Association of antinucleosome antibodies with disease flare in serologically active clinically quiescent patients with systemic lupus erythematosus

Phenotypic subgroup in serologically active clinically quiescent systemic lupus erythematosus: A cluster analysis based on CSTAR cohort

BACKGROUND

Serologically active clinically quiescent (SACQ) is a state within systemic lupus erythematosus (SLE) characterized by elevated serologic markers without clinical activity. The heterogeneity in SACQ patients poses challenges in disease management. This multicenter prospective study aimed to identify distinct SACQ subgroups and assess their utility in predicting organ damage.

METHODS

SACQ was defined as a sustained period of at least 6 months with persistent serologic activity, marked by positive anti-double-stranded DNA (dsDNA) antibodies and/or hypocomplementemia, and without clinical activity. Cluster analysis was employed, utilizing 16 independent components to delineate phenotypes.

FINDINGS

Among the 4,107 patients with SLE, 990 (24.1%) achieved SACQ within 2.0 ± 2.3 years on average. Over a total follow-up of 7,105.1 patient years, 340 (34.3%) experienced flares, and 134 (13.5%) developed organ damage. Three distinct SACQ subgroups were identified. Cluster 1 (n = 219, 22.1%) consisted predominantly of elderly males with a history of major organ involvement at SLE diagnosis, showing the highest risk of severe flares (16.4%) and organ damage (27.9%). Cluster 2 (n = 279, 28.2%) was characterized by milder disease and a lower risk of damage accrual (5.7%). Notably, 86 patients (30.8%) in cluster 2 successfully discontinued low-dose glucocorticoids, with 49 of them doing so without experiencing flares. Cluster 3 (n = 492, 49.7%) featured the highest proportion of lupus nephritis and a moderate risk of organ damage (11.8%), with male patients showing significantly higher risk of damage (hazard ratio [HR] = 4.51, 95% confidence interval [CI], 1.82-11.79).

CONCLUSION

This study identified three distinct SACQ clusters, each with specific prognostic implications. This classification could enhance personalized management for SACQ patients.

FUNDING

This work was funded by the National Key R&D Program (2021YFC2501300), the Beijing Municipal Science & Technology Commission (Z201100005520023), the CAMS Innovation Fund (2021-I2M-1-005), and National High-Level Hospital Clinical Research Funding (2022-PUMCH-D-009).

Impact of serological activity on flare following clinically inactive disease and remission in childhood-onset systemic lupus erythematosus

OBJECTIVES

The objectives of this study were to assess the association between serological activity (SA) and clinical inactivity in SLE and to investigate whether SA predicts flare after the attainment of clinically inactive disease (CID) and remission.

METHODS

The longitudinal data of children from three paediatric rheumatology referral centres were retrospectively reviewed. CID was interpreted as the beginning of a transitional phase of clinical inactivity on a moderate glucocorticoid dose during which tapering was expected and defined as the absence of disease activity in clinical domains of SLEDAI, without haemolytic anaemia or gastrointestinal activity, in patients using <15 mg/day prednisolone treatment. Modified DORIS remission on treatment criteria were used to determine remission.

RESULTS

Of the 124 patients included, 89.5% displayed SA at onset. Through follow-up, the rate of SA decreased to 43.3% at first CID and 12.1% at remission. Among the patients with CID, 24 (20.7%) experienced a moderate-to-severe flare before the attainment of remission. While previous proliferative LN [odds ratio (OR): 10.2, P: 0.01) and autoimmune haemolytic anaemia (OR: 6.4, P: 0.02) were significantly associated with increased odds of flare after CID, SA at CID was not associated with flare. In contrast, 21 (19.6%) patients experienced flare in a median of 18 months after remission. Hypocomplementemia (OR: 9.8, P: 0.02) and a daily HCQ dose of <5 mg/kg (OR: 5.8, P: 0.02) during remission significantly increased the odds of flare.

CONCLUSION

SA during remission increases the odds of flare, but SA at CID does not. Suboptimal dosing of HCQ should be avoided, especially in children with SA in remission, to lower the risk of flares.

Major determinants of prolonged remission in systemic lupus erythematosus: retrospective study over a 41+ year period

OBJECTIVES

To investigate predictors of sustained complete remission (CR) for 3 and 5 years, minimum.

METHODS

Retrospective observational study from January 1978 to December 2019, including systemic lupus erythmatosus (SLE) patients who attended the Lupus Clinic in a tertiary hospital, for at least 3 years. We used the BILAG score and serological profile to classify patients into CR, serologically active clinically quiescent (SACQ) and serological remission (SR). Multivariable Cox regression analysis was performed to investigate predictors of CR and Kaplan-Meier curves were obtained.

RESULTS

We included 564 patients; 15% achieved CR, 7% SACQ and 15% SR. Some 63% attained no remission. In the CR group, 73% sustained the remission for 5 years or more. Patients who did not reach any kind of sustained remission died significantly earlier (P < 0.001). Cumulative survival figures at 5, 10, 20 and 30 years were 100, 100, 94 and 90%, respectively, for CR patients and 96, 93, 77 and 58%, respectively, for patients in the no-remission group. Significant predictors of CR were White ethnicity [adjusted hazard ratio (HR) 2.16 (95% CI 1.30-3.59); P = 0.003]; older age at diagnosis (>32 years) [HR 1.92 (1.24-2.97); P = 0.003]; absence of renal involvement [HR 2.55 (1.39-4.67); P = 0.002]; and of antiphospholipid syndrome (APS) [HR 4.92 (1.55-15.59); P = 0.007].

CONCLUSION

Patients not achieving any kind of sustained remission have a higher risk of early mortality. White ethnicity, older age at diagnosis, absence of renal involvement and of APS were significantly associated with CR. Predictors for sustained CR do not change whether a 3-year or 5-year period is applied.

The Role of Autoantibody Testing in Modern Personalized Medicine

Personalized medicine (PM) aims individualized approach to prevention, diagnosis, and treatment. Precision Medicine applies the paradigm of PM by defining groups of individuals with akin characteristics. Often the two terms have been used interchangeably. The quest for PM has been advancing for centuries as traditional nosology classification defines groups of clinical conditions with relatively similar prognoses and treatment options. However, any individual is characterized by a unique set of multiple characteristics and therefore the achievement of PM implies the determination of myriad demographic, epidemiological, clinical, laboratory, and imaging parameters. The accelerated identification of numerous biological variables associated with diverse health conditions contributes to the fulfillment of one of the pre-requisites for PM. The advent of multiplex analytical platforms contributes to the determination of thousands of biological parameters using minute amounts of serum or other biological matrixes. Finally, big data analysis and machine learning contribute to the processing and integration of the multiplexed data at the individual level, allowing for the personalized definition of susceptibility, diagnosis, prognosis, prevention, and treatment. Autoantibodies are traditional biomarkers for autoimmune diseases and can contribute to PM in many aspects, including identification of individuals at risk, early diagnosis, disease sub-phenotyping, definition of prognosis, and treatment, as well as monitoring disease activity. Herein we address how autoantibodies can promote PM in autoimmune diseases using the examples of systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, Sjögren syndrome, systemic sclerosis, idiopathic inflammatory myopathies, autoimmune hepatitis, primary biliary cholangitis, and autoimmune neurologic diseases.

Interkit Reproducibility of the Indirect Immunofluorescence Assay on HEp-2 Cells Depends on the Immunofluorescence Reactivity Intensity and Pattern

Introduction

The indirect immunofluorescence assay on HEp-2 cells (HEp-2/IFA) is used worldwide for screening for autoantibodies to cellular antigens. Cell culture and fixation methods influence the cell distribution of autoantigens and the preservation of epitopes. Therefore, discrepancy of results obtained using different HEp-2/IFA kits (interkit nonreproducibility) is a common phenomenon in the clinical laboratory routine.

Objective

This study evaluated the interkit nonreproducibility of HEp-2/IFA results using samples from patients with systemic autoimmune disease (SAD), nonautoimmune diseases (NAD), and healthy blood donors (HBD).

