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.

The Transcriptional and Protein Profile From Human Infected Neuroprogenitor Cells Is Strongly Correlated to Zika Virus Microcephaly Cytokines Phenotype Evidencing a Persistent Inflammation in the CNS.

Zika virus (ZIKV) infection during pregnancy is associated with microcephaly, a congenital malformation resulting from neuroinflammation and direct effects of virus replication on the developing central nervous system (CNS). However, the exact changes in the affected CNS remain unknown. Here, we show by transcriptome analysis (at 48 h post-infection) and multiplex immune profiling that human induced-neuroprogenitor stem cells (hiNPCs) respond to ZIKV infection with a strong induction of type-I interferons (IFNs) and several type-I IFNs stimulated genes (ISGs), notably cytokines and the pro-apoptotic chemokines CXCL9 and CXCL10. By comparing the inflammatory profile induced by a ZIKV Brazilian strain with an ancestral strain isolated from Cambodia in 2010, we observed that the response magnitude differs among them. Compared to ZIKV/Cambodia, the experimental infection of hiNPCs with ZIKV/Brazil resulted in a diminished induction of ISGs and lower induction of several cytokines (IFN-α, IL-1α/ß, IL-6, IL-8, and IL-15), consequently favoring virus replication. From ZIKV-confirmed infant microcephaly cases, we detected a similar profile characterized by the presence of IFN-α, CXCL10, and CXCL9 in cerebrospinal fluid (CSF) samples collected after birth, evidencing a sustained CNS inflammation. Altogether, our data suggest that the CNS may be directly affected due to an unbalanced and chronic local inflammatory response, elicited by ZIKV infection, which contributes to damage to the fetal brain.

Detection of interferon alpha protein reveals differential levels and cellular sources in disease.

Type I interferons (IFNs) are essential mediators of antiviral responses. These cytokines have been implicated in the pathogenesis of autoimmunity, most notably systemic lupus erythematosus (SLE), diabetes mellitus, and dermatomyositis, as well as monogenic type I interferonopathies. Despite a fundamental role in health and disease, the direct quantification of type I IFNs has been challenging. Using single-molecule array (Simoa) digital ELISA technology, we recorded attomolar concentrations of IFNα in healthy donors, viral infection, and complex and monogenic interferonopathies. IFNα protein correlated well with functional activity and IFN-stimulated gene expression. High circulating IFNα levels were associated with increased clinical severity in SLE patients, and a study of the cellular source of IFNα protein indicated disease-specific mechanisms. Measurement of IFNα attomolar concentrations by digital ELISA will enhance our understanding of IFN biology and potentially improve the diagnosis and stratification of pathologies associated with IFN dysregulation.

Cerebrospinal fluid interferon alpha levels correlate with neurocognitive impairment in ambulatory HIV-Infected individuals.

HIV-associated neurocognitive disorders (HANDs) continue to be common and are associated with increased morbidity and mortality. However, the underlying mechanisms in the combination antiretroviral therapy (cART) era are not fully understood. Interferon alpha (IFNα) is an antiviral cytokine found to be elevated in the cerebrospinal fluid (CSF) of individuals with advanced HIV-associated dementia in the pre-cART era. In this cross-sectional study, we investigated the association between IFNα and neurocognitive performance in ambulatory HIV-infected individuals with milder impairment. An eight-test neuropsychological battery representing six cognitive domains was administered. Individual scores were adjusted for demographic characteristics, and a composite neuropsychological score (NPT-8) was calculated. IFNα and CSF neurofilament light chain (NFL) levels were measured using enzyme-linked immunosorbent assay (ELISA). There were 15 chronically infected participants with a history of significant immunocompromise (median nadir CD4+ of 49 cells/µl). Most participants were neurocognitively impaired (mean global deficit score of 0.86). CSF IFNα negatively correlated with three individual tests (Trailmaking A, Trailmaking B, and Stroop Color-Word) as well as the composite NPT-8 score (r = -0.67, p = 0.006). These negative correlations persisted in multivariable analyses adjusting for chronic hepatitis B and C. Additionally, CSF IFNα correlated strongly with CSF NFL, a marker of neuronal damage (rho = 0.748, p = 0.0013). These results extend findings from individuals with severe HIV-associated dementia in the pre-cART era and suggest that IFNα may continue to play a role in HAND pathogenesis during the cART era. Further investigation into the role of IFNα is indicated.

