Clinical characteristics and risk factors of infection in patients with systemic lupus erythematosus: A systematic review and meta-analysis of observational studies

Systemic Lupus Erythematosus: A Review

Importance

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by inflammation and immune-mediated injury to multiple organ systems, including the mucocutaneous, musculoskeletal, hematologic, and kidney systems. Approximately 3.4 million people worldwide have received a diagnosis of SLE.

Observations

Approximately 90% of people with SLE are female. Although there are no uniformly accepted diagnostic criteria for SLE, the 2019 European Alliance of Associations for Rheumatology (formerly the European League Against Rheumatism)/American College of Rheumatology classification criteria developed for scientific study are an estimated 96.1% sensitive and 93.4% specific for SLE. These classification criteria include both clinical factors, such as fever, cytopenia, rash, arthritis, and proteinuria, which may be indicative of lupus nephritis; and immunologic measures, such as SLE-specific autoantibodies and low complement levels. Approximately 40% of people with SLE develop lupus nephritis, and an estimated 10% of people with lupus nephritis develop end-stage kidney disease after 10 years. The primary goal of treatment is to achieve disease remission or quiescence, defined by minimal symptoms, low levels of autoimmune inflammatory markers, and minimal systemic glucocorticoid requirement while the patient is treated with maintenance doses of immunomodulatory or immunosuppressive medications. Treatment goals include reducing disease exacerbations, hospitalizations, and organ damage due to the disease or treatment toxicity. Hydroxychloroquine is standard of care for SLE and has been associated with a significant reduction in mortality. Treatments in addition to hydroxychloroquine are individualized, with immunosuppressive agents, such as azathioprine, mycophenolate mofetil, and cyclophosphamide, typically used for treating moderate to severe disease. Three SLE medications were recently approved by the Food and Drug Administration: belimumab (for active SLE in 2011 and for lupus nephritis in 2020), voclosporin (for lupus nephritis), and anifrolumab (for active SLE).

Conclusions and Relevance

Systemic lupus erythematosus is associated with immune-mediated damage to multiple organs and increased mortality. Hydroxychloroquine is first-line therapy and reduces disease activity, morbidity, and mortality. When needed, additional immunosuppressive and biologic therapies include azathioprine, mycophenolate mofetil, cyclophosphamide, belimumab, voclosporin, and anifrolumab.

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.

Risk factors for initial and recurrent severe infections in first hospitalized patients with systemic lupus erythematosus: A retrospective study of a Chinese cohort

OBJECTIVE

To evaluate the incidence and associated factors of initial and recurrent severe infections in hospitalized patients with systemic lupus erythematosus (SLE).

METHODS

SLE patients that first hospitalized between 2010 and 2021 were studied retrospectively and divided into SLE with and without baseline severe infection groups. The primary outcome was the occurrence of severe infection during follow-up. Cox regression models were used to calculate the hazard ratio (HR) and 95% confidence interval (CI) for initial and recurrent severe infections.

RESULTS

Among 1051 first hospitalized SLE patients, 164 (15.6%) had severe infection on admission. During a median follow-up of 4.1 years, 113 (10.8%) patients reached severe infection outcomes, including 27 with reinfection and 86 with initial severe infection (16.5% vs. 9.7%, p = .010). Patients with baseline severe infection had a higher cumulative incidence of reinfection (p = .007). After adjusting for confounding factors, renal involvement, elevated serum creatinine, hypoalbuminemia, cyclophosphamide, and mycophenolate mofetil treatment were associated with an increased risk of severe infection, especially initial severe infection. Low immunoglobulin, anti-dsDNA antibody positivity, and cyclophosphamide use significantly increased the risk of recurrent severe infection, with adjusted HR (95% CI) of 3.15 (1.22, 8.14), 3.60 (1.56, 8.28), and 2.14 (1.01, 5.76), respectively. Moreover, baseline severe infection and low immunoglobulin had a multiplicative interaction on reinfection, with adjusted RHR (95% CI) of 3.91 (1.27, 12.09).

CONCLUSION

In this cohort of SLE, patients with severe infection had a higher risk of reinfection, and low immunoglobulin, anti-dsDNA antibody positivity, and cyclophosphamide use were independent risk factors for recurrent severe infection.

Vaccination updates and special considerations for systemic lupus erythematosus patients

PURPOSE OF REVIEW

We review the latest guidelines and note special considerations for systemic lupus erythematosus (SLE) patients when approaching vaccination against SARS-CoV-2, influenza, pneumococcus, herpes zoster, and potentially respiratory syncytial virus (RSV) vaccine in the future.

