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Background: Enterovirus (EV) infections, being among the most prevalent viruses worldwide, have been associated with reduced risk of allergic diseases. We sought to determine the association between EVs and allergic sensitization and disease in early childhood., Methods: The study was carried out in a nested case-control setting within a prospective birth cohort in Finland. We included 138 case children who had specific IgE (s-IgE) sensitization at the age of 5 years and 138 control children without s-IgE sensitization. Allergic disease was recorded at study visits and identified with the ISAAC questionnaire. We screened for the presence of serotype-specific antibodies against 41 EVs at 1-5 years of age and assessed their association with allergic sensitization and disease., Results: The overall number of EV infections did not differ between s-IgE-sensitized children and non-sensitized control children. However, there was a tendency of case children with an allergic disease having less EV infections than their controls. This observation was statistically significant for species A EVs in case children with atopic dermatitis vs. control children: OR 0.6 (95% CI 0.36-0.99), p = .048., Conclusion: This study supports the evidence that EV exposure and development of allergic disease are inversely associated. Interestingly, the inverse association was not observed for bare atopic IgE sensitization, but for IgE sensitization coupled with clinical atopic disease. This suggests that environmental factors influencing IgE sensitization may differ from those influencing progression to clinical allergic disease., (© 2021 The Authors. Pediatric Allergy and Immunology published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: PCR techniques have proved to be more sensitive than traditional cell culture in the diagnosis of enterovirus and rhinovirus infections and are widely used in clinical virus laboratories. However, PCR assays are relatively time-consuming and labor intensive, particularly if separate hybridization steps are used to confirm the specificity of positive findings., Objectives: The aim of the present study was to develop fast and sensitive real-time PCR assay, which would allow simultaneous detection of entero- and rhinoviruses and their quantification in clinical and experimental samples., Study Design: Two real-time RT-PCR protocols were developed using LightCycler (LC) technology; SYBRGreen and hybridization probe assays. The sensitivity of these assays to detect entero- and rhinoviruses was compared with that of a traditional reference RT-PCR-hybridization assay and cell culture. All PCR protocols used the same primers amplifying the 5'-non coding region (NCR) of entero- and rhinoviruses. The LC probe assay and the reference RT-PCR used almost identical detection probes, which bind to enterovirus specific amplicons., Results and Conclusions: Both real-time PCR assays were equally sensitive as the reference RT-PCR-assay and all were more sensitive than cell culture. Both real-time assays quantified reliably the amount of the virus and took much shorter time than the reference RT-PCR. As the real-time SYBRGreen assay detects both entero- and rhinoviruses it can be used for primary screening of samples, which can be positive for either of these viruses. The real-time probe-assay can confirm the presence of enterovirus in SYBRGreen positive samples or it can be used for selective screening of enteroviruses e.g. from CSF samples.

Recent prospective studies have documented serologically an increased frequency of enterovirus infections in prediabetic children, indicating that these infections may initiate and accelerate the beta-cell damaging process several years before the clinical manifestation of type 1 diabetes. The aim of the present study was to establish whether these serological findings would be supported by the detection of enterovirus RNA in a unique prospective series of sera collected from prediabetic children 0-10 years before the manifestation of clinical type 1 diabetes. Reverse transcription followed by polymerase chain reaction employing highly conserved primers among enteroviruses were used to amplify enteroviral sequences. Viral RNA was found in 22% (11/49) of follow-up samples from prediabetic children but in only 2% (2/105) of those from controls (OR 14.9, P < 0.001). Persisting RNA positivity was not observed in any of these children. The presence of enterovirus RNA was associated with concomitant increases in the levels of autoantibodies against islet cells (OR 21.7, P < 0.01) and glutamic acid decarboxylase (OR 15.4, P < 0.05), but not in the levels of antibodies against insulin or the tyrosine phosphatase-like IA-2 protein. In contrast to the prediabetic children, those with newly diagnosed type 1 diabetes were negative for enterovirus RNA. The results thus complement previous serological data, suggesting that enterovirus infections are an important risk factor underlying type 1 diabetes and associated with the induction of beta-cell autoimmunity even years before symptoms appear., (Copyright 2000 Wiley-Liss, Inc.)

Detection of enteroviruses and rhinoviruses has traditionally been based on laborious and time-consuming virus isolation. Recently, rapid and sensitive assays for detecting enterovirus and rhinovirus genomic sequences by reverse transcription-polymerase chain reaction (RT-PCR) have been introduced. An RT-PCR assay is described that amplifies both enteroviral and rhinoviral sequences, followed by liquid-phase hybridization carried out in a microtiter plate format. In the hybridization assay, amplicons are identified by enterovirus- or rhinovirus-specific probes carrying lanthanide chelate labels, which can be detected simultaneously by time-resolved fluorometry. The sensitivity and specificity of the RT-PCR-hybridization method were evaluated with a representative collection of enteroviruses and rhinoviruses and tested further its applicability to the clinical setting with cerebrospinal fluid samples and nasopharyngeal aspirates. The RT-PCR assay amplified all enteroviruses and rhinoviruses tested, and all but one amplicon gave a positive result in the subsequent hybridization assay. The RT-PCR-hybridization method was more sensitive than virus isolation for the detection of enteroviruses and rhinoviruses in the clinical samples. High sensitivity, rapidity, and easy performance make the assay suitable for the routine diagnosis of enterovirus and rhinovirus infections., (Copyright 1999 Wiley-Liss, Inc.)

Enterovirus infections may initiate and accelerate the beta-cell damaging process leading to Type 1 (insulin-dependent) diabetes mellitus (Type 1 DM). Recent prospective studies have suggested that this can happen long before overt disease and even in utero. We describe an infant, followed regularly from birth, who progressed to clinical Type 1 DM at the age of 14 months. He had a strong enterovirus exposure exceptionally early in life; the first enterovirus infection occurred before the age of 3 months and the second between the age of 9 and 12 months. The first infection probably occurred at birth, when the child had symptoms of a respiratory infection. This infection was followed by the appearance of beta-cell autoimmunity, and clinical Type 1 DM was diagnosed shortly after the second infection. The child had a low level of maternal enterovirus antibodies and short duration of breast-feeding, both associated with increased risk for enterovirus infections during the fetal period and infancy. This case fits with the current hypothesis that enterovirus infections can induce the process resulting in Type 1 DM, especially when occurring early in life. Furthermore, this demonstrates the feasibility of the present study design, which is applicable also in large-scale birth-cohort studies.

The development of enterovirus specific T-cell and antibody responses were examined in a cohort of 60 healthy infants at the ages of 3, 6, 9, and 12 months. By the age of 6 months, 68% of the infants had developed T-cell responses against enterovirus antigens by lymphocyte proliferation test, whereas only 30% had serological evidence of an enterovirus infection. By this age, only 7% of the infants had adenovirus specific T-cell responses and 3% had serologically verified adenovirus infection. Enterovirus specific T-cell responses correlated with the lack of enterovirus antibodies in cord blood and the number of sibs reflecting protection by maternal antibodies and the rate of exposures, respectively. T-cell responses cross-reacted between different enterovirus serotypes. The results show that enterovirus infections occur frequently in infancy and induce T-cell immunity. Cellular immunity may be a more sensitive indicator of neonatal enterovirus infections than antibodies.