Treat to target and shared decision-making in systemic lupus erythematosus from the patients' perspective: results from an international patient survey.

OBJECTIVES: Treat-to-target (T2T) is being recognised as a promising concept to significantly improve the outcomes of patients with systemic lupus erythematosus (SLE). Despite its success being closely tied to patients' involvement, the patients' perspective regarding T2T has not been evaluated. We aimed to investigate patients' attitude towards T2T and their involvement in treatment decisions. METHODS: We designed a 13-question online survey on T2T, examining acceptance, willingness to participate in T2T trials, and potential obstacles. This was distributed amongst Dutch, Austrian, German, and Bulgarian patient organisations. RESULTS: In total, 863 patients participated of whom 48.4% reported being in remission, while 13% were uncertain about their remission status. Regarding shared decision-making, 62.1% reported being somewhat fully involved in treatment decisions, while 20.7% felt uninvolved. Shared decision-making was associated with disease duration, Dutch origin and satisfaction with treatment and remission. As for satisfaction with their health status, 56.2% were somewhat fully satisfied, while 29.3% were unsatisfied. 65.5% were satisfied with their treatment, 14.8% were not. Leading treatment goals were quality of life (QoL) normalisation (37.4%), organ damage prevention (24.6%) and absence of disease activity (22.6%). T2T was mainly seen positive with additional doctors' visits and initiation of new immunosuppressive drugs as potential disadvantages. CONCLUSIONS: T2T was perceived as beneficial with improvement of QoL as the most important treatment goal and the possibility of additional doctors' visits and initiation of new immunosuppressive agents as potential drawbacks. Patients unsatisfied with their health status and treatment may benefit from greater involvement in treatment decisions.

Systemic lupus erythematosus is associated with an increased frequency of spontaneous preterm births: systematic review and meta-analysis.

OBJECTIVE: Preterm birth is one of the most frequent complications of pregnancy in women with systemic lupus erythematosus. The high indicated preterm birth proportion due to hypertensive disorders of pregnancy and/or fetal growth restriction is well known, and preventive measures and screening for early detection are performed. The risk of spontaneous preterm birth is less well recognized. This study aimed to determine the proportions of spontaneous and indicated preterm birth in pregnancies of women with systemic lupus erythematosus. DATA SOURCES: A systematic literature search using Pubmed, Embase, Web of Science, and Google Scholar was performed in June 2021. STUDY ELIGIBILITY CRITERIA: Studies in pregnant women with systemic lupus erythematosus reporting spontaneous and indicated preterm birth rates were selected. Original research articles published from 1995 to June 2021 were included. METHODS: Quality and risk of bias of the included studies were assessed using the Newcastle-Ottawa quality assessment scale. To estimate the pooled event rates and 95% confidence intervals, meta-analysis of single proportions with a random-effects model was performed. RESULTS: We included 21 articles, containing data of 8157 pregnancies in women with systemic lupus erythematosus. On average, 31% (95% prediction interval, 0.14-0.50) of the pregnancies resulted in preterm birth, including 14% (95% prediction interval, 0.04-0.27) spontaneous and 16% (95% prediction interval, 0.03-0.35) indicated preterm birth. CONCLUSION: In pregnant women with systemic lupus erythematosus, spontaneous and indicated preterm birth proportions are high. This information should be applied in (prepregnancy) counseling and management in pregnancy. The knowledge obtained by this meta-analysis paves the way for further research of associated risk factors and development of interventions to reduce spontaneous preterm birth in systemic lupus erythematosus pregnancies.

Corrigendum to "Maternal and Perinatal Outcome in Women with Systemic Lupus Erythematosus: A Retrospective Bicenter Cohort Study".

[This corrects the article DOI: 10.1155/2017/8245879.].

Work participation in patients with systematic lupus erythematosus: a systematic review.