RECENT FINDINGS

SLE patients have unique infectious risks due to newer treatments and the nature of the disease itself. It is important to balance the benefit of additional protective immunity from updated vaccines against the possible risk of disease activity exacerbations.

SUMMARY

It is important to continuously evaluate the safety and immunogenicity of updated vaccines specifically for SLE patients. Additionally, the newly approved RSV vaccine should be considered for this population to reduce severe respiratory illness.

Predictive Factors of Hospital-Acquired Bacterial Infections in Patients With Systemic Lupus Erythematosus

OBJECTIVE

We aimed to identify the predictive factors of hospital-acquired bacterial infections in patients with systemic lupus erythematosus (SLE).

METHODS

This chart review study included patients with SLE who were hospitalized between 2009 and 2020 for reasons other than infection. The outcome was defined as any infection confirmed using any bacterial isolation method or diagnosed by treating physicians and required treatment with intravenous antibiotics. For statistical analysis, logistic regression analyses were performed.

RESULTS

In total, 1678 patients (87.6% women) were included. The median age was 33 years (interquartile range, 24-47 years). The incidence of hospital-acquired infections was 13.9% (233 infections). Age, Systemic Lupus Erythematosus Disease Activity Index score, Systemic Lupus International Collaborating Clinics damage score, blood urea nitrogen and C-reactive protein levels, dosage of steroid in the previous month, recent use of 1 or more immunosuppressants, admission with a central venous catheter (or dialysis catheter), and use of central venous catheter or bladder catheter in the first 5 days were the predictive factors of nosocomial infections.

CONCLUSION

The patients' infection risk profile should be assessed to accurately determine the risk-benefit balance of any therapeutic intervention, minimize exposure to steroids and immunosuppressants, and maintain a low threshold for the early diagnosis of infections. Further studies should assess whether the modification of some identified factors could reduce the incidence of nosocomial infections.

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.

Early infection risk in patients with systemic lupus erythematosus treated with rituximab or belimumab from the British Isles Lupus Assessment Group Biologics Register (BILAG-BR): a prospective longitudinal study

BACKGROUND

Patients with systemic lupus erythematosus (SLE) are at an increased risk of infection relative to the general population. We aimed to describe the frequency and risk factors for serious infections in patients with moderate-to-severe SLE treated with rituximab, belimumab, and standard of care therapies in a large national observational cohort.

METHODS

The British Isles Lupus Assessment Group Biologics Register (BILAG-BR) is a UK-based prospective register of patients with SLE. Patients were recruited by their treating physician as part of their scheduled care from 64 centres across the UK by use of a standardised case report form. Inclusion criteria for the BILAG-BR included age older than 5 years, ability to provide informed consent, a diagnosis of SLE, and starting a new biological therapy within the last 12 months or a new standard of care drug within the last month. The primary outcome for this study was the rate of serious infections within the first 12 months of therapy. Serious infections were defined as those requiring intravenous antibiotic treatment, hospital admission, or resulting in morbidity or death. Infection and mortality data were collected from study centres and further mortality data were collected from the UK Office for National Statistics. The relationship between serious infection and drug type was analysed using a multiple-failure Cox proportional hazards model.

FINDINGS

Between July 1, 2010, and Feb 23, 2021, 1383 individuals were recruited to the BILAG-BR. 335 patients were excluded from this analysis. The remaining 1048 participants contributed 1002·7 person-years of follow-up and included 746 (71%) participants on rituximab, 119 (11%) participants on belimumab, and 183 (17%) participants on standard of care. The median age of the cohort was 39 years (IQR 30-50), 942 (90%) of 1048 patients were women and 106 (10%) were men. Of the patients with available ethnicity data, 514 (56%) of 911 were White, 169 (19%) were Asian, 161 (18%) were Black, and 67 (7%) were of multiple-mixed or other ethnic backgrounds. 118 serious infections occurred in 76 individuals during the 12-month study period, which included 92 serious infections in 58 individuals on rituximab, eight serious infections in five individuals receiving belimumab, and 18 serious infections in 13 individuals on standard of care. The overall crude incidence rate of serious infection was 117·7 (95% CI 98·3-141·0) per 1000 person-years. Compared with standard of care, the serious infection risk was similar in the rituximab (adjusted hazard ratio [HR] 1·68 [0·60-4·68]) and belimumab groups (1·01 [0·21-4·80]). Across the whole cohort in multivariate analysis, serious infection risk was associated with prednisolone dose (>10 mg; 2·38 [95%CI 1·47-3·84]), hypogammaglobulinaemia (<6 g/L; 2·16 [1·38-3·37]), and multimorbidity (1·45 [1·17-1·80]). Additional concomitant immunosuppressive use appeared to be associated with a reduced risk (0·60 [0·41-0·90]). We found no significant safety signals regarding atypical infections. Six infection-related deaths occurred at a median of 121 days (IQR 60-151) days from cohort entry.

