Novel molecular, structural and clinical findings in an Italian cohort of congenital cataract.

The current genetic diagnostic workup of congenital cataract (CC) is mainly based on NGS panels, whereas exome sequencing (ES) has occasionally been employed. In this multicentre study, we investigated by ES the detection yield, mutational spectrum and genotype-phenotype correlations in a CC cohort recruited between 2020 and mid-2022. The cohort consisted of 67 affected individuals from 51 unrelated families and included both non-syndromic (75%) and syndromic (25%) phenotypes, with extra-CC ocular/visual features present in both groups (48% and 76%, respectively). The functional effect of variants was predicted by 3D modelling and hydropathy properties changes. Variant clustering was used for the in-depth assessment of genotype-phenotype correlations. A diagnostic (pathogenic or likely pathogenic) variant was identified in 19 out of 51 probands/families (~37%). In a further 14 probands/families a candidate variant was identified: in 12 families a VUS was detected, of which 9 were considered plausibly pathogenic (i.e., 4 or 5 points according to ACMG criteria), while in 2 probands ES identified a single variant in an autosomal recessive gene associated with CC. Eighteen probands/families, manifesting primarily non-syndromic CC (15/18, 83%), remained unsolved. The identified variants (8 P, 12 LP, 10 VUS-PP, and 5 VUS), half of which were unreported in the literature, affected five functional categories of genes involved in transcription/splicing, lens formation/homeostasis (i.e., crystallin genes), membrane signalling, cell-cell interaction, and immune response. A phenotype-specific variant clustering was observed in four genes (KIF1A, MAF, PAX6, SPTAN1), whereas variable expressivity and potential phenotypic expansion in two (BCOR, NHS) and five genes (CWC27, KIF1A, IFIH1, PAX6, SPTAN1), respectively. Finally, ES allowed to detect variants in six genes not commonly included in commercial CC panels. These findings broaden the genotype-phenotype correlations in one of the largest CC cohorts tested by ES, providing novel insights into the underlying pathogenetic mechanisms and emphasising the power of ES as first-tier test.

Visual intervention in early onset visual impairment: A review.

Vision is a primary and motivating sense. Early visual experience derived from the external world is known to have an important impact on the development of central visual pathways, and not surprisingly, visual impairment constitutes a risk factor for overall development. In light of the role of vision in early brain development, infants and young children with visual impairment should be thus entitled to early and effective visual intervention programmes. In this review, we discuss early visual interventions in infants and young children with visual impairment, focusing on their contents and outcomes. We defined a PICO format to critically review different models with a particular focus on parent-mediated and therapist-mediated approaches. We consider protocols that involved direct manipulation or improvement of the infants' visual inputs or were based on behavioural strategies and communication towards infants with visual impairment. We also provide an overview of the effectiveness of these protocols. A total of nine intervention protocols were selected for the purposes of this review. Substantial agreement regarding the importance of promoting the enrichment of infant environments, and more specifically in the context of active play that engages the whole family, has been reported in most of the studies. However, there is no clear agreement on methodological aspects, including clinical population characteristics, outcome measures, length of treatment and follow-up programmes. Further high-quality, carefully designed and adequately reported studies are needed in order to improve the clinical efficacy of these approaches to treating infants with visual impairment.

Altered DNA methylation and gene expression predict disease severity in patients with Aicardi-Goutières syndrome.

Aicardi-Goutières Syndrome (AGS) is a rare neuro-inflammatory disease characterized by increased expression of interferon-stimulated genes (ISGs). Disease-causing mutations are present in genes associated with innate antiviral responses. Disease presentation and severity vary, even between patients with identical mutations from the same family. This study investigated DNA methylation signatures in PBMCs to understand phenotypic heterogeneity in AGS patients with mutations in RNASEH2B. AGS patients presented hypomethylation of ISGs and differential methylation patterns (DMPs) in genes involved in "neutrophil and platelet activation". Patients with "mild" phenotypes exhibited DMPs in genes involved in "DNA damage and repair", whereas patients with "severe" phenotypes had DMPs in "cell fate commitment" and "organ development" associated genes. DMPs in two ISGs (IFI44L, RSAD2) associated with increased gene expression in patients with "severe" when compared to "mild" phenotypes. In conclusion, altered DNA methylation and ISG expression as biomarkers and potential future treatment targets in AGS.