OBJECTIVES: This systematic review assessed which variables are associated with or are predictors for work participation outcomes in patients with systematic lupus erythematosus (SLE). METHODS: A literature search using MEDLINE, The Cochrane Library, Embase and CINAHL was conducted to identify all studies published from inception (1947) to June 2021 on factors related to and/or predicting employment status, absenteeism and/or presenteeism in SLE patients aged ≥18 years. The quality of included articles was assessed using the QUIPS tool. Narrative summaries were used to present the data. RESULTS: Fifteen studies (nine on associations, four on predictions, and two assessing both) were included, encompassing data of 3800 employed patients. Younger age, Caucasian ethnicity, higher educational level, lower disease activity score, shorter disease duration, absence of specific disease manifestations, higher levels of physical functioning and less physical job demands and higher levels of psychological/cognitive functioning were associated with or predicted favorable work outcomes. Older age, non-Caucasian ethnicity, female gender, never being married, poverty, lower educational level, higher disease activity score, longer disease duration, specific disease manifestations, lower levels of physical functioning, more physical job demands and low job control, less job tenure and lower levels of cognitive functioning were associated with or predicted an unfavorable work outcome. Limitations of the evidence were the quality of the studies and the use of heterogeneous outcome measures, applied statistical methods and instruments used to assess work participation. CONCLUSION: We recommend applying the EULAR points to consider for designing, analysing and reporting on work participation in inflammatory arthritis also to SLE studies on work participation, to enhance the quality and comparability between studies and to better understand the impact of SLE on work participation. TRIAL REGISTRATION: registration in PROSPERO (CRD42020161275; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=161275).

New developments in systemic lupus erythematosus.

In this review, the results of recent and ongoing clinical trials in patients with SLE are discussed. After many unsuccessful trials in the past decade, belimumab was the first biologic specifically designed for SLE that met its primary end point. At the same time, studies on the pathophysiology of SLE have further elucidated the pathways involved in the disease, which has led to the identification of new possible therapeutics and has encouraged the initiation of new trials. These new drugs include biologics that target B cells, T cells and type 1 interferons, and small molecules that inhibit kinases. Other therapeutics aim to restore immunological balance by restoring tolerance. Results from phase II and even phase III trials are promising and it is likely that some of the therapeutics discussed will receive approval in the following years. Hopefully, this will allow for more tailor-made medicine for SLE patients in the future.

Hydroxychloroquine treatment in European patients with lupus erythematosus: dosing, retinopathy screening and adherence.

BACKGROUND: Use of hydroxychloroquine (HCQ) is common in patients with lupus erythematosus. Long-term use (ie, ≥5 years) and high-dose HCQ (ie, >5 mg/kg/day) are both risk factors for developing HCQ retinopathy. Advances in our understanding of HCQ retinopathy have led to changes in the recommendations for HCQ dosing and retinopathy screening. The latest EULAR guidelines for the management of SLE recommend a maximum HCQ dose of 5 mg/kg/day and ophthalmological screening at baseline and annually after 5 years of HCQ treatment. OBJECTIVES: This study aimed to assess whether the EULAR guidelines are affecting HCQ prescription patterns and screening frequencies in Europe. Furthermore, we inventoried adherence to HCQ. RESULTS: The online questionnaire was completed by 2936 patients with systemic, cutaneous or juvenile lupus from 33 countries. The majority were female (86.5%) and diagnosed with SLE (81.2%). Among those taking HCQ, the median HCQ dose reported was 4.26 mg/kg/day. More than one-third of respondents (36.8%) exceeded the recommended maximal HCQ dose of 5 mg/kg/day. Baseline ophthalmological screening had been done in 857 out of 1017 respondents diagnosed in the past 10 years (84.3%). Of patients using HCQ ≥5 years, 69.2% reported yearly retinopathy screening. Lastly, 17.3% of patients reported that they skipped HCQ once a week or more often. CONCLUSION: The results of our study demonstrate that higher than recommended dosages of HCQ are prescribed to more than one-third of patients with lupus in Europe. Recent recommendations regarding screening for retinopathy are incompletely implemented.

Management of glucocorticoid-induced osteoporosis.

Long-term glucocorticoid (GC) therapy is frequently indicated to treat autoimmune and chronic inflammatory diseases in daily clinical practice. Two of the most devastating untoward effects are bone loss and fractures. Doses as low as 2.5 mg of prednisone for more than 3 months can impair bone integrity. Population at risk is defined based on the dose and duration of GC therapy and should be stratified according to FRAX (Fracture Risk Assessment Tool), major osteoporotic fracture, prior fractures, and bone mineral density values (BMD). General measures include to prescribe the lowest dose of GC to control the underlying disease for the shortest possible time, maintain adequate vitamin D levels and calcium intake, maintain mobility, and prescribe a bone acting agent in patients at high risk of fracture. These agents include oral and intravenous bisphosphonates, denosumab, and teriparatide.

