Comparative analysis of eleven SARS-CoV-2 immunoassays and neutralisation data: time to enhance standardisation and correlation of protection.

BACKGROUND: To infer a reliable SARS-CoV-2 antibody protection level from a serological test, an appropriate quantitative threshold and solid equivalence across serological tests are needed. Additionally, tests should show a solid correlation with neutralising assays and with the protection observed in large population cohorts even against emerging variants. OBJECTIVES: We studied convalescent and vaccinated populations using 11 commercial antibody assays. Results were compared to evaluate discrepancies across tests. Neutralisation capacity was measured in a subset of the samples with a lentiviral-based assay. METHODS: Serum from convalescent (n = 121) and vaccinated individuals (n = 471, 260 with Comirnaty, 110 with Spikevax, and 96 with Vaxzevria) was assessed using 11 different assays, including two from Abbott, Euroimmun, Liaison, Roche, and Vircell, and one from Siemens. A spike protein-lentiviral vector with a fluorescent reporter was used for neutralisation assay of serum from convalescent (n = 26) and vaccinated (n = 39) individuals. RESULTS: Positivity ranged between 81.3 and 94.3% after infection and 99.4 and 99.7% after vaccination, depending on the assay. Both cohorts showed a high level of qualitative agreement across tests (Fleiss' kappa = 0.598 and 0.719 for convalescent and vaccinated respectively). Spikevax vaccine recipients showed the highest level of antibodies in all tests. Effectiveness of each test predicting SARS-CoV-2 neutralising capacity depended on assay type and target, with CLIA and anti-S being more effective than ELISA and anti-N assays, respectively. CONCLUSIONS: High-throughput immunoassays are good predictors of neutralising capacity. Updated targets and better standardisation would be required to find an effective correlate of protection, especially to account for antibodies against new variants.

Sequence Analysis of In Vivo-Expressed HIV-1 Spliced RNAs Reveals the Usage of New and Unusual Splice Sites by Viruses of Different Subtypes.

HIV-1 RNAs are generated through a complex splicing mechanism, resulting in a great diversity of transcripts, which are classified in three major categories: unspliced, singly spliced (SS), and doubly spliced (DS). Knowledge on HIV-1 RNA splicing in vivo and by non-subtype B viruses is scarce. Here we analyze HIV-1 RNA splice site usage in CD4+CD25+ lymphocytes from HIV-1-infected individuals through pyrosequencing. HIV-1 DS and SS RNAs were amplified by RT-PCR in 19 and 12 samples, respectively. 13,108 sequences from HIV-1 spliced RNAs, derived from viruses of five subtypes (A, B, C, F, G), were identified. In four samples, three of non-B subtypes, five 3' splice sites (3'ss) mapping to unreported positions in the HIV-1 genome were identified. Two, designated A4i and A4j, were used in 22% and 25% of rev RNAs in two viruses of subtypes B and A, respectively. Given their close proximity (one or two nucleotides) to A4c and A4d, respectively, they could be viewed as variants of these sites. Three 3'ss, designated A7g, A7h, and A7i, located 20, 32, and 18 nucleotides downstream of A7, respectively, were identified in a subtype C (A7g, A7h) and a subtype G (A7i) viruses, each in around 2% of nef RNAs. The new splice sites or variants of splice sites were associated with the usual sequence features of 3'ss. Usage of unusual 3'ss A4d, A4e, A5a, A7a, and A7b was also detected. A4f, previously identified in two subtype C viruses, was preferentially used by rev RNAs of a subtype C virus. These results highlight the great diversity of in vivo splice site usage by HIV-1 RNAs. The fact that four of five newly identified splice sites or variants of splice sites were detected in non-subtype B viruses allows anticipating an even greater diversity of HIV-1 splice site usage than currently known.

Prevalence of HPV 16 and HPV 18 lineages in Galicia, Spain.

Genetic variants of human papillomavirus types 16 and 18 (HPV16/18) could differ in their cancer risk. We studied the prevalence and association with high-grade cervical lesions of different HPV16/18 variant lineages in a case-control study including 217 cases (cervical intraepithelial neoplasia grade 2 or grade 3 or worse: CIN2 or CIN3+) and 116 controls (no CIN2 or CIN3+ in two-year follow-up). HPV lineages were determined by sequencing the long control region (LCR) and the E6 gene. Phylogenetic analysis of HPV16 confirmed that isolates clustered into previously described lineages: A (260, 87.5%), B (4, 1.3%), C (8, 2.7%), and D (25, 8.4%). Lineage D/lineage A strains were, respectively, detected in 4/82 control patients, 19/126 CIN3+ cases (OR = 3.1, 95%CI: 1.0-12.9, p = 0.04), 6/1 glandular high-grade lesions (OR = 123, 95%CI: 9.7-5713.6, p<0.0001), and 4/5 invasive lesions (OR = 16.4, 95%CI: 2.2-113.7, p = 0.002). HPV18 clustered in lineages A (32, 88.9%) and B (4, 11.1%). Lineage B/lineage A strains were respectively detected in 1/23 control patients and 2/5 CIN3+ cases (OR = 9.2, 95%CI: 0.4-565.4, p = 0.12). In conclusion, lineages A of HPV16/18 were predominant in Spain. Lineage D of HPV16 was associated with increased risk for CIN3+, glandular high-grade lesions, and invasive lesions compared with lineage A. Lineage B of HPV18 may be associated with increased risk for CIN3+ compared with lineage A, but the association was not significant. Large well-designed studies are needed before the application of HPV lineage detection in clinical settings.

Cervical intraepithelial neoplasia grade 2 or worse in Galicia, Spain: HPV 16 prevalence and vaccination impact.

INTRODUCTION: The etiology of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) can influence the efficacy of Public Health preventive strategies. This study aimed to determine the high-risk papillomavirus (HR-HPV) prevalence in CIN2+ cases in unvaccinated women in Galicia (Spain), the expected impact of bivalent vaccination, and the distribution of HPV 16 in squamous lesions. MATERIAL AND METHODS: Ninety-four histologically confirmed cases of CIN2+ (2009-2010) were retrospectively studied: 23 CIN2, 58 CIN3- squamous carcinoma in situ (CIN3-CIS), 5 adenocarcinoma in situ (AIS), and 8 invasive squamous cervical cancer (SCC). Linear Array HPV Genotyping Test (Roche Diagnostics, Mannheim, Germany) was performed on the cervical specimens. Bivalent vaccination impact was calculated, based on regional vaccination coverage data, local HR-HPV prevalence, and reported efficacy (direct and cross-protection) of the vaccine. RESULTS: HR-HPV prevalence was 96.8%. The most frequent genotypes were HPV 16 (48.8-58.2%) and HPV 31 (9.3%-12.1%), considering single infections or single-multiple infections, respectively (hierarchical attribution). In squamous lesions, HPV 16 prevalence in women younger than 45 years of age increased in severe lesions (CIN3-CIS/SCC, OR 4.2), and was higher than in older women (OR 5.5). The vaccine could reduce the cumulative incidence of CIN2+ by 50.6% (direct protection), or by 62.7% (direct and cross-protection). CONCLUSION: HPV vaccination could have a great impact in women younger than 45 years of age due to the high prevalence of HPV 16 in their lesions.

Human papillomavirus (HPV) E6/E7 mRNA as a triage test after detection of HPV 16 and HPV 18 DNA.

High-risk human papillomavirus (HPV) DNA detection provides high sensitivity but low specificity for moderate-grade cervical intraepithelial neoplasia or worse histological identification. A prospective study evaluated mRNA testing efficacy for predicting this histological diagnosis in case of HPV 16 and/or 18 DNA detection. A total of 165 endocervical samples harboring HPV 16 and/or 18 DNA were tested with NucliSENS-EasyQ® HPV E6/E7-mRNA-assay (Biomerieux, Marcy l´Etoile, France). Women with cytological alterations were referred to colposcopy (n = 111). Moderate-grade cervical intraepithelial neoplasia or worse was diagnosed in 25.8% of women presenting atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesions and in 89.8% of women with high-grade squamous intraepithelial lesions. mRNA sensitivity was 81.3% and 84.1%, respectively. Specificity was 52.2%, and 80.0%, respectively. Negative predictive value (NPV) was 88.9% in undetermined or low-grade squamous lesions. Positive predictive value (PPV) was 97.4% in high-grade squamous lesions. mRNA reduced colposcopies by 44.3% in undetermined or low-grade squamous lesions. Direct treatment of mRNA-positive cases reduced 77.5% of colposcopies in high-grade squamous lesions. Women without cytological alterations were followed for 18 months (n = 35), and moderate-grade cervical intraepithelial neoplasia or worse was diagnosed in 34.3%; mRNA sensitivity and specificity were 83.3% and 86.9%, respectively. PPV and NPV were 76.9% and 90.9%, respectively for predicting moderate-grade cervical intraepithelial neoplasia or worse in 18 months. mRNA reduced the number of visits for follow-up in 62.2%. In conclusion, NucliSENS-EasyQ® HPV E6/E7-mRNA-assay (Biomerieux) can serve as a triage test in case of HPV 16 and/or 18 DNA detection.

Genetic diversity of influenza A(H1N1)2009 virus circulating during the season 2010-2011 in Spain.

BACKGROUND: Genetic diversity of influenza A(H1N1)2009 viruses has been reported since the pandemic virus emerged in April 2009. Different genetic clades have been identified and defined based on amino acid substitutions found in the haemagglutinin (HA) protein sequences. In Spain, circulating influenza viruses are monitored each season by the regional laboratories enrolled in the Spanish Influenza Surveillance System (SISS). The analysis of the HA gene sequence helps to detect the genetic diversity and viral evolution. OBJECTIVES: To perform an analysis of the genetic diversity of influenza A(H1N1)2009 viruses circulating in Spain during the season 2010-2011 based on analysis of the HA sequence gene. STUDY DESIGN: Phylogenetic analysis based on the HA1 subunit of the haemagglutinin gene was carried out on 220 influenza A(H1N1)2009 viruses circulating during the season 2010-2011. RESULTS: Six different genetic groups were identified among circulating A(H1N1)2009 viruses, five of them were previously reported during season 2010-2011. A new group, characterized by E172K and K308E changes and a proline at position 83, was observed in 12.27% of the Spanish viruses. CONCLUSION: Co-circulation of six different genetic groups of influenza A(H1N1)2009 viruses was identified in Spain during the season 2010-2011. Nevertheless, at this stage, none of the groups identified to date have resulted in significant antigenic changes according to data collected by World Health Organization Collaborating Centres for influenza surveillance.

Intestinal microsporidiosis due to Enterocytozoon bieneusi in elderly human immunodeficiency virus--negative patients from Vigo, Spain.

We report what is, to our knowledge, the first study in which microsporidial infection was detected in elderly human immunodeficiency virus (HIV)--negative patients. Of the 60 elderly patients studied, 47 had diarrhea. Intestinal microsporidiosis due to Enterocytozoon bieneusi was diagnosed in 8 patients (17.02%) by use of Weber's chromotrope-based stain and polymerase chain reaction with species-specific primers. The mean age of these 8 patients was 75 years; 7 had chronic diarrhea and 1 had nonchronic diarrhea. Six of the patients with chronic diarrhea had no other pathogens isolated. In our opinion, elderly patients, because of their special immunological characteristics, should be considered a group at risk for the acquisition of intestinal microsporidiosis.