INTERPRETATION

In patients with moderate-to-severe SLE, rituximab, belimumab, and standard immunosuppressive therapy have similar serious infection risks. Key risk factors for serious infections included multimorbidity, hypogammaglobulinaemia, and increased glucocorticoid doses. When considering the risk of serious infection, we propose that immunosupppressives, rituximab, and belimumab should be prioritised as mainstay therapies to optimise SLE management and support proactive minimisation of glucocorticoid use.

FUNDING

None.

Tuberculosis remains a leading contributor to morbidity due to serious infections in Indian patients of SLE

INTRODUCTION

Infections are a major cause of morbidity and mortality in systemic lupus erythematosus (SLE). We assessed the incidence and risk factors for major infections in SLE in India.

METHODS

A retrospective review of a cohort of 1354 patients of adult SLE (ACR 1997 criteria) seen between 2000 and 2021 at a single center was conducted. Serious infections (need for hospitalisation, prolonged intravenous antibiotics, disability, or death) were recorded. Cox regression was used to determine factors associated with serious infection and the effects of serious infection on survival and damage.

RESULTS

Among the 1354 patients (1258 females, mean age of 30.3 years, follow-up of 7127.89 person-years), there were 439 serious infections in 339 patients (61.6 per 1000 person-years follow-up). Bacterial infections (N = 226) were the most common infection followed by mycobacterial infections (n = 81), viral (n = 35), and then invasive fungal infections (N = 13). Mycobacterium tuberculosis was the single most common microbiologically confirmed organism with incidence of 1136.4/100,000 person-years with 72.8% of them being extrapulmonary. Infection free survival at 1 year and 5 years was 82.9% and 73.8%. There were 119 deaths with infection attributable mortality in 65 (54.6%). On multivariable Cox regression analysis, higher baseline activity (HR 1.02, 1.01-1.05), gastrointestinal involvement (HR 2.75, 1.65-4.69), current steroid dose (HR 1.65, 1.55-1.76), and average cumulative steroid dose per year (HR 1.007, 1.005-1.009) were associated with serious infection and higher albumin (HR 0.65, 0.56-0.76) was protective. Serious infections led to greater damage accrual (median SLICC damage index of 1 vs. 0) and mortality (HR was 18.2, 32.7 and 81.6 for the first, second, and third infections).

CONCLUSION

Serious infections remain a major cause of mortality and damage accrual in SLE and higher disease activity, gastrointestinal involvement, hypoalbuminemia, current steroid dose, and cumulative steroid dose are the risk factors for it.

Glucocorticoids selectively affect the memory T cell response to SARS-Cov2 spike in vaccinated and post-infected patients with systemic lupus erythematosus

Immune response to vaccines and pathogens remains unclear in patients with systemic lupus erythematosus (SLE). To investigate this, a single-center retrospective study was conducted with 47 SLE patients vaccinated against COVID-19, including 13 who subsequently developed an asymptomatic/mild disease. As compared to controls, post-vaccine response against Spike was reduced in SLE patients when considering both memory T-cells in a whole blood interferon gamma release assay (IGRA-S) and IgG anti-Spike antibody (Ab) responses. The SLE-associated defective IGRA-S response was associated with a serum albumin level below 40 g/L and with the use of glucocorticoids, while a defective IgG anti-Spike Ab response was associated with lower levels of anti-dsDNA and anti-SSA/Ro 52 kDa Abs. IGRA-S and IgG anti-Spike responses were independent from SLE activity and clinical phenotype, low complement, hypergammaglobulinemia, and lymphopenia. As compared to controls, SLE patients showed a rapid decay of anti-Spike T-cell memory and stable IgG anti-Spike Ab responses. In conclusion, both T cell and humoral anti-Spike responses were independently affected in our SLE patients cohort, which supports the exploration of both responses in the follow-up of SLE patients and especially in those receiving glucocorticoids.

Predictors of infection requiring hospitalization in patients with systemic lupus erythematosus: a time-to-event analysis

OBJECTIVES

To evaluate the predictors of serious infection in patients with systemic lupus erythematosus (SLE).

METHODS

Serious infections were identified in SLE patients in a prospectively-followed single centre cohort. Associations of serious infection with disease-related variables and medication use were analysed using Cox and related regression models.