Early predictors of renal outcome in patients with proliferative lupus nephritis: a 36-month cohort study.

OBJECTIVES: To identify predictors of complete renal response (CRR) and renal flares in SLE patients with active proliferative LN. METHODS: This was a retrospective cohort study over 36 months including patients with biopsy-proven proliferative LN (class III/IV), from two European tertiary centres. CRR and renal flare were defined as proteinuria <0.5 g/day with normal renal function and proteinuria >1 g/day after CRR attainment, respectively. Demographic, clinical and analytic parameters were evaluated as early predictors of renal outcome, using survival analysis. Candidate variables were tested as predictors for CRR at time 0, 3 and 6 months after starting induction treatment. Potential predictors for renal flare were evaluated at time of reaching CRR. Variables with P < 0.10 on univariate analysis with log-rank tests were further tested with multivariate Cox proportional hazards regression models. RESULTS: We included 104 patients [81.7% female, mean (s.d.) age at baseline 32.0 (13.3) years]. Over follow-up, 91.7% reached CRR, within a median time of 6.0 months. Proteinuria <2 g/day at baseline [hazard ratio (HR) = 1.80, 95% CI 1.16, 2.79, P < 0.01] and 3 months (HR = 2.32, 95% CI 1.24, 4.32, P < 0.01) after starting induction therapy were independent predictors of CRR. Renal flares occurred in 18.4% of patients reaching CRR, after a mean time of 16.5 (8.6) months. Age up to 25 years at time of LN diagnosis (HR = 5.41, 95% CI 1.72, 16.97, P < 0.01) and positive anti-RNP (HR = 3.52, 95% CI 1.21, 10.20, P = 0.02) were independent predictors of renal flares. CONCLUSION: In patients with SLE and proliferative LN, factors assessed at baseline and 3 months from starting induction treatment can predict CRR and renal flares once CRR is achieved.

Mortality, causes of death and influence of medication use in patients with systemic lupus erythematosus vs matched controls.

OBJECTIVES: We wanted to estimate the magnitude of the risk from all-cause, cause-specific and sex-specific mortality in patients with SLE and relative risks compared with matched controls and to evaluate the influence of exposure to medication on risk of mortality in SLE. METHODS: We conducted a population-based cohort study using the Clinical Practice Research Datalink, Hospital Episode Statistics and national death certificates (from 1987 to 2012). Each SLE patient (n = 4343) was matched with up to six controls (n = 21 780) by age and sex. Cox proportional hazards models were used to estimate overall and cause-specific mortality rate ratios. RESULTS: Patients with SLE had a 1.8-fold increased mortality rate for all-cause mortality compared with age- and sex-matched subjects [adjusted hazard ratio (HR) = 1.80, 95% CI: 1.57, 2.08]. The HR was highest in patients aged 18-39 years (adjusted HR = 4.87, 95% CI: 1.93, 12.3). Mortality rates were not significantly different between male and female patients. Cumulative glucocorticoid use raised the mortality rate, whereas the HR was reduced by 45% with cumulative low-dose HCQ use. Patients with SLE had increased cause-specific mortality rates for cardiovascular disease, infections, non-infectious respiratory disease and for death attributable to accidents or suicide, whereas the mortality rate for cancer was reduced in comparison to controls. CONCLUSION: British patients with SLE had a 1.8-fold increased mortality rate compared with the general population. Glucocorticoid use and being diagnosed at a younger age were associated with an increased risk of mortality. HCQ use significantly reduced the mortality rate, but this association was found only in the lowest cumulative dosage exposure group.

Current Treatments and New Developments in the Management of Glucocorticoid-induced Osteoporosis.