Methods

Serum from 275 SAD patients, 293 NAD patients, and 300 HBD were processed at 1:80 dilution using four HEp-2 kits according to the manufacturers’ instructions. Interkit reproducibility was determined for positive/negative results and patterns. The agreement of positive/negative results among kits for each sample was determined as the reactivity agreement score (RAS). The pattern reproducibility score (PRS) in each sample was calculated as a function of the number of kits showing equivalent patterns. Qualitative variables and ordinal variables were analyzed by the Chi-square and Mann-Whitney U tests, respectively.

Results

A total of 402 samples were nonreactive in all kits and were considered devoid of autoantibodies. Further analysis included the 466 reactive samples (238 SAD, 119 NAD, 109 HBD). Reactivity to the nucleus had the highest interkit reproducibility (RAS = 83.6), followed by the metaphase plate (RAS = 78.9), cytoplasm (RAS = 77.4), and nucleolus (RAS = 72.4). Interkit reproducibility was higher in SAD (RAS = 78.0) than in NAD (RAS = 70.6) and HBD (RAS = 71.3) groups. Samples with strong reactivity (++++/4 and +++/4) had higher interkit reproducibility than those with weak reactivity (+/4). In the SAD group, RAS for nuclear reactivity was 87.5% for strongly reactive samples as opposed to 4.4% for weakly reactive samples, and the same was observed for NAD and HBD samples. The most robust patterns were the centromere AC-3 (PRS = 78.4), multiple nuclear dots AC-6 (PRS = 73.6), nuclear coarse speckled AC-5 (PRS = 71.3), nuclear homogeneous AC-1 (PRS = 67.9), and the reticular cytoplasmic AC-21 (PRS = 68.6).

Conclusion

Interkit nonreproducibility in HEp-2/IFA is prevalent and occurs with the highest frequency with weakly reactive samples. International initiatives with the engagement of in vitro diagnostic industry are encouraged to promote the harmonization of the properties and performance of HEp-2/IFA commercial kits.

Treatments and outcomes in Chinese patients with serologically active clinically quiescent systemic lupus erythematosus: a retrospective observational study

Objective

To clarify the frequency and outcome of patients with systemic lupus erythematosus (SLE) who achieved the clinical state as serologically active clinically quiescent (SACQ) and to identify factors associated with the flare of disease.

Methods

Clinical data of patients diagnosed as SLE and followed in Peking University First Hospital from 2009 to 2015 were retrospectively reviewed. Six hundred eighty-two patients who were followed up for more than 6 months were analyzed. SACQ was defined as an at least a 6-month period with persistent serologic activity and without clinical activity and daily dose of prednisone or equivalent were less than 7.5 mg. Serologically quiescent clinically quiescent (SQCQ) patients served as control groups. Data including demographics, initial symptoms, duration to SACQ, treatments before and after SACQ, and characteristics of the patients suffered from flare were analyzed.

Results

Among the 682 patients, 170 patients were SACQ (24.9%) and 187 patients were SQCQ. SQCQ patients (38.61 ± 15.08 years old) were older at baseline than SACQ patients (38.61 ± 15.08 years vs. 32.09 ± 14.35 years, p < 0.001). Of 170 SACQ patients, 32.9% experienced flare that was significantly higher than 15.5% of SQCQ patients (29/187). Corticosteroids (OR 1.323, 95% CI 1.129 to 1.550; p = 0.001) was an independent risk factor for flare, while antimalarials (OR 0.045, 95% CI 0.004 to 0.474; p = 0.010) and immunosuppressants (OR 0.332, 95% CI 0.156 to 0.706; p = 0.004) were protective factors in SACQ patients; however, only antimalarials was protective factors in SQCQ patients (OR 0.028, 95% CI 0.001 to 0.743; p = 0.033).

Conclusion

About one third of SLE patients with SACQ experience flare, significantly more frequent than that of patients with SQCQ. Thus, approach to prevent flare in SACQ patient is required. Maintenance therapy of hydroxychloroquine and immunosuppressant agents may be protective and beneficial treatment strategy in these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02641-5.

Follow-up and management of serologically active clinically quiescent cases in pediatric systemic lupus erythematosus

Objectives

Our aim is to identify the presence of serologically active clinically quiescent (SACQ) episodes in pediatric systemic lupus erythematosus (SLE) patients. We aim to identify serologic biomarkers associated with SACQ episodes and discuss risks and benefits of escalating treatments.

Material and methods

We evaluated 25 pediatric SLE patients, 13 of whom experienced SACQ episodes. Serologically active clinically quiescent was defined as two consecutive clinic visits without any clinical symptoms or clinical examination findings of a lupus flare with a clinical Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score of zero, but either elevated anti-ds-DNA antibodies or low complement (C3 and/or C4) levels.

Results

Among the 13 patients who experienced a SACQ episode, there were a total of 24 episodes, with each patient experiencing 1–4 SACQ episodes. Erythrocyte sedimentation rate (ESR) was the most commonly elevated laboratory marker in a SACQ episode, followed by low hemoglobin levels, and then elevated anti-dsDNA antibodies. Of the 17 episodes treated during a SACQ episode, 15 (88%) did not progress to a clinical flare within six months, while two did. Furthermore, of the 7 patients who were not treated during their SACQ episode, 2 (29%) continued to be SACQ without flare, whereas 5 led to a clinical flare within six months.

Conclusions

Serologically active clinically quiescent episodes were identified in pediatric SLE patients, suggesting that the presence of SACQ is not limited to adults with SLE. Serologic markers such as increased ESR, hemoglobin, and elevated anti-dsDNA antibodies are preliminarily associated with pediatric SACQ episodes. Treating these SACQ episodes in pediatric SLE patients was less likely to lead to a clinical flare within six months when compared to not treating (p < 0.05). More research with a larger sample size is needed to define SACQ episodes, determine the prevalence in pediatric SLE patients, and establish SACQ treatment guidelines.

Changes in the result of antinuclear antibody immunofluorescence assay on HEp-2 cells reflect disease activity status in systemic lupus erythematosus

Background The objective of the study was to determine whether the staining pattern and titer of indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) are associated with systemic lupus erythematosus (SLE) disease activity. Methods A total of 269 consecutive patients meeting the ACR and SLICC criteria for SLE were classified into three groups according to the SLE Disease Activity Index 2000 (SLEDAI2K): Remission (SLEDAI2K = 0; n = 47); Intermediate (SLEDAI2K = 1-5; n = 111); Active (SLEDAI2K ≥ 6; n = 111). All subjects were assessed for HEp-2 IFA titer and staining pattern and nine traditional parameters of SLE disease activity. After a 6 to 12-month interval, 101 of the 269 patients were reassessed. Results HEp-2 IFA homogeneous nuclear pattern (AC-1) occurred more frequently in the Active Group compared to the Remission Group (p < 0.001). Fine speckled nuclear pattern (AC-4) tended to occur more frequently in the Remission Group compared to the Active Group (p = 0.054). Subjects with AC-1 pattern had higher SLEDAI (8.8 ± 7.6) than those with AC-4 (4.8 ± 5.2) (p < 0.001). HEp-2 IFA titer and anti-nuclear antibody by enzyme-linked immunosorbent assay (ANA-ELISA) values were lower in the Remission Group compared to the other two groups (p < 0.001). Multivariate analyses identified only ELISA anti-dsDNA as an independent variable associated with disease activity. In follow-up analysis, HEp-2 IFA titer decreased significantly in the 33 subjects with decreased disease activity (p = 0.002). Receiver operator characteristic (ROC) curve analysis for determination of disease activity showed equivalent areas under the curve (AUC) for HEp-2 IFA titer and traditional disease activity parameters. Conclusions HEp-2 IFA pattern and titer can reflect SLE disease activity and may be considered in conjunction with other laboratory and clinical parameters in the assessment of SLE disease activity.

Which patients with systemic lupus erythematosus in remission can withdraw low dose steroids? Results from a single inception cohort study

BACKGROUND

A progressive tapering until withdrawal of glucocorticoids (GC) is considered one of the main goals of Systemic Lupus Erythematosus (SLE) management. However, which patient may be a candidate for safe GC withdrawal has not been determined yet. This study aimed to evaluate the rate of low-dose GC withdrawal in SLE patients in remission and to identify predictors of flares.

METHODS

Eligible patients were SLE patients in prolonged clinical remission defined by a cSLEDAI = 0 for at least 2 years and on a stable SLE treatment (including daily 5 mg prednisone). Flares were defined by SELENA-SLEDAI Flare Index. Predictors of flares after GC withdrawal were analyzed by Cox regression.