RESULTS

346 patients were followed for a mean (SD) of 6.6 (3.7) years. 86 episodes of serious infection were observed, with an incidence rate of 3.8 episodes per 100 person-years. Patients who had serious infection had higher baseline SLE Damage Index (SDI) and Charlston Comorbidity Index (CCI); they were also more likely to have high disease activity status (HDAS), and higher disease activity in multiple clinical domains, higher flare rates, higher time-adjusted prednisolone dose exposure, and less time in lupus low disease activity state (LLDAS). Patients who have received cyclophosphamide, rituximab and mycophenolate were more likely to have experienced serious infection. After multivariable adjustment in Cox regression analysis, cyclophosphamide, higher SDI score, and higher disease activity were associated with an increased hazard of first serious infection. History of previous serious infection conferred the highest risk. Lymphopenia was also a modest but statistically significant predictor of serious infection.

CONCLUSION

History of previous serious infection was the strongest predictor of serious infection in our SLE cohort. This study also suggests that clinical factors such as damage accrual, disease activity, and choice of immunosuppressant, can each have an independent risk in predicting serious infection particularly the first episode.

Infection in Hospitalized Patients With Systemic Lupus Erythematosus: Proposal of an Algorithm for Diagnosis

BACKGROUND

Identification of infection in patients with systemic lupus erythematosus (SLE) is a major challenge in clinical practice.

OBJECTIVE

This medical records review study evaluated clinical markers, including the performance of C-reactive protein (CRP), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) in the diagnosis of infection in SLE patients.

METHODS

One hundred four SLE patients hospitalized between 2014 and 2018 were allocated into 3 groups, namely, infection, infection and disease activity, and isolated disease activity. Groups were compared in relation to clinical and laboratory variables. Accuracy measures were calculated for CRP, NLR, and PLR.

RESULTS

C-reactive protein, NLR, and PLR differed between the groups with higher values observed in the infected group, intermediate values in the mixed group, and lower values in the group with isolated activity-CRP (56 vs 26 vs 15 mg/dL, p = 0.002), NLR (7.9 vs 4.0 vs 3.1, p = 0.005), and PLR (270 vs 227 vs 134, p = 0.025). Fever, tachypnea, and PLR were independently associated with infection. The cutoff points of the CRP of 20 mg/L, NLR of 3.5, and PLR of 151.4 presented values of sensitivity and specificity for the prediction of infection equal to 67% and 67%, 65% and 58%, and 71% and 53%, respectively. The developed algorithm showed a sensitivity of 86.6% and specificity of 81% for the diagnosis of infection.

CONCLUSIONS

The combined use of clinical and laboratory markers presented superior accuracy than their isolated use, suggesting a great potential for the application of the algorithm in clinical practice.

Increased oxidative stress contributes to impaired peripheral CD56dimCD57+ NK cells from patients with systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE) is characterized by loss of immune tolerance and imbalance of immune cell subsets. Natural killer (NK) cells contribute to regulate both the innate and adaptive immune response. In this study, we aimed to detect alterations of peripheral NK cells and explore intrinsic mechanisms involving in NK cell abnormality in SLE.

Methods

Blood samples from healthy controls (HCs) and patients with SLE and rheumatoid arthritis (RA) were collected. The NK count, NK subsets (CD56^bright, CD56^dimCD57⁻, and CD56^dimCD57⁺), phenotypes, and apoptosis were evaluated with flow cytometer. Mitochondrial reactive oxygen species (mtROS) and total ROS levels were detected with MitoSOX Red and DCFH-DA staining respectively. Published data (GSE63829 and GSE23695) from Gene Expression Omnibus (GEO) was analyzed by Gene Set Enrichment Analysis (GSEA).

Results

Total peripheral NK count was down-regulated in untreated SLE patients in comparison to that in untreated RA patients and HCs. SLE patients exhibited a selective reduction in peripheral CD56^dimCD57⁺ NK cell proportion, which was negatively associated with disease activity and positively correlated with levels of complement(C)3 and C4. Compared with HCs, peripheral CD56^dimCD57⁺ NK cells from SLE patients exhibited altered phenotypes, increased endogenous apoptosis and higher levels of mtROS and ROS. In addition, when treated with hydrogen peroxide (H₂O₂), peripheral CD56^dimCD57⁺ NK cell subset was more prone to undergo apoptosis than CD56^dimCD57⁻ NK cells. Furthermore, this NK cell subset from SLE patients exhibited impaired cytotoxicity in response to activated CD4⁺ T cells in vitro.

Conclusion

Our study demonstrated a selective loss of mature CD56^dimCD57⁺ NK cell subset in SLE patients, which may caused by preferential apoptosis of this subset under increased oxidative stress in SLE. The attenuated in vitro cytotoxicity of CD56^dimCD57⁺ NK cells may contribute to the impaired ability of eliminating pathogenic CD4⁺ T cells in SLE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02731-y.