Glucocorticoids (GCs) are often used for improvement of quality of life, particularly in the elderly, but long-term GC use may cause harm; bone loss and fractures are among the most devastating side effects. Fracture risk is particularly high in patients with a severe underlying disease with an urgent need for treatment with high-dose GCs. Moreover, it is important to realize that these patients suffer from an augmented background fracture risk as these patients have a high presence of traditional risk factors for osteoporosis, such as high age, low body mass index (BMI), smoking and relatives with osteoporosis or hip fractures. It is thus crucial for prevention of osteoporotic fractures to use the lowest dose of GC for a short period of time to prevent fractures. Another important task is optimal treatment of the underlying disease; for instance, fracture risk is higher in patients with active rheumatoid arthritis than in patients in whom rheumatoid arthritis is in remission. Thus, fracture risk is generally highest in the early phase, when GC dosage and the disease activity of the underlying disease are high. Finally, some of the traditional risk factors can be modulated, e.g., smoking and low BMI. Life-style measures, such as adequate amounts of calcium and vitamin D and exercise therapy are also crucial. In some patients, anti-osteoporotic drugs are also indicated. In general, oral bisphosphonates (BPs) are the first choice, because of their efficacy and safety combined with the low cost of the drug. However, for those patients who do not tolerate oral BPs, alternatives ("second-line therapies") are available: BP intravenously (zoledronic acid), denosumab (Dmab), and teriparatide. Both zoledronic acid and Dmab have been proven to be superior to oral bisphosphonates like risedronate in improvement of bone mineral density. For teriparatide, vertebral fracture reduction has been shown in comparison with alendronate. Thus, to reduce the global burden of GC use and fracture risk, fracture risk management in GC users should involve at least involve life-style measures and the use of the lowest possible dose of GC. In high-risk patients, anti-osteoporotic drugs should be initiated. First choice drugs are oral BPs; however, in those with contraindications and those who do not tolerate oral BPs, second-line therapies should be started. Although this is a reasonable treatment algorithm, an unmet need is that the most pivotal (second-line) drugs are not used in daily clinical practice at the initial phase, usually characterized by high-dose GC and active underlying disease, when they are most needed. In some patients second-line drugs are started later in the disease course, with lower GC dosages and higher disease activity. As this is a paradox, we think it is a challenge for physicians and expert committees to develop an algorithm with clear indications in which specific patient groups second-line anti-osteoporotic drugs should or could be initiated as first-choice treatment.

The relationship between remission and health-related quality of life in a cohort of SLE patients.

OBJECTIVE: To investigate the relationship between remission and health-related quality of life (HRQoL) in patients with SLE in a longitudinal observational cohort. METHODS: HRQoL was measured at cohort visits using the physical and mental component score (PCS and MCS, respectively) of the Short Form 36 questionnaire. Definitions of Remission in SLE remission categories (no remission/remission on therapy/remission off therapy) were applied. Determinants of PCS and MCS were identified with simple linear regression analyses. Association between remission and HRQoL was assessed using generalized estimating equation models. RESULTS: Data from 154 patients with 2 years of follow-up were analysed. At baseline 60/154 (39.0%) patients were in either form of remission. Patients in remission had higher Short Form 36 scores in all subdomains compared with patients not in remission. PCS was positively associated with remission and employment, and negatively associated with SLICC damage index, ESR, medication, patient global assessment and BMI. MCS was positively associated with Caucasian ethnicity and negatively associated with patient global assessment. In generalized estimating equation analysis, a gradual and significant increase of PCS was observed from patients not in remission (mean PCS 36.0) to remission on therapy (41.8) to remission off therapy (44.8). No significant difference in MCS was found between remission states. CONCLUSION: we show a strong and persistent association between remission and PCS, but not MCS. These results support the relevance (construct validity) of the Definition of Remission in SLE remission definitions and the further development of a treat-to-target approach in SLE.

Glucocorticoids, Inflammation and Bone.

The current review on glucocorticoids (GCs), inflammation and bone is focused on three aspects: (1) the mutual effects between GCs, inflammation and bone in inflammatory rheumatic diseases, (2) current views on fracture risk assessment in patients using GCs and (3) non-pharmacological and pharmacological treatment to prevent fractures in GC-using patients with inflammatory rheumatic diseases. The use of GCs results in increased risk for fractures due to both direct and indirect negative effects of GCs on bone mass, and on bone and muscle strength. However, also the underlying inflammatory rheumatic disease is associated with the increased bone loss and fracture risk due to the chronic inflammation itself, and due to disability/immobility caused by active disease or joint destruction. The rapid and strong anti-inflammatory effect of GCs in patients with rheumatoid arthritis seems to balance the negative effects of GCs on bone in the early, active phase of the disease. Recently, an update of the American College of Rheumatology guidelines for prevention and treatment of GC-induced osteoporosis was published with renewed recommendations. To prevent fractures, general measures, including treatment of the underlying inflammatory disease adequately (even with GCs when indicated), a healthy lifestyle, including adequate calcium and vitamin D supplementation, and regular weight bearing exercises are important. In rheumatic patients with high fracture risk using GCs, especially when the cumulative dose is high and/or the underlying inflammatory disease is active, treatment with anti-osteoporotic drugs, usually an oral bisphosphonate, is indicated.

