NCF1-339 polymorphism is associated with altered formation of neutrophil extracellular traps, high serum interferon activity and antiphospholipid syndrome in systemic lupus erythematosus

​OBJECTIVES: A single nucleotide polymorphism in the NCF1 gene (NCF1-339, rs201802880), encoding NADPH oxidase type II subunit NCF1/p47phox, reducing production of reactive oxygen species (ROS) is strongly associated with the development of systemic lupus erythematosus (SLE). This study aimed at characterising NCF1-339 effects on neutrophil extracellular trap (NET) formation, type I interferon activity and antibody profile in patients with SLE. ​METHODS: Neutrophil NET-release pathways (n=31), serum interferon (n=141) and finally antibody profiles (n=305) were investigated in SLE subjects from Lund, genotyped for NCF1-339. Then, 1087 SLE subjects from the rheumatology departments of four Swedish SLE centres, genotyped for NCF1-339, were clinically characterised to validate these findings. ​RESULTS: Compared with patients with normal-ROS NCF1-339 genotypes, neutrophils from patients with SLE with low-ROS NCF1-339 genotypes displayed impaired NET formation (p<0.01) and increased dependence on mitochondrial ROS (p<0.05). Low-ROS patients also had increased frequency of high serum interferon activity (80% vs 21.4%, p<0.05) and positivity for anti-β2 glycoprotein I (p<0.01) and anticardiolipin antibodies (p<0.05) but were not associated with other antibodies. We confirmed an over-representation of having any antiphospholipid antibody, OR 1.40 (95% CI 1.01 to 1.95), anti-β2 glycoprotein I, OR 1.82 (95% CI 1.02 to 3.24) and the antiphospholipid syndrome (APS), OR 1.74 (95% CI 1.19 to 2.55) in all four cohorts (n=1087). ​CONCLUSIONS: The NCF1-339 SNP mediated decreased NADPH oxidase function, is associated with high interferon activity and impaired formation of NETs in SLE, allowing dependence on mitochondrial ROS. Unexpectedly, we revealed a striking connection between the ROS deficient NCF1-339 genotypes and the presence of phospholipid antibodies and APS.

High genetic risk score is associated with early disease onset, damage accrual and decreased survival in systemic lupus erythematosus

Objectives

To investigate associations between a high genetic disease risk and disease severity in patients with systemic lupus erythematosus (SLE).

Methods

Patients with SLE (n=1001, discovery cohort and n=5524, replication cohort) and healthy controls (n=2802 and n=9859) were genotyped using a 200K Immunochip single nucleotide polymorphism array. A genetic risk score (GRS) was assigned to each individual based on 57 SLE risk loci.

Results

SLE was more prevalent in the high, compared with the low, GRS-quartile (OR 12.32 (9.53 to 15.71), p=7.9×10^–86 and OR 7.48 (6.73 to 8.32), p=2.2×10^–304 for the discovery and the replication cohorts, respectively). In the discovery cohort, patients in the high GRS-quartile had a 6-year earlier mean disease onset (HR 1.47 (1.22 to 1.75), p=4.3×10^–5), displayed higher prevalence of damage accrual (OR 1.47 (1.06 to 2.04), p=2.0×10^–2), renal disorder (OR 2.22 (1.50 to 3.27), p=5.9×10^–5), anti-dsDNA (OR 1.83 (1.19 to 2.81), p=6.1×10^–3), end-stage renal disease (ESRD) (OR 5.58 (1.50 to 20.79), p=1.0×10^–2), proliferative nephritis (OR 2.42 (1.30 to 4.49), p=5.1×10^–3), anti-cardiolipin-IgG (OR 1.89 (1.13 to 3.18), p=1.6×10^–2), anti-β₂-glycoprotein-I-IgG (OR 2.29 (1.29 to 4.06), p=4.8×10^–3) and positive lupus anticoagulant test (OR 2.12 (1.16 to 3.89), p=1.5×10^–2) compared with patients in the low GRS-quartile. Survival analysis showed earlier onset of the first organ damage (HR 1.51 (1.04 to 2.25), p=3.7×10^–2), first cardiovascular event (HR 1.65 (1.03 to 2.64), p=2.6×10^–2), nephritis (HR 2.53 (1.72 to 3.71), p=9.6×10^–7), ESRD (HR 6.78 (1.78 to 26.86), p=6.5×10^–3) and decreased overall survival (HR 1.83 (1.02 to 3.30), p=4.3×10^–2) in high to low quartile comparison.