Hydroxychloroquine in systemic lupus erythematosus: overview of current knowledge

The antimalarial hydroxychloroquine (HCQ) has demonstrated several crucial properties for the treatment of systemic lupus erythematosus (SLE). Herein, we reviewed the main HCQ pharmacologic features, detailed its mechanism of action, and summarized the existing guidelines and recommendations for HCQ use in rheumatology with a systematic literature search for the randomized controlled trials focused on lupus. HCQ has been shown to decrease SLE activity, especially in mild and moderate disease, to prevent disease flare and to lower the long-term glucocorticoid need. The numerous benefits of HCQ are extended to pregnancy and breastfeeding period. Based on cohort studies, antithrombotic and metabolic HCQ’s effects were shown, including lipid-lowering properties, which might contribute to an improved cardiovascular risk. Moreover, early HCQ use in antinuclear antibodies positive individuals might delay the progression to SLE. Finally, HCQ has a significant favorable impact on long-term outcomes such as damage accrual and mortality in SLE. Based on these multiple benefits, HCQ is now the mainstay long-term treatment in SLE, recommended by current guidelines in all patients unless contraindications or side effects. The daily dose associated with the best compromise between efficacy and safety is matter of debate. The concern regarding retinal toxicity rather than proper efficacy data is the one that dictated the daily dosage of ⩽5 mg/kg/day actual body weight currently agreed upon.

Antimalarials may reduce cancer risk in patients with systemic lupus erythematosus: a systematic review and meta-analysis of prospective studies

OBJECTIVE

To investigate the effect of antimalarials on cancer risk in patients with systemic lupus erythematosus (SLE).

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library were searched from their inception to October 3, 2020. Relative risk (RR) with 95% confidence intervals (CI) was used to evaluate the results. Subgroup analyses were used to assess heterogeneity. A funnel plot was used to explore publication bias. STATA was applied for all analyses.

RESULTS

A total of nine studies consisted of four nested case-control, two case-cohort and three cohort studies were included. The results showed that antimalarials might reduce the risk of cancer in SLE (RR = 0.68, 95%CI: 0.55-0.85). In the subgroup analysis of four nested case-control and two case-cohort studies, the pooled RR was estimated as 0.69 (95% CI: 0.60-0.80). In four studies about hydroxychloroquine, the pooled RR was estimated as 0.70 (95% CI: 0.53-0.93). Antimalarials might reduce the risk of cancer in SLE among the Asian population (RR = 0.66; 95% CI: 0.49-0.88) (I2 = 43.1%, p = .173). And the consistent result was also found in SLE from multiple centres (RR = 0.72; 95%CI: 0.60-0.87) (I2 = 0%, p = .671). On disease course- and comorbidities-matched studies, the pooled RRs were 0.69 (95% CI: 0.52-0.93) and 0.59 (95% CI: 0.46-0.75), respectively.

CONCLUSION

Results of this meta-analysis showed that antimalarial drugs might be protective factors for cancer in SLE. Hydroxychloroquine might be a protective factor for cancer in SLE patients.KEY MESSAGESAntimalarials might be protective factors for cancer in SLE.Hydroxychloroquine might be a protective factor for cancer in SLE patients.The first article to perform the meta-analysis of antimalarial drugs on the risk of cancer in SLE patients.

Antimalarial treatment and minimizing prednisolone are associated with lower risk of infection in SLE: a 24-month prospective cohort study

INTRODUCTION/OBJECTIVES

Infections are a major cause of morbidity and death in systemic lupus erythematosus (SLE). Perfecting the understanding of contributors to infection burden in SLE is pivotal to improve management and outcomes. This study aims to identify clinical predictors of infection in SLE.

METHOD

We conducted a prospective cohort study at a referral SLE clinic. Infections were identified at each visit and categorized as (a) any type, (b) serious, (c) non-serious, and (d) bacterial. Survival analysis followed by multivariate Cox regression with an estimation of hazard ratios (HR) with 95% confidence intervals (95%CI) was performed.