Bone Disease in Connective Tissue Disease/Systemic Lupus Erythematosus.

This article reviews recent advances in the research of the mechanisms of bone loss, as well as clinical features, economic impact and therapeutic implications of osteoporosis and fractures in patients with systemic lupus erythematosus (SLE) as an illustration of bone disease in a complex systemic autoimmune connective tissue disease. Recent studies demonstrated an increased incidence of osteoporosis and peripheral and vertebral fractures in patients with SLE. The aetiology of bone loss in SLE is multifactorial, including clinical osteoporosis risk factors, systemic inflammation, serological factors, metabolic factors, hormonal factors, possibly genetic factors and medication-induced adverse effects. The incidence of symptomatic fractures in patients with SLE is increased 1.2-4.7-fold and age, disease duration, glucocorticoid use, previous cyclophosphamide use, seizures and a prior cerebrovascular event have been identified as important risk factors. Moreover, a high prevalence of morphometric vertebral fractures was demonstrated, while one in three of these patients has normal bone density, which finding points to the multifactorial aetiology of fractures in SLE. The clinical consequences and economic burden of osteoporosis and fractures as glucocorticoid treatment-related adverse events and the high frequency of glucocorticoid therapy underline the importance of reducing glucocorticoid treatment and prescribing steroid-sparing agents. No data on fall risk and its determinants and the relationship with the occurrence of fractures in patients with SLE are currently available. Fall risk might be increased in lupus patients for several reasons. In addition, the recently reported high prevalence (20%) of frailty in SLE patients may contribute to the increased fracture incidence. Therefore, the relationships between fall risk, frailty and fracture occurrence in SLE might be interesting subjects for future studies.

Maternal and Perinatal Outcome in Women with Systemic Lupus Erythematosus: A Retrospective Bicenter Cohort Study.

OBJECTIVE: To investigate disease activity around and during pregnancy and pregnancy outcome in women with systemic lupus erythematosus (SLE) considering antiphospholipid antibody status. Moreover, differences between first and consecutive pregnancies were examined. METHODS: Pregnancies > 16 weeks gestation of SLE patients receiving joint care from rheumatologists and gynecologists in two tertiary centers in the Netherlands between 2000 and 2015 were included. Disease activity, flare rate, and pregnancy outcomes and complications were assessed. RESULTS: Ninety-six women (84% Caucasian) with 144 pregnancies were included. The median SLE(P)DAI score was 2 before, during, and after pregnancy. Flare rates were 6.3%, 20.1%, and 15.3%, respectively. Severe hypertensive disorder of pregnancy, intrauterine fetal death, preterm birth, and small-for-gestational age infants occurred in 18.1%, 4.1%, 32.7%, and 14.8%, respectively. Complication rates were similar in the first and consecutive pregnancies. Half of the women did not experience any pregnancy complication whereas 42.7% developed a complication during all pregnancies. Mean number of pregnancies was 2.4 and live births 1.7. CONCLUSION: In this SLE population with low disease activity, pregnancy complications were present irrespective of antiphospholipid antibody status. Furthermore, there were no differences in complication rates between the first and consecutive pregnancies as seen in healthy mothers. This information is useful for patient counseling.

Similar efficacy and safety of initial COBRA-light and COBRA therapy in rheumatoid arthritis: 4-year results from the COBRA-light trial.

Objective: To assess the efficacy and safety of initial COBRA-light vs COBRA therapy in RA patients after a 4-year follow-up period. Methods: In the COBRA-light trial, 162 consecutive patients with recent-onset RA were randomized to either COBRA-light (prednisolone and MTX) or COBRA therapy (prednisolone, MTX and SSZ) for 1 year. After 1 year, treatment was continued without protocol, and adjusted by the treating physician according to clinical judgement, preferably with a treat-to-target strategy. Four years after trial initiation, all patients were invited to participate in the COBRA-light extension study, in which patients were interviewed and physically examined, patient reported outcomes were assessed, radiographs were made and clinical records were examined for comorbidities and medication use. Results: In the extension study, 149 out of 162 (92%) original trial patients participated: 72 COBRA-light and 77 COBRA patients. Initial COBRA-light and COBRA therapy showed similar effect on disease activity, physical functioning, radiological outcome and Boolean remission over the 4-year follow-up period. In addition, both treatment groups showed similar survival and major comorbidities, although the power to detect differences was limited. Besides protocolled differences in prednisolone, MTX and SSZ use, the use of other synthetic and biologic DMARDs and intra-articular and intramuscular glucocorticoid injections was similar in both treatment groups over the 4-year period. Conclusion: Early RA patients initially treated with COBRA-light or COBRA therapy had similar efficacy and safety outcomes over a 4-year follow-up period.