Expanding the spectrum of clinical severity of AICA-ribosiduria: Report of two siblings with mild phenotype caused by a novel pathogenic variant in ATIC gene.

5-Amino-4-imidazolecarboxamide-ribosiduria (AICA-ribosiduria) is an extremely rare inborn error of purine biosynthesis metabolism caused by pathogenic variants in ATIC gene that encodes a protein catalyzing the last steps of the de novo purine biosynthesis. To date, only six cases have been reported presenting a severe phenotype characterized by coarse facies and variable dysmorphic features, intrauterine and postnatal growth retardation, severe and early neurodevelopment delay, profound congenital visual deficit, scoliosis and, less frequently, epilepsy, aortic coarctation, chronic hepatic cytolysis, nephrocalcinosis and mild genitalia malformation. In this article, we report two new cases of AICA-ribosiduria carrying new pathogenic variants in ATIC (c.421C>T;p.Arg141Ter and c.1753A>G p.Thr585Ala) associated to a milder phenotype compared to previously reported patients. Particularly, the children showed few dysmorphic features (bulging forehead, depressed nasal bridge, and flat nasal tip), postnatal growth impairment, psychomotor delay since the second year of life, reduction of visual acuity (from mild impairment to low vision from the age of 5 years and to partial blindness from the age of 7 years) and mild hepatic dysfunctions. Scoliosis as well as epilepsy, renal involvement, or genitalia malformation were not detected. According to literature data, we found an abnormal accumulation of intermediates of de novo purine biosynthesis in the urine of both siblings. This report expands the spectrum of phenotypic severity associated to ATIC biallelic pathogenic variants and prompts the need to investigate ultra-rare causes of metabolic disorders such as AICA-ribosiduria in subjects with early neurological and sensory involvement of uncertain etiology.

Long-Term Visual and Neurodevelopmental Outcomes in Two Children with Congenital Nystagmus Secondary to Methadone Exposure In utero.

Methadone is used as a substitute for illicit opioids during pregnancy. However, the real effect of this molecule on visual and neurodevelopmental outcomes of the children exposed is not fully understood, since studies considered subjects born to polydrug-dependent mothers and followed for few months/years. We report the long-term outcomes of two infants with congenital nystagmus solely exposed to methadone in utero. Neurological and neurovisual evaluations were performed every year from the first year of life to 11 years of age. One child was diagnosed with developmental coordination disorder. Both cases presented with ophthalmologic (refractive errors), oculomotor (nystagmus and fixation, smooth pursuit, and saccades dysfunctions), and perceptive problems (reduced visual acuity and contrast sensitivity). While nystagmus and other oculomotor dysfunctions remained stable over time, visual acuity and contrast sensitivity improved; refractive errors worsened and required corrective lenses. Both children showed normal neurodevelopmental and cognitive profile. This report highlights the long-term visual and developmental outcomes of two children exclusively exposed to methadone underlining the possibility of a visual dysfunction and motor coordination disorder. These observations prompt the need to investigate prenatal drug exposure as a cause of congenital nystagmus.

Academic skills in children with cerebral palsy and specific learning disorders.

AIM: To investigate the prevalence and clinical manifestations of reading, writing, and mathematics disorders in children with cerebral palsy (CP). We explored how the clinical profile of these children differed from those with specific learning disorders (SLDs), taking into account several factors, particularly IQ scores, neuropsychological aspects, and the presence of a visual impairment. METHOD: A prospective cross-sectional study was conducted in 42 children with CP (mean age 9 years 8 months; SD = 2 years 2 months) and 60 children with SLDs (mean age 10 years; SD = 1 year 7 months). Clinical characteristics, neuromotor and cognitive profiles, neuropsychological aspects (speech performance, academic skills, visual attention, phonological awareness, working memory), and signs of visual impairment (visual acuity, contrast sensitivity, visual field, oculomotor functions) were assessed. A machine learning approach consisting of a random forest algorithm, where the outcome was the diagnosis and the covariates were the clinical variables collected in the sample, was used for the analyses. RESULTS: About 59% of the children with CP had reading, writing, or mathematics disorders. Children with CP with learning disorders had a low performance IQ, normal phonological awareness, and working memory difficulties, whereas children with SLDs had normal performance IQ, impaired phonological awareness, and mild working memory difficulties. There were no differences in verbal IQ between the two groups. INTERPRETATION: Learning disorders are frequently associated with CP, with different clinical characteristics, compared with SLDs. Assessment of academic skills is mandatory in these children, even if the IQ is normal. At school age, specific interventions to promote academic skills in children with CP could be a major rehabilitative goal.