RESULTS

We selected 56 patients in whom a GC withdrawal was attempted. 98 patients were in the prednisone maintenance group. The proportion of patients experiencing a flare was not significantly lower in the maintenance group than in the withdrawal group (p = 0.81). However, among the withdrawal group, the rate of flares was significantly higher in serologically active clinically quiescent (SACQ) patients (p < 0,0001). At Cox regression analysis, duration of hydroxychloroquine (HCQ) therapy and ≥5 year remission at withdrawal were protective factors, while a SACQ disease and history of lupus nephritis increased the risk of disease flare.

CONCLUSION

GC withdrawal is an achievable target in SLE and may be attempted in patients in complete remission.However, it might underline a caution in patients with SACQ disease who may be at greater risk forflare when GCare discontinued. HCQ therapy and durable remission can significantly reduce the risk.

Treatment targets in SLE: remission and low disease activity state

Treat-to-target strategies have changed the approach to management of many chronic conditions, with improvements in patient outcomes. The key to success of treat to target is the availability of validated treatment endpoints, which have been difficult to derive for SLE, a condition notorious for its heterogeneity. This review will focus on the development and validation of the definitions of remission in SLE framework and the lupus low disease activity state. Lupus low disease activity state is more attainable than remission, with a stepwise concentric relationship between the target states indicating increasing stringency. Both lupus low disease activity state and definitions of remission in SLE remission have been proven to be associated with reduction in disease flares, reduced risk of accrual of irreversible end organ damage, and improvement in patient reported outcomes. These endpoints have therefore provided the key for the development of a treat-to-target approach in clinical practice in SLE and for the design of future clinical trials.

Prevalence, predictors and prognostic benefits of remission achievement in patients with systemic lupus erythematosus: a systematic review

OBJECTIVES

To systematically review and evaluate the prevalence, potential predictors and prognostic benefits of remission achievement in patients with systemic lupus erythematosus (SLE).

METHODS

Studies reporting prevalence, predictors and prognostic benefits of remission in adult SLE patients were searched and selected from Pubmed and EMBASE databases. Studies were reviewed for relevance and quality. Two reviewers independently assessed studies and extracted data.

RESULTS

Data from forty-one studies including 17270 patients were included and analyzed. Although no consensus has been achieved on the definition of remission, clinical disease activity, serological activity, duration and treatment are agreed to be critical components of defining remission status. In most studies published in the recent 5 years, 42.4% to 88% patients achieved and maintained the remission status for one year, and 21.1% to 70% for at least 5 years. Factors associated with remission included older age at diagnosis, lower baseline disease activity and absence of major organ involvement, while positive serological results were shown to be negatively associated with remission. Remission-especially prolonged remission-when achieved, demonstrated an association with lower accrual of damage and better quality of life among patients with SLE.

CONCLUSIONS

Remission is an achievable and desirable target for SLE patients, proven to be associated with prognostic benefits. Further development and assessment of a clear remission definition, a risk stratification model as well as a full algorithm with frequency of monitoring, timepoints for treatment adjustment and drug withdrawal are required.

Anti-nucleosome antibodies increase the risk of renal relapse in a prospective cohort of patients with clinically inactive systemic lupus erythematosus

An important goal in the management of systemic lupus erythematosus (SLE) is the prediction of relapses. This study assesses whether anti-nucleosome antibodies (anti-NCS) increase the risk of renal relapse in inactive SLE. A prospective cohort of 115 patients with inactive SLE (M-SLEDAI ≤ 2) were followed for 12 months to assess the development of relapse (increase of M-SLEDAI ≥ 4) and specific renal flare (renal SLEDAI ≥ 4). At baseline, we identified potential risk factors for relapse, including anti-NCS. At baseline, 18 (16%) of the 115 patients with inactive SLE were anti-NCS positive. At the 12-month follow-up, anti-NCS-positive patients had a higher incidence of renal relapse compared to anti-NCS-negative patients (38.9% vs 13.4%, respectively). In Cox regression analysis, after adjusting for age, disease duration, anti-dsDNA, and immunosuppressive drugs, the presence of anti-NCS positivity at baseline increased the risk of renal relapse (HR: 5.31, 95% CI 2.03–13.92). Nevertheless, there were no differences in the incidence of other relapses in anti-NCS-positive versus anti-NCS-negative. Our results indicate that in inactive SLE, anti-NCS determination can be useful for identifying patients with a higher risk of developing renal relapse. Interestingly, this study identified that continued use of oral immunosuppressive therapy in patients with inactive SLE can reduce the risk of renal relapse.

Association of toll-like receptor 9 expression with prognosis of systemic lupus erythematosus

The current study assessed the association between toll-like receptor 9 (TLR9) and systemic lupus erythematosus (SLE) and subsequently determined the predictive value of TLR9 in assessing the prognosis of SLE. A total of 90 newly diagnosed patients with SLE and 49 healthy control subjects were enrolled in the current study. The expression of TLR9 mRNA was measured in whole blood samples from patients and controls. All patients were followed up for ≥2 years and their clinical parameters were recorded. After 2 years, 30 patients were randomly chosen from patient subgroups with high (n=20) or low (n=10) TLR9 levels and the expression of TLR9 mRNA were measured again. Cox proportional hazards regression was used to identify the risk factors of SLE prognosis. Patients with SLE and high SLE disease activity exhibited significantly increased TLR9 expression (P<0.05). Persistent proteinuria of >0.5 g/day [hazard ratio (HR), 6.314; 95% confidence interval (CI), 2.858-13.947], C-reactive protein levels (HR, 1.013; 95% CI, 1.007-1.019) and high-TLR9 mRNA expression (HR, 3.852; 95% CI, 1.931-7.684) were independent risk factors of poor prognosis during a 2-year follow-up period, whereas patient treatment with >1 immunosuppressant (HR, 0.374; 95% CI, 0.173-0.808) was a factor indicating favorable prognosis. Furthermore, the expression of TLR9 mRNA remained high in patients with poor prognosis at the end of a 2-year follow-up period but in patients with a favorable prognosis, TLR9 mRNA expression was significantly reduced compared with the levels measured at SLE onset (P<0.0001). Therefore, the expression of TLR9 mRNA in whole blood samples at SLE onset is associated with SLE disease activity and its expression may be used as an indicator of poor prognosis in patients with SLE.

Progressive reduction of serum complement levels: a risk factor for relapse in patients with hypocomplementemia in systemic lupus erythematosus

Objective

Serologically active clinically quiescent (SACQ)-SLE is a subtype of systemic lupus erythematosus (SLE); most SACQ-SLE patients relapse. Although complement and/or anti-dsDNA level fluctuations during SACQ status are reportedly not useful for predicting relapse, they might be useful in specific clinical settings. We aimed to assess the correlation between future relapse and progressive reductions in serum complement levels following remission in patients with hypocomplementemia .

Methods

We retrospectively reviewed patients aged ≥15 years who were treated with ≥20 mg/day of prednisolone for remission induction. After achieving remission, the patients treated with prednisolone tapered to ≤15 mg/day without relapse and followed by hypocomplementemia (first hypocomplementemia point) were analyzed. The primary outcome was the relapse during the first 24 months.

Results

Seventy-six patients were enrolled; 31 (40.8%) relapsed. A ≥10% reduction after the first hypocomplementemia point in serum C3, C4, and CH50 levels was found in 10, 21, and 16 patients, respectively. Hazard ratios (95% confidence intervals) for relapse were 2.32 (0.92–5.12) for serum C3 levels and 2.46 (1.18–5.01) for serum C4 levels. Progressive reductions in serum C3 and C4 levels had relatively high specificity (93.3% and 82.2%) but limited sensitivity (22.6% and 41.9%) for predicting relapse. However, simultaneous progressive reduction in C3 levels and increase in anti-dsDNA antibody levels had the highest specificity (97.8%), and simultaneous progressive reduction in C4 levels or increase in anti-dsDNA antibody levels had the highest sensitivity (71.0%).

Conclusion

Simultaneous progressive reductions in complement levels and increases in anti-dsDNA antibody levels may indicate future relapse SACQ-SLE patients.