Prevalence of malnutrition and validation of bioelectrical impedance analysis for the assessment of body composition in patients with systemic sclerosis.

Objectives: The aims were to assess the prevalence of malnutrition and to validate bioelectrical impedance analysis (BIA) against whole-body DXA for the assessment of body composition in patients with SSc. Methods: Malnutrition was defined as BMI <18.5 kg/m 2 or unintentional weight loss >10% in combination with a fat-free mass index (FFMI) <15 kg/m 2 for women or <17 kg/m 2 for men or BMI <20.0 kg/m 2 (age <70 years) or <22 kg/m 2 (age >70 years). Body composition was assessed in 72 patients with whole-body DXA (Hologic, Discovery A) and BIA (Bodystat Quadscan 400). The manufacturer's equation and the Geneva equation were used to estimate FFM and fat mass. The agreement between BIA and whole-body DXA was assessed with Bland-Altman analysis and intraclass correlation coefficient. Results: Malnutrition was found in 8.3% (n = 6) and low FFMI in 20.8% (n = 15) of patients. The mean difference in FFM between BIA and DXA applying the Geneva equation was 0.02 ( s . d . 2.4) kg, intraclass correlation coefficient 0.97 (95% CI: 0.95, 0.98). Limits of agreement were ±4.6 kg. The manufacturer's equation was less adequate to predict FFM. Conclusion: This study shows a relatively low prevalence of malnutrition in comparison with other studies, but a high prevalence of low FFMI, underlining the necessity of measuring body composition in SSc patients with a standardized and validated method. A good validity of BIA in determining FFM was found at a group level, while at an individual level the FFM may vary by 4.6 kg.

Anti-Hinge Antibodies Recognize IgG Subclass- and Protease-Restricted Neoepitopes.

Anti-hinge Abs (AHAs) target neoepitopes exposed after proteolytic cleavage of IgG. In this study, we explored the diversity of protease- and IgG subclass-restricted AHAs and their potential as immunological markers in healthy donors (HDs) and patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE). AHA reactivity against IgG-degrading enzyme of Streptococcus pyogenes (IdeS)- or pepsin-generated F(ab')2 fragments of all four human IgG subclasses was determined. AHA reactivity against one or more out of eight F(ab')2 targets was found in 68% (68 of 100) of HDs, 69% (68 of 99) of SLE patients, and 81% (79 of 97) of RA patients. Specific recognition of hinge epitopes was dependent on IgG subclass and protease used to create the F(ab')2 targets, as confirmed by inhibition experiments with F(ab')2 fragments and hinge peptides. Reactivity against IdeS-generated F(ab')2 targets was found most frequently, whereas reactivity against pepsin-generated F(ab')2 targets better discriminated between RA and HDs or SLE, with significantly higher AHA levels against IgG1/3/4. In contrast, AHA levels against pepsin-cleaved IgG2 were comparable. No reactivity against IdeS-generated IgG2-F(ab')2s was detected. The most discriminatory AHA reactivity in RA was against pepsin-cleaved IgG4, with a 35% prevalence, ≥5.8-fold higher than in HDs/SLE, and significantly higher levels (p < 0.0001). Cross-reactivity for F(ab')2s generated from different IgG subclasses was only observed for subclasses having homologous F(ab')2 C termini (IgG1/3/4). For IgG2, two pepsin cleavage sites were identified; anti-hinge reactivity was restricted to only one of these. In conclusion, AHAs specifically recognize IgG subclass- and protease-restricted hinge neoepitopes. Their protease-restricted specificity suggests that different AHA responses developed under distinct inflammatory or infectious conditions and may be markers of, and participants in, such processes.