Immune profile alterations of systemic lupus erythematosus patients with infections

This study aimed to elucidate the immune status of systemic lupus erythematosus (SLE) patients with infections. We enrolled 253 SLE patients including 77 patients with infections. Clinical features and immunological parameters were analyzed, with particular reference to neutrophil CD64 (nCD64) expression, myeloid-derived suppressor cells (MDSCs), activated T cells and multiple cytokines. Among the 77 SLE patients with infections, 32 patients (41.56%) developed fever and 20 patients (25.97%) developed serositis, which were higher compared to the non-infection group. A considerably higher level of nCD64 was found in the infection group (4.65 vs 1.01, P < 0.001). In addition, the infection group exhibited higher percentages of total MDSCs (6.99 vs 4.30%, P = 0.003), polymorphonuclear MDSCs (PMN-MDSCs) (P = 0.032) and monocytic MDSCs (M-MDSCs) (P = 0.015). T cells were more activated during infections, with an elevated level of IL-2R (P < 0.001). Specifically, higher percentages of CD4+CD38+ T cells (55.73 vs 50.17%, P = 0.036), CD8+HLA-DR+ T cells (59.82 vs 47.99%, P < 0.001) and CD8+CD38+ T cells (68.59 vs 63.90%, P = 0.044) were identified in the infection group. Furthermore, the serum levels of IL-6, IL-8 and IL-10 were elevated in the infection group (all P < 0.001). Higher proportions of neutrophils, CD4+ and CD8+ T cells, and MDSCs were activated during infections in SLE patients. Additionally, the serum cytokines altered during infections, with noticeably elevated levels of IL-6, IL-8 and IL-10. Infections may lead to the amplification of immune alterations in SLE.

A Framework to Overcome Challenges in the Management of Infections in Patients with Systemic Lupus Erythematosus

Infections remain one of the leading causes of death in systemic lupus erythematosus (SLE), despite awareness of factors contributing to increased susceptibility to infectious diseases in SLE. Clinicians report challenges and barriers when encountering infection in SLE as certain infections may mimic a lupus flare. There are no evidence-based practice guidelines in the management of fever in SLE, with suboptimal implementations of evidence-based benefits related to infectious disease control and/or prevention strategies in SLE. Vigilance in identifying an opportunistic infection must be stressed when confronted by a diagnostic challenge during a presentation with a febrile illness in SLE. A balanced approach must focus on management of infections in SLE, and reduction in the glucocorticoids dose, given the need to control lupus disease activity to avoid lupus related organ damage and mortality. Clinical judgement and application of biomarkers of lupus flares could reduce false positives and overdiagnosis and improve differentiation of infections from lupus flares. Further precision-based risk and screening measures must identify individuals who would benefit most from low dose immunosuppressive therapy, targeted immune therapy, and vaccination programs.

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

BACKGROUND

Bacterial infections of the lung, skin, bloodstream and other tissues are common in patients with systemic lupus erythematosus (lupus) and are often more severe and invasive than similar infections in control populations. A variety of studies have explored the changes in bacterial abundance in lupus patients, the rates of infection and the influence of particular bacterial species on disease progression, using both human patient samples and mouse models of lupus.

OBJECTIVE

The aim of this review is to summarize human and mouse studies that describe changes in the bacterial microbiome in lupus, the role of a leaky gut in stimulating inflammation, identification of specific bacterial species associated with lupus, and the potential roles of certain common bacterial infections in promoting lupus progression.

METHODS

Information was collected using searches of the Pubmed database for articles relevant to bacterial infections in lupus and to microbiome changes associated with lupus.

RESULTS

The reviewed studies demonstrate significant changes in the bacterial microbiome of lupus patients as compared to control subjects and in lupus-prone mice compared to control mice. Furthermore, there is evidence supporting the existence of a leaky gut in lupus patients and in lupus-prone mice. This leaky gut may allow live bacteria or bacterial components to enter the circulation and cause inflammation. Invasive bacterial infections are more common and often more severe in lupus patients. These include infections caused by Staphylococcus aureus, Salmonella enterica, Escherichia coli, Streptococcus pneumoniae and mycobacteria. These bacterial infections can trigger increased immune activation and inflammation, potentially stimulating activation of autoreactive lymphocytes and leading to worsening of lupus symptoms.

CONCLUSIONS

Together, the evidence suggests that lupus predisposes to infection, while infection may trigger worsening lupus, leading to a feedback loop that may reinforce autoimmune symptoms.

