH/CON< R-LPS/DHA ≈ R-LPS/TPPU<<< R-LPS/TPPU+DHA ≈ R-LPS/CON. In contrast, these interventions had modest-to- negligible effects on R-LPS-induced splenomegaly, plasma antibody responses, liver inflammation, and inflammation-associated kidney gene expression.

Discussion

We show for the first time that absence of O-antigenic polysaccharide in R-LPS is critical to accelerated GN in lupus-prone mice. Furthermore, intervention by lipidome modulation through DHA feeding or sEH inhibition suppressed R-LPS-induced GN; however, these ameliorative effects were greatly diminished upon combining the treatments.

Systemic Lupus Erythematosus Risk: The Role of Environmental Factors

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease. The etiology of SLE is multifactorial and includes potential environmental triggers, which may occur sequentially (the "multi-hit" hypothesis). This review focuses on SLE risk potentially associated with environmental factors including infections, the microbiome, diet, respirable exposures (eg, crystalline silica, smoking, air pollution), organic pollutants, heavy metals, and ultraviolet radiation.

Staphylococcus aureus skin colonization promotes SLE-like autoimmune inflammation via neutrophil activation and the IL-23/IL-17 axis

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by inflammation of various organs such as skin, kidneys, bones, and brain and the presence of autoantibodies. Although the cause of SLE is not completely understood, environmental factors, genetic susceptibility, hormone factors, and environmental factors are thought to play essential roles in the pathogenesis of SLE. Among environmental factors, the microbiota are linked to the development of different autoimmune diseases. The microbiota in the nasal cavity and gut are involved in SLE development, but the influence of skin microbiota is still unclear. Here, we demonstrated that epithelial cell-specific IκBζ-deficient (Nfkbiz^ΔK5) mice showed spontaneous skin inflammation with increased abundance of Staphylococcus aureus on the skin. When S. aureus was epicutaneously applied on Nfkbiz^ΔK5 mice, Nfkbiz^ΔK5 mice developed SLE-associated autoantibodies, anti-dsDNA antibodies, anti-Sm antibodies, and glomerulonephritis with IgG deposition. Epicutaneous S. aureus application significantly increased staphylococcal colonization on the skin of Nfkbiz^ΔK5 mice with reduced expression of several antimicrobial peptides in the skin. This staphylococcal skin colonization promoted caspase-mediated keratinocyte apoptosis and neutrophil activation, inducing the interleukin-23 (IL-23)/IL-17 immune response by activating dendritic cells and T cells. Furthermore, the subcutaneous administration of anti-IL-23p19 and anti-IL-17A antibodies alleviated the systemic autoimmune response. Together, these findings underscore epithelial-immune cross-talk disturbances caused by skin dysbiosis as an essential mediator inducing autoimmune diseases.

The characteristics of bacteremia among patients with acute febrile illness requiring hospitalization in Indonesia

Blood culturing remains the "gold standard" for bloodstream infection (BSI) diagnosis, but the method is inaccessible to many developing countries due to high costs and insufficient resources. To better understand the utility of blood cultures among patients in Indonesia, a country where blood cultures are not routinely performed, we evaluated data from a previous cohort study that included blood cultures for all participants. An acute febrile illness study was conducted from July 2013 to June 2016 at eight major hospitals in seven provincial capitals in Indonesia. All participants presented with a fever, and two-sided aerobic blood cultures were performed within 48 hours of hospital admission. Positive cultures were further assessed for antimicrobial resistance (AMR) patterns. Specimens from participants with negative culture results were screened by advanced molecular and serological methods for evidence of causal pathogens. Blood cultures were performed for 1,459 of 1,464 participants, and the 70.6% (1,030) participants that were negative by dengue NS1 antigen test were included in further analysis. Bacteremia was observed in 8.9% (92) participants, with the most frequent pathogens being Salmonella enterica serovar Typhi (41) and Paratyphi A (10), Escherichia coli (14), and Staphylococcus aureus (10). Two S. Paratyphi A cases had evidence of AMR, and several E. coli cases were multidrug resistant (42.9%, 6/14) or monoresistant (14.3%, 2/14). Culture contamination was observed in 3.6% (37) cases. Molecular and serological assays identified etiological agents in participants having negative cultures, with 23.1% to 90% of cases being missed by blood cultures. Blood cultures are a valuable diagnostic tool for hospitalized patients presenting with fever. In Indonesia, pre-screening patients for the most common viral infections, such as dengue, influenza, and chikungunya viruses, would maximize the benefit to the patient while also conserving resources. Blood cultures should also be supplemented with advanced laboratory tests when available.

Gut microbiota in systemic lupus erythematosus patients and lupus mouse model: a cross species comparative analysis for biomarker discovery

An increasing number of studies have provided strong evidence that gut microbiota interact with the immune system and stimulate various mechanisms involved in the pathogenesis of auto-immune diseases such as Systemic Lupus Erythematosus (SLE). Indeed, gut microbiota could be a source of diagnostic and prognostic biomarkers but also hold the promise to discover novel therapeutic strategies. Thus far, specific SLE microbial signatures have not yet been clearly identified with alteration patterns that may vary between human and animal studies. In this study, a comparative analysis of a clinically well-characterized cohort of adult patients with SLE showed reduced biodiversity, a lower Firmicutes/Bacteroidetes (F/B) ratio, and six differentially abundant taxa compared with healthy controls. An unsupervised clustering of patients with SLE patients identified a subgroup of patients with a stronger alteration of their gut microbiota. Interestingly, this clustering was strongly correlated with the disease activity assessed with the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score (p = 0.03, odd ratio = 15) and the identification of specific alterations involving the F/B ratio and some different taxa. Then, the gut microbiota of pristane-induced lupus and control mice were analyzed for comparison with our human data. Among the six differentially abundant taxa of the human disease signature, five were common with our murine model. Finally, an exhaustive cross-species comparison between our data and previous human and murine SLE studies revealed a core-set of gut microbiome species that might constitute biomarker panels relevant for future validation studies.

Loss of Gut Barrier Integrity In Lupus

Systemic Lupus Erythematosus is a complex autoimmune disease and its etiology remains unknown. Increased gut permeability has been reported in lupus patients, yet whether it promotes or results from lupus progression is unclear. Recent studies indicate that an impaired intestinal barrier allows the translocation of bacteria and bacterial components into systemic organs, increasing immune cell activation and autoantibody generation. Indeed, induced gut leakage in a mouse model of lupus enhanced disease characteristics, including the production of anti-dsDNA antibody, serum IL-6 as well as cell apoptosis. Gut microbiota dysbiosis has been suggested to be one of the factors that decreases gut barrier integrity by outgrowing harmful bacteria and their products, or by perturbation of gut immune homeostasis, which in turn affects gut barrier integrity. The restoration of microbial balance eliminates gut leakage in mice, further confirming the role of microbiota in maintaining gut barrier integrity. In this review, we discuss recent advances on the association between microbiota dysbiosis and leaky gut, as well as their influences on the progression of lupus. The modifications on host microbiota and gut integrity may offer insights into the development of new lupus treatment.

The role of environmental exposures and gene-environment interactions in the etiology of systemic lupus erythematous

Systemic lupus erythematosus (SLE) is a complex, chronic autoimmune disease, whose etiology includes both genetic and environmental factors. Individual genetic risk factors likely only account for about one-third of observed heritability among individuals with a family history of SLE. A large portion of the remaining risk may be attributable to environmental exposures and gene-environment interactions. This review focuses on SLE risk associated with environmental factors, ranging from chemical and physical environmental exposures to lifestyle behaviors, with the weight of evidence supporting positive associations between SLE and occupational exposure to crystalline silica, current smoking, and exogenous estrogens (e.g., oral contraceptives and postmenopausal hormones). Other risk factors may include lifestyle behaviors (e.g., dietary intake and sleep) and other exposures (e.g., ultraviolet [UV] radiation, air pollution, solvents, pesticides, vaccines and medications, and infections). Alcohol use may be associated with decreased SLE risk. We also describe the more limited body of knowledge on gene-environment interactions and SLE risk, including IL-10, ESR1, IL-33, ITGAM, and NAT2 and observed interactions with smoking, UV exposure, and alcohol. Understanding genetic and environmental risk factors for SLE, and how they may interact, can help to elucidate SLE pathogenesis and its clinical heterogeneity. Ultimately, this knowledge may facilitate the development of preventive interventions that address modifiable risk factors in susceptible individuals and vulnerable populations.