Conclusions

A high GRS is associated with increased risk of organ damage, renal dysfunction and all-cause mortality. Our results indicate that genetic profiling may be useful for predicting outcomes in patients with SLE.

Neutrophils-Important Communicators in Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are two autoimmune diseases that can occur together or separately. Insights into the pathogenesis have revealed similarities, such as development of autoantibodies targeting subcellular antigens as well as a shared increased risk of cardiovascular morbidity, potentially due to mutual pathologic mechanisms. In this review, we will address the evidence implicating neutrophils in the pathogenesis of these conditions, highlighting their shared features. The neutrophil is the most abundant leukocyte, recognized for its role in infectious and inflammatory diseases, but dysregulation of neutrophil effector functions, including phagocytosis, oxidative burst and formation of neutrophil extracellular traps (NETs) may also contribute to an autoimmune process. The phenotype of neutrophils in SLE and APS differs from neutrophils of healthy individuals, where neutrophils in SLE and APS are activated and prone to aggregate. A specific subset of low-density neutrophils with different function compared to normal-density neutrophils can also be found within the peripheral blood mononuclear cell (PBMC) fraction after density gradient centrifugation of whole blood. Neutrophil phagocytosis is required for regular clearance of cell remnants and nuclear material. Reactive oxygen species (ROS) released by neutrophils during oxidative burst are important for immune suppression and impairment of ROS production is seen in SLE. NETs mediate pathology in both SLE and APS via several mechanisms, including exposure of autoantigens, priming of T-cells and activation of autoreactive B-cells. NETs are also involved in cardiovascular events by forming a pro-thrombotic scaffolding surface. Lastly, neutrophils communicate with other cells by producing cytokines, such as Interferon (IFN) -α, and via direct cell-cell contact. Physiological neutrophil effector functions are necessary to prevent autoimmunity, but in SLE and APS these are altered.

TLR7/8 activation in neutrophils impairs immune complex phagocytosis through shedding of FcgRIIA

Lood et al. find that neutrophil TLR7/8 activation shifts neutrophils from phagocytosis of immune complexes to NETosis. Reduced phagocytosis of immune complexes is associated with partial proteolytic cleavage of FcgRIIA. Cleaved FcgRIIA is found in SLE neutrophils ex vivo.

Neutrophils play a crucial role in host defense. However, neutrophil activation is also linked to autoimmune diseases such as systemic lupus erythematosus (SLE), where nucleic acid–containing immune complexes (IC) drive inflammation. The role of Toll-like receptor (TLR) signaling in processing of SLE ICs and downstream inflammatory neutrophil effector functions is not known. We observed that TLR7/8 activation leads to a furin-dependent proteolytic cleavage of the N-terminal part of FcgRIIA, shifting neutrophils away from phagocytosis of ICs toward the programmed form of necrosis, NETosis. TLR7/8-activated neutrophils promoted cleavage of FcgRIIA on plasmacytoid dendritic cells and monocytes, resulting in impaired overall clearance of ICs and increased complement C5a generation. Importantly, ex vivo derived activated neutrophils from SLE patients demonstrated a similar cleavage of FcgRIIA that was correlated with markers of disease activity, as well as complement activation. Therapeutic approaches aimed at blocking TLR7/8 activation would be predicted to increase phagocytosis of circulating ICs, while disarming their inflammatory potential.

A novel enzyme with antioxidant capacity produced by the ubiquitous skin colonizer Propionibacterium acnes

The role of the skin microbiota in human health is poorly understood. Here, we identified and characterized a novel antioxidant enzyme produced by the skin microbiota, designated RoxP for radical oxygenase of Propionibacterium acnes. RoxP is uniquely produced by the predominant skin bacterium P. acnes, with no homologs in other bacteria; it is highly expressed and strongly secreted into culture supernatants. We show that RoxP binds heme, reduces free radicals, and can protect molecules from oxidation. Strikingly, RoxP is crucial for the survival of P. acnes in oxic conditions and for skin colonization of P. acnes ex vivo. Taken together, our study strongly suggests that RoxP facilitates P. acnes’ survival on human skin, and is an important beneficial factor for the host-commensal interaction. Thus, RoxP is the first described skin microbiota-derived mutualistic factor that potentially can be exploited for human skin protection.