Can we validate a clinical score to predict the risk of severe infection in patients with systemic lupus erythematosus? A longitudinal retrospective study in a British Cohort

OBJECTIVE

Severe infections are a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Our primary objective was to use data from a large Spanish cohort to develop a risk score for severe infection in SLE, the SLE Severe Infection Score (SLESIS) and to validate SLESIS in a separate cohort of 699 British patients.

DESIGN AND SETTING

Retrospective longitudinal study in a specialist tertiary care clinic in London, UK.

PARTICIPANTS

Patients fulfilling international classification criteria for SLE (n=209). This included 98 patients who had suffered severe infections (defined as infection leading to hospitalisation and/or death) and 111 randomly selected patients who had never suffered severe infections.

OUTCOMES

We retrospectively calculated SLESIS at diagnosis for all 209 patients. For the infection cases we also calculated SLESIS just prior to infection and compared it to SLESIS in 98 controls matched for disease duration. We carried out receiver operator characteristic (ROC) analysis to quantify predictive value of SLESIS for severe infection.

RESULTS

Median SLESIS (IQR) at diagnosis was higher in the infection group than in the control group (4.27 (3.18) vs 2.55 (3.79), p=0.0008). Median SLESIS prior to infection was higher than at diagnosis (6.64 vs 4.27, p<0.001). In ROC analysis, predictive value of SLESIS just before the infection (area under the curve (AUC)=0.79) was higher than that of SLESIS at diagnosis (AUC=0.63).

CONCLUSIONS

We validated the association of SLESIS with severe infection in an independent cohort. Calculation of SLESIS at each clinic visit may help in management of infection risk in patients with SLE. Prospective studies are needed to confirm these findings.

Streptococcus pneumoniae sepsis as the initial presentation of systemic lupus erythematosus

Objective

Infections are among the most important causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE) but are rare initial presentation of the disease. Therefore, in this study, we describe a case of Streptococcus pneumoniae sepsis in a young woman with previously undiagnosed SLE.

Case report

A 23-year-old female patient was admitted to our outpatient clinic complaining of high fever (40°C), chills, fatigue, generalized myalgia, and cough with brown sputum for 5 days. Blood cultures grew gram-positive coccus defined as S. pneumoniae using standard procedures. Antinuclear antibody was positive at a titer of 1/1,000, and anti-double-stranded DNA was positive at 984 IU/mL. She was diagnosed with SLE. Her respiratory symptoms and pleural effusion were considered to be due to pulmonary manifestation of SLE.

Conclusion

The underlying immunosuppression caused by SLE could have predisposed the patient to invasive pneumococcal disease. It may also occur as a primary presenting feature, although a rare condition.

Vaccine-preventable infections in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is characterized by abnormal autoantibody production and clearance. Infections are among the most important causes of morbidity and mortality in SLE patients; they have an increased frequency of severe bacterial and viral infections possibly due to inherited genetic and immunologic defects and to immunosuppressive therapies. In addition, infectious agents can switch on lupus disease expression and activity. Among the strategies to reduce the risk of infection, vaccination can be considered the most reliable option. Most vaccines are effective and safe in SLE patients, although in certain cases immunogenicity may be sub-optimal and vaccination can trigger a flare. Although these issues are currently unresolved, the risk benefit balance is in favor for vaccination to reduce the risk of infection in SLE patients. In the present review we discuss the preventive strategies currently recommended to reduce bacterial and viral infections in SLE.

Streptococcus pneumoniae necrotizing fasciitis in systemic lupus erythematosus

Necrotizing fasciitis is a rapidly progressive destructive soft tissue infection with high mortality. Streptococcus pneumoniae as etiologic agent of necrotizing fasciitis is extremely unusual. The increased susceptibility to Streptococcus pneumoniae infection in patients with systemic lupus erythematosus is probably a multifactorial phenomenon. We report a case of a patient, a 36-year-old Caucasian female with 8-year history of systemic lupus erythematosus who presented a fatal Streptococcus pneumoniae necrotizing fasciitis. The role of computed tomography and the high performance of blood cultures for isolation of the causative microorganism are emphasized. Once diagnosis is suspected, empiric antibiotic treatment must be prescribed and prompt surgical exploration is mandatory.

Clinical and Immunogenetic Factors Associated with Pneumonia in Patients with Systemic Lupus Erythematosus: A Case-Control Study

Objective.

To determine the incidence of pneumonia and associated factors in a single-center systemic lupus erythematosus (SLE) cohort.

Methods.