Oculocutaneous albinism: the neurological, behavioral, and neuro-ophthalmological perspective.

Oculocutaneous albinism (OCA) is a group of rare, genetic disorders caused by absent/reduced melanin biosynthesis. The aim of this study was to explore the neurovisual, cognitive, adaptive, and behavioral profile of children affected by OCA, also evaluating any possible effect of the visual acuity deficit on the clinical profile and genotype-phenotype correlations. Eighteen children (9 males, mean age 84 months ± 41; range 18-181 months) with a molecular confirmed diagnosis of OCA were enrolled in the study. We collected data on clinical history, neurodevelopmental profile, neurological and neurovisual examination, and cognitive, adaptive, and emotional/behavioral functioning. A global neurodevelopmental impairment was detected in 56% of the children, without evolving into an intellectual disability. All the patients showed signs and symptoms of visual impairment. Low adaptive functioning was observed in 3 cases (17%). A risk for internalizing behavioral problems was documented in 6 cases (33%), for externalizing problems in 2 (11%), and for both in 5 (28%). Twelve children (67%) showed one or more autistic-like features. Correlation analyses revealed significant associations between the visual acuity level and performance intelligence quotient (p = 0.001), processing speed index (p = 0.021), Vineland total score (p = 0.020), Vineland communication (p = 0.020), and socialization (p = 0.037) domains. No significant correlations were found between genotype and phenotype. CONCLUSION: Children with OCA may present a global neurodevelopmental delay that seems to improve with age and emotional/behavioral difficulties, along with the well-known visual impairment. An early neuropsychiatric evaluation and habilitative training are recommended to improve vision-related performance, neurodevelopment, and any psychological difficulties. WHAT IS KNOWN: • Children with oculocutaneous albinism show dermatological and ophthalmological problems. • An early visual impairment may have negative implications on motor, emotional, and cognitive processes that would allow the child to organize his or her experiences. WHAT IS NEW: • In addition to a variable combination of ocular signs and symptoms, children with oculocutaneous albinism may present an early neurodevelopmental delay and emotional/behavioral difficulties. • An early visual treatment is recommended to improve vision-related performance, neurodevelopment, and any psychological difficulties.

Neurodevelopmental Profile in Children Affected by Ocular Albinism.

AIM: The aim of this study was to detail the neurodevelopmental profile of subjects affected by ocular albinism (OA) and to collect data on GPR143 gene analysis. DESIGN: The design of the study involves a retrospective longitudinal observational case series. METHODS: We collected data on the neurodevelopmental profile of 13 children affected by OA from clinical annual assessments conducted for a period of 6 years after the first evaluation. We described visual profile, neuromotor development and neurological examination, cognitive profile, communication and language skills and behavioral characteristics. The GPR143 gene analysis was performed as well. RESULTS: Children presented a variable combination of ocular and oculomotor disorders unchanged during the follow-up, a deficit in visual acuity and in contrast sensitivity that progressively improved. Abnormalities in pattern visual evoked potential were found. No deficits were detected at neurological examination and neuromotor development except for a mild impairment in hand-eye coordination observed in five cases. A language delay was observed in five cases, two of whom had also a developmental quotient delay at 2 years evolving to a borderline/deficit cognitive level at preschool age, difficulties in adaptive behavior and autistic-like features were found. Mutations in the GPR143 gene were identified in the two patients who presented the most severe clinical phenotype. CONCLUSION: Children with OA may share, in addition to a variable combination of ocular signs and symptoms, a neurodevelopment impairment regarding mostly the cognitive, communicative, and social area, especially those with GPR143 mutation.

Early visual training and environmental adaptation for infants with visual impairment.