RESULTS

We included 259 patients during a mean follow-up of 23.3 ± 5.7 months. The incidence rate of infection of any type was 59.3 cases per 100 patient-years. Multivariate Cox models showed that (a) prednisolone ≥ 7.5 mg/day (HR = 1.95, 95%CI 1.26-3.03) and female gender (HR = 2.08, 95%CI 1.12-3.86) were associated with higher risk of infection of any type; (b) prednisolone ≥ 10 mg/day was associated with higher (HR = 4.32, 95%CI 1.39-13.40), and antimalarials with lower risk (HR = 0.18, 95%CI 0.06-0.51) of serious infection; (c) female gender (HR = 1.92, 95%CI 1.04-3.57) and prednisolone ≥ 7.5 mg/day (HR = 1.89, 95%CI 1.21-2.96) were associated with higher risk of non-serious infection; (d) antimalarials were associated with lower (HR = 0.49, 95%CI 0.26-0.93) and female gender (HR = 5.12; 95%CI 1.62-16.18) with higher risk of bacterial infection.

CONCLUSIONS

The risk of infection was higher in females in this young, well-controlled, low-comorbidity SLE cohort. Antimalarials were associated with lower and prednisolone ≥ 7.5 mg with higher risk of infection. Key Points • Lupus patients treated with prednisolone ≥ 7.5 mg/day were 89% more likely to present infections. • Lupus patients receiving prednisolone ≥ 10 mg/day were four times more likely to present serious infections. • Lupus patients receiving antimalarials were 82% less likely to present serious infections.

MHC haplotype and B cell autoimmunity: Correlation with pathogenic IgG autoantibody subclasses and Fc glycosylation patterns

Genome-wide association studies (GWAS) have identified many genes that are associated with the development of certain autoimmune disorders, but the MHC haplotypes still represent the most prevalent genetic risk factor for many autoimmune diseases. The mechanisms by which MHC-associated genetic susceptibility translates into B cell autoimmunity and the development of autoimmune diseases are complex. There is increasing evidence that the MHC haplotype modulates autoreactive B cell responses in multiple ways. Instead of merely inhibiting the production of IgG autoantibodies and mediating complete immunological tolerance, the non-permitting MHC haplotypes seem to facilitate the production of IgG autoantibodies exhibiting Fc glycosylation patterns that are associated with reduced pathogenicity and a protective cytokine profile of T follicular helper (Tfh) cells. Here, we discuss mechanisms linking MHC haplotypes to the production of pathogenic IgG autoantibodies, which could be relevant for the development of improved diagnosis, particularly in the context of individual medicine.

Challenges of Egyptian patients with systemic lupus erythematosus during the COVID-19 pandemic

Objectives

The coronavirus disease 2019 (COVID-19) pandemic in Egypt is part of the worldwide COVID-19 pandemic that has contributed to substantial deterioration of healthcare systems. The aim of this study was to assess the challenges faced by Egyptian systemic lupus erythematosus (SLE) patients during the COVID-19 pandemic.

Material and methods

This questionnaire-based study was carried out on 200 patients with SLE from Egypt. The questionnaire provided covered socioeconomic status, lupus disease data, information about COVID-19 infection, and medical and family history of COVID-19 infection.

Results

The mean age of the participants was 30.1 ±8.4 years. 140/200 (70%) of the participants reported difficulty in obtaining medications during the COVID-19 pandemic, particularly antimalarials (60%). The lupus disease condition became worse because of the drug shortage in half of the participants. Wearing protective masks (74%) and using disinfectants of the hands several times per day (67%) were the most reported used measures. Forty patients (20%) had to stop or reduce taking nonsteroidal anti-inflammatory drugs while 10 patients (5%) had to start taking antimalarials as a prophylaxis against COVID-19 infection. Among those who needed hospitalization, the main cause was lupus activity, and most of them (71%) experienced difficulty in hospital admission. Thirty-two patients (16%) had confirmed COVID-19 infection. About half of them had lupus flare and had to change the medications used for treatment of lupus.

Conclusions

The current COVID-19 pandemic has a negative impact on the healthcare provided to SLE patients in Egypt. Patients with SLE faced a shortage of their medications, especially antimalarials, and difficulty in hospital admission.

Infection hospitalisation in systemic lupus in Sweden

Objective

Immune dysregulation in SLE and the corresponding immune-modulating and immunosuppressive nature of the treatments may play key roles in infection risk. We compared serious infection rates among individuals with incident SLE with the general population, and examined the role of treatment initiation in SLE.

Methods

Newly diagnosed patients with SLE (2006–2013) and general population comparators from the Swedish Lupus Linkage cohort were followed for serious infection through 2016. Adjusted Cox and frailty models estimated the relative risk of first and recurrent infections, respectively. Using a new-user design, rates of serious infections were compared between disease-modifying antirheumatic drugs (DMARDs) and hydroxychloroquine (HCQ) initiators. We then evaluated three DMARDs (azathioprine, mycophenolate mofetil and methotrexate) in multivariable-adjusted models.