We included all our SLE patients [1997 American College of Rheumatology (ACR) criteria] with ≥ 1 pneumonia event, and 196 age and sex-matched SLE controls with no pneumonia events. Cumulative clinical data, weighted Systemic Lupus International Collaborating Clinics/ACR damage index (wSLICC/ACR-DI), comorbidities, and risk factors for pneumonia were retrospectively collected. The standardized incidence ratio (SIR) of pneumonia was estimated. Polymorphisms at genes coding for mannose binding lectin (MBL), MBL-associated serine protease 2, Fc-gamma receptors, and surfactant proteins A1, A2, and D were determined, and their potential association with pneumonia was analyzed. Patients with and without pneumonia were compared using a multivariate logistic regression model for adjustment of pneumonia-associated factors.

Results.

Thirty-six of 232 patients with SLE had experienced ≥ 1 pneumonia event. SIR for pneumonia was 5.1 (95% CI 3.5–7.4; p < 0.0001). Excluding patients receiving immunosuppressive therapy at the time of pneumonia (13%), associations were found for Katz Severity Index (KSI) (p = 0.016), wSLICC/ACR-DI (p = 0.044), number of SLE criteria (p = 0.005), hospital admissions (p < 0.001), FCGR2A HH genotype (p = 0.03), previous use of immunosuppressive therapy (p = 0.049), cutaneous ulcers (p < 0.001), and vasculitis (p = 0.008) in bivariate analyses. In the multivariate analysis adjusted to previous immunosuppressive treatment, only KSI and FCGR2A HH genotype remained statistically significant (p = 0.05 and p = 0.03, respectively).

Conclusion.

The incidence of pneumonia in patients with SLE is higher than that in the general population, and particularly high in severe SLE, regardless of immunosuppressive therapy. The HH genetic variant of FCGR2A appears to predispose patients with SLE to pneumonia.

Invasive pneumococcal diseases in children and adolescents--a single centre experience

Background

S. pneumoniae is a major cause of meningitis, pneumonia and sepsis in children. In 2006 universal pneumococcal vaccination was recommended in Germany for all children up to their second birthday. We have compared the prevalence and outcome of IPD at a single hospital before and after the introduction of vaccination.

Findings

55 cases of IPD were identified over an 11 year period. Almost half of the patients were younger than 2 years of age. Most of the children were affected by pneumonia. The second highest incidence seen was for meningitis and sepsis. 17 patients exhibited additional complications. Significant pre-existing and predisposing disorders, such as IRAK 4 defect, ALPS or SLE were identified in 4 patients. Complete recovery was seen in 78% of affected children; 11% had a fatal outcome and 11% suffered from long term complications. Only 31% overall had been vaccinated. The most common serotype was 14. Serotypes not covered by any of the current vaccines were also found. Antibiotic treatment commenced with cephalosporins in over 90%.

Conclusion

Frequency of IPD in our hospital did not decrease after initiation of the pneumococcal vaccination. This might be due to vaccinations not being administered satisfactorily as well as to poor education about the need of the vaccination. Pre-existing diseases must be monitored and treated accordingly and rare deficiencies taken into account when IPD takes a foudroyant course. In addition, antibiotic stewardship has been initiated at this hospital centre as a consequence of the high cephalosporin use detected in this study.

Impaired opsonization with complement and phagocytosis of Streptococcus pyogenes in sera from subjects with inherited C2 deficiency

Although subjects with inherited defects of the classical complement pathway component C2 are at increased risk of infection, there are few experimental data available on which bacterial pathogens they might be susceptible to. In order to investigate whether patients with inherited C2 deficiency may have increased susceptibility to Streptococcus pyogenes infection we have analysed opsonization with C3b/iC3b and phagocytosis of three different strains of S. pyogenes in serum from 8 C2(-/-) subjects using flow cytometry assays. Sera from patients with C2 deficiency had a markedly reduced ability to opsonise S. pyogenes with C3b/iC3b. In addition, phagocytosis of all three S. pyogenes strains was impaired in sera from C2(-/-) subjects. Both the reduced opsonisation with C3b/iC3b and phagocytosis in C2(-/-) sera were markedly improved by addition of exogenous C2 protein. Neutrophil dependent killing was also reduced, confirming the functional importance of C2 deficiency for immunity to S. pyogenes. Impaired opsonisation with C3b/iC3b and phagocytosis was not related to reduced recognition of the bacteria by antibody. These data suggest that patients with C2 deficiency are at increased risk of S. pyogenes infections.