Autoantibodies Recognizing Secondary NEcrotic Cells Promote Neutrophilic Phagocytosis and Identify Patients With Systemic Lupus Erythematosus

Deficient clearance of apoptotic cells reportedly contributes to the etiopathogenesis of the autoimmune disease systemic lupus erythematosus (SLE). Based on this knowledge, we developed a highly specific and sensitive test for the detection of SLE autoantibodies (AAb) utilizing secondary NEcrotic cell (SNEC)-derived material as a substrate. The goal of the present study was to validate the use of SNEC as an appropriate antigen for the diagnosis of SLE in large cohort of patients. We confirmed the presence of apoptotically modified autoantigens on SNEC (dsDNA, high mobility group box 1 protein, apoptosis-associated chromatin modifications, e.g., histones H3-K27-me3; H2A/H4 AcK8,12,16; and H2B-AcK12). Anti-SNEC AAb were measured in the serum of 155 patients with SLE, 89 normal healthy donors (NHD), and 169 patients with other autoimmune connective tissue diseases employing SNEC-based indirect enzyme-linked immunosorbent assay (SNEC ELISA). We compared the test performance of SNEC ELISA with the routine diagnostic tests dsDNA Farr radioimmunoassay (RIA) and nucleosome-based ELISA (anti-dsDNA-NcX-ELISA). SNEC ELISA distinguished patients with SLE with a specificity of 98.9% and a sensitivity of 70.6% from NHD clearly surpassing RIA and anti-dsDNA-NcX-ELISA. In contrast to the other tests, SNEC ELISA significantly discriminated patients with SLE from patients with rheumatoid arthritis, primary anti-phospholipid syndrome, spondyloarthropathy, psoriatic arthritis, and systemic sclerosis. A positive test result in SNEC ELISA significantly correlated with serological variables and reflected the uptake of opsonized SNEC by neutrophils. This stresses the relevance of SNECs in the pathogenesis of SLE. We conclude that SNEC ELISA allows for the sensitive detection of pathologically relevant AAb, enabling its diagnostic usage. A positive SNEC test reflects the opsonization of cell remnants by AAb, the neutrophil recruitment to tissues, and the enhancement of local and systemic inflammatory responses.

Urinary levels of sirtuin-1 associated with disease activity in lupus nephritis

Identifying new markers of disease flares in lupus nephritis (LN) that facilitate patient stratification and prognosis is important. Therefore, the aim of the present study was to analyze whether urinary SIRT1 expression was altered in LN and whether SIRT1 values in urine could be valuable biomarker of disease activity. In a cohort study, urinary pellets from 40 patients diagnosed with systemic lupus erythematosus (SLE) were analyzed. Clinical measures of lupus activity were assessed. The expression of SIRT1 was quantified by quantitative PCR (qRT-PCR) and immunoblot, then compared between patients with active lupus nephritis, in remission and healthy controls. Association with lupus activity and renal histological features was also analyzed. A significant increase in SIRT1 mRNA levels in patients with active LN was observed compared with those in remission (P=0.02) or healthy controls (P=0.009). In addition, SIRT-1 protein levels were also augmented in LN group than remission (P=0.029) and controls (P=0.001). A strong association was found between SIRT1 expression with anti-dsDNA in SLE and in patients with LN. In addition, histological features in LN biopsies were related with SIRT1, increasing its expression in proliferative forms. Finally, SIRT1 expression values showed a strong discriminatory power of renal injury in SLE. Our study demonstrated an altered urinary expression of SIRT1 and a strong association with disease activity in LN patients, being a valuable marker of renal injury. These results showed the role of the SIRT1 pathway in the SLE pathogenesis.

Biomarkers in connective tissue diseases

Autoimmune connective tissue diseases are clinically variable, making biomarkers desirable for assessing future disease risk, supporting early and accurate diagnosis, monitoring disease activity and progression, selecting therapeutics, and assessing treatment response. Because of their correlations with specific clinical characteristics and often with disease progression, autoantibodies and other soluble mediators are considered potential biomarkers. Additional biomarkers might reflect downstream pathologic processes or appear because of ongoing inflammation and damage. Because of overlap between diseases, some biomarkers have limited specificity for a single autoimmune connective tissue disease. This review describes select current biomarkers that aid in the diagnosis and treatment of several major systemic autoimmune connective tissue disorders: systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody-associated vasculitides. Newly proposed biomarkers that target various stages in disease onset or progression are also discussed. Newer approaches to overcome the diversity observed in patients with these diseases and to facilitate personalized disease monitoring and treatment are also addressed.

Failure to achieve lupus low disease activity state (LLDAS) six months after diagnosis is associated with early damage accrual in Caucasian patients with systemic lupus erythematosus

Background

The aim was to assess the attainability and outcome of the lupus low disease activity state (LLDAS) in the early stages of systemic lupus erythematosus (SLE).

Methods

LLDAS prevalence was evaluated at 6 (T1) and 18 (T2) months after diagnosis and treatment initiation (T0) in a monocentric cohort of 107 (median disease duration 9.7 months) prospectively followed Caucasian patients with SLE. Reasons for failure to achieve LLDAS were also investigated. Multivariate models were built to identify factors associated with lack of LLDAS achievement and to investigate the relationship between LLDAS and Systemic Lupus International Collaboration Clinics (SLICC)/Damage Index (SDI) accrual.

Results

There were 47 (43.9%) patients in LLDAS at T1 and 48 (44.9%) at T2. The most frequent unmet LLDAS criterion was prednisolone dose >7.5 mg/day (83% of patients with no LLDAS at T1). Disease manifestations with the lowest remission rate during follow up were increased anti-double-stranded DNA (persistently present in 85.7% and 67.5% of cases at T1 and T2, respectively), low serum complement fractions (73.2% and 66.3%) and renal abnormalities (46.4% and 28.6%). Renal involvement at T0 was significantly associated with failure to achieve LLDAS both at T1 (OR 7.8, 95% CI 1.4–43.4; p = 0.019) and T2 (OR 3.9, 95% CI 1.4–10.6; p = 0.008). Presence of any organ damage (SDI ≥1) at T2 was significantly associated with lack of LLDAS at T1 (OR 5.0, 95% CI 1.5–16.6; p = 0.009) and older age at diagnosis (OR 1.05 per year, 95% CI 1.01–1.09; p = 0.020).

Conclusion

LLDAS is a promising treatment target in the early stages of SLE, being attainable and negatively associated with damage accrual, but it fit poorly to patients with renal involvement.

Predictive biological markers of systemic lupus erythematosus flares: a systematic literature review

BACKGROUND

The aim of this study was to identify the most reliable biomarkers in the literature that could be used as flare predictors in systemic lupus erythematosus (SLE).

METHODS

A systematic review of the literature was performed using two databases (MEDLINE and EMBASE) through April 2015 and congress abstracts from the American College of Rheumatology and the European League Against Rheumatism were reviewed from 2010 to 2014. Two independent reviewers screened titles and abstracts and analysed selected papers in detail, using a specific questionnaire. Reports addressing the relationships between one or more defined biological test(s) and the occurrence of disease exacerbation were included in the systematic review.

RESULTS

From all of the databases, 4668 records were retrieved, of which 69 studies or congress abstracts were selected for the systematic review. The performance of seven types of biomarkers performed routinely in clinical practice and nine types of novel biological markers was evaluated. Despite some encouraging results for anti-double-stranded DNA antibodies, anti-C1q antibodies, B-lymphocyte stimulator and tumour necrosis factor-like weak inducer of apoptosis, none of the biomarkers stood out from the others as a potential gold standard for flare prediction. The results were heterogeneous, and a lack of standardized data prevented us from identifying a powerful biomarker.

CONCLUSIONS

No powerful conclusions could be drawn from this systematic review due to a lack of standardized data. Efforts should be undertaken to optimize future research on potential SLE biomarkers to develop validated candidates. Thus, we propose a standardized pattern for future studies.

Acetylated Histones in Apoptotic Microparticles Drive the Formation of Neutrophil Extracellular Traps in Active Lupus Nephritis

Objective

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of autoantibodies against nuclear components. Lupus nephritis (LN) is the major cause of morbidity and mortality in patients with SLE. Central to the pathogenesis of SLE is the accumulation of cellular waste, especially apoptotic microparticles (MPs), which stimulates diverse immune reactions including the formation of neutrophil extracellular traps (NETs). In this study, we investigated the content of MPs from SLE patients with and without (active) LN, their capacity to stimulate NET release, and assessed the molecular mechanisms underlying MP-induced NETosis.