Encephalitis and CSF increased level of interferon-α in Kikuchi-Fujimoto disease.

Neurological manifestations have been reported in Kikuchi-Fujimoto disease (KFD). Characteristics of brain lesions are not defined. In addition, no biological indexes are known to help clinicians along the diagnosis process. The authors describe encephalitis associated with KFD. Brain MRI, positron emission tomography (PET) scan and a large biological assessment including interferon α (INF-α) level measurement in cerebrospinal fluid (CSF) were performed. A 39-year-old man with chronic headaches developed diplopia, slow ideation and behavioural disturbances. MRI showed brain lesions particularly in the pontine region and internal temporal lobes with enhancement of the perivacular space and the walls of the lateral ventricle. The IFN-α level was increased in the CSF without viral infection. Cervical and mediastinal adenitis were evident as a hypermetabolic focus on a PET scan, and biopsy confirmed the diagnosis of KFD. The encephalitis spontaneously remitted. The authors characterised brain lesions especially related to KFD in association with increased of IFN-α level in the CSF.

Utility of interferon-α as a biomarker in central neuropsychiatric involvement in systemic lupus erythematosus.

OBJECTIVE: To assess the utility of interferon-α (IFN-α) in serum and cerebrospinal fluid (CSF) as a biomarker of disease activity in central neuropsychiatric systemic lupus erythematosus (cNPSLE). METHODS: Serum and CSF samples were drawn at hospitalization in 34 patients with cNPSLE, 16 surgical SLE, 4 primary neuropsychiatric conditions, and 25 with nonautoimmune conditions, except in 44 non-NPSLE patients in whom only serum was studied. Six months later, serum/CSF and serum samples were taken in 20 cNPSLE and 35 non-NPSLE patients, respectively. SLE activity was assessed at hospitalization, and 6 months later in cNPSLE and non-NPSLE patients. IFN-α was detected by Luminex technology. RESULTS: The mean ± SD age of patients with cNPSLE was 31.4 ± 12.2 years, which was similar across the study groups (p = 0.46). Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) scores among cNPSLE, non-NPSLE, and SLE-surgical patients were 15.3 ± 8.2, 12.4 ± 8.2, and 3.8 ± 1.5, respectively. IFN-α levels in serum were higher in cNPSLE than in nonautoimmune patients (p = 0.02), but were similar to non-NPSLE and SLE-surgical groups. In CSF samples, IFN-α levels were higher in cNPSLE than in nonautoimmune patients (p = 0.03), and were nonsignificantly higher than in SLE-surgical and primary neuropsychiatric patients. Six months later, serum levels of IFN-α did not vary from baseline values despite a significant decrease in SLEDAI-2K score in cNPSLE and non-NPSLE patients. IFN-α levels in the CSF of patients with cNPSLE also remained stable. Among specific cNPSLE syndromes, CSF IFN-α levels were significantly higher among patients with acute confusional syndrome. CONCLUSION: IFN-α does not seem to represent a useful biomarker of cNPSLE syndromes; its utility in specific cNPSLE manifestations merits further investigation.

Different mutations in three prime repair exonuclease 1 and ribonuclease H2 genes affect clinical features in Aicardi-Goutieres syndrome.

Aicardi-Goutières syndrome is a rare encephalopathy of mutational origin characterized by increased levels of interferon alpha in cerebrospinal fluid. The aim of this study was to explore the influence of different Aicardi-Goutières syndrome genotypes on the clinical course of patients, seeking to identify specific gene expression profiles able to explain Aicardi-Goutières syndrome phenotype differences. We detected the occurrence of Aicardi-Goutières syndrome mutations in 21 patients and compared microarray gene-expression data of cerebrospinal fluid lymphocytes with clinical variables. The levels of interferon alpha in cerebrospinal fluid were high in all patients; we found differences in the expression of genes encoding for Toll-like receptor, endogenous RNases, T lymphocyte activation, angiogenesis inhibition, and peripheral interferon alpha production. These results indicate that further to interferon alpha production in the central nervous system, a variety of other pathogenic mechanisms is activated in Aicardi-Goutières syndrome to various degrees in different patients, thus explaining the interindividual difference in Aicardi-Goutières syndrome course.