Proton pump inhibitors induce changes in the gut microbiome composition of systemic lupus erythematosus patients

BACKGROUND

Currently, few studies focus on the association between gut microbiota and systemic lupus erythematosus (SLE), and much less studies consider the effect of drug usage. Proton pump inhibitors (PPIs) are commonly used to treat drug-related gastrointestinal damage in SLE patients. Therefore, the purpose of this study is to examine the gut microbiota of SLE patients using PPIs.

METHODS

Fecal samples from 20 SLE patients with PPIs (P-SLE), 20 SLE patients without PPIs (NP-SLE) and 17 healthy controls (HCs) were obtained. The structure of the bacterial community in the fecal samples was analyzed by 16S rRNA gene sequencing. Redundancy analysis (RDA) was performed to observe the relationship between clinical variables and microbiome composition in P-SLE and NP-SLE patients. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, functional capabilities of microbiota were estimated. Network analysis was performed to analyze the association of metabolic pathway alterations with altered gut microbiota in P-SLE and NP-SLE patients.

RESULTS

P-SLE patients exhibited increased alpha-diversity and an altered composition of the gut microbiota compared with NP-SLE patients. The alpha-diversity of NP-SLE patients was significantly lower than HCs but also of P-SLE patients, whose alpha-diversity had become similar to HCs. Compared with NP-SLE patients, the relative abundances of Lactobacillus, Roseburia, Oxalobacter, and Desulfovibrio were increased, while those of Veillonella, Escherichia, Morganella, Pseudomonas and Stenotrophomonas were decreased in P-SLE patients. RDA indicated that PPI use was the only significant exploratory variable for the microbiome composition when comparing SLE patients. KEGG analysis showed that 16 metabolic pathways were significantly different between NP-SLE and P-SLE patients. These metabolic pathways were mainly associated with changes in Escherichia, Roseburia, Stenotrophomonas, Morganella and Alipipes as determined by the network analysis.

CONCLUSIONS

PPI use is associated with an improved microbiome composition of SLE patients as it 1) increases alpha-diversity levels back to normal, 2) increases the abundance of various (beneficial) commensals, and 3) decreases the abundance of certain opportunistic pathogenic genera such as Escherichia. Validation studies with higher patient numbers are however recommended to explore these patterns in more detail.

Mehr als nur der Schmetterling – ein Leitfaden durch die Vielfalt des kutanen Lupus erythematodes

Die vielen klinischen Varianten des kutanen Lupus erythematodes (CLE) können solitär oder im Rahmen eines systemischen Lupus erythematodes (SLE) auftreten, auf dessen Vorkommen regelmäßig gescreent werden muss. Neben dem weiblichen Geschlecht und genetischen Faktoren stellen Sonnenexposition, Rauchen und manche Medikamente Risikofaktoren dar. Die wichtigsten CLE-Formen sind der akut-kutane LE (z. B. Schmetterlingserythem, generalisiert makulopapulös, enoral), der subakut-kutane LE (z. B. anuläre Form) und der chronisch-kutane LE (z. B. vernarbend diskoide Läsionen, Pannikulitis, Chilblain-LE). Die Diagnose beruht vor allem auf der Klinik und der Histopathologie, hinzu kommen autoimmunserologische Befunde und die direkte Immunfluoreszenz. Milde CLE-Formen können lokal therapiert werden. Reicht dies nicht aus, ist neben einem Steroidstoß Hydroxychloroquin die Systemtherapie der Wahl. Erweiterte therapeutische Optionen stellen Methotrexat, Retinoide, Dapson, Mycophenolat Mofetil, Azathioprin, Thalidomid, Belimumab und Rituximab dar. Alle CLE-Therapien sind off-label. Eine Aktualisierung der Impfungen sollte nach Möglichkeit vor Beginn einer Immunsuppression stattfinden. Zur Objektivierung des therapeutischen Ansprechens eines CLE empfiehlt sich das regelmäßige Scoring mittels RCLASI (Revised CLE Disease Area and Severity Index). Präventiv ist Sonnenschutz (Cremen, Kleidung, Reiseziele) von höchster Wichtigkeit, da Sonnenexposition Schübe provozieren kann. Ein LE stellt keine Kontraindikation gegen eine Schwangerschaft (SS) dar, jedoch sollte diese nicht in einem Schub eintreten, da dies das Risiko für Fetus und Mutter erhöht. Therapeutisch kommen während einer SS v. a. Steroide, Hydroxychloroquin, Dapson und Azathioprin in Betracht.