TLR8 activation shifts neutrophils from phagocytosis to NETosis through furin-dependent shedding of FcgRIIA

Background

Immune complex (IC)-mediated formation of neutrophil extracellular traps (NETs) has emerged as a mechanism to increase the autoantigenic burden as well as promote the prominent type I interferon (IFN) signature seen in patients with the autoimmune disease systemic lupus erythematosus (SLE). The aim of the current study was to explore properties of ICs regulating their ability to induce phagocytosis and NETosis.

Results

Whereas immobilized IgG, mimicking tissue-deposited ICs, induced NETs in a TLR-independent manner, both FcgR- and TLR-engagement were required for induction of NETosis by soluble RNA-ICs, as demonstrated by FcgR blocking antibodies as well as RNase-treatment. Despite that degradation of RNA inhibited NETosis, removal of the TLR ligand by RNase markedly increased the phagocytosis of RNA-ICs by neutrophils suggesting that TLR activation suppressed phagocytosis. Consistent with this hypothesis, addition of a TLR8 agonist (R848) inhibited phagocytosis of ICs, but not beads, in neutrophils. Mechanistically, we observed that TLR8 induced ROS-dependent activation of the serine protease furin, participating in shedding of cell surface FcgRIIA reducing the phagocytic capacity but promoting progression into NETosis.

Conclusions

i) In the fluid phase, both FcgRIIA and TLR8 ligation are necessary for IC-mediated NETosis; ii) TLR8 activation induces furin-mediated shedding of FcgRIIA, thereby inhibiting further phagocytosis of ICs but enabling NETosis. Therapeutic approaches aimed at degrading the TLR8 ligand, such as RNases, would be predicted to increase uptake of circulating ICs, while disarming their inflammatory potential and ability to induce NETs.

Clinical pathway of elderly persons with lowered mood in the health care services

Elderly persons with mild depression are notable consumers of somatic health services. This study describes the typical clinical pathway including institutional care of two groups, depressed and non-depressed elderly persons, in different stages of the health care system, and compares possible changes in the use of health care services between the two groups. We also compare differences in morbidity and mortality between depressed and non-depressed persons. The depressed group of 50 persons in our follow-up study were selected randomly from among those persons who were diagnosed as having symptoms of depression, as shown in the Zung Self-Rating Depression Scale (n = 109). Persons (n = 50) who were not diagnosed as suffering from depression and who showed no signs of cognitive impairment (n = 833) were likewise chosen at random as a control group. We found that people suffering from symptoms of depression utilized institutional care, home health care and the outpatient clinics more than non-depressed people. Depressed people were more likely to suffer cardiovascular (p < 0.023) and pulmonary diseases (p < 0.04) than non-depressed controls. The mortality among depressed people was significantly higher than that in the control group. The results of our study give reason to believe that home-care staff are in a key position to identify depressed subjects. They have to understand the relationship between depression and the effect of various diseases on health and functional capacity. It is also important to ensure efficient communication between those responsible for health care.

[The nursing care of a dying patient on the health center ward--the relatives' point of view]

The purposes of the study were to find out relatives' opinions about the care of dying patients as well as to find out how relatives assess the nursing care which was given to their nearest on the hospital wards. In order to collect the data for the study, the family members of patients (N = 628) who had died not more than one year before in the hospital, were interviewed. The interviewing was done by sending a questionnaire to every other relative (N = 314), 210 of which (62%) answered the questions. The answers to the structured questions were analyzed with the SAS-software and open-ended questions by the content analysis method. The relatives found that the hospital ward was quite a suitable environment for the nursing care of a dying patient. They found visiting hours flexible but they wished that they had the possibility to rest or stay over night in the hospital. The health care professionals responsible for the care of dying patients were considered to succeed in the field of the patient's rest and hygiene, but they took less well care of patient's physical exercise and dental hygiene. The relatives were satisfied with the pain relief the patient got. According to the relatives, examinations, medication, nursing interventions or the "futile" care given did not cause additional suffering. Although the nurses did not response to patients' spiritual well-being or needs of affections, they were able to make the patients happy with their kindness, presence and with good basic care. The relatives were best informed about patients' every day well-being, medication as well as practical matters concerning the time after the death of the patient. If the patient was transferred to another hospital for the terminal care, the relatives found, however, that they didn't get enough information of the situation. The health care professionals did not console the relatives for their grief and they had not been encouraged to participate in the care of their family members.