Potential role of IFNα in adult lupus.

Patients with lupus have a continuous production of IFNα and display an increased expression of IFNα-regulated genes. The reason for the ongoing IFNα synthesis in these patients seems to be an activation of plasmacytoid dendritic cells (pDCs) by immune complexes (ICs), consisting of autoantibodies in combination with DNA-containing or RNA-containing autoantigens. The mechanisms behind the activation of pDCs by such ICs have to some extent been elucidated during the last years. Thus, interferogenic ICs are internalized via the FcγRIIa expressed on pDCs, reach the endosomes and stimulate Toll-like receptor (TLR) 7 or 9, which subsequently leads to IFNα gene transcription. Variants of genes involved in both the IFNα synthesis and response have been linked to an increased risk to develop lupus. Among these genes are interferon regulatory factor 5 (IRF5), which is involved in TLR signaling, and the signal transducer and activator of transcription 4 (STAT4) that interacts with the type I interferon receptor. Produced IFNα may at least partially be responsible for several of the observed alterations in the immune system of lupus patients and contribute to the autoimmune disease process, which will be discussed in the present review. How produced IFNα can contribute to some clinical manifestations will briefly be described, as well as the possible consequences of this knowledge in clinical practice for disease monitoring and therapy.

Interferon-related transcriptome alterations in the cerebrospinal fluid cells of Aicardi-Goutières patients.

Aicardi-Goutières syndrome (AGS) is a rare interferon (IFN)-related encephalopathy with onset during the first year of life. AGS, is clinically characterized by progressive microcephaly, bilateral basal ganglia calcification, cerebral atrophy, cerebrospinal fluid (CSF), lymphocytosis, delayed development of psychomotor abilities with pyramidal-extrapyramidal syndrome and mimics congenital viral infections. Microarray analysis examining the expression of 18 880 human genes has been applied to the CSF lymphocytes of 20 AGS cases (age 4.5 +/- 4.4 years, mean +/- standard deviation) characterized by high IFN-alpha levels in CSF and 20 matched controls (age 4.4 +/- 4.3 years, mean +/- standard deviation). Gene-expression data reveal significant differences between AGS cases and controls for all controls and 18 AGS cases. The two AGS cases unclassified as compared with controls were both older than 7 years. AGS cases presented upregulation of genes involved in IFN-dependent pathways and lymphocyte functions, paralleled by the downregulation of genes encoding for angiopoietic activities. The cystatin F and DNAJ genes, having a negative feedback on IFN pathways, underwent a progressive age-related increase in their expression. These gene-expression signature parallels a progressive attenuation of clinical symptoms with age. Obtained results provide evidence that exposure to IFN-alpha is harmful for developing brain.

Aicardi-Goutières syndrome: description of a late onset case.

Aicardi-Goutières syndrome (AGS) is a genetically determined encephalopathy usually inherited as an autosomal recessive trait. The syndrome can be caused by mutations in the AGS1 gene encoding the exonuclease TREX1, or in any of the AGS2, AGS3, or AGS4 genes that encode the three subunits of the human ribonuclease H2 (RNaseH2) complex. Typically, AGS has an early onset, usually manifesting by the age of 4 months. We describe a female infant in whom the onset of the neurological symptoms of AGS occurred after the age of 12 months, and her younger brother who was identified to be affected by AGS at the age of 8 months on the basis of the presence of non-neurological features alone. This paper is important in providing a detailed description of the late-onset presentation of AGS in patients with proven pathogenic mutations and highlights the occurrence of both chilblains and abnormal neuroimaging many months before the onset of neurological features. Our paper also considers the possible value of immunomodulatory therapy in AGS.

Aicardi-Goutières syndrome presenting atypically as a sub-acute leukoencephalopathy.