Methods

MPs from SLE patients with biopsy-proven active LN, remissive LN, without LN, and healthy controls were characterized by flow cytometry. Isolated neutrophils were exposed to MPs derived from either patient plasma or apoptotic human umbilical vein endothelial cells, and NET release was quantified by immunofluorescence imaging, spectrofluorometry or an in-house developed NET ELISA.

Results

MPs from SLE patients with active LN contain higher levels of acetylated chromatin compared to MPs from those with remissive LN, without LN, or healthy controls. MPs enriched in hyperacetylated chromatin are more potent in inducing NETosis when compared to MPs containing moderate acetylated chromatin. The release of NETs in response to MPs occurs rapidly in a concentration-dependent manner and proceeds independent from the formation of reactive oxygen species (ROS).

Conclusion

Our data suggest that MPs containing acetylated chromatin drive ROS-independent NET release in SLE patients with active LN, which may lead to the glomerular deposition of NETs and subsequent NET-driven LN.

Predictive factors of flares in systemic lupus erythematosus patients: data from a multiethnic Latin American cohort

Purpose The purpose of this paper is to determine the factors predictive of flares in systemic lupus erythematosus (SLE) patients. Methods A case-control study nested within the Grupo Latino Americano De Estudio de Lupus (GLADEL) cohort was conducted. Flare was defined as an increase ≥4 points in the SLEDAI. Cases were defined as patients with at least one flare. Controls were selected by matching cases by length of follow-up. Demographic and clinical manifestations were systematically recorded by a common protocol. Glucocorticoid use was recorded as average daily dose of prednisone and antimalarial use as percentage of time on antimalarial and categorized as never (0%), rarely (>0-25%), occasionally (>25%-50%), commonly (˃50%-75%) and frequently (˃75%). Immunosuppressive drugs were recorded as used or not used. The association between demographic, clinical manifestations, therapy and flares was examined using univariable and multivariable conditional logistic regression models. Results A total of 465 cases and controls were included. Mean age at diagnosis among cases and controls was 27.5 vs 29.9 years, p = 0.003; gender and ethnic distributions were comparable among both groups and so was the baseline SLEDAI. Independent factors protective of flares identified by multivariable analysis were older age at diagnosis (OR = 0.929 per every five years, 95% CI 0.869-0.975; p = 0.004) and antimalarial use (frequently vs never, OR = 0.722, 95% CI 0.522-0.998; p = 0.049) whereas azathioprine use (OR = 1.820, 95% CI 1.309-2.531; p < 0.001) and SLEDAI post-baseline were predictive of them (OR = 1.034, 95% CI 1.005-1.064; p = 0.022). Conclusions In this large, longitudinal Latin American cohort, older age at diagnosis and more frequent antimalarial use were protective whereas azathioprine use and higher disease activity were predictive of flares.

Analysis of Complete Remission in Systemic Lupus Erythematosus Patients Over a 32-Year Period

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by an unpredictable and fluctuating course. Although various methods have been developed to measure disease activity, there is still a lack of consensus about the optimal criteria for SLE remission. The principal aim of our study was to identify the number of lupus patients achieving a complete remission (implying that for 3 years there were no clinical or serologic features and no treatment with steroids and immunosuppressive drugs) in a single cohort of patients followed for a period of up to 32 years. In addition, we have identified patients in clinical but not serologic remission (known as serologically active, clinically quiescent disease [SACQ]) and vice versa. We were particularly interested to determine the factors associated with complete remission.

METHODS

Eligible patients were followed up in the University College Hospital Lupus cohort from January 1978 until December 2010 for a period of at least 3 years. Complete remission was defined as a period of at least 3 years with clinical inactivity (British Isles Lupus Assessment Group scores of C, D, or E only) and laboratory remission (no antibodies to double-stranded DNA and normal complement C3 levels), and being off-treatment with corticosteroids and immunosuppressants. Antimalarial and nonsteroidal antiinflammatory drugs were allowed.

RESULTS

Of 624 lupus patients at our hospital, a total of 532 patients met the strict inclusion criteria for the study. Of these 532 patients, 77 patients (14.5%) achieved complete remission for at least 3 years, and 23 (4.3%) achieved complete remission for a minimum period of 10 years. Ten of these 77 patients were subsequently lost to followup, and, interestingly, flares occurred subsequently in 15 of the 67 remaining patients (22.4%). Three patients relapsed after the tenth year of remission. Forty-five patients (8.5%) fulfilled the requirement for SACQ, and 66 patients (12.4%) achieved only serologic remission.

CONCLUSION

Our study indicated that 14.5% of lupus patients achieved a complete remission for 3 years. However, flares may continue to occur beyond 10 years of remission. Long-term followup of SLE is therefore mandatory.

The impact of biological treatments on the anti-dsDNA and anti-nucleosome tests

Background Anti-double stranded DNA antibodies are a very heterogeneous group of antibodies, quite specific for systemic lupus erythematosus. Newer technologies, such as addressable laser bead immunoassays (ALBIA), show great potential as a diagnostic application. The production of anti-double stranded DNA antibodies is often encountered in inflammatory arthritis; however, literature reports that the actual onset of drug induced lupus in patients treated with biological drugs is a rare event. False positive results for anti-double stranded DNA and anti-nucleosome antibodies detected in patients with inflammatory arthritis treated with different biologics prompted the investigation of full autoantibody profiles to evaluate each biomarker's diagnostic performance in systemic lupus erythematosus. The aim of the study was to compare the diagnostic performance of anti-double stranded DNA antibody and anti-nucleosome antibody methods and to evaluate the value of simultaneously measuring anti-double stranded DNA and anti-nucleosome antibodies, along with other anti-nuclear antibody analytes, as biomarkers for systemic lupus erythematosus, using a more appropriate control cohort including inflammatory arthritis patients with a non-clinical drug induced lupus. Methods Anti-double stranded DNA and anti-nucleosome antibody levels were evaluated in 247 patient samples: 70 systemic lupus erythematosus, 177 disease controls (including 97 inflammatory arthritis during treatment with different biologics) using the Bio-Rad BioPlex® 2200. Results Anti-nucleosome antibodies demonstrated greater clinical sensitivity and specificity than anti-double stranded DNA antibodies. At the manufacturers' cut-off range, considering the two markers as a single or combined test, the "anti-double stranded DNA test or anti-nucleosome antibodies" was the most sensitive combination (0.400) with the best negative likelihood ratio (0.62) and negative predictive value (0.803). Conclusion Anti-nucleosome antibodies are a more sensitive and specific biomarker of systemic lupus erythematosus than anti-double stranded DNA antibodies. Anti-nucleosome antibodies and anti-double stranded DNA antibodies are independent and complementary markers of systemic lupus erythematosus diagnosis and, therefore, are strongly suggested as combined tests (positive predictive value = 0.938). Moreover, the combined use of the two tests may help to overcome the decreased specificity percentage of the anti-double stranded DNA test, when considering an inflammatory arthritis cohort under biological therapies. The ALBIA method for anti-nuclear specificity detection allows a full autoantibody assessment, resulting in a much higher clinical specificity for systemic lupus erythematosus in the presence of ≥3 positive markers and significantly more positive likelihood ratio when ≥2 positive markers are present.

Flares in systemic lupus erythematosus: diagnosis, risk factors and preventive strategies

Despite advances in the treatment, patients with systemic lupus erythematosus (SLE) often experience disease exacerbations (flares) of varying severity. Their diagnosis is primarily made on clinical grounds after exclusion of other diseases or disturbances, primarily infections, and can be assisted by the use of validated clinical indices. Serological tests such as serum complement fractions and anti-dsDNA autoantibodies, are helpful in monitoring SLE activity, but they lack high diagnostic accuracy. Flares are more frequent in patients with persistent immunological and clinical activity, and have been described as significant risk factor for development of irreversible end-organ damage. Accordingly, prevention of flares has been recognized as a distinct therapeutic target in SLE and involves adequate control of disease activity, use of hydroxychloroquine, maintaining immunosuppressive or biologic therapy for several years, and avoiding non-compliance issues. The future holds promise for the discovery of biomarkers that will accurately predict or diagnose SLE flares, thus allowing for the implementation of patient-tailored preventive strategies.

