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BACKGROUND: Disease morbidity of tick-borne encephalitis (TBE) has been increasing over the last decades. Since the 1990s, however, no extensive seroprevalence studies on TBE in humans have been performed in Switzerland. Here we assessed the prevalence of anti-TBE virus (TBEV) antibodies among different groups of the Swiss blood donor population. MATERIALS AND METHODS: The study was carried out from July 2014 to January 2015. Blood donors participating in the study (n=9,328) were asked to fill in a questionnaire relating to vaccination against or infection with different flaviviruses, and blood samples were collected. All samples were screened for the presence of anti-TBEV IgG antibodies using ELISA testing. Seropositivity rates in different groups of blood donors were compared using Chi square tests with Bonferroni correction. RESULTS: In 2014 and 2015, 24.6% of healthy Swiss blood donors indicated vaccination against TBE. Among vaccinated blood donors, antibody prevalence was significantly higher in younger (

Results of genotyping with true high-throughput capability for MNSs antigens are underrepresented, probably because of technical issues, due to the high level of nucleotide sequence homology of the paralogous genes GYPA, GYPB and GYPE. Eight MNSs-specific single nucleotide polymorphisms (SNP) were detected using matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry (MALDI-TOF MS) in 5800 serologically M/N and S/s pre-typed Swiss blood donors and 50 individuals of known or presumptive black African ethnicity. Comparison of serotype with genotype delivered concordance rates of 99·70% and 99·90% and accuracy of genotyping alone of 99·88% and 99·95%, for M/N and S/s, respectively. The area under the curve of peak signals was measured in intron 1 of the two highly homologous genes GYPB and GYPE and allowed for gene copy number variation estimates in all individuals investigated. Elevated GYPB:GYPE ratios accumulated in several carriers of two newly observed GYP*401 variants, termed type G and H, both encoding for the low incidence antigen St(a). In black Africans, reduced GYPB gene contents were proven in pre-typed S-s-U- phenotypes and could be reproduced in unknown specimens. Quantitative gene copy number estimates represented a highly attractive supplement to conventional genotyping, solely based on MNSs SNPs.

Background and aim Hepatitis E virus (HEV) is a virus of emerging importance to transfusion medicine. Studies from several European countries, including Switzerland, have reported high seroprevalence of hepatitis E as a consequence of endemic infections. Published HEV seroprevalence estimates within developed countries vary considerably; primarily due to improved diagnostic assays. The purpose of this study was to investigate the seroprevalence of anti-HEV IgG in Swiss blood donations. Methods: We used the highly sensitive Wantai HEV IgG EIA and assessed regional distribution patterns. We analysed age- and sex-matched archive plasma dating back 20 years from canton Bern to investigate recent changes in HEV seroprevalence levels. Results: On average, 20.4% (95% confidence intervals: 19.1–21.8) of the 3,609 blood samples collected in 2014–16 were anti-HEV IgG positive; however, distinct differences between geographical regions were observed (range: 12.8–33.6%). Seroprevalence increased with age with 30.7% of males and 34.3% of women being positive donors over > 60 years old. Differences between sexes may be attributed to dissimilarities in the average age of this group. Within the specified region of the Bern canton, overall prevalence has declined over two decades from 30.3% in 1997/98 to 27.0% in 2006 and 22.3% in 2015/6. Conclusions: HEV seroprevalence in Switzerland is high, but has declined over the last decades. The result shows that primarily endemic HEV infections occur and that current blood products may pose a risk to vulnerable transfusion recipients. Nucleic acid screening of all blood products for HEV will begin in November 2018.

Background: High-frequency blood group antigens (HFA) are present in >90% of the human population, according to some reports even in >99% of individuals. Therefore, patients lacking HFA may become challenging for transfusion support because compatible blood is hardly found, and if the patient carries alloantibodies, the cross-match will be positive with virtual every red cell unit tested. Methods: In this study, we applied high-throughput blood group SNP genotyping on >37,000 Swiss blood donors, intending to identify homozygous carriers of low-frequency blood group antigens (LFA). Results: 326 such individuals were identified and made available to transfusion specialists for future support of patients in need of rare blood products. Conclusion: Thorough comparison of minor allele frequencies using population genetics revealed heterogeneity of allele distributions among Swiss blood donors which may be explained by the topographical and cultural peculiarities of Switzerland. Moreover, geographically localized donor subpopulations are described which contain above-average numbers of individuals carrying rare blood group genotypes.

Background: Data on blood donor status obtained from general surveys and health interview surveys have been widely used. However, the integrity of data on self-reported blood donor status from surveys may be threatened by sampling and non-sampling error. Our study aimed to compare self-reported blood donors (including one-time as well as regular donors) from the Swiss Health Survey 2012 (SHS) with register-based blood donors recorded by blood establishments and evaluate the direction and magnitude of bias in the SHS. Methods: We compared population-weighted SHS point estimates of the number of blood donors with their corresponding 95% confidence intervals to the respective figures from blood donor registries (birth cohorts 1978-1993) and estimates of donors based on period donor tables derived from blood donor registries (birth cohorts 1920-1993). Results: In the birth cohorts 1978-1993, the SHS-predicted number of donors was 1.8 times higher than the respective number of donors based on registry data. Adjusting for foreign and naturalized Swiss nationals that immigrated after their 18th birthday, the SHS overall predicted number of donors was 1.6 times higher. Similarly, SHS estimates for the 1920-1993 birth cohorts were 2.4 and 2.1 times higher as compared to register-based estimates. Generally, the differences between SHS and register-based donors were more pronounced in men than in women. Conclusion: Self-reported blood donor status in the SHS is biased. Estimates of blood donors are substantially higher than respective estimates based on blood donor registries.

Background and Objectives Transfusion-related acute lung injury (TRALI) prevention strategies in platelet (PLT) apheresis donors focus on identifying antileucocyte antibody-positive donors. The use of microbead based assays for screening purposes is hampered by the lack of a consensus cut-off for TRALI prevention and the undefined role of anti-leucocyte antibodies in never-alloexposed donors. This study evaluated anti-leucocyte antibody assays in PLT apheresis donors with and without prior immunizing events with special focus on microbead assay cut-offs, antibody specificities and their potential significance in never-alloexposed donors. Material and Methods Blood samples of male and female PLT apheresis donors with and without history of prior immunization were tested for anti-leucocyte antibodies. Results Of 262 female and 118 male PLT apheresis donors, 37·4% had prior immunizing events. Fifty-eight of 238 (24·4%) donors without prior immunizing event had anti-HLA antibodies confirmed in microbead single antigen assay (mean fluorescence intensity (MFI) >500). Even with a cut-off MFI >3000, anti-HLA antibodies were detected in 10·6% of female and 4·3% of male donors without history of immunization. Of the antibody specificities found, 6 of 17 (35·3%) anti-HLA-A, 4 of 8 (50·0%) anti-HLA-B and 4 of 6 (66·6%) anti-HLA class II antibodies have been detected in donors associated with TRALI cases in the literature. Conclusion Platelet apheresis donors without history of immunization have anti-leucocyte antibodies that potentially can cause TRALI. In our opinion, this cohort should be included in screening strategies for TRALI prevention. As references and consensus cut-offs have not yet been established, it is premature to use microbead assays as standard for donor screening.

Background: This study was designed to apply modern statistical methods to evaluate risk factors for anastomotic leakage after rectal cancer resection in a retrospective cohort of patients who received a colorectostomy. Whereas a diverting stoma and tumor height are considered proven risk factors for anastomotic leakage, a lack of evidence about additional risk factors persists. Methods: In a single-center study, 527 consecutive patients who received a colorectostomy after rectal cancer resection between 1991 and 2008 were retrospectively assessed. In addition to traditional uni- and multivariate regression, locally weighted scatterplot smoothing (LOWESS) regression and bootstrap analysis were applied to increase internal validity. Results: Anastomotic leakage occurred in 70 patients (13.3%; 95% confidence interval (CI), 10.5-16.5%) and mortality was 2.5% (95% CI, 1.4-4.2%). Diverting stoma (odds ratio (OR), 0.4; 95% CI, 0.17-0.61) and tumor height (OR, 0.88; 95% CI, 0.8-0.94) were proven to be protective. Neoadjuvant radiotherapy (OR, 2.15; 95% CI, 1.58-4.24) and intraoperative blood loss (OR, 1.05; 95% CI, 1.02-1.09) had a derogatory effect. Bootstrap analysis identified pre-existing vascular disease (95.5%), more advanced UICC stage III or IV tumors (95.7% or 91.5%, respectively), and intraoperative (96.1%) and postoperative (99.4%) blood substitution as harmful. Both intraoperative and postoperative blood substitution caused a dose-dependent increase in risk. Conclusions: Applying statistical resampling methods identified intraoperative blood loss, blood substitution, vascular disease, and advanced UICC stage as risk factors for anastomotic leakage. Greater distances between the tumor and the anal verge and performance of a diverting stoma were associated with a decreased risk of anastomotic leakage

This work aims to assess the value of a generalized molecular RHD screening strategy which could replace routine serological screening of weak D by indirect antiglobulin test. Three independent studies were performed at the two Blood Transfusion Services Berne and Zurich. Donors investigated were 652 RhD negative, but RhC and/or RhE positive, 17,391 mainly Rhccee, and 8200 with normal RhCcEe phenotype distribution. In study I single samples, in studies II and III minipools of 24 and 20 donor samples were tested, respectively. Among 26,243 phenotypically RhD negative blood donors, 65 carriers of RHD alleles were identified. Thirty-one of them were redefined as RhD positive.