AIM: To evaluate the effectiveness of early visual training and environmental adaptation on visual function and neurological development in infants with visual impairment. METHOD: This was a pilot intervention clinical trial study. Thirty infants (mean age 5.9mo, SD 2.1mo, range 4-11mo; 16 males, 14 females) with peripheral visual impairment (PVI, n=15) or cerebral visual impairment (CVI, n=15) participated in a 6-month visual intervention programme. Thirty matched infants (mean age 6mo, SD 1.4mo, range 4-9mo; 18 males, 12 females) served as a comparison group. Primary outcome measures were visual acuity, contrast sensitivity, and qualitative ocular motor functions. Secondary outcomes were scores on the Griffiths Mental Developmental Scales (GMDS). RESULTS: The treatment group showed a significant improvement in all the primary outcomes (p<0.01). The comparison group improved only in visual acuity and contrast sensitivity (p<0.01). The treatment group showed greater improvement than the comparison group in visual fixation (p=0.033) and smooth pursuit (p<0.01). The CVI subgroup showed greater improvement in visual acuity than the PVI subgroup (p<0.01). GMDS subscales of hand-eye coordination (p=0.01) and performance (p<0.01) increased in the treatment group, while the total score of the comparison group decreased, driven by language (p=0.039) and hand-eye coordination (p=0.025) subscales. INTERPRETATION: Results suggest that, in infants with visual impairment, visual function and certain developmental outcomes improve in response to early visual training and environmental adaptation, in an interactive context. What this paper adds Early visual training and environmental adaptation are associated with enhanced visual acuity and smooth pursuit. Early visual training and environmental adaptation are associated with an improvement of neurological developmental outcome. Performance, hand-eye coordination, and language scores in Griffiths Mental Developmental Scales increase after visual training. After training, visual acuity improves more in infants with cerebral rather than anterior visual impairment. Type and complexity of visual impairment contribute to determine infants' response to training.

Being adults with cerebral palsy: results of a multicenter Italian study on quality of life and participation.

Cerebral palsy (CP) is still the most common cause of disability developing in infancy. How such a complex disorder affects adult life raises important questions on the critical issues to consider and the most appropriate care pathway right from early childhood. We conducted a multicenter study on a sample of 109 individuals with CP followed up from infancy and recalled for an assessment at ages ranging between 18 and 50 years (mean age 26 years). Semi-structured interviews and specific questionnaires (SF36, LIFE-H and Hollingshead Index) were conducted to assess general psychological state, quality of life, and socio-economic conditions. Our findings showed a globally positive perception of quality of life, albeit with lower scores for physical than for mental health. Our cases generally showed good scores on participation scales, though those with more severe forms scored lower on parameters such as mobility, autonomy, and self-care. These findings were investigated in more depth in interviews, in which our participants painted a picture showing that gradual improvements have been made in several aspects over the years, in the academic attainment and employment, for instance. On the downside, our sample reported persistent limitations on autonomy in daily life. As for the more profound psychological domain, there was evidence of suffering due to isolation and relational difficulties in most cases that had not emerged from the questionnaires. Our data have possible implications for the management of CP during childhood, suggesting the need to avoid an exclusive focus on motor function goals, and to promote strategies to facilitate communication, participation, autonomy, and social relations.

Genetic and phenotypic spectrum associated with IFIH1 gain-of-function.

IFIH1 gain-of-function has been reported as a cause of a type I interferonopathy encompassing a spectrum of autoinflammatory phenotypes including Aicardi-Goutières syndrome and Singleton Merten syndrome. Ascertaining patients through a European and North American collaboration, we set out to describe the molecular, clinical and interferon status of a cohort of individuals with pathogenic heterozygous mutations in IFIH1. We identified 74 individuals from 51 families segregating a total of 27 likely pathogenic mutations in IFIH1. Ten adult individuals, 13.5% of all mutation carriers, were clinically asymptomatic (with seven of these aged over 50 years). All mutations were associated with enhanced type I interferon signaling, including six variants (22%) which were predicted as benign according to multiple in silico pathogenicity programs. The identified mutations cluster close to the ATP binding region of the protein. These data confirm variable expression and nonpenetrance as important characteristics of the IFIH1 genotype, a consistent association with enhanced type I interferon signaling, and a common mutational mechanism involving increased RNA binding affinity or decreased efficiency of ATP hydrolysis and filament disassembly rate.

Development of a neurologic severity scale for Aicardi Goutières Syndrome.

BACKGROUND AND PURPOSE: Aicardi Goutières Syndrome (AGS) is a severe, autoinflammatory leukodystrophy characterized by global neurologic dysfunction. Our goal was to create an easy-to-apply scale relevant to the unique developmental challenges associated with AGS. METHODS: All individuals were recruited through our natural history study. Individuals were classified by AGS severity as mild, moderate, or severe, and clinical encounters were assigned a composite score for neurologic function calculated from the sum of three functional classification scales. Through expert consensus, we identified 11 key items to reflect the severity of AGS across gross motor, fine motor, and cognitive skills to create the AGS Scale. There was strong interrater reliability. The AGS scale was applied across available medical records to evaluate neurologic function over time. The AGS scale was compared to performance on a standard measure of gross motor function (Gross Motor Function Measure-88, GMFM-88) and a putative diagnostic biomarker of disease, the interferon signaling gene expression score (ISG). RESULTS: The AGS scale score correlated with severity classifications and the composite neurologic function scores. When retrospectively applied across our natural history study, the majority of individuals demonstrated an initial decline in function followed by stable scores. Within the first 6 months of disease, the AGS score was the most dynamic. The AGS scale correlated with performance by the GMFM-88, but did not correlate with ISG levels. CONCLUSIONS: This study demonstrates the utility of the AGS scale as a multimodal tool for the assessment of neurologic function in AGS. The AGS scale correlates with clinical severity and with a more labor-intensive tool, GMFM-88. This study underscores the limitations of the ISG score as a marker of disease severity. With the AGS scale, we found that AGS neurologic severity is the most dynamic early in disease. This novel AGS scale is a promising tool to longitudinally follow neurologic function in this unique population.

Morpho-functional survey in children suspected of inherited retinal dystrophies via video recording, electrophysiology and genetic analysis.

PURPOSE: To present a detailed study matching functional response and video imaging with genetic analysis in children suspected of inherited retinal dystrophy (IRD). METHODS: Sixteen children underwent fundus examination via video recording (Heine Omega 500 indirect ophthalmoscope with DV1 camera) and electroretinogram (ERG) under general anesthesia to investigate the cause of suspected low vision. The patients [median age 12 (interquartile range 8-57.5) months] had associated genetic analysis performed with next-generation sequencing or array-comparative genomic hybridization. RESULTS: Four children had potential pathogenic variants in genes involved in Leber congenital amaurosis and Joubert syndrome (NMNAT1, CEP290, KCNJ13, IMPDH1); 1 child had a 16p11.2 microdeletion and 1 in 2q22.1. The ERG was altered in 6 patients, fundus imaging showed serious abnormality matching an IRD in 7 children, and less severe fundus alterations were found in 2 subjects. CONCLUSION: Fundus imaging associated with ERG may be significant in IRD diagnosis and visual impairment prognosis, alongside genetic analysis and therapy in selected cases.

White matter changes associated with cognitive visual dysfunctions in children with cerebral palsy: A diffusion tensor imaging study.

Children with cerebral palsy often present with cognitive-visual dysfunctions characterized by visuo-perceptual and/or visuo-spatial deficits associated with a malfunctioning of visual-associative areas. The neurofunctional model of this condition remains poorly understood due to the lack of a clear correlation between cognitive-visual deficit and morphological brain anomalies. The aim of our study was to quantify the pattern of white matter abnormalities within the whole brain in children with cerebral palsy, and to identify white matter tracts sub-serving cognitive-visual functions, in order to better understand the basis of cognitive-visual processing. Nine subjects (three males, mean age 8 years 9 months) with cerebral palsy underwent a visual and cognitive-visual evaluation. Conventional brain MRI and diffusion tensor imaging were performed. The fractional anisotropy maps were calculated for every child and compared with data from 13 (four males, mean age 10 years 7 months) healthy children. Children with cerebral palsy showed decreased fractional anisotropy (a marker of white matter integrity) in corticospinal tract bilaterally, left superior longitudinal fasciculus and bilateral hippocampus. Focusing on the superior longitudinal fasciculus, the mean fractional anisotropy values were significantly lower in children affected by cerebral palsy with cognitive-visual deficits than in those without cognitive-visual deficits. Our findings reveal an association between cognitive-visual profile and the superior longitudinal fasciculus integrity in children with cerebral palsy, supporting the hypothesis that visuo-associative deficits are related to changes in fibers connecting the occipital cortex with the parietal-frontal cortices. Decreased fractional anisotropy within the superior longitudinal fasciculus could be considered a biomarker for cognitive-visual dysfunctions.