Molecular and Immunological Basis of Tubulo-Interstitial Injury in Lupus Nephritis: a Comprehensive Review

Lupus nephritis is an important cause of kidney failure in patients of Asian, African, or Hispanic descent. Its etiology and pathogenesis are multifactorial and remain to be elucidated. Accumulating evidence suggests that anti-double-stranded DNA (dsDNA) antibodies play a critical role in the pathogenesis, through its direct binding to cross-reactive antigens on resident renal cells or indirect binding through chromatin material to extracellular matrix components, resulting in complement activation, cell activation and proliferation, and induction of inflammatory and fibrotic processes. While tubulo-interstitial damage portends poor long-term renal prognosis, the mechanisms leading to tubulo-interstitial injury in lupus nephritis has received relatively less attention to date. Immune deposition along the tubular basement membrane is often observed in lupus nephritis and correlates with tubulo-interstitial infiltration of immune cells and interstitial fibrosis. Anti-dsDNA antibodies bind to resident renal cells, including proximal renal tubular epithelial cells, and contribute to renal inflammation and fibrosis. There is emerging evidence that epigenetic influence such as DNA methylation, histone modification, and microRNAs (miRs) also contribute to kidney fibrosis. Overexpression of miR-150 is observed in renal biopsies from patients with lupus nephritis and correlates with kidney fibrosis and chronicity score. Mycophenolate mofetil (MMF) is an established and effective standard-of-care therapy for patients with lupus nephritis. Accumulating data suggest that in addition to its immunosuppressive actions on lymphocyte proliferation, mycophenolic acid (MPA), the active metabolite of MMF, can exert a direct effect on nonimmune cells. Mediators of inflammation and fibrosis induced by anti-dsDNA antibodies in cultured proximal renal tubular epithelial cells are ameliorated by the addition of MPA, suggesting that in addition to its immunosuppressive actions, MPA may also have a beneficial effect in improving tubulo-interstitial inflammation and fibrosis through its direct action on proximal renal tubular epithelial cells.

Does expert opinion match the operational definition of the Lupus Low Disease Activity State (LLDAS)? A case-based construct validity study

OBJECTIVE

To evaluate the construct validity of the Lupus Low Disease Activity State (LLDAS), a treatment target in systemic lupus erythematosus (SLE).

METHODS

Fifty SLE case summaries based on real patients were prepared and assessed independently for meeting the operational definition of LLDAS. Fifty international rheumatologists with expertise in SLE, but with no prior involvement in the LLDAS project, responded to a survey in which they were asked to categorize the disease activity state of each case as remission, low, moderate, or high. Agreement between expert opinion and LLDAS was assessed using Cohen's kappa.

RESULTS

Overall agreement between expert opinion and the operational definition of LLDAS was 77.96% (95% CI: 76.34-79.58%), with a Cohen's kappa of 0.57 (95% CI: 0.55-0.61). Of the cases (22 of 50) that fulfilled the operational definition of LLDAS, only 5.34% (59 of 22 × 50) of responses classified the cases as moderate/high activity. Of the cases that did not fulfill the operational definition of LLDAS (28 of 50), 35.14% (492 of 28 × 50) of responses classified the cases as remission/low activity. Common reasons for discordance were assignment to remission/low activity of cases with higher corticosteroid doses than defined in LLDAS (prednisolone ≤ 7.5mg) or with SLEDAI-2K >4 due to serological activity (high anti-dsDNA antibody and/or low complement).

CONCLUSIONS

LLDAS has good construct validity with high overall agreement between the operational definition of LLDAS and expert opinion. Discordance of results suggests that the operational definition of LLDAS is more stringent than expert opinion at defining a low disease activity state.

Autoantibodies against Modified Histone Peptides in SLE Patients Are Associated with Disease Activity and Lupus Nephritis

Persistent exposure of the immune system to death cell debris leads to autoantibodies against chromatin in patients with systemic lupus erythematosus (SLE). Deposition of anti-chromatin/chromatin complexes can instigate inflammation in multiple organs including the kidney. Previously we identified specific cell death-associated histone modifications as targets of autoantibodies in SLE. In this study we addressed, in a large cohort of SLE patients and controls, the question whether plasma reactivities with specific histone peptides associated with serology and clinical features. Plasma from SLE patients with and without lupus nephritis, disease controls, and healthy controls, were tested in ELISA with histone H4 peptide acetylated at lysines 8, 12 and 16 (H4p^ac), H2B peptide acetylated at lysine 12 (H2Bp^ac), H3 peptide trimethylated at lysine 27 (H3p^me), and their unmodified equivalents. SLE patients displayed a higher reactivity with the modified equivalent of each peptide. Reactivity with H4p^ac showed both a high sensitivity (89%) and specificity (91%) for SLE, while H2Bp^ac exhibited a high specificity (96%) but lower sensitivity (69%). Reactivity with H3p^me appeared not specific for SLE. Anti-H4p^ac and anti-H2Bp^ac reactivity demonstrated a high correlation with disease activity. Moreover, patients reacting with multiple modified histone peptides exhibited higher SLEDAI and lower C3 levels. SLE patients with renal involvement showed higher reactivity with H2B/H2Bp^ac and a more pronounced reactivity with the modified equivalent of H3p^me and H2Bp^ac. In conclusion, reactivity with H4p^ac and H2Bp^ac is specific for SLE patients and correlates with disease activity, whereas reactivity with H2Bp^ac is in particular associated with lupus nephritis.

Autoantibodies, complement and type I interferon as biomarkers for personalized medicine in SLE

Systemic lupus erythematosus (SLE) can be a mysterious disease, presenting with extremely divergent clinical phenotypes. Already, biomarkers are very helpful tools for diagnosis, assessment and monitoring of disease activity, differential diagnosis of clinical manifestations, prediction of the disease course and stratified therapy, and they hold the key to personalized medicine in SLE. We summarize the clinical information that can only be supplied by autoantibodies, complement components and interferon biomarkers in this diverse disease.

[Clinical practice guidelines for systemic lupus erythematosus: Recommendations for general clinical management]

Systemic lupus erythematosus (SLE) is a complex rheumatic multisystemic disease of autoimmune origin with significant potential morbidity and mortality. It is one of the most common autoimmune diseases with an estimated prevalence of 20-150 cases per 100,000 inhabitants. The clinical spectrum of SLE is wide and variable both in clinical manifestations and severity. This prompted the Spanish Ministry of Health, Social Services and Equality to promote and fund the development of a clinical practice guideline (CPG) for the clinical care of SLE patients within the Programme of CPG in the National Health System which coordinates GuiaSalud. This CPG is is intended as the reference tool in the Spanish National Health System in order to support the comprehensive clinical management of people with SLE by all health professionals involved, regardless of specialty and level of care, helping to standardize and improve the quality of clinical decisions in our context in order to improve the health outcomes of the people affected. The purpose of this document is to present and discuss the rationale of the recommendations on the general management of SLE, specifically, clinical follow-up, general therapeutic approach, healthy lifestyles, photoprotection, and training programmes for patients. These recommendations are based on the best available scientific evidence, on discussion and the consensus of expert groups.

