Low density granulocytes and neutrophil extracellular trap formation are increased in incomplete systemic lupus erythematosus.

OBJECTIVE: To investigate the proportion of low-density granulocytes (LDGs), circulating plasma neutrophil extracellular traps (NETs), and serum-induced NET formation in patients with incomplete systemic lupus erythematosus (iSLE) and systemic lupus erythematosus (SLE). METHODS: LDGs were measured cross-sectionally in 18 iSLE patients, 11 SLE patients and 14 healthy controls (HCs), whereas circulating NETs and serum-induced NET formation were assessed in 35 iSLE patients, 41 SLE patients and 16 HCs. LDGs (CD14lowCD15+) were measured in PBMCs using flow cytometry and circulating plasma NETs were measured using anti-myeloperoxidase-DNA, anti-citrullinated histone H3 and anti-elastase-DNA complex ELISAs. Serum-induced NET formation was assessed by incubating healthy neutrophils with serum from iSLE patients, SLE patients or HCs and visualizing NETs with fluorescence microscopy. RESULTS: Proportions of LDGs and circulating plasma NETs were similarly elevated in iSLE and SLE patients compared with those in HCs. Furthermore, patients under hydroxychloroquine (HCQ) treatment had lower proportions of LDGs than those without. Serum from iSLE and SLE patients similarly induced NET formation in healthy neutrophils. In iSLE patients, myeloperoxidase-DNA complexes were correlated with proportions of age-associated B-cells, memory B-cells and negatively with naïve B-cells, while we did not find associations between measures of NETs or serum-induced NET formation and interferon score or clinical parameters. CONCLUSION: These results show that neutrophil dysfunction, including higher proportions of LDGs, and increased NET formation, already occur in iSLE, similar to SLE, despite differences in disease manifestations. Thereby, neutrophil dysfunction may contribute to sustained exposure to autoantigens and autoreactivity in early stages of SLE.

The effects of hydroxychloroquine and its promising use in refractory obstetric antiphospholipid syndrome.

Hydroxychloroquine (HCQ) is obtained by hydroxylation of chloroquine (CQ) and the first indication was malaria. Nowadays, HCQ is commonly used in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) with favorable results. Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombosis and/or pregnancy morbidity and persistent positivity of antiphospholipid antibodies. Around 20-30% of pregnant women with APS develop adverse pregnancy outcomes despite conventional treatment with aspirin and heparin, called refractory obstetric APS. Interestingly, HCQ has shown positive effects on top of the standard of care in some refractory obstetric APS patients. HCQ mechanisms of action in APS comprise its ability to bind sialic acid present in cell membranes, its capacity to block the binding of antiphospholipid antibodies to the cell and the induced increase of pH in extracellular and intracellular compartments. However, the precise mechanisms of HCQ in the specific situation of refractory APS still need to be fully clarified. Therefore, this review summarizes the known modulating effects of HCQ and CQ, their side effects and use in APS and different pathologies to understand the benefit effects and the mechanism of action of HCQ in refractory obstetric APS.

Pregnancy outcome predictors in systemic lupus erythematosus: a systematic review and meta-analysis.

