Identification of new risk factors for hydroxychloroquine and chloroquine retinopathy in systemic lupus erythematosus patients.

BACKGROUND: Long-term hydroxychloroquine (HCQ) or chloroquine (CQ) intake causes retinal toxicity in 0.3-8 % of patients with rheumatic diseases. Numerous risk factors have been described, eg, daily dose by weight, treatment duration, chronic kidney disease, concurrent tamoxifen therapy and pre-existing retinal or macular disease. However, those factors cannot explain the entire risk of developing antimalarial retinopathy. OBJECTIVE: This study was undertaken to identify new risk factors associated with HCQ or CQ retinopathy (QRNP) in systemic lupus erythematosus (SLE) patients. METHODS: This case-control (1:2) study compared SLE patients with QRNP (cases) to those without (controls). Controls were matched for sex and known QRNP risk factors: HCQ and/or CQ treatment duration (±1 year) and age (±5 year) at SLE diagnosis. RESULTS: Forty-eight cases were compared to 96 SLE controls. Multivariable logistic-regression analysis retained the following as independent determinants significantly associated with QRNP: concomitant selective serotonin-reuptake inhibitor (SSRI) or serotonin- and norepinephrine-reuptake inhibitor (SNRI) intake (OR [95 % confidence interval] 6.6 [1.2 to 40.9]; p < 0.01); antiphospholipid syndrome (OR=8.9 [2.2 to 41.4] p < 0.01); blood hydroxychloroquine/desethylchloroquine concentration ([HCQ]/[DCQ]) ratio <7.2 (OR 8.4 [2.7 to 30.8]; p < 0.01) or skin phototype ≥4 (OR 5.5 [1.4 to 26.5]; p = 0.02), but not daily HCQ dose, blood [HCQ] or body mass index. CONCLUSION: The results of this case-control study identified blood [HCQ]/[DCQ] ratio, concurrent SSRI/SNRI therapy, skin phototype ≥4 and antiphospholipid syndrome as new risk factors for QRNP.

Prognostic value of hypermetabolic bone sarcoidosis observed by 18F-fluorodeoxyglucose positron emission tomography.

OBJECTIVES: Sarcoidosis is a multisystemic granulomatosis diagnosed mainly in young adults.18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) is useful in sarcoidosis cases to search for a biopsiable site or assess disease activity.18F-FDG PET-CT can reveal bone hypermetabolism in sarcoidosis patients, even in the absence of osteoarticular symptoms. The aim of this study was to describe metabolic bone involvement in sarcoidosis patients and to evaluate its prognostic impact. METHODS: This was an observational, comparative, retrospective, monocentric study. Inclusion criteria were a confirmed diagnosis of sarcoidosis according to the World Association of Sarcoidosis and Other Granulomatous Diseases (WASOG) criteria and at least one 18F-FDG PET-CT scan during follow-up. Metabolic bone involvement of sarcoidosis was defined as focal bone hypermetabolism with no argument for a differential diagnosis of bone 18F-FDG uptake. Patients with and without bone involvement were compared. RESULTS: Among the 175 included patients, 32 (18%) had metabolic bone involvement of sarcoidosis. The metabolic bone involvement was mainly axial and mostly without bone abnormalities on CT. Metabolic bone involvement was associated with intrathoracic and extrathoracic lymph node involvement and with a higher number of organs involved. Patients with metabolic bone involvement more frequently received corticosteroids, methotrexate and tumor necrosis factor (TNF)-α inhibitors and a higher number of treatments. Relapse of sarcoidosis occurred sooner in patients with metabolic bone involvement. CONCLUSION: These results suggest that metabolic bone involvement is associated with more diffuse and more severe sarcoidosis.

ANCA-associated scleritis: impact of ANCA on presentation, response to therapy and outcome.

OBJECTIVES: To describe the characteristics, treatment and outcome of isolated ANCA-associated scleritis at diagnosis compared with idiopathic scleritis with negative ANCA tests. METHODS: This retrospective multicentre case-control study was performed within the French Vasculitis Study Group (FVSG) network and in three French tertiary ophthalmologic centres. Data from patients with scleritis without any systemic manifestation and with positive ANCA results were compared with those of a control group of patients with idiopathic scleritis with negative ANCA tests. RESULTS: A total of 120 patients, including 38 patients with ANCA-associated scleritis and 82 control patients, diagnosed between January 2007 and April 2022 were included. The median follow-up was 28 months (IQR 10-60). The median age at diagnosis was 48 years (IQR 33-60) and 75% were females. Scleromalacia was more frequent in ANCA-positive patients (P = 0.027) and 54% had associated ophthalmologic manifestations, without significant differences. ANCA-associated scleritis more frequently required systemic medications, including glucocorticoids (76% vs 34%; P < 0.001), and rituximab (P = 0.03) and had a lower remission rate after the first- and second-line treatment. Systemic ANCA-associated vasculitis (AAV) occurred in 30.7% of patients with PR3- or MPO-ANCA, after a median interval of 30 months (IQR 16.3-44). Increased CRP >5 mg/l at diagnosis was the only significant risk factor of progression to systemic AAV [adjusted hazard ratio 5.85 (95% CI 1.10, 31.01), P = 0.038]. CONCLUSION: Isolated ANCA-associated scleritis is mostly anterior scleritis with a higher risk of scleromalacia than ANCA-negative idiopathic scleritis and is more often difficult to treat. One-third of patients with PR3- or MPO-ANCA scleritis progressed to systemic AAV.

IgG4-related uveitis. A French cohort and literature review.

INTRODUCTION: IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder that can affect almost any organ. IgG4-related ophthalmic disease is a protean condition involving the orbit and ocular adnexa. Although a few cases of uveitis have been reported, the exact pattern of IgG4-related intraocular manifestations remains unclear. Here, we report on a nationwide French multicenter cohort of patients with IgG4-RD and uveitis and conducted a literature review. METHODS: Patients with uveitis and a concomitant definite diagnosis of IgG4-RD (Revised Comprehensive Diagnostic criteria, American College of Rheumatology/European League Against Rheumatism classification criteria for IgG4-RD, International Consensus Diagnostic Criteria for auto-immune pancreatitis, or diagnostic criteria for IgG4-related hypophysitis), were screened from our national IgG4-RD and systemic fibrosis database. Concomitantly, we conducted a PubMed literature review and selected cases of definite IgG4-RD with uveitis. RESULTS: We reported on 16 patients (8 from our database and 8 from the literature) and a total of 30 episodes of uveitis. Uveitis cases represented 3 % of total IgG4-RD patients in the national database on IgG4-RD and systemic fibrosis. Uveitis was inaugural in IgG4-RD in 4/16 cases (25 %) (appearing before any other IgG4-related symptom, at a median of 9 months), occurred concurrently to other IgG4-related symptoms in 9/16 cases (56 %) (at a median of 15 months before IgG4-RD diagnosis), and appeared during follow up in 3/16 patients (19 %) (at a median of 57 months after first IgG4-related symptoms). When uveitis occurred during follow up, it was associated with IgG4-RD manifestations in other organs in 6/9 patients (67 %). Uveitis was bilateral in 8/16 cases (50 %) and granulomatous in 5/10 cases (50 %). It was anterior in 8/13 (62 %), intermediate in 3/13 (23 %), and global (panuveitis) in 4/13 patients (31 %). Median serum IgG4 at diagnosis was 3.2 g/L. Median follow up time was of 6 years, during which 8/16 patients (50 %) experienced at least one relapse of uveitis. Treatment data was available for 29/30 uveitis flares. Steroids were used in 28/29 episodes of uveitis (97 %), leading to remission of uveitis in 16/28 cases (57 %). Methotrexate and rituximab (in combination with systemic steroids) were administered as second- or third-line therapy in 6/29 (21 %) and 5/29 (17 %) episodes of uveitis, respectively, and led to remission of uveitis in 4/6 cases (67 %) and 4/5 cases (80 %), respectively. One third of uveitides required at least two different lines of treatment for remission induction (mainly a combination of both systemic steroids and methotrexate or rituximab). DISCUSSION AND CONCLUSIONS: Uveitis may be one of the initial symptoms of IgG4-RD, and IgG4-RD should be considered in the diagnostic workup of uveitis. Its early onset in IgG4-RD may help with early diagnosis and treatment of the disease. Steroid monotherapy may be sufficient to treat IgG4-related uveitis, yet relapses were frequent (50 %) and ultimately a third of patients required at least two lines of treatment. Hence, steroid-sparing agents can be considered at early stages of the disease, particularly for patients with a high risk of relapse or steroid-related complications.

Cerebro-Ocular Toxocariasis Revealed by Bilateral Cystoid Macular Edema.

DESIGN: Case Report Case description: This report describes the case of a female patient diagnosed with oculo-cerebral toxocariasis manifesting initially in the form of isolated bilateral cystoid macular edema. Diagnosis was made by means of positive anterior chamber and lumbar puncture western blots. The unusual presentation, ancillary findings and treatment are discussed. The control of intraocular inflammation that was only partially responsive to steroids was eventually achieved with pegylated interferon alfa-2a. CONCLUSION: Isolated macular edema is a rare presentation of ocular toxocariasis. Interferon alfa-2a may prove useful in case of insufficient control of inflammation.

Impaired metabolism predicts coronary artery calcification in women with systemic lupus erythematosus.

BACKGROUND: Patients with systemic lupus erythematosus (SLE) exhibit a high risk for cardiovascular diseases (CVD) which is not fully explained by the classical Framingham risk factors. SLE is characterized by major metabolic alterations which can contribute to the elevated prevalence of CVD. METHODS: A comprehensive analysis of the circulating metabolome and lipidome was conducted in a large cohort of 211 women with SLE who underwent a multi-detector computed tomography scan for quantification of coronary artery calcium (CAC), a robust predictor of coronary heart disease (CHD). FINDINGS: Beyond traditional risk factors, including age and hypertension, disease activity and duration were independent risk factors for developing CAC in women with SLE. The presence of coronary calcium was associated with major alterations of circulating lipidome dominated by an elevated abundance of ceramides with very long chain fatty acids. Alterations in multiple metabolic pathways, including purine, arginine and proline metabolism, and microbiota-derived metabolites, were also associated with CAC in women with SLE. Logistic regression with bootstrapping of lipidomic and metabolomic variables were used to develop prognostic scores. Strikingly, combining metabolic and lipidomic variables with clinical and biological parameters markedly improved the prediction (area under the curve: 0.887, p < 0.001) of the presence of coronary calcium in women with SLE. INTERPRETATION: The present study uncovers the contribution of disturbed metabolism to the presence of coronary artery calcium and the associated risk of CHD in SLE. Identification of novel lipid and metabolite biomarkers may help stratifying patients for reducing CVD morbidity and mortality in SLE. FUNDING: INSERM and Sorbonne Université.

Systemic lupus erythematosus-related acute lung disease.

INTRODUCTION: Systemic lupus erythematosus (SLE) is non-organ specific autoimmune disease with mainly skin, joint, and kidney involvement. SLE-related acute lung disease (ALD) is rare, poorly investigated and can lead to acute respiratory failure. We conducted a retrospective study aiming to describe clinical features, treatments and outcome of SLE-related APD. METHODS: We retrospectively included all patients with SLE and ALD admitted from November 1996 and September 2018 to La Pitié-Salpêtrière Hospital, after exclusion of viral or bacterial lung infection, cardiac failure or any other alternate diagnosis. RESULTS: During the time of the study, 14 patients with 16 episodes were admitted to our center: female 79%, mean age ± SD at admission 24 ± 11 years. ALD was inaugural of the SLE in 70% cases. SLE main organ involvement were: arthritis 93%, skin 79%, serositis 79%, hematological 79%, kidney 64%, neuropsychiatric 36% and cardiac 21%. 11 episodes required ICU admission for a median time of 8 days. Chest CT-scan revealed mostly basal consolidation and ground-glass opacities. When available, bronchoalveolar lavage mostly revealed a neutrophilic alveolitis with alveolar hemorrhage in 67% cases. Symptomatic respiratory treatments were: oxygen 81%, high-flow nasal canula oxygen 27%, non-invasive ventilation 36%, mechanical ventilation 64% and venovenous extracorporeal membrane oxygenation 18%. SLE-specific treatments were: corticosteroids 100%, cyclophosphamide 56% and plasma exchange 25%. All patients but one survived to ICU and hospital discharge. Two patients had a relapse of SLE-related ALD but none had interstitial lung disease during follow-up. CONCLUSION: Systemic lupus erythematosus-related acute respiratory failure is a severe event, mostly occurring at SLE onset, typical harboring a basal consolidation pattern on chest CT-scan and alveolar hemorrhage on BAL pathological examination. Mortality in our cohort is lower than previously reported but these results needs to be confirmed in further larger studies.

DOCK11 deficiency in patients with X-linked actinopathy and autoimmunity.

Dedicator of cytokinesis (DOCK) proteins play a central role in actin cytoskeleton regulation. This is highlighted by the DOCK2 and DOCK8 deficiencies leading to actinopathies and immune deficiencies. DOCK8 and DOCK11 activate CDC42, a Rho-guanosine triphosphate hydrolases involved in actin cytoskeleton dynamics, among many cellular functions. The role of DOCK11 in human immune disease has been long suspected but, to the best of our knowledge, has never been described to date. We studied 8 male patients, from 7 unrelated families, with hemizygous DOCK11 missense variants leading to reduced DOCK11 expression. The patients were presenting with early-onset autoimmunity, including cytopenia, systemic lupus erythematosus, skin, and digestive manifestations. Patients' platelets exhibited abnormal ultrastructural morphology and spreading as well as impaired CDC42 activity. In vitro activated T cells and B-lymphoblastoid cell lines from patients exhibited aberrant protrusions and abnormal migration speed in confined channels concomitant with altered actin polymerization during migration. Knock down of DOCK11 recapitulated these abnormal cellular phenotypes in monocytes-derived dendritic cells and primary activated T cells from healthy controls. Lastly, in line with the patients' autoimmune manifestations, we also observed abnormal regulatory T-cell (Treg) phenotype with profoundly reduced FOXP3 and IKZF2 expression. Moreover, we found reduced T-cell proliferation and impaired STAT5B phosphorylation upon interleukin-2 stimulation of the patients' lymphocytes. In conclusion, DOCK11 deficiency is a new X-linked immune-related actinopathy leading to impaired CDC42 activity and STAT5 activation, and is associated with abnormal actin cytoskeleton remodeling as well as Treg phenotype, culminating in immune dysregulation and severe early-onset autoimmunity.

Lower disease activity but higher risk of severe COVID-19 and herpes zoster in patients with systemic lupus erythematosus with pre-existing autoantibodies neutralising IFN-α.

OBJECTIVES: Type-I interferons (IFNs-I) have potent antiviral effects. IFNs-I are also overproduced in patients with systemic lupus erythematosus (SLE). Autoantibodies (AAbs) neutralising IFN-α, IFN-ß and/or IFN-ω subtypes are strong determinants of hypoxemic COVID-19 pneumonia, but their impact on inflammation remains unknown. METHODS: We retrospectively analysed a monocentric longitudinal cohort of 609 patients with SLE. Serum AAbs against IFN-α were quantified by ELISA and functionally assessed by abolishment of Madin-Darby bovine kidney cell protection by IFN-α2 against vesicular stomatitis virus challenge. Serum-neutralising activity against IFN-α2, IFN-ß and IFN-ω was also determined with a reporter luciferase activity assay. SARS-CoV-2 antibody responses were measured against wild-type spike antigen, while serum-neutralising activity was assessed against the SARS-CoV-2 historical strain and variants of concerns. RESULTS: Neutralising and non-neutralising anti-IFN-α antibodies are present at a frequency of 3.3% and 8.4%, respectively, in individuals with SLE. AAbs neutralising IFN-α, unlike non-neutralising AAbs, are associated with reduced IFN-α serum levels and a reduced likelihood to develop active disease. However, they predispose patients to an increased risk of herpes zoster and severe COVID-19 pneumonia. Severe COVID-19 pneumonia in patients with SLE is mostly associated with combined neutralisation of different IFNs-I. Finally, anti-IFN-α AAbs do not interfere with COVID-19 vaccine humoral immunogenicity. CONCLUSION: The production of non-neutralising and neutralising anti-IFN-I antibodies in SLE is likely to be a consequence of SLE-associated high IFN-I serum levels, with a beneficial effect on disease activity, yet a greater viral risk. This finding reinforces the recommendations for vaccination against SARS-CoV-2 in SLE.

Intravenous Immunoglobulins Tapering and Withdrawal in Systemic Capillary Leak Syndrome (Clarkson Disease).

BACKGROUND: The systemic capillary leak syndrome (SCLS), also known as Clarkson disease, is a very rare condition characterized by recurrent life-threatening episodes of vascular hyperpermeability in the presence of a monoclonal gammopathy. Extended intravenous immunoglobulin (IVIG) treatment is associated with fewer recurrences and improved survival, but the optimal treatment dosage and duration remain unknown. OBJECTIVE: We aim to evaluate the safety of IVIG tapering and withdrawal in patients with SCLS. METHODS: We conducted a retrospective multicenter study including all adult patients with monoclonal gammopathy-associated SCLS from the EurêClark registry who received at least 1 course of IVIG. The primary end point was overall survival according to IVIG withdrawal. RESULTS: Fifty-nine patients of mean ± SD age 51 ± 13 years were included. Overall cumulative probabilities of 2-, 5-, 10- and 15-year survival were 100%, 85%, 72%, 44%, respectively. The IVIG was withdrawn at least once in 18 patients (31%; W+ group) and never in 41 patients (69%; W- group). Cumulative probabilities of 10-year survival in W+ versus W- groups were 50% and 83% (log rank test, P = .02), respectively. Relapse rate and the median number of relapses in the W+ versus the W- groups were 72% versus 58% (P = 0.3) and 2.5 (0.3-4) versus 1 (0-2) (P = .03), respectively. The IVIG tapering was not statistically associated with increased person-year incidence of attacks using a mixed linear model. CONCLUSIONS: The IVIG withdrawal was associated with increased mortality and higher rate of recurrence in SCLS patients. The IVIG tapering might be cautiously considered in stable SCLS patients.

Casitas B-lineage lymphoma Gene Mutation Ocular Phenotype.

This article describes the ocular phenotype associated with the identified Casitas B-lineage lymphoma (CBL) gene mutation and reviews the current literature. This work also includes the longitudinal follow-up of five unrelated cases of unexplained fundus lesions with visual loss associated with a history of hepatosplenomegaly. Wide repeated workup was made to rule out infections, inflammatory diseases, and lysosomal diseases. No variants in genes associated with retinitis pigmentosa, cone-rod dystrophy, and inherited optic neuropathy were found. Molecular analysis was made using next-generation sequencing (NGS) and whole-exome sequencing (WES). The results included two cases sharing ophthalmological signs including chronic macular edema, vascular leakage, visual field narrowing, and electroretinography alteration. Two other cases showed damage to the optic nerve head and a fifth young patient exhibited bilateral complicated vitreoretinal traction and carried a heterozygous mutation in the CBL gene associated with a mutation in the IKAROS gene. Ruxolitinib as a treatment for RASopathy did not improve eye conditions, whereas systemic lesions were resolved in one patient. Mutations in the CBL gene were found in all five cases. In conclusion, a detailed description may pave the way for the CBL mutation ocular phenotype. Genetic analysis using whole-exome sequencing could be useful in the diagnosis of unusual clinical features.

Characteristics of thrombocytopenia, anasarca, fever, reticulin fibrosis and organomegaly syndrome: a retrospective study from a large Western cohort.

Idiopathic multicentric Castleman disease (iMCD) is a non-clonal inflammatory lymphoproliferative disorder of unknown origin. Recently, TAFRO syndrome (thrombocytopenia, anasarca, fever, reticulin fibrosis and organomegaly) emerged as a singular variant of iMCD in Asia and was associated with a severe course and a poor outcome. The present study describes the first large Western cohort of TAFRO syndrome patients (n = 25) meeting the All Japan TAFRO Syndrome Research Group diagnostic criteria. Characteristics of TAFRO patients were compared to iMCD-not otherwise specified (iMCD-NOS) patients used as a control group (n = 43). Our results show that despite baseline characteristics in accordance with previously reported series, Western TAFRO syndrome patients do not appear to present with a worse outcome than iMCD-NOS patients. There were no significant differences between the two groups regarding treatment choice, response to rituximab (71% vs. 67%) or tocilizumab (69% vs. 91%) in TAFRO and iMCD-NOS, respectively. The two-year overall survival was above 95% in both groups. Limits of inclusion and exclusion criteria for TAFRO definition are also discussed. Our findings raise the question of the singularity of the TAFRO entity in Western countries. The data should promote further research using unsupervised models to identify markers of disease severity in Western cohorts of iMCD patients.

Cerebral Vein Thrombosis in the Antiphospholipid Syndrome: Analysis of a Series of 27 Patients and Review of the Literature.

(1) Background: The Antiphospholipid Syndrome (APS) is a systemic autoimmune disorder characterized by arterial and/or venous thrombosis, pregnancy morbidity and raised titers of antiphospholipid antibodies. Cerebral vein thrombosis (CVT) is a rare form of cerebrovascular accident and an uncommon APS manifestation; the information in the literature about this feature consists of case reports and small case series. Our purpose is to describe the particular characteristics of CVT when occurs as part of the APS and compare our series with the patients published in the literature. (2) Methods: We conducted a retrospective observational study collecting data from medical records in three referral centers for APS and CVT, and a systematic review of the literature for CVT cases in APS patients. (3) Results: Twenty-seven APS patients with CVT were identified in our medical records, the majority of them diagnosed as primary APS and with the CVT being the first manifestation of the disease; additional risk factors for thrombosis were identified. The review of the literature yielded 86 cases, with similar characteristics as those of our retrospective series. (4) Conclusions: To our knowledge, our study is the largest CVT series in APS patients published to date, providing a unique point of view in this rare thrombotic manifestation.

Shiga Toxin-Associated Hemolytic Uremic Syndrome in Adults, France, 2009-2017.

We conducted a retrospective study on hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC) in 96 adults enrolled in the cohort of the National Reference Center for Thrombotic Microangiopathies network in France during 2009-2017. Most infections were caused by STEC strains not belonging to the O157 or O104 serogroups. Thirty (31.3%) patients had multiple risk factors for thrombotic microangiopathy. In total, 61 (63.5%) patients required dialysis, 50 (52.1%) had a serious neurologic complication, 34 (35.4%) required mechanical ventilation, and 19 (19.8%) died during hospitalization. We used multivariate analysis to determine that the greatest risk factors for death were underlying immunodeficiency (hazard ratio 3.54) and severe neurologic events (hazard ratio 3.40). According to multivariate analysis and propensity score-matching, eculizumab treatment was not associated with survival. We found that underlying conditions, especially immunodeficiency, are strongly associated with decreased survival in adults who have hemolytic uremic syndrome caused by STEC.

