57. Jahrestagung der Deutschen Gesellschaft für Transfusionsmedizin und Immunhämatologie

Dr. med.

Dr. phil. nat.

Malaria Screening: Results after Introducing Serological Testing

Blood Safety and Transfusion Transmitted Infections

Malaria Screening: Ergebnisse nach Einführung der Serologischen Testung

Introduction: According to German Guidelines (GG), persons with a special risk for Malaria may only be admitted for blood donation if laboratory diagnostics show that there is no evidence for infectivity. After a restriction period of 3 years an antibody test is performed, although the specificity is low. In 2022 we were able to identify two potential donors who had reproducible reactive plasmodia genome in the NAT test. Since only one case showed a reactive result for antibodies against plasmodia, we combine infection serological testing with a NAT method.Methods: In accordance with GG, nucleic acid testing by NAT is performed at our facility after a retention period of 3 years using the AltoStar Purification Kit 1.5 combined with RealStar Malaria PCR Kit 1.0 and Alto Star AM 16 system (altona Diagnostics). In addition to the molecular biological testing, an infectious serological examination by means of an ELISA, which is approved for donor testing in Germany, is performed. Therefore, the NovaLISA malaria immunoassay and the ETI-Max 3000 analyzer are used. The results of the two methods are shown and compared.Results: Since January 2024, 439 people have been tested with both methods. A reactive ELISA result was found in 31 samples (7.1%, 22 male and 9 female persons). 18 persons were tested before first-time donation, 4 were first-time donors and 7 repeat donors. Two persons were undergoing preliminary testing for a bone marrow or stem cell donation. A reactive result in the PCR test was obtained in 2 of 31 people (0.5%). In 29 cases, the antibody screening led to donor exclusion. A confirmatory test was not possible in any case.Discussion/conclusion: The results are discussed against the background of the GG recommendation. The question is be raised how to deal with reactive findings in a serological screening test and if PCR tests are dispensable. As a further conclusion the necessity of a confirmatory test is discussed. More specific and sensitive tests are desirable.No disclosures.

Poster

Mag.pharm. MSc PhD

Dr. Dr. LL.M.

A hematology analyzer can be suitable to count residual cells in blood components

Ein Hämatologie-Analysegerät kann zur Bestimmung von Restzellen in Blutkomponenten herangezogen werden

Flow cytometry is currently used in many laboratories to measure residual cells in blood components, which needs to be performed as part of routine quality control measurements. However, since recently the so-called blood bank mode software is available for the Sysmex XN-1000 and XN-2000 hematology analyzers, providing an alternative method. There is still uncertainty if results of the hematology analyzer are comparable to flow cytometry when counting residual cells in blood components.In the present study, residual cells were measured in red blood cell concentrates (RCCs), plasma and platelet concentrates (PCs) using two different measuring approaches: flow cytometry (BD FACS Lyric) and the blood bank mode software of a hematology analyzer (Sysmex XN-1000). Medians of residual cells per µL were quantified using Bland-Altman analysis and Spearman correlation for all measured residual cell types including residual white blood cells (rWBC) in RCCs, plasma and PCs, residual red blood cells (rRBC) in plasma and PCs and residual platelets (rPLT) in plasma. Furthermore, we quantified pass rates according to cut-off value guidelines.No significant differences were detected in RCCs that were manufactured in a system using whole blood in-line filtration, as a median of 0.4 (interquartile range (IQR): 0.2-0.7) rWBC/µL was detected by FACS compared to 0.4 (0.2-0.9) rWBC/µL when using XN-1000 (n=61). In red cell in-line filtrated RCCs a median of 0.1 (0.0.-0.2) rWBC/µL was detected by FACS compared to 0.1 (0.1-0.3) rWBC/µL by XN-1000 (n=40) which was also not significantly different. In plasma, rWBC/µL were also highly similar when using FACS compared to XN-1000 (n=60). In contrast, in pooled PCs (after pathogen inactivation (PI) with Intercept), significantly higher rWBCs/µL were detected (1.1 (0.4-1.7) rWBC/µL when using FACS and 2.3 (1.4-3.0) rWBC/µL when using XN-1000) (n=34).The blood bank mode software of the Sysmex XN-1000 hematology analyzer is a useful and reliable tool to count residual cells (rWBC, rRBC, rPLT) in blood components (RCCs and plasma) instead of using flow cytometry. This is highly valuable as costs and handling times by staff are reduced by using this new methodological approach. However, especially when concerning pooled PCs after PI, rWBCs are significantly higher when using the XN-1000 and therefore flow cytometry might still be required.Die Autor:innen haben keinen Interessenskonflikt offenzulegen.

PD Dr. med.

Prof.