Aicardi-Goutières syndrome is an autosomal recessive encephalopathy characterised by acquired microcephaly, basal ganglia calcifications, leukodystrophy, cerebral atrophy, chronic cerebrospinal lymphocytosis, and raised titres of interferon alpha in the cerebrospinal fluid. The disease onset is generally within the first months of life. We here report a case of Aicardi-Goutières syndrome presenting atypically as a sub-acute leukoencephalopathy following satisfactory psychomotor development up to the age of 16 months. This case highlights the importance of considering Aicardi-Goutières syndrome in the differential diagnosis of an unexplained leukoencephalopathy and the possibility of later onset of the disease.

Diagnostic reliability of cerebral spinal fluid tests for acute confusional state (delirium) in patients with systemic lupus erythematosus: interleukin 6 (IL-6), IL-8, interferon-alpha, IgG index, and Q-albumin.

OBJECTIVE: Acute confusional state (ACS) is an uncommon but severe central nervous system (CNS) syndrome in systemic lupus erythematosus (SLE) defined by clinical manifestations. To develop useful and reliable diagnostic tools for ACS, we evaluated the association of cerebral spinal fluid (CSF) tests with ACS and their predictive values for the diagnosis of ACS in SLE. METHODS: We performed a prospective study using a cohort of 59 patients with SLE and compared those with and without ACS. Associations between ACS and each CSF test [interleukin 6 (IL-6), IL-8, interferon-alpha, IgG index, and Q-albumin] were statistically evaluated. Each patient underwent all CSF evaluations. RESULTS: ACS was diagnosed in 10 patients (ACS group), SLE-related CNS syndromes except ACS in 13, and no CNS syndromes in 36 (non-CNS group). CSF IL-6 levels in the ACS group were significantly higher than those in the non-CNS group (p < 0.05). A positive IgG index (p = 0.028) was significantly associated with ACS. No other test showed a significant association with ACS. The positive and negative predictive values for the diagnosis of ACS in SLE were 80% and 85% for elevated CSF IL-6 levels (> or = 31.8 pg/ml), and 75% and 83% for the IgG index, respectively. CONCLUSION: No single CSF test had sufficient predictive value to diagnose ACS in SLE, although CSF IL-6 levels and the IgG index showed statistical associations with ACS. Use of CSF tests combined with careful history and clinical examinations is recommended for proper diagnosis of ACS in SLE.

Childhood encephalopathy: viruses, immune response, and outcome.

This study examined children with an acute encephalopathy illness for evidence of viral infection, disordered blood-brain barrier function, intrathecal immunoglobulin synthesis, and interferon (IFN) production, and related their temporal occurrence to outcome. A prospective study of 22 children (13 males, 9 females; age range 1mo to 13y, median 2y 4mo), recorded clinical details, with serum and cerebrospinal fluid (CSF) analysis near presentation and then on convalescent specimens taken up to day 39 of the neurological illness. Outcome was assessed with standard scales between 18 months and 3 years after presentation. A history consistent with viral infection was given in 17 children but laboratory evidence of viral infection was found in only 7 (7/17). In 18 out of 21 children, an elevated CSF:serum albumin ratio indicative of impairment of the blood-CSF and blood-brain barriers was detected at some stage of the illness. In 14 of the 15 children with a raised immunoglobulin G index, and in 12 of the 14 children where the CSF was positive for oligoclonal bands, this was preceded by, or was observed at the same time as, an abnormal albumin ratio. Sixteen children (16/18) had elevated IFN-alpha levels in serum, or CSF, or in both. We conclude that these findings indicate an initial disruption of the blood-brain barrier followed by intrathecal antibody production by activated lymphocytes, clonally restricted to a few antigens. This is the first in vivo study to show this as an important pathogenetic mechanism of encephalitis in children. Poor outcome was associated with young age, a deteriorating electroencephalogram pattern from grade 1 to grade 2, and the degree of blood-brain barrier impairment, particularly when prolonged, but not with Glasgow Coma Scale score. The persistence of IFN-alpha was associated with a good prognosis.

Respiratory chain deficiency in a female with Aicardi-Goutières syndrome.

