Reactivity of anti-SARS-CoV-2 antibodies in Serbian voluntary blood donors.

BACKGROUND: The COVID-19 pandemic has major implications on the entire blood supply system worldwide. Seroepidemiological studies are certainly necessary for better understanding the global burden that the COVID-19 pandemic represents. OBJECTIVES: In this study, we analysed the association between demographic factors, COVID-19 severity, vaccination status and the reactivity of anti-SARS-CoV-2 IgG antibodies in Serbian blood donors. