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Background: Primary diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is based on detection of virus RNA in nasopharyngeal swab samples. In addition, analysis of humoral immunity against SARS-CoV-2 has an important role in viral diagnostics and seroprevalence estimates., Methods: We developed and optimized an enzyme immunoassays (EIA) using SARS-CoV-2 nucleoprotein (N), S1 and receptor binding domain (RBD) of the viral spike protein, and N proteins from SARS, Middle East respiratory syndrome (MERS), and 4 low-pathogenic human CoVs. Neutralizing antibody activity was compared with SARS-CoV-2 IgG, IgA, and IgM EIA results., Results: The sensitivity of EIA for detecting immune response in COVID-19 patients (n = 101) was 77% in the acute phase and 100% in the convalescent phase of SARS-CoV-2 infection when N and RBD were used as antigens in IgG and IgA specific EIAs. SARS-CoV-2 infection significantly increased humoral immune responses against the 229E and NL63 N proteins. S1 and RBD-based EIA results had a strong correlation with microneutralization test results., Conclusions: The data indicate a combination of SARS-CoV-2 S1 or RBD and N proteins and analysis of IgG and IgA immunoglobulin classes in sera provide an excellent basis for specific and sensitive serological diagnostics of COVID-19., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Congenital cytomegalovirus (cCMV) infection is the most common congenital infection and causes significant morbidity. This study was undertaken to evaluate the benefits of screening newborns for cCMV and to understand the cCMV disease burden in Finland., Methods: Infants born in Helsinki area hospitals were screened for CMV by testing their saliva with a real-time polymerase chain reaction assay. The CMV-positive infants and matched controls were monitored to determine their neurodevelopmental, audiological, and ophthalmological outcomes at 18 months of age. Griffiths Mental Development Scales, otoacoustic emission and sound field audiometry, and ophthalmologic examination were performed., Results: Of the 19868 infants screened, 40 had confirmed cCMV infection (prevalence, 2 in 1000 [95% confidence interval, 1.4-2.6 in 1000]). Four (10%) infants had symptomatic cCMV. Griffiths general quotients did not differ significantly between the CMV-positive (mean, 101.0) and control (mean, 101.6) infants (P = .557), nor did quotients for any of the Griffiths subscales (locomotion, personal-social, hearing and language, eye and hand, performance) (P = .173-.721). Four of 54 CMV-positive ears and 6 of 80 CMV-negative ears failed otoacoustic emission testing (P = 1.000). The mean minimal response levels over the frequencies 500 Hz to 4 kHz in the sound field audiometry did not differ between CMV-positive (mean, 34.31-dB hearing level) and control (mean, 32.73-dB hearing level) infants (P = .338). No CMV-related ophthalmologic findings were observed., Conclusions: The prevalence of cCMV was low, and outcomes at 18 months of age did not differ between the infected infants and healthy control infants. With such a low burden in Finland, universal newborn screening for cCMV seems unwarranted., (© The Author(s) 2018. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The first European rotavirus surveillance network, EuroRotaNet, comprising 16 laboratories in 15 European countries, has been established., Methods: Fecal samples from gastroenteritis cases positive for group A rotavirus antigen were collected from multiple European countries from 2005 to mid-2008 and were subjected to G and P genotyping. Epidemiological data collected included age, sex, geographical location, setting, dates of onset and sample collection, and clinical symptoms., Results: A total of 8879 rotavirus-positive samples were characterized: 2129 cases were from the 2005-2006 season, 4030 from the 2006-2007 season, and 2720 from the ongoing 2007-2008 season. A total of 30 different G and P type combinations of strains circulated in the region from 2005 through 2008. Of these strains, 90% had genotypes commonly associated with human infections-G1P[8], G2P[4], G3P[8], G4P[8], and G9P[8]-and 1.37% represented potential zoonotic introductions. G1P[8] remained the most prevalent genotype in Europe as a whole, but the incidence of infection with G1P[8] rotavirus strains was <50% overall, and all 3 seasons were characterized by a significant diversity of cocirculating strains. The peak incidence of rotavirus infection occurred from January through May, and 81% of case patients were aged <2.5 years. Conclusions. Data gathered through EuroRotaNet will provide valuable background information on the rotavirus strain diversity in Europe before the introduction of rotavirus vaccines, and the network will provide a robust method for surveillance during vaccine implementation.

Background: Human polymorphisms affecting gut epithelial barrier and interactions with bacteria predispose to the inflammatory bowel diseases (IBD) Crohn's disease (CD) and ulcerative colitis (UC). The intestinal transporter PepT1, encoded by the SLC15A1 gene, mediates intracellular uptake of bacterial products that can induce inflammation and NF-kappaB activation upon binding to NOD2, a protein often mutated in CD. Hence, we tested SLC15A1 polymorphisms for association with IBD., Methods: Twelve SLC15A1 single nucleotide polymorphisms (SNPs) were genotyped in 1783 individuals from 2 cohorts of Swedish and Finnish IBD patients and controls. An in vitro system was set up to evaluate the potential impact of SLC15A1 polymorphism on PepT1 transporter function by quantification of NOD2-mediated activation of NF-kappaB., Results: The common allele (C) of a coding polymorphism (rs2297322, Ser117Asn) was associated with CD susceptibility both in Sweden and in Finland, but with genetic effects in opposite directions (risk and protection, respectively). The best evidence of association was found in both populations when the analysis was performed on individuals not carrying NOD2 common risk alleles (Sweden allelic P = 0.0007, OR 1.97, 95% confidence interval [CI] 1.34-2.92; Finland genotype P = 0.0013, OR 0.63, 95% CI 0.44-0.90). The PepT1 variant encoded by the C allele (PepT1-Ser117) was associated with reduced signaling downstream of NOD2 (P < 0.0001 compared to Pept1-Asn117)., Conclusions: A functional polymorphism in the SLC15A1 gene might be of relevance to inflammation and antibacterial responses in IBD. Whether this polymorphism truly contributes to disease susceptibility needs to be further addressed, and should stimulate additional studies in other populations.

Background: Crohn's disease (CD) and ulcerative colitis (UC), 2 major forms of inflammatory bowel disease (IBD), are complex disorders with significant genetic predisposition. The first CD-associated gene, CARD15/NOD2, was recently identified and since then several reports on novel IBD candidate genes have emerged. We investigated disease phenotype association to genetic variations in IL23R, ATG16L1, DLG5, ABCB1/MDR1, TLR4, TNFRSF1A, chromosome 5 risk haplotype including SLC22A4 and SLC22A5, and HLA-DRB1*0103 allele among Finnish IBD patients., Methods: A total of 699 IBD patients were genotyped for disease-associated variants by polymerase chain reaction (PCR) and restriction enzyme digestion or Sequenom iPLEX method., Results: Five markers spanning the IL23R gene were associated with CD. The SNP (single nucleotide polymorphism) rs2201841 gave the strongest association (P = 0.002). The rare HLA-DRB1*0103 allele was found to associate with UC (P = 0.008), and the TNFRSF1A A36G variant was associated with familial UC (P = 0.007). Upon phenotypic analysis we detected association between familial UC and rare TNFRSF1A alleles 36G and IVS6+10G (P = 0.001 and P = 0.042, respectively). In addition, IL23R markers were associated with stricturing CD (P = 0.010-0.017), and ileocolonic CD was more prevalent in the carriers of the same 2 TNFRSF1A variants (P = 0.021 and P = 0.028, respectively). Less significant genotype-phenotype associations were observed for the TLR4 and HLA variants., Conclusions: We were able to replicate the association of the IL23R variants with CD as well as HLA-DRB1*0103 with UC; confirmation of TNFRSF1A association with UC needs additional studies. Our findings also suggest that polymorphisms at IL23R and TNFRSF1A, and possibly HLA and TLR4, loci may account for phenotypic variation in IBD.

Background: Three mutations (R702W, G908R, and 1007fs) of the CARD15/NOD2 gene associate with Crohn's disease (CD). Despite a strong linkage of CD to the inflammatory bowel disease (IBD) 1 region, only 16% of the Finnish CD patients carry 1 of these 3 mutations, pointing to the possibility of yet undetected founder mutations in the genetically isolated Finns. The aim of this study was to screen for CARD15 mutations in Finnish CD patients and to assess their functional consequences and relation to clinical phenotype., Methods: We performed CARD15 mutation screening in 240 CD probands. For functional studies, blood mononuclear cells were cultured alone or with muramyl dipeptide (MDP) and IL-8 levels were determined., Results: We identified 30 different variants, including 12 new ones. Allele frequencies for the R702W, G908R, and 1007fs mutations were 3.3%, 0.4%, and 4.8%, respectively. The 1007fs variant was the only 1 associated significantly with CD. Five novel variants (R38M, W355X, P727L, W907R, R1019X) were found in 5 patients. The biochemical nature of these new mutations, data obtained by cross-species comparisons, as well as low IL-8 production favors their pathogenic role. All 5 patients with novel mutations presented a complicated form of ileal or ileocolonic disease., Conclusions: In conclusion, we identified 5 novel CARD15 mutations with an apparent pathophysiological role, but could not identify a putative Finnish founder mutation. It is still possible that regulatory mutations present in the flanking or intronic areas of the CARD15 gene contribute to the genetic susceptibility of CD. Homozygosity or compound heterozygosity for CARD15 gene mutations must be considered especially in complicated CD patients.

Background: Immunogenetic factors predisposing to recurrent genital herpes remain poorly characterized., Methods: In a prospective case-control study, 52 consecutive patients with frequently recurring outbreaks of genital herpes were compared with 80 herpes simplex virus (HSV)-seropositive (types 1 and 2) and 70 HSV-seronegative control subjects. Immunoglobulins (Igs), type-specific anti-HSV-2 IgG and IgG subclass antibodies against glycoprotein G, levels of C3 and C4, and classical pathway hemolytic complement activity were measured, and IgG1 and IgG3 allotyping; C4 immunophenotyping; C4* real-time polymerase chain reaction (PCR) genotyping; and HLA-A*, B*, and DR* typing were performed., Results: The G3m(g),G1m(a/a(x)) haplotype was more frequent in patients than in HSV-seronegative control subjects (P=.047). Compared with all control subjects, low levels of total IgG1 (odds ratio [OR], 4.9 [95% confidence interval {CI}, 2.0-12.5]; P=.001) and IgG3 (OR 3.6 [95% CI 1.7-7.8]; P=.001), but not of anti-HSV-2 antibodies, were associated with recurrences. Levels of complement were lowest in patients. The C4* null type was negatively associated with neuralgia (OR, 0.2 [95% CI, 0.06-0.81]; P=.022)., Conclusions: Low levels of antibody-dependent cellular cytotoxicity-mediating IgG1 and IgG3 antibodies, partly dependent of allotype, may predispose to recurrent genital herpes. Antibodies produced by T helper type 1 responses, potentially against an unknown epitope, appear to be relevant in recurrences. In patients, C4* deficiencies are associated with protection from herpetic neuralgias, possibly through reduced inflammation.

A 30-year-old man developed bilateral optic neuritis 1 week after acute viral meningitis caused by echovirus type 4. He received a high-dose steroid treatment combined with intravenous gamma -globulin. His visual recovery was good, and there was no sign of a primary demyelinating disease.

Three consecutive patients with no apparent immunodeficiency who had frequent intraoral herpes simplex type 1 recurrences, a rare complication of herpes simplex virus infection, were found to have a total deficiency of either the A or B isotype of the complement component C4 and to be homozygous for the studied HLA antigens. A combination of HLA homozygosity, which may lead to impaired T cell recognition of viral peptides, and deficiency in the classical complement pathway, which can compromise virus neutralization, may predispose to severe and frequent herpes simplex virus infections.

In order to investigate the accuracy and practicability of the polymerase chain reaction (PCR) in the antenatal diagnosis of congenital toxoplasmosis, a collaborative study involving 15 European laboratories was performed under the auspices of the Biomed 2 Programme of the European Community. Each team received 12 aliquots (four negative, eight positive) of 'artificial samples' made of amniotic fluid spiked with tachyzoites of the RH strain of Toxoplasma gondii. Each team performed its own PCR protocol (all were different). Nine of the 15 laboratories were able to detect a single parasite, but two of the 15 found all samples negative. Four of the 15 laboratories found one or more control samples to be falsely positive. This study highlights the lack of homogeneity between PCR protocols and performance and underlines the need for an external quality assurance scheme which could provide 'reference' samples that could be used by any laboratory wanting to establish and maintain an accurate diagnostic test based on PCR.

Serodiagnostic methods were evaluated in prenatal screening for primary Toxoplasma infections acquired during pregnancy in the Helsinki area. Altogether 44,181 sera were obtained consecutively during each trimester from 16,733 mothers. All IgG-containing samples were first examined by a sensitive mu-capture (IgM) ELISA, and positive results were reassessed by IgM immunoblotting and indirect IgM ELISA. An assay measuring the avidity of toxoplasma IgG was used for the first time under screening conditions. Patients suspected to have recent toxoplasmosis were reexamined by IgA ELISA and selectively by the differential agglutination assay (HS/AC test) and IgE ELISA; 16 women with diagnostic increases in IgG titer, 36 with IgM fulfilling strict specificity criteria, and 25 with IgG of low avidity were identified. The measurement of IgG avidity was a highly specific and sensitive method suitable for verification of acute primary Toxoplasma infections during pregnancy.

An unusual assay was developed for the serologic diagnosis of recent primary infection by Toxoplasma gondii. This test measures the antigen-binding avidity of toxoplasma-specific IgG antibodies. Serum samples from 5 patients with recent primary toxoplasma infection were compared with those from 21 subjects with preexisting toxoplasma immunity. Patients with primary infection exhibited a low avidity of toxoplasma-specific IgG, which persisted for several months after the onset of symptoms of toxoplasmosis. In contrast, all subjects with past immunity had a high avidity of toxoplasma-IgG. This IgG avidity assay should assist in the diagnosis of acquired toxoplasmosis and may be used to identify pregnancies that are at risk for congenital toxoplasmosis.