Aicardi-Goutières syndrome (AGS) is an early-onset progressive encephalopathy characterized by calcifications of the basal ganglia, white matter abnormalities, chronic cerebrospinal fluid (CSF) lymphocytosis, and/or a raised level of CSF interferon (INF)-alpha. We report a female with mitochondrial respiratory chain deficiency fulfilling the criteria of AGS. Disease onset was in the first year of age with seizures and psychomotor regression. To date, at 4 years of age, she presents a severe encephalopathy, increased INF-alpha in the CSF, and calcifications of basal ganglia on computerized tomography. Cerebral magnetic resonance imaging showed bilateral and symmetric hypersignal of the posterior white matter. A complex I deficiency of the mitochondrial respiratory chain was found in skeletal muscle, which was associated with a complex IV deficiency in cultured skin fibroblasts. The question of whether this oxidative phosphorylation deficiency is primary or secondary in AGS is open to debate. We suggest giving consideration to systematic evaluation of the mitochondrial respiratory chain in skeletal muscle and skin fibroblasts of other AGS patients.

Elevated interferon-alpha in fetal blood in the prenatal diagnosis of Aicardi-Goutières syndrome.

A case of Aicardi-Goutières syndrome is described in a family with index cases. The diagnosis was made prenatally based on high fetal blood concentration of interferon alpha. The biological measurement could be of interest for further diagnosis of other cases.

The natural history of Aicardi-Goutières syndrome: follow-up of 11 Italian patients.

Described are the outcomes of 11 Italian patients with Aicardi-Goutières syndrome. Neurologic symptoms progressed in the first year of life and stabilized by the end of the second year in 10 patients. White matter abnormalities remained stable; cerebral atrophy was stable in four patients and progressive in two. Calcifications increased (in number and size) in two of six patients. Serial CSF and serum interferon-alpha measurements (three patients) showed reduced CSF interferon-alpha levels.

Aicardi-Goutières syndrome.

Aicardi-Goutieres syndrome is a familial progressive early onset encephalopathy with basal ganglia calcifications, chronic CSF lymphocytosis and high level of interferon-alpha in CSF. Cutaneous necrotic lesions and the neuropathological aspect of microangiopathy and microinfarctions suggest a vascular process in relation to elevated interferon-alpha. A genetic defect in the regulation of its synthesis may be the causal factor of the disorder.

Case of Aicardi-Goutières syndrome with long-lasting increase of cerebrospinal interferon-alpha.

Aicardi-Goutières syndrome is a rare progressive encephalopathy characterized by a typical clinical picture, bilateral basal ganglia calcifications, leukodystrophy and brain atrophy, lymphocytosis, and elevated interferon-alpha in the cerebrospinal fluid. Among the cases described to date, variability in the clinical expression or in the cerebrospinal fluid abnormalities has been reported. We present a case with a delayed diagnosis at the age of 8 years, when brain computed tomography was done because there was no first image from the age of 8 months, when the disease started. Symmetric basal ganglia calcifications were visualized and led to purposeful investigation of the cerebrospinal fluid. It revealed an interferon-alpha titer of 103 IU/mL, which, together with the progressive brain damage and disease course, was crucial for the diagnosis. This rare finding of long-term highly elevated interferon-alpha in the cerebrospinal fluid is discussed with respect to the clinical course.

[Interferon alpha production in the serum of very young infants after viral infections]. / Production d'interféron alpha dans le sérum des très jeunes nourrissons lors d'infections virales.

UNLABELLED: IFN-alpha detection is useful in some clinical circumstances, but its use has never been validated in young infants with viral infections. OBJECTIVE: The authors wanted to determine it there was any difference in the assessment of IFN-alpha production between infants under or over six months of age. PATIENTS AND METHOD: A series of 233 children with identified common viral infections who had been assessed for IFN-alpha production was retrospectively analyzed. The viral infections were enteroviral meningitis (n =103), respiratory syncytial virus infections (n =60), and rotavirus gastroenteritis (n =70). Data collected from the group of infants under six months of age (n =105) was compared to that of the older children (n =128). Qualitative and quantitative values of interferon-alpha were determined for each group. RESULTS: Interferon-alpha was detected in very young infants (81.9% of cases) as often as in the older age group (80.3% of cases), for any of the three viral infections (P =0.3-0.63). The mean level of interferon-alpha production detected was not lower in the youngest group, and even higher in the group under six months of age with enteroviral meningitis. CONCLUSION: Interferon-alpha detection in very young infants is efficient and may be useful to differentiate between viral and bacterial infection particularly when the etiological diagnosis appears uncertain.