Low transmission rate of hepatitis E virus (HEV) by transfusion of HEV RNA-positive blood products

Niedrige Übertragungsrate des Hepatitis-E-Virus (HEV) durch Transfusion von HEV-RNA-positiven Blutprodukten

Since 1 January 2020, testing of all blood donors for hepatitis E virus (HEV) RNA is mandatory in Germany. However, this measure is not without controversy. Other countries have decided against routine screening [1, 2]. To estimate the benefit of this measure, the rate of HEV transmission through blood products before the introduction of mandatory testing was investigated retrospectively in our institution.All blood donations given between 26 May 2017 and 31 December 2018 were retrospectively tested for HEV RNA by NAT (cobas HEV, Roche Diagnostics, Mannheim, Germany) in minipools up to 48 samples. After resolution of reactive minipools recipients of the HEV RNA-positive blood products were identified. For some recipients, archive samples that have been collected at the day of transfusion and additional samples collected thereafter, were available for follow-up. Whether a transmission of HEV by transfusion has occurred, was investigated by ID-NAT-testing as well as antibody testing of the recipients archive samples (HEV ELISA IgG, EUROIMMUN, Lübeck, Germany). Clinical courses in HEV-infected patients were assessed by medical records.75,905 blood donations were given by 23,703 donors. 85 HEV RNA positive donations from 76 donors were identified. This represents 0.12% of all blood donations and 0.32% of donors. 139 HEV RNA-positive blood products were transfused. From 30 recipients archive samples were available for further analysis. In 3/30 (10 %) patients, IgG-antibodies were detectable already before transfusion. IgG antibodies were detected in 6/27 (22,2 %) other recipients, in four recipients of red blood cell (RBC) concentrates and in two recipients of platelet concentrates. HEV RNA was detected in only one of these recipients 55 days after transfusion of a RBC. She had no other laboratory or clinical signs of hepatitis, the clinical course was uneventful.In six of the HEV antibody-negative patients, HEV-IgG antibodies could be detected after transfusion, in five of them passive antibody transfer might explain this finding. In only 1/27 (3.7 %) presumably susceptible patient, HEV RNA was detectable after transfusion of an HEV RNA-positive RBC. The transmission rate of HEV by transfusion was lower than expected based on the data available [3]. It may therefore be reasonable to reassess the cost-benefit ratio of HEV RNA-testing in blood donors.There is no conflict of interest.

Prof. Dr. med.

Quantification of UVC-induced DNA damages in Escherichia coli by UVC treatment of platelet concentrates

Quantifizierung von UVC-induzierten DNA-Schäden in Escherichia coli durch UVC-Behandlung von Thrombozytenkonzentraten

THERAFLEX UV-Platelets system (Macopharma), a novel PI technology for platelet concentrates (PC), works by UVC illumination of PC. According to the literature the inactivation of pathogens is based on the UVC-induced damage of nucleic acids. The absorption of UVC light produces two predominant types of DNA damage: Cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4PP).Aim of the current study was to quantify the amounts of UVC-induced photoproducts in the DNA of Escherichia coli (E. coli) introduced by pathogen inactivation treatment of bacterially contaminated PCs using the THERAFLEX UV-Platelets system. Plasma-reduced PCs in additive solution SSP+ (Macopharma) were inoculated with E. coli (PEI-B-P-19) to a final concentration of approx. 106 colony forming units (CFU)/mL. PCs (n=3, 350 mL) were UVC-treated on the MacoTronic UV illumination device (Macopharma) and samples were taken for determination of the bacterial concentration and for quantification of the amounts of photoproducts by ELISA (OxiSelect UV-induced DNA Damage ELISA Kit, Cell Biolabs).The results are shown in Table 1. E. coli was inactivated by UVC treatment down to the detection limit resulting in a reduction factor of ≥ 6.1 log steps. UVC-induced damage in the DNA of E. coli was monitored by the quantification of CPD and 6-4PP photoproducts. The amount of CPD and 6-4PP increased dose dependently to a final CPD concentration of 32.9 ± 7.4 ng/µg DNA and 6-4PP concentration of 8.2 ± 2.7 ng/µg DNA at 100% UVC dose, respectively.The results of this study suggest that the mode of action of the THERAFLEX UV-Platelets system is based on dose-dependent, UVC-mediated alterations in nucleic acids including CPD and 6-4PP photoproducts.UG received grants from the Research Foundation of the German Red Cross Blood Services (Deutsche Forschungsgemeinschaft der Blutspendedienste des Deutschen Roten Kreuzes) and Macopharma for the development of the UVC-based PI technology for platelets

Posterausstellung 11

Wintergartenrestaurant + Foyer

Posterausstellung

Posterausstellung 11
Blood Safety and Transfusion Transmitted Infections

Appointment

Programme

Posterausstellung 11Blood Safety and Transfusion Transmitted Infections

Appointment

Programme

Posterausstellung 11
Blood Safety and Transfusion Transmitted Infections