Serum antibodies to human leucocyte antigen (HLA)-E, HLA-F and HLA-G in patients with systemic lupus erythematosus (SLE) during disease flares: Clinical relevance of HLA-F autoantibodies

T lymphocyte hyperactivity and progressive inflammation in systemic lupus erythematosus (SLE) patients results in over-expression of human leucocyte antigen (HLA)-Ib on the surface of lymphocytes. These are shed into the circulation upon inflammation, and may augment production of antibodies promoting pathogenicity of the disease. The objective was to evaluate the association of HLA-Ib (HLA-E, HLA-F and HLA-G) antibodies to the disease activity of SLE. The immunoglobulin (Ig)G/IgM reactivity to HLA-Ib and β2m in the sera of 69 German, 29 Mexican female SLE patients and 17 German female controls was measured by multiplex Luminex(®)-based flow cytometry. The values were expressed as mean flourescence intensity (MFI). Only the German SLE cohort was analysed in relation to the clinical disease activity. In the controls, anti-HLA-G IgG predominated over other HLA-Ib antibodies, whereas SLE patients had a preponderance of anti-HLA-F IgG over the other HLA-Ib antibodies. The disease activity index, Systemic Lupus Erythematosus Disease Activity Index (SLEDAI)-2000, was reflected only in the levels of anti-HLA-F IgG. Anti-HLA-F IgG with MFI level of 500-1999 was associated with active SLE, whereas inactive SLE revealed higher MFI (>2000). When anti-HLA-F IgG were cross-reactive with other HLA-Ib alleles, their reactivity was reflected in the levels of anti-HLA-E and -G IgG. The prevalence of HLA-F-monospecific antibodies in SLE patients was also associated with the clinical disease activity. Anti-HLA-F IgG is possibly involved in the clearance of HLA-F shed from lymphocytes and inflamed tissues to lessen the disease's severity, and thus emerges as a beneficial immune biomarker. Therefore, anti-HLA-Ib IgG should be considered as a biomarker in standard SLE diagnostics.

Impaired phagocytosis of apoptotic cell material in serologically active clinically quiescent patients with systemic lupus erythematosis

AIM

Serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE) account for 8-12% of all patients with SLE, but there is disagreement about whether such patients are indeed clinically stable. Patients with clinically active SLE have decreased macrophage function, although the status of SACQ patients with SLE is unclear.

METHOD

This study compared 18 patients who met the diagnostic criteria for SACQ SLE with 18 healthy volunteers with regard to the capability of macrophages to clear apoptotic bodies by use of a modified serum-free phagocytosis test. Macrophages that naturally differentiated from monocytes were used to engulf apoptotic cells developed from polymorphonuclear neutrophils.

RESULTS

The results showed that macrophages from SACQ patients with SLE had less phagocytotic capability than those from healthy controls.

CONCLUSION

The significant reduction of macrophage phagocytotic capability in these patients suggests the potential for disease recurrence. The use of a serum-free method confirmed the presence of intrinsic factors that modulate the decrease of macrophage function in SLE.

Anti-dsDNA and Antichromatin Antibody Isotypes in Serologically Active Clinically Quiescent Systemic Lupus Erythematosus

OBJECTIVE

Serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE) are clinically quiescent despite serologic activity. Since studies suggest that antichromatin antibodies are more sensitive than anti-dsDNA antibodies in detecting active SLE, and that immunoglobulin (Ig) G, in particular complement-fixing subclasses, may be more pathogenic than IgM, we investigated the levels of anti-dsDNA and antichromatin isotypes in SACQ patients as compared to non-SACQ patients with SLE.

METHODS

Levels of IgM, IgA, IgG, and IgG1-4 antichromatin and anti-dsDNA were measured by ELISA. SACQ was defined as ≥ 2 years with the SLE Disease Activity Index 2000 (SLEDAI-2K) at 2 or 4 from serologic activity, during which patients could be taking antimalarials, but not corticosteroids or immunosuppressives. Unselected non-SACQ patients with SLE were used as comparators. SACQ patient serum samples were further stratified based on subsequent development of flare, defined as clinical SLEDAI-2K ≥ 1 and/or treatment initiation. Nonparametric statistics were used, and generalized estimating equations were applied to account for multiple samples in the same patient.

RESULTS

SACQ patients' complement-fixing antichromatin and anti-dsDNA IgG subclasses were significantly higher than those of non-SACQ patients. When the sample drawn latest in a SACQ period was analyzed, there was no difference between antichromatin or anti-dsDNA isotype or IgG subclass levels between patients who flared and those who remained SACQ, nor were consistent trends seen when samples were examined during SACQ and flare in the same patient.

CONCLUSION

The SACQ phenotype does not arise from a lack of pathogenic anti-dsDNA and/or antichromatin autoantibodies. Neither increases in antichromatin nor anti-dsDNA isotype or IgG subclass levels were predictive of or coincident with flare in SACQ patients.

Assessment of long-term remission in lupus nephritis patients: a retrospective analysis over 30 years

OBJECTIVE

To review the likelihood of very long-term remission in patients with biopsy-proven LN attempting to identify good prognostic features.

METHODS

We reviewed patients with LN whose renal biopsies showed World Health Organization (WHO) classes III, IV and V and who had a follow-up of at least 5 years between 1973 and 2008. We analysed demographic, clinical, laboratory and therapeutic parameters comparing those patients with (group A) and without (group B) 5 year remission.

RESULTS

Of 191 LN patients followed, 105 patients met the strict inclusion criteria. Ninety-five patients were female. Mean age at diagnosis of lupus was 24.1 years (s.d. 10.7). ean age at diagnosis of LN was 28.4 years (s.d. 11.3). The mean duration of follow-up was 13.7 years (s.d. 14.1). Forty (38%) patients achieved 5 year remission, of whom 17 (16.2%) had remission for ≥15 years. The incidence of flares per year from 5 to 15 years was 7.9%; however, no flares were observed after 15 years of remission. The only distinguishing feature found in this study was the association of WHO class IV on kidney biopsy with LN progression (P = 0.03).

CONCLUSION

Renal histology with WHO class IV predicted a poor long-term remission rate. Age, sex, ethnicity, serological parameters and treatment received did not predict long-term remission. Renal flares can occur up to 15 years after a patient has gone into remission.

[Biologics in SLE]

Biologics have become indispensable in the last decade in the treatment of the more common rheumatic diseases. For treating systemic lupus erythematodes (SLE), B-cell depletion, albeit off-label, has been a well-accepted strategy in severe and refractory disease. Unexpectedly, however, the results of the first randomized controlled rituximab trials in SLE were negative. New trials with improved study protocols are ongoing, which should resolve this issue. In 2012, with the approval of belimumab, SLE finally entered the era of approved biological therapies. The anti-Blys/BAFF antibody belimumab showed prevention of SLE flares, glucocorticoid sparing, and significant improvement in the quality of life of SLE patients, in part by drastically reducing immune complex mediated fatigue. Positive reports on further targeting approaches give hope that additional biological agents will be available for SLE therapy soon.

Chance, genetics, and the heterogeneity of disease and pathogenesis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a remarkably complex and heterogeneous systemic autoimmune disease. Disease complexity within individuals and heterogeneity among individuals, even genetically identical individuals, is driven by stochastic execution of a complex inherited program. Genome-wide association studies (GWAS) have progressively improved understanding of which genes are most critical to the potential for SLE and provided illuminating insight about the immune mechanisms that are engaged in SLE. What initiates expression of the genetic program to cause SLE within an individual and how that program is initiated remains poorly understood. If we extrapolate from all of the different experimental mouse models for SLE, we can begin to appreciate why SLE is so heterogeneous and consequently why prediction of disease outcome is so difficult. In this review, we critically evaluate extrinsic versus intrinsic cellular functions in the clearance and elimination of cellular debris and how dysfunction in that system may promote autoimmunity to nuclear antigens. We also examine several mouse models genetically prone to SLE either because of natural inheritance or inheritance of induced mutations to illustrate how different immune mechanisms may initiate autoimmunity and affect disease pathogenesis. Finally, we describe the heterogeneity of disease manifestations in SLE and discuss the mechanisms of disease pathogenesis with emphasis on glomerulonephritis. Particular attention is given to discussion of how anti-DNA autoantibody initiates experimental lupus nephritis (LN) in mice.

Serology of Lupus Erythematosus: Correlation between Immunopathological Features and Clinical Aspects

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the aberrant production of a broad and heterogenous group of autoantibodies. Even though the presence of autoantibodies in SLE has been known, for more than 60 years, still nowadays a great effort is being made to understand the pathogenetic, diagnostic, and prognostic meaning of such autoantibodies. Antibodies to ds-DNA are useful for the diagnosis of SLE, to monitor the disease activity, and correlate with renal and central nervous involvements. Anti-Sm antibodies are highly specific for SLE. Anti-nucleosome antibodies are an excellent marker for SLE and good predictors of flares in quiescent lupus. Anti-histone antibodies characterize drug-induced lupus, while anti-SSA/Ro and anti-SSB/La antibodies are associated with neonatal lupus erythematosus and photosensitivity. Anti-ribosomal P antibodies play a role in neuropsychiatric lupus, but their association with clinical manifestations is still unclear. Anti-phospholipid antibodies are associated with the anti-phospholipid syndrome, cerebral vascular disease, and neuropsychiatric lupus. Anti-C1q antibodies amplify glomerular injury, and the elevation of their titers may predict renal flares. Anti-RNP antibodies are a marker of Sharp's syndrome but can be found in SLE as well. Anti-PCNA antibodies are present in 5–10% of SLE patients especially those with arthritis and hypocomplementemia.