Results

Individuals with SLE experienced more infections (22% vs 6%), especially during the first year of follow-up, and recurrent serious infections were also more common (HR=2.22, 95% CI 1.93 to 2.56). DMARDs were associated with a higher rate of serious infection versus HCQ (HR=1.82, 95% CI 1.27 to 2.60), which attenuated after multivariable-adjustment (HR=1.30, 95% CI 0.86 to 1.95). Among DMARDs, azathioprine was associated with infection (HR=2.19, 95% CI 1.14 to 4.21) and mycophenolate mofetil yielded an HR=1.39 (95% CI 0.65 to 2.96) in multivariable-adjusted models compared with methotrexate. Results were comparable across numerous sensitivity analyses.

Conclusion

Individuals with incident SLE were 2–4 times more likely to be hospitalised for infection and experienced more recurrent infections than the general population. Among DMARD initiators, azathioprine was associated with the highest rate.

Exposure levels of mycophenolic acid are associated with comorbidities in children with systemic lupus erythematosus

INTRODUCTION

Little is known about the relationship between exposure levels of mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), and comorbidities of systemic lupus erythematosus (SLE) in children. This study aims to explore this association.

METHODS

Longitudinal data from SLE children, who were taking MMF for immunosuppression and under therapeutic drug monitoring (TDM), were retrospectively collected. Area under the concentration-time curve of mycophenolic acid (MPA) over 24 hours (AUC_0-24h) was estimated with Bayesian methods. Logistic regression and random forest models were used to explore the association between comorbidities and MPA exposure levels.

RESULTS

This study included 107 children with 358 times of follow-up (median age 169.02 months). The incidence of diabetes, acute kidney injury (AKI), or pneumonia was significantly associated with AUC_0-24h (odds ratio [OR] 0.991, 95% confidence interval [CI] 0.982-0.999), SLE duration (OR 1.012, 95% CI 1.002-1.022), lymphocyte percentage (OR 0.959, 95% CI 0.925-0.991), plasma albumin levels (OR 0.891, 95% CI 0.843-0.940), use of aspirin (OR 0.292, 95% CI 0.126-0.633) and hydroxychloroquine (OR 0.407, 95% CI 0.184-0.906). The random forest model showed that albumin and AUC_0-24h were two important predictors. The case group (with the three comorbidities) had a mean AUC_0-24h of 73.63 mg · h/L, while the control group had a mean AUC_0-24h of 100.39 mg · h/L.

CONCLUSIONS

Increased levels of MPA exposure are associated with decreased incidence odds of diabetes, AKI or pneumonia in SLE children. An AUC_0-24h of 100.39 mg · h/L or an AUC_0-12h of 50.20 mg · h/L could be used as the targeted exposure level for clinical practice.

Prevalence of periapical abscesses in patients with systemic lupus erythematosus

AIMS

To assess the prevalence of periapical abscesses in patients with systemic lupus erythematosus (SLE), and to evaluate the effect of glucocorticoids (GCs) used to treat SLE, on the prevalence of such lesions.

METHODS

Integrated data of hospital patients was used. Data from the corresponding diagnosis codes for SLE and periapical abscess was retrieved by searching the appropriate query in the database. The odd ratio (OR) of periapical abscesses and its association with SLE and intake of GCs were calculated and analyzed statistically.

RESULTS

The prevalence of periapical abscesses in patients treated with GCs was 1.5% compared to 0.39% in patients who were not treated with GCs. The OR for periapical abscesses in patients treated with GCs was 2.53 compared with OR of 0.66 in patients not treated with GCs. The differences were statistically significant (p < .0001). The prevalence of periapical abscesses in patients with SLE was 1.88%. The OR was 3.18 and the difference statistically significant (p < .0001).

CONCLUSIONS

Under the conditions of this study, it appears that the prevalence of periapical abscesses is higher in patients with SLE. Patients receiving GCs therapy, either for SLE or for other conditions, may present higher prevalence of periapical abscesses.

Hypoalbuminemia as Surrogate and Culprit of Infections

Hypoalbuminemia is associated with the acquisition and severity of infectious diseases, and intact innate and adaptive immune responses depend on albumin. Albumin oxidation and breakdown affect interactions with bioactive lipid mediators that play important roles in antimicrobial defense and repair. There is bio-mechanistic plausibility for a causal link between hypoalbuminemia and increased risks of primary and secondary infections. Serum albumin levels have prognostic value for complications in viral, bacterial and fungal infections, and for infectious complications of non-infective chronic conditions. Hypoalbuminemia predicts the development of healthcare-associated infections, particularly with Clostridium difficile. In coronavirus disease 2019, hypoalbuminemia correlates with viral load and degree of acute lung injury and organ dysfunction. Non-oncotic properties of albumin affect the pharmacokinetics and pharmacodynamics of antimicrobials. Low serum albumin is associated with inadequate antimicrobial treatment. Infusion of human albumin solution (HAS) supplements endogenous albumin in patients with cirrhosis of the liver and effectively supported antimicrobial therapy in randomized controlled trials (RCTs). Evidence of the beneficial effects of HAS on infections in hypoalbuminemic patients without cirrhosis is largely observational. Prospective RCTs are underway and, if hypotheses are confirmed, could lead to changes in clinical practice for the management of hypoalbuminemic patients with infections or at risk of infectious complications.