Systemic autoimmune disorders associated with thrombotic microangiopathy: A cross-sectional analysis from the French National TMA registry: Systemic autoimmune disease-associated TMA.

CONTEXT: The management of systemic auto-immune diseases (SAID) -associated thrombotic microangiopathies (TMA) [SAID-TMA] remains debated. OBJECTIVES: To provide a demographic, clinical and therapeutic picture of SAID-TMA. METHODS: A cross-sectional analysis was conducted on adult patients presenting with SAID and TMA from the French National TMA Registry over a 20-year period. Clinical features were extracted and compared to those from a historical cohort of atypical haemolytic and uremic syndrome (aHUS) patients. RESULTS: Forty-one patients with SAID-TMA were compared to 78 patients with aHUS from a historical cohort. Connective tissue diseases (CTD) were systemic lupus erythematosus (n=18), primary Sjögren's syndrome (n=7), systemic sclerosis (n=11), mixed CTD (n=2) and 2 cases of vasculitides, including 7 overlapping forms and 8 cases of primary antiphospholipid syndromes (APLS). Patients with SAID-TMA generally had pre-existing chronic kidney failure (OR= 3.17, 95%CI: 1.204 to 7.923; p= 0.016) compared to aHUS patients, though creatinine levels were significantly lower (216 [IQR, 108-334] µmol/L vs. 368 [IQR, 170-722] µmol/L; p= 0.002). Patients were less likely to recover if renal replacement therapy was needed at onset (OR= 0.07; 0.02 to 0.34; p <0.0005). Two patients died. Thirty patients responded to immunosuppressive treatment and complete remission was achieved in 25 cases. By contrast, therapeutic plasma exchange (TPE) did not have an early effect on TMA features at Day-7 nor Day-15 (p >0.05). CONCLUSION: The management of SAID-TMA implies an early initiation of immunosuppressive drugs for flares of the associated SAID, whereas TPE seem ineffective. KEY MESSAGES.

Differential Expression of Interferon-Alpha Protein Provides Clues to Tissue Specificity Across Type I Interferonopathies.

Whilst upregulation of type I interferon (IFN) signaling is common across the type I interferonopathies (T1Is), central nervous system (CNS) involvement varies between these disorders, the basis of which remains unclear. We collected cerebrospinal fluid (CSF) and serum from patients with Aicardi-Goutières syndrome (AGS), STING-associated vasculopathy with onset in infancy (SAVI), presumed monogenic T1Is (pT1I), childhood systemic lupus erythematosus with neuropsychiatric features (nSLE), non-IFN-related autoinflammation (AI) and non-inflammatory hydrocephalus (as controls). We measured IFN-alpha protein using digital ELISA. Eighty-two and 63 measurements were recorded respectively in CSF and serum of 42 patients and 6 controls. In an intergroup comparison (taking one sample per individual), median CSF IFN-alpha levels were elevated in AGS, SAVI, pT1I, and nSLE compared to AI and controls, with levels highest in AGS compared to all other groups. In AGS, CSF IFN-alpha concentrations were higher than in paired serum samples. In contrast, serum IFN was consistently higher compared to CSF levels in SAVI, pT1I, and nSLE. Whilst IFN-alpha is present in the CSF and serum of all IFN-related diseases studied here, our data suggest the primary sites of IFN production in the monogenic T1I AGS and SAVI are, respectively, the CNS and the periphery. These results inform the diagnosis of, and future therapeutic approaches to, monogenic and multifactorial T1Is.