Pathology of systemic lupus erythematosus: the challenges ahead

Many studies have explored the pathology of systemic lupus erythematosus (SLE), an autoimmune rheumatic disorder with a striking female predominance. Numerous autoimmune phenomena are present in this disease, which ultimately result in organ damage. However, the specific cellular and humoral mechanisms underlying the immune dysfunction are not yet fully understood. It is postulated that autoimmunity is based on the interaction of genetic predisposition, hormonal and environmental triggers that result in reduced tolerance to self-tissues. These phenomena could occur because of altered antigen presentation, abnormalities in B cell responses, increases in the function of T-helper cells, abnormal cytokine production, exaggerated effector responses, or loss of regulatory T cells or B cells. Abnormalities in all of these components of the immune response have been implicated to varying degrees in the pathogenesis of SLE. This chapter will attempt to provide a "state-of-the-art" review of the evidence about the mechanisms underlying the pathology of SLE.

Detection of autoantibodies in a point-of-care rheumatology setting

Autoimmune rheumatic diseases are common and confront society with serious medical, social, and financial burdens imposed by their debilitating nature. Many autoimmune diseases are associated with a particular set of autoantibodies, which have emerged as highly useful to define and classify disease, predict flares, or monitor efficacy of therapy. However, current practice for monitoring autoantibodies is protracted, labor-intensive, and expensive. This review provides an overview on the value of point-of-care (POC) biosensor technology in the diagnosis and management of patients with autoimmune rheumatic diseases. Real-time measurement of autoantibodies will clearly benefit the rheumatology practice in emergency and urgent care settings, where definitive diagnosis is essential for initiation of correct critical care therapy. Immediate serological information in clinic will provide considerable value for long-term patient care and an opportunity for an instant, result-deduced therapeutic action, avoiding delays and improving compliance, especially in field-based and remote areas. We describe the particular autoantibodies that are useful disease and activity markers and would, therefore, be attractive to POC applications. Already existing biosensors and platforms that show promise for autoantibody testing are summarized and comparatively evaluated. As POC assessment is gaining momentum in several areas of patient care, we propose that rheumatology is poised to benefit from this innovative and affordable technology.

Linking complement and anti-dsDNA antibodies in the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus is a severe autoimmune disease that affects multiple organ systems resulting in diverse symptoms and outcomes. It is characterized by antibody production to a variety of self-antigens, but it is specifically associated with those against anti-dsDNA. Anti-dsDNA antibodies are present before the onset of clinical disease and are associated with severe manifestations of lupus such as glomerulonephritis. Their levels fluctuate with changes in disease activity and, in combination with the levels of complement proteins C3 and C4, are strong indicators of disease flare and treatment response in patients with lupus. The decreased complement levels that are noted during flares of lupus activity are believed to be secondary to increased autoantibody production and immune complex formation that results in tissue damage; however, recent data suggest that complement activation can also drive development of these pathogenic autoantibodies. This review will explore the various roles of complement in the development and pathogenesis of anti-dsDNA antibodies.

IFNα and its response proteins, IP-10 and SIGLEC-1, are biomarkers of disease activity in systemic lupus erythematosus

OBJECTIVES

To evaluate and compare the clinical efficacy of three biomarkers for interferon (IFN) activity (measured directly and indirectly) and six traditional biomarkers in indicating current and prospective disease activity (DA) in systemic lupus erythematosus (SLE).

METHODS

IFNα (dissociation-enhanced lanthanide fluorescent immunoassay), IFNγ-inducible protein 10 (IP-10) (ELISA) and sialic acid-binding Ig-like lectin 1 (SIGLEC-1) (flow cytometry) were measured in 79 accurately characterised patients with lupus and compared with serum titres of Anti-dsDNA (ELISA and radioimmunoassay), Anti-dsDNA-NcX ELISA, Anti-Nuc ELISA, and complement C3 and C4. DA was evaluated using the British Isles Lupus Assessment Group 2004 Index (BILAG-2004) and a modified SLE Disease Activity Index-2000 (mSLEDAI-2K). In addition, 31 clinically quiescent patients were monitored for flares over the course of 180 days.

RESULTS

Increased levels of IFNα, IP-10 and SIGLEC-1 were found in 32%, 50% and 86%, respectively, of 66 patients with active SLE. IFNα (r=0.45; p<0.0001) and SIGLEC-1 (r=0.54; p<0.0001) correlated better with BILAG-2004 than did IP-10 (r=0.38; p=0.0002), Farr assay (r=0.40; p=0.0001), Anti-dsDNA-NcX ELISA (r=0.28; p=0.0061), Anti-dsDNA ELISA (r=0.31; p=0.0025), Anti-Nuc ELISA (r=0.25; p=0.0121), C3 (r=-0.43; p<0.0001) and C4 (r=-0.33; p=0.0013). Predictors of SLE flares were disease duration ≤92 months, mild clinical activity (in contrast with no activity), complement C3≤89 mg/dl and IFNα≥20 pg/ml, while only lymphocyte count and age were independent predictors in multivariate analysis.

CONCLUSIONS

IFNα, IP-10 and SIGLEC-1 emerged as beneficial biomarkers of DA in patients with SLE. Therefore the implementation of IFN biomarkers in standard lupus diagnostics should be reappraised, especially in view of emerging anti-IFN-directed therapies.

Simultaneous positivity for anti-DNA, anti-nucleosome and anti-histone antibodies is a marker for more severe lupus nephritis

OBJECTIVE

The purpose of this study is to examine autoantibody profile of systemic lupus erythematosus (SLE) patients with lupus nephritis (LN) and to establish the correlation between the antibody reactivity and disease activity of LN.

METHODS

Autoantibodies and serological parameters were measured and analyzed in 589 SLE patients. The associations of the co-positivity of anti-dsDNA, -nucleosome and -histone antibodies (3-pos) with clinical, serological and outcome parameters were analyzed.

RESULTS

At the study entry, the prevalence for anti-dsDNA (61.52 % vs. 34.11 %, P < 0.0001), anti-nucleosome (56.09 % vs. 37.21 %, P = 0.0002) and anti-histone (49.35 % vs. 33.33 %, P = 0.0013) antibodies in patients with LN were significantly higher than that in patients without LN. Patients with 3-pos had a higher proportion of proliferative renal lesions (class III + IV). The incidence of a poor renal outcome (7.14 % vs. 2.52 %, P = 0.0174) in LN patients with 3-pos was significantly higher than those without 3-pos. Moreover, the rate of remission (73.63 % vs. 82.37 %, P = 0.0245) was significantly reduced and recurrence increased (58.90 % vs. 23.44 %, P < 0.0001) in 3-pos patients as compared to that in non 3-pos within the LN group.

CONCLUSION

Our data indicate a strong association between the 3-pos and renal disease activities, especially proliferative glomerulonephritis. The ability of 3-pos to predict renal flares may lead to major additional benefits in the follow-up of these patients.

Autoantibodies and resident renal cells in the pathogenesis of lupus nephritis: getting to know the unknown

Systemic lupus erythematosus is characterized by a breakdown of self-tolerance and production of autoantibodies. Kidney involvement (i.e., lupus nephritis) is both common and severe and can result in permanent damage within the glomerular, vascular, and tubulo-interstitial compartments of the kidney, leading to acute or chronic renal failure. Accumulating evidence shows that anti-dsDNA antibodies play a critical role in the pathogenesis of lupus nephritis through their binding to cell surface proteins of resident kidney cells, thereby triggering the downstream activation of signaling pathways and the release of mediators of inflammation and fibrosis. This paper describes the mechanisms through which autoantibodies interact with resident renal cells and how this interaction plays a part in disease pathogenesis that ultimately leads to structural and functional alterations in lupus nephritis.