BACKGROUND: To enhance patient-tailored preconception risk assessment for women with systemic lupus erythematosus (SLE), knowledge on risk factors associated with adverse pregnancy outcomes is required. Therefore, we did a systematic review and meta-analysis to identify and provide unambiguous effect sizes of preconception predictors of pregnancy outcomes in women with SLE. METHODS: In this systematic review and meta-analysis, we searched PubMed and Embase for studies reporting preconception predictors of pregnancy outcomes in women with SLE, from database inception to Aug 22, 2023. Studies were included if they presented original, quantitative data on pregnant women with SLE and reported on preconception risk factors on at least one of the outcomes as defined in the protocol. Studies were excluded if they had a sample size of less than 20 patients, were restricted to multiple pregnancies, had unclear timing of prognostication, or exclusively reported a composite outcome. Literature screening, data extraction, and risk-of-bias assessment (quality in prognostic studies tool) were done by two reviewers independently, in a blinded, standardised manner. The reported outcomes included livebirth, pre-eclampsia, small for gestational age, preterm birth, pregnancy loss before and after 20 weeks of gestation, and SLE flares. We computed pooled univariate odds ratios (ORs) and 95% CIs using a random effects model. We assessed heterogeneity using the I2 statistic and prediction intervals. This study is registered with PROSPERO, CRD42022344732. FINDINGS: Of the 6705 unique articles identified, 72 (1·1%) were included in the meta-analysis, comprising 10 355 pregnancies in 8065 women with SLE. One potentially eligible study was retracted and therefore removed from our analysis. Previous lupus nephritis was associated with decreased livebirth probability (OR 0·62 [95% CI 0·47-0·81]; I2=0%), increased risk of preterm birth (2·00 [1·55-2·57]; I2=17%), and increased risk of pre-eclampsia (3·11 [2·35-4·12]; I2=0%). Chronic hypertension was associated with increased risk of disease flare (2·50 [1·74-3·58]; I2=0%), preterm birth (2·65 [1·87-3·77]; I2=0%), and pre-eclampsia (5·86 [3·41-10·06]; I2=33%). SLE disease activity at conception or preconception was associated with increased risk of preterm birth (2·91 [1·96-4·33]; I2=21%) and pre-eclampsia (2·32 [1·40-3·83]; I2=0%). Secondary antiphospholipid syndrome was associated with decreased livebirth probability (0·40 [0·27-0·58]; I2=0%), increased risk of pregnancy loss after 20 weeks of gestation (2·77 [1·44-5·31]; I2=0%), and increased risk of preterm birth (1·65 [1·29-2·11]; I2=0%). Across studies, risk-of-bias assessment suggested considerable bias in study attrition and confounding. INTERPRETATION: We identified previous lupus nephritis, chronic hypertension, SLE disease activity before and at conception, and secondary antiphospholipid syndrome as predictors of adverse pregnancy outcomes in women with SLE. These findings contribute to an optimal patient-tailored risk assessment in preconception counselling. FUNDING: None.

Preconception clinical factors related to adverse pregnancy outcomes in patients with systemic lupus erythematosus or primary Sjögren's syndrome: a retrospective cohort study.

OBJECTIVE: To identify preconception clinical factors associated with adverse pregnancy outcomes (APO) in patients with systemic lupus erythematosus (SLE) or primary Sjögren's syndrome (pSS). METHODS: A single-centre, retrospective cohort study was conducted, which included pregnant women treated at the University Medical Center Groningen between January 2010 and August 2021 who fulfilled classification criteria for SLE or pSS. Demographic data, relevant comorbidities, disease duration, disease activity before and during pregnancy, APO, laboratory parameters and treatment regimens were recorded. Associations between the presence of APO and preconception characteristics were evaluated. RESULTS: Our study population included 48 (70%) SLE and 21 (30%) pSS pregnancies concerning 70 fetuses (one twin). Preterm birth (n=9, 19%) was the most frequent APO in SLE pregnancies, while in pSS pregnancies this was miscarriages (n=3, 14%). There were no associations between the presence of APO in SLE pregnancies and clinical parameters, laboratory parameters or medication use prior to conception. In the pSS group, significant associations were found between the presence of APO and body mass index (p=0.010), parity (p=0.046), C4 (p=0.021) and low C4 levels (p=0.002). CONCLUSIONS: No preconception risk factors related to APO were found in SLE pregnancies, whereas preconception complement levels were associated with APO development in patients with pSS.

Effects of anti-beta 2-glycoprotein 1 antibodies and its association with pregnancy-related morbidity in antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous, arterial, or small-vessel thrombosis and/or pregnancy-related morbidity, associated with persistent positivity of antiphospholipid antibodies (aPL). Pregnancy-related morbidity in APS patients is characterized by unexplained fetal deaths, premature birth of morphologically normal newborns, and/or consecutive pregnancy losses before the 10th week of gestation. Beta 2-glycoprotein 1 (ß2GP1) is the main antigen recognized by aPL and plays an essential role in the pathogenesis of APS. Antibodies against ß2GP1 (aß2GP1) are involved in damage-generating mechanisms in APS due to their interaction with trophoblasts, decidua, and endothelial cells. aß2GP1 might be used as a prognostic tool for obstetric risk stratification and ß2GP1 could be a target for molecular-targeted treatment to prevent pregnancy morbidity in APS. This review describes these aspects of aß2GP1, including effects on different cellular targets, its association with the severity of obstetric manifestations and the potential of ß2GP1-targeted therapies for APS.