Viral Infections and Systemic Lupus Erythematosus: New Players in an Old Story

A causal link between viral infections and autoimmunity has been studied for a long time and the role of some viruses in the induction or exacerbation of systemic lupus erythematosus (SLE) in genetically predisposed patients has been proved. The strength of the association between different viral agents and SLE is variable. Epstein-Barr virus (EBV), parvovirus B19 (B19V), and human endogenous retroviruses (HERVs) are involved in SLE pathogenesis, whereas other viruses such as Cytomegalovirus (CMV) probably play a less prominent role. However, the mechanisms of viral-host interactions and the impact of viruses on disease course have yet to be elucidated. In addition to classical mechanisms of viral-triggered autoimmunity, such as molecular mimicry and epitope spreading, there has been a growing appreciation of the role of direct activation of innate response by viral nucleic acids and epigenetic modulation of interferon-related immune response. The latter is especially important for HERVs, which may represent the molecular link between environmental triggers and critical immune genes. Virus-specific proteins modulating interaction with the host immune system have been characterized especially for Epstein-Barr virus and explain immune evasion, persistent infection and self-reactive B-cell "immortalization". Knowledge has also been expanding on key viral proteins of B19-V and CMV and their possible association with specific phenotypes such as antiphospholipid syndrome. This progress may pave the way to new therapeutic perspectives, including the use of known or new antiviral drugs, postviral immune response modulation and innate immunity inhibition. We herein describe the state-of-the-art knowledge on the role of viral infections in SLE, with a focus on their mechanisms of action and potential therapeutic targets.

Lymphocyte subset clustering analysis in treatment-naive patients with systemic lupus erythematosus

OBJECTIVES

The aim of the study is to identify clusters of lymphocyte subsets within treatment-naive systemic lupus erythematosus (SLE) patients and evaluate the potential association of these clusters with disease activities.

METHODS

We conducted a cross-sectional study of consecutive 143 treatment-naive SLE patients in the Affiliated Hospital of Nantong University, China. We used hierarchical cluster analysis to classify individuals into clusters based on circulating lymphocyte subset proportions (CD3⁺CD4⁺T cell, CD3⁺CD8⁺T cell, CD19⁺B cell, and CD3-CD16 + CD56 NK cell) via R software. Demographic variables, clinical manifestations, laboratory variables, and disease activities were compared among clusters.

RESULTS

The SLE patients (median age 35 (26-48) years, 90.9% female) were divided into four clusters. The clustering features were as follows: cluster 1 (B high), cluster 2 (CD4 high), cluster 3 (CD8 high), and cluster 4 (NK high). SLE patients in cluster 1 showed the highest incidence of arthritis (70.6%, 34.2%, 48.3%, and 42.9% in clusters 1, 2, 3, and 4, respectively; P = 0.046), and patients in cluster 3 and cluster 4 showed significantly a higher incidence of nephritis (35.3%, 25.0%, 48.3%, and 61.9% in in clusters 1, 2, 3, and 4, respectively; P = 0.008). Patients in cluster 2 suffered from lower SLE Disease Activity Index (SLEDAI) score (12.1 ± 5.0, 10.3 ± 5.6, 12.2 ± 4.6, and 14.4 ± 7.3 in clusters 1, 2, 3, and 4, respectively; P = 0.046). Regression analysis indicated that, compared with patients in cluster 2, patients in cluster 1 exhibited higher rate of arthritis (OR 4.53, 95% CI 1.38-14.86, P = 0.013), while patients in cluster 3 (OR 2.85, 95%CI 1.15-7.08, P = 0.024) and cluster 4 (OR 4.93, 95%CI 1.76-13.85, P = 0.002) exhibited higher rate of nephritis.

CONCLUSION

This study supports the existence of lymphocyte subset clusters with different clinical features in treatment-naive SLE patients, which could help to differentiate between various subsets of SLE. Key Points • Lymphocyte subsets may occur in a pattern of cluster in treatment-naive SLE patients.