Patient’s and general practitioner’s different views on patient’s depression

Differences between patient's and general practitioner's view on patient's depressive syndromes was investigated in a prospective birth cohort study of 70 year old people (n=1032) in Turku City, Finland. The aim of this study was to find factors which are typical for people having depressive syndromes in old age and help medical and nursing staff to identify depressive syndromes in the general aged people. The study consisted of a structural postal questionnaire including patient's perception of his depression, an interview made by a public health nurse included mini-mental state examination (MMSE) and the self-rating depression scale of Zung, an interview and comprehensive clinical examination by a general practitioner. Out of the 847 persons who completed the depression test, 12.6% showed symptoms of depressive syndrome. The views of those who scored more than 45 points in the Zung depression scale on their own depressiveness differed from the general practitioner's opinion. In the general practitioner's examination and interview 58% of the subjects had no depressive symptoms even though the test results indicated that they were depressed. The depressed group stood out most clearly in two questions: Do you feel you are needed and do you have future plans? When the same questions were repeated 5 years later, the difference was still statistically significant between depressed and non-depressed group (P<0.0001). The data indicated that medical and nursing staff should take self-assessments seriously and look into them in closer detail. General practitioners and nurses should learn to ask right questions and use short depression scale systematically in order to facilitate the detection of depressive syndromes.

Coexistence of lowered mood and cognitive impairment of elderly people in five birth cohorts

The prevalences of lowered mood and cognitive impairment, and their combination were investigated in 1993 random subjects of five birth cohorts (at age of 65, 70, 75, 80 and 85 years). The frequency of a high Zung-score (> 45), indicating depressive symptoms, in the five age groups was 11%, 13%, 20%, 16%, and 36%, respectively. The corresponding figures for a low MMSE-score (Mini Mental State Examination < 24) were 11%, 9%, 25%, 46%, and 60%; the respective frequencies of subjects fulfilling both criteria simultaneously were 2%, 3%, 8%, 12% and 24%, respectively. Overall, about 30% of the subjects with a low MMSE-score had a high Zung-score. However, more than half of the old subjects (over 75 years) with a high Zung-score also had low MMSE-scores. The data indicate that the combination of impaired cognition and lowered mood doubles in frequency by five-year intervals after the age of 70 years in the general aged population, and that this condition is present in one of four subjects at the age of 85 years.

Why is the pain relief of dying patients often unsuccessful? The relatives' perspectives

In order to determine relatives' opinions of the pain relief of dying patients a postal questionnaire was sent to close relatives (n = 371) of aged patients (mean age 80.1 years) who had died one to two years earlier. In the relatives' opinions, 57% of the patients (n = 211) had suffered from moderate to severe pain and in 22% (n = 46) of these the pain relief was unsuccessful. Inadequate pain relief was associated with a feeling of helplessness in the patients (odds ratio 2.6), insufficient self-determination of analgesic use (9.4), unsatisfactory care of daily needs such as nutrition (8.3), and insufficient care of concomitant symptoms such as dry mouth (6.2). The pain relief was also evaluated as having been unsuccessful when the relatives received limited information about the forthcoming death (5.7), when it was difficult to discuss with the clinical staff (5.7), and when the relatives were not supported by, for example, comforting and heartening (7.9) or encouraging to participate in the care (7.2). In the multivariate analysis, the self-determination of the patients about their pain medication (5.7), difficulties of the relatives to discuss issues with the nursing staff (3.7) and poor atmosphere of the treatment environment (2.8) emerged as the most significant associates of unsuccessful pain relief. The results show that dissatisfaction with the pain management is associated with low appreciation of the treatment of other discomforts and complaints. Successful pain management therefore requires a holistic approach to the wider spectrum of problems in dying patients.