Neurovisual Assessment in Children with Ataxia Telangiectasia.

AIM: Visual impairment is present in almost all patients with ataxia telangiectasia (AT) and, due to their early onset, constitute an important disabling aspect of the syndrome: the quality of vision is limited by dyspraxia and oculomotor abnormal movements. The purpose of this observational study was to describe visual disorders, notably oculomotor impairment, in a sample of children with AT. METHODS: Fifteen AT patients (mean age 12 years and 4 months) underwent a neurovisual evaluation, particularly focused on oculomotor functions (fixation, smooth pursuit, saccades, and abnormal ocular movements). We compared the visual profile obtained with that described using the International Cooperative Ataxia Rating Scale (ICARS) subscale of oculomotor dysfunction. RESULTS: Refractive errors were seen in eight patients and strabismus in three. Major oculomotor findings were fixation abnormalities (6/15), saccadic impairment (15/15), and abnormal smooth pursuit (14/15). Abnormal ocular movements were seen in 13/15 (saccadic intrusion in 8 and nystagmus in 5). Using ICARS scale, 13/15 children presented gaze-evoked nystagmus, 4/15 a clearly saccadic pursuit, and 11/15 dysmetria of saccades. DISCUSSION: We propose a clinical neurovisual evaluation, which could be integrated with ICARS scores in the study of oculomotor involvement in AT pediatric patients. We strongly recommend the empowerment of visual functions to slow down progressive global disability of these patients.

Action Observation Treatment Improves Upper Limb Motor Functions in Children with Cerebral Palsy: A Combined Clinical and Brain Imaging Study.

The aim of the present study was to assess the role of action observation treatment (AOT) in the rehabilitation of upper limb motor functions in children with cerebral palsy. We carried out a two-group, parallel randomized controlled trial. Eighteen children (aged 5-11 yr) entered the study: 11 were treated children, and 7 served as controls. Outcome measures were scores on two functional scales: Melbourne Assessment of Unilateral Upper Limb Function Scale (MUUL) and the Assisting Hand Assessment (AHA). We collected functional scores before treatment (T1), at the end of treatment (T2), and at two months of follow-up (T3). As compared to controls, treated children improved significantly in both scales at T2 and this improvement persisted at T3. AOT has therefore the potential to become a routine rehabilitation practice in children with CP. Twelve out of 18 enrolled children also underwent a functional magnetic resonance study at T1 and T2. As compared to controls, at T2, treated children showed stronger activation in a parieto-premotor circuit for hand-object interactions. These findings support the notion that AOT contributes to reorganize brain circuits subserving the impaired function rather than activating supplementary or vicariating ones.

Exploring Autoimmunity in a Cohort of Children with Genetically Confirmed Aicardi-Goutières Syndrome.

PURPOSE: The purpose of this study was to explore the presence of autoimmune manifestations and characterize the autoantibody production in a cohort of patients with Aicardi-Goutières syndrome (AGS). METHODS: Seventeen patients with a genetically-confirmed diagnosis of AGS were recruited. At the time of enrollment, past medical and family history was reviewed, looking for possible signs or symptoms of autoimmune disorders. Blood samples were taken, for the detection of a panel of autoantibodies: anti-nuclear, anti-double-stranded-DNA, anti-nucleosome, anti-extractable nuclear antigens, anti-cardiolipin IgG/IgM, anti-ß2glycoprotein I IgG/IgM, and anti-neutrophil cytoplasmic. We also measured complement levels determined as C3 and C4 quantification and total complement activity, measured as CH50. RESULTS: Nine of seventeen patients presented with at least one first- or second-degree relative with a history of autoimmune diseases (the childrens' mother or grand-mother in the majority of cases). A specific autoimmune disease was present in only one AGS patient, namely an autoimmune thyroiditis. Autoantibodies were present in 9/17 patients, with different patterns of positivity. Complement levels were normal in all the patients. There was no correlation between auto-antibody production and personal or family history of autoimmune diseases. CONCLUSIONS: Definite autoimmune diseases are not common in patients with AGS. Autoantibodies are mainly directed towards nucleic acids-containing elements but seem not to be pathogenic and, rather, may represent an epiphenomenon of the enhanced interferon production.