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 choroid plexus transcriptome reveals changes in type I and II interferon responses in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a marked decline in cognition and memory function. Increasing evidence highlights the essential role of neuroinflammatory and immune-related molecules, including those produced at the brain barriers, on brain immune surveillance, cellular dysfunction and amyloid beta (Aß) pathology in AD. Therefore, understanding the response at the brain barriers may unravel novel pathways of relevance for the pathophysiology of AD. Herein, we focused on the study of the choroid plexus (CP), which constitutes the blood-cerebrospinal fluid barrier, in aging and in AD. Specifically, we used the PDGFB-APPSwInd (J20) transgenic mouse model of AD, which presents early memory decline and progressive Aß accumulation, and littermate age-matched wild-type (WT) mice, to characterize the CP transcriptome at 3, 5-6 and 11-12months of age. The most striking observation was that the CP of J20 mice displayed an overall overexpression of type I interferon (IFN) response genes at all ages. Moreover, J20 mice presented a high expression of type II IFN genes in the CP at 3months, which became lower than WT at 5-6 and 11-12months. Importantly, along with a marked memory impairment and increased glial activation, J20 mice also presented a similar overexpression of type I IFN genes in the dorsal hippocampus at 3months. Altogether, these findings provide new insights on a possible interplay between type I and II IFN responses in AD and point to IFNs as targets for modulation in cognitive decline.

Type I interferon and proinflammatory cytokine levels in cerebrospinal fluid of newborns with rotavirus-associated leukoencephalopathy.

OBJECTIVE: The purpose of this study was to identify whether there is an increase in type I interferon and proinflammatory cytokine levels in the cerebrospinal fluid of newborns with rotavirus-associated leukoencephalopathy. METHODS: Levels of type I interferons (interferon-alpha and interferon-beta) and proinflammatory cytokines (interleukin-6 and interferon-gamma) were measured in the cerebrospinal fluid of 23 newborns with rotavirus-associated leukoencephalopathy (patient group) and 39 infants under 90 days-of-age (control group). RESULTS: Cerebrospinal fluid pleocytosis was not observed in either group. Cerebrospinal fluid interleukin-6 levels were significantly higher in the patient group (7.02 ±â€¯5.88 pg/mL) than in the control group (1.14 ±â€¯1.90 pg/mL) (p < .0001). The mean cerebrospinal fluid interferon-gamma levels of the patient group (24.43 ±â€¯40.16 pg/mL) were also significantly higher than those of the controls group (0.0 ±â€¯0.0 pg/mL) (p < .0001). Cerebrospinal fluid interferon-alpha was not detected in any patient (0%) from the patient group, but was detected in four (10.3%) of the controls. Interferon-beta was detected in only two patients (8.7%) from the patient group and in one (2.6%) of the controls. Cerebrospinal fluid interleukin-6 levels correlated positively with the extent of white matter lesions on diffusion-weighted magnetic resonance imaging (r = 0.607, p = .002). CONCLUSIONS: Significant increases in proinflammatory cytokine levels accompanied by very low detection rates of type I interferon in cerebrospinal fluid indicate that rotavirus-associated leukoencephalopathy in newborns can be correlated with central nervous system inflammatory processes without direct virus invasion into the central nervous system.

Distribution of alpha interferon in serum and cerebrospinal fluid after systemic administration.

After intravenous infusion of recombinant leukocyte interferon (rIFN-alpha A) to four subjects with an indwelling reservoir, serial serum and cerebrospinal fluid samples were taken over 48 hr and were analyzed for interferon by an enzyme immunoassay method (ELISA). On separate occasions, 18 and 50 X 10(6) of rIFN-alpha A were infused over 10 min. Maximum serum concentrations of rIFN-alpha A ranged from 6720 to 11,000 pg/ml and from 32,900 to 43,400 pg/ml after the 18 and 50 X 10(6) U doses. There was no measurable concentration of rIFN-alpha A in the cerebrospinal fluid of subjects who received 18 X 10(6) U doses. In three of four subjects who received 50 X 10(6) U rIFN-alpha A, concentrations ranged from 17 to 70 pg/ml that were measurable no earlier than 1 hr after the start of the infusion and that in two cases were measurable throughout 24 hr.

Serum interferon in patients with psychosis.

High titers of interferon were found in serum from 20 (24.4%) of 82 patients with psychosis and from only two (3.1%) of 64 control subjects. Interferon-positive patients were more likely than interferon-negative patients to have had a recent onset or exacerbation of their illness and to be on low-dose or no medication. No interferon was detected in the CSF of 65 patients or 20 control subjects. These findings suggest that there may be immunological abnormalities or viral infections in some patients with psychosis.

Intrathecal interferon in the treatment of multiple sclerosis. Patient follow-up.

Follow-up observations on patients with multiple sclerosis who were treated with human fibroblast interferon (interferon beta) administered intrathecally for six months revealed a persisting beneficial effect in terms of a reduction in exacerbation rates. At the time of our last report in 1982, ten interferon beta recipients had shown a reduction in their mean exacerbation rate from 1.8/yr before the study to 0.2/yr during the study while ten control patients with multiple sclerosis showed no change in their rates during the study (0.69/yr) compared with before it (0.68/yr). That report was based on observations made for means of 1.9 years in the recipients and 1.6 years in the controls. The recipient patients have now been followed up for 4.4 years (mean) and their exacerbation rates have continued to decrease to a current mean level of 0.16/yr. The control patients were "crossed over" and began receiving interferon beta intrathecally after they had been in the study for two years without showing any change in their rate. During the 2.0 years since crossover they also have shown a reduction in exacerbation rate to a mean of 0.30/yr. The toxic side effects of interferon beta administered intrathecally were acceptable in view of the benefit achieved. Interferon was identified in the cerebrospinal fluid (but not the serum) of two patients prior to treatment, which is probably a manifestation of de novo production of interferon by the central nervous system in response to the multiple sclerosis disease process.

Intrathecal interferon in multiple sclerosis.

Human fibroblast interferon (IFN-beta) was administered by serial lumbar puncture to ten patients with multiple sclerosis (MS). Their clinical courses were compared with those of ten MS control patients who did not receive IFN-beta. As of this writing, the recipients have been followed up for 1.8 to 2.0 years (mean, 1.9 years), and the controls for 1.5 to 1.7 years (mean, 1.6 years). During the study, two recipients suffered four exacerbations, and six controls suffered 11 exacerbations. The recipients' rates of exacerbation during the study were significantly less than their rates both for the entire prestudy duration of the disease and for the 1.8 to 2.0 years immediately preceding entry into the study. The controls' rates of exacerbation before the study and during the study period did not differ significantly. Clinically, the conditions of five recipients and two controls improved, those of three recipients and four controls were unchanged, and those of two recipients and four controls worsened. Headaches, sometimes accompanied by fever and rarely by nausea and vomiting, occurred after injections of IFN-beta. Toxic symptoms usually disappeared within 24, hours; rarely, they persisted for seven to ten days. Each recipient had transient CSF pleocytosis and elevated levels to total protein (the latter remaining elevated in seven). These findings show that intrathecal administration of IFN-beta is feasible in patients with MS, warrant cautious optimism that intrathecal IFN-beta may be effective in altering the course of the disease, and support concepts of a viral or dysimmune cause of MS.

Intrathecal IgG synthesis and blood-brain barrier impairment in patients with systemic lupus erythematosus and central nervous system dysfunction.

Paired serum and cerebrospinal fluid specimens from 19 patients with SLE and central nervous system dysfunction were studied with respect to cerebrospinal fluid IgG index (a measure of intrathecal IgG synthesis), isoelectric focusing using immunoperoxidase staining techniques to detect oligoclonal IgG, and determination of the cerebrospinal fluid/serum albumin quotient (Q albumin) as a measure of blood-brain barrier integrity. Twenty-five patients without neurologic disease and 70 patients with a variety of non-SLE neurologic disorders were also studied for comparison. Of most interest was the observation that 42 percent of the patients with SLE had cerebrospinal fluid oligoclonal IgG, usually in association with elevation of the cerebrospinal fluid IgG index. In addition, two of the cerebrospinal fluid specimens that exhibited oligoclonal IgG also had increased titers of alpha-interferon. Q albumin was normal (under 9.0) in 12 of 13 patients with SLE, who had seizure, psychosis, or cranial neuropathy as principal central nervous system manifestations (mean +/- SD = 5.3 +/- 2.4), but was significantly elevated (mean +/- SD = 27.4 +/- 18.8, p less than 0.001) in five of six patients with diffuse, major central nervous system injury, for example, encephalopathy with coma, transverse myelopathy, paraparesis. Blood-brain barrier impairment was not correlated either with presence of circulating immune complexes or with other clinical or serologic evidence for extra-central nervous system disease activity. Taken together, the data suggest that, within the limitations of the techniques used, impairment of the blood-brain barrier in SLE may be secondary to the central nervous system lesion, rather than a result of systemic immune complex injury. In addition, substantial evidence is provided for an ongoing humoral immune response within the central nervous system in this disorder, which, in certain patients, may be associated with the production of intrathecal alpha-interferon.

Alpha-interferon responses in cerebrospinal fluid of patients with suspected meningitis.

Cerebrospinal fluid from 100 patients with clinically diagnosed meningitis was examined for alpha-interferon. In the laboratory four patient groups were identified: bacterial meningitis (n = 12), viral meningitis (n = 15), normal cerebrospinal fluid (n = 57) and abnormal cerebrospinal fluid (n = 16). A further 14 patients with cerebrospinal fluid shunts but no abnormality in the cerebrospinal fluid provided a control group for alpha-interferon determinations. The group with viral meningitis and the group with abnormal cerebrospinal fluid had significantly higher alpha-interferon concentrations (p less than 0.001) when compared with those of the three other groups. This assay had great predictive value in determining those patients with abnormal cerebrospinal fluid who did not have a bacterial cause of meningitis. As the groups with abnormal cerebrospinal fluid and viral meningitis had a similar spread in alpha-interferon values it is likely that both reflect viral infection of the central nervous system.

Intrathecal synthesis of interferon-alpha in infants with progressive familial encephalopathy.

IFN-alpha was detected in cerebrospinal fluid and/or sera from 7 of 8 patients with a progressive familial encephalopathy associated with calcifications of the basal ganglia and white matter alterations. The secretion of IFN-alpha was prolonged, as shown by its presence at different times between birth and 5 years, and was not associated with IFN-gamma. Virological investigations excluded various congenital infections. In only 2 patients, high levels of Epstein-Barr virus antibodies were observed, indicating the possibility of an abnormal response to viral infection rather than a congenital infection. Further investigations are required for characterization of the recessive autosomal trait of this syndrome and its relation to the IFN system.

Assessment of an immunoassay for interferon-alpha in cerebrospinal fluid as a diagnostic aid in infections of the central nervous system.

A highly sensitive and specific immunoradiometric assay, based upon a monoclonal antibody, was used to measure interferon-alpha (IFN-alpha) in the cerebrospinal fluid (CSF) of patients with central nervous system infections and in controls with non-infectious neurological disorders. IFN-alpha was detected in all 21 patients with viral meningitis but in only one of four patients with non-viral aseptic meningitis. It was also present in the CSF of three of four patients with herpes encephalitis and five of seven patients with acute bacterial meningitis. By contrast, IFN-alpha was present in the CSF in low concentrations in only five (7%) of 71 neurological controls. This rapid test is positive in viral meningitis and may help in distinguishing viral infection from other causes of aseptic meningitis. It is usually negative in non-infective disorders but will not distinguish between viral and bacterial infections.

Early intrathecal production of specific IgM and IgG antibodies and alpha-interferon in herpes simplex virus encephalitis.

A complex approach was used in order to establish non-invasively the aetiology in three cases of encephalitis presumptively caused by herpes simplex virus (HSV). As indicative of brain HSV infection was considered the lowered serum to cerebrospinal fluid specific antibody ratio, which also assessed the humoral immune response within the CNS. For this purpose, during ongoing brain tissue infection, the early intrathecal (ITH) production of IgG and IgM antibodies was analysed by a differential enzyme-linked immunosorbent assay (ELISA) along with changing levels of complement-fixing (CF) antibodies in the serum and cerebrospinal fluid (CSF). Antiviral antibody (AA) response was markedly preceded by the appearance of alpha-interferon (IFN) in the serum and CSF. From the CNS biopsy and autopsy specimens one HSV-1 and one HSV-2 strain were recovered.

Failure of interferon alfa and tribavirin in rabies encephalitis.

OBJECTIVE: To test the effect of interferon alfa and tribavirin (ribavirin) in patients with rabies encephalitis. DESIGN: An open trial of chemotherapy and intensive care in patients with early rabies. SETTING: The intensive care unit of a Bangkok hospital. PATIENTS: Four conscious men with clinical rabies encephalitis. INTERVENTIONS: Rapid virological diagnosis of rabies. Treatment with intravenous and intraventricular injections of high doses of lymphoblastoid interferon alfa in three patients and tribavirin in one patient. Intensive care was given throughout. MAIN OUTCOME MEASURES: Rabies infection confirmed by antigen detection and virus isolation. Rabies neutralising antibody and specific IgM sought in serum and cerebrospinal fluid. Interferon concentrations monitored before and during treatment in three patients. RESULTS: Interferon alfa treatment produced high concentrations in serum and cerebrospinal fluid. All four patients died after 5 1/2 to 12 1/2 days of treatment with no evidence of virostatic or clinically beneficial effects from either treatment. CONCLUSION: Interferon alfa treatment is not effective in rabies encephalitis. The use of tribavirin warrants further study, possibly combined with new therapeutic methods.

Assessment of interferon-related biomarkers in Aicardi-Goutières syndrome associated with mutations in TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, and ADAR: a case-control study.

BACKGROUND: Aicardi-Goutières syndrome (AGS) is an inflammatory disorder caused by mutations in any of six genes (TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, and ADAR). The disease is severe and effective treatments are urgently needed. We investigated the status of interferon-related biomarkers in patients with AGS with a view to future use in diagnosis and clinical trials. METHODS: In this case-control study, samples were collected prospectively from patients with mutation-proven AGS. The expression of six interferon-stimulated genes (ISGs) was measured by quantitative PCR, and the median fold change, when compared with the median of healthy controls, was used to create an interferon score for each patient. Scores higher than the mean of controls plus two SD (>2·466) were designated as positive. Additionally, we collated historical data for interferon activity, measured with a viral cytopathic assay, in CSF and serum from mutation-positive patients with AGS. We also undertook neutralisation assays of interferon activity in serum, and looked for the presence of autoantibodies against a panel of interferon proteins. FINDINGS: 74 (90%) of 82 patients had a positive interferon score (median 12·90, IQR 6·14-20·41) compared with two (7%) of 29 controls (median 0·93, IQR 0·57-1·30). Of the eight patients with a negative interferon score, seven had mutations in RNASEH2B (seven [27%] of all 26 patients with mutations in this gene). Repeat sampling in 16 patients was consistent for the presence or absence of an interferon signature on 39 of 41 occasions. Interferon activity (tested in 147 patients) was negatively correlated with age (CSF, r=-0·604; serum, r=-0·289), and was higher in CSF than in serum in 104 of 136 paired samples. Neutralisation assays suggested that measurable antiviral activity was related to interferon α production. We did not record significantly increased concentrations of autoantibodies to interferon subtypes in patients with AGS, or an association between the presence of autoantibodies and interferon score or serum interferon activity. INTERPRETATION: AGS is consistently associated with an interferon signature, which is apparently sustained over time and can thus be used to differentiate patients with AGS from controls. If future studies show that interferon status is a reactive biomarker, the measurement of an interferon score might prove useful in the assessment of treatment efficacy in clinical trials. FUNDING: European Union's Seventh Framework Programme; European Research Council.

Treatment of subacute sclerosing panencephalitis with human leukocyte interferon.

In five patients with subacute sclerosing panencephalitis (SSPE), human leukocyte interferon (IFN) therapy was tried. IFN was administered intramuscularly, intravenously, and intrathecally. The total dose of administered IFN ranged from 13 X 10(6) to 116.92 X 10(6) IU. There were no severe side effects except for temporary high fever and vomiting. Observation of the clinical course were made for 26-60 months. At the beginning of the treatment, one of the patients was at the first stage of Jabbour's classification and the other four at the second stage. No clinical improvement was observed and the clinical course was progressive in all patients. At present, one of the patients was at the second stage and the other four were at the fourth stage. EEGs showed progressive deterioration, and cranial CT scan demonstrated progressive cortical atrophy and ventricular enlargement. Measles antibody titers in the serum and CSF also unchanged. On the other hand, permeability of IFN at blood-brain barrier (BBB) was relatively good.

Synthesis of intrathecal interferon in systemic lupus erythematosus with neurological complications.

Intrathecal synthesis of interferon in the absence of viral or bacterial infection was detected during the occurrence of neurological complications in two patients with systemic lupus erythematosus. The interferons displayed characteristics similar to those observed in the sera of patients with the disease. No interferon inducing activity was detected in the cerebrospinal fluid or serum of the two patients. These observations support the hypothesis of a localised mechanism of interferon induction in systemic lupus erythematosus which includes the interaction of lymphocytes with damaged tissues.

Neutralizing antibody and interferon-alpha in cerebrospinal fluids and sera of acute aseptic meningitis.

Cerebrospinal fluids (CSFs) and sera from 20 patients with echovirus 30 (E 30) meningitis, 4 patients with enterovirus 71 (EV 71) meningitis, and 5 patients with acute aseptic meningitis (AM) of unknown etiology were investigated at the acute and the convalescent phases of the disease to elucidate the roles of neutralizing antibody (NT) and interferon-alpha (IFN-alpha) in the central nervous system (CNS) in cases of AM in humans. Viruses were isolated from the CSFs at the acute phase of AM, but not at the convalescent phase. There was a fourfold or greater rise in NT titer between paired sera to E 30 or EV 71 but only a slight rise between paired CSFs. IFN-alpha was detected in the CSFs ranging from less than 10 to 25.5 IU/ml but not in the sera, and the IFN-alpha level in the CSF was significantly higher in the acute phase than in the convalescent phase. These results suggest that in cases of acute enteroviral infections in the CNS, NT plays only a small role in the recovery from AM, and IFN-alpha plays a direct or indirect role in curbing the local spread of the virus and eliminating the virus from the CNS at the acute phase of AM.

Intrathecal synthesis of different alpha-interferons in patients with various neurological diseases.

CSF and sera from 238 newborns and children with various neurological diseases were assayed on bovine cells for the presence of alpha-interferon (IFN). An intrathecal synthesis of pH 2-resistant alpha-IFN was recovered in all newborns and in more than 90% of children with herpes encephalitis. It was also observed in one case of mumps encephalitis and in one case of encephalitis associated with Influenza A infection. An acid-labile alpha-IFN production was detected in CSF from more than one half of patients with viral meningitis or active congenital rubella and in those with neurological complications of systemic lupus erythematosus. This alpha-IFN subtype was also detected in CSF from only 2/37 children with measles encephalitis. In contrast, no alpha-IFN (less than 2 IU) in CSF was found among patients with subacute sclerosing panencephalitis, Guillain-Barré syndrome, Reye's syndrome, acute cerebellar ataxia, infantile spasms or facial paralysis of unknown origin.

Interferon gamma in acute and subacute encephalitis.

Intrathecal synthesis of interferon gamma was shown in 14 out of 16 samples of cerebrospinal fluid collected in the first days of disease in adults, children, and newborn infants with herpes encephalitis. This synthesis was concomitant with that of interferon alpha and was switched off when the specific antibodies in the central nervous system increased. No endogenous interferon gamma was detected in 11 serum samples or 13 samples of cerebrospinal fluid collected early in the course of the disease from patients with measles encephalitis and rubella encephalitis, or in serum and cerebrospinal fluid samples from seven patients with subacute sclerosing panencephalitis. In serum collected after the 10th day after the onset of neurological symptoms interferon gamma was present at low concentrations in only three out of 11 serum specimens from patients with measles encephalitis or rubella encephalitis. Interferon gamma was present in patients with acute herpes encephalitis and there was active virus replication, but it was not present in postinfectious encephalitis. Possibly the local production of specific antibodies masks the viral antigens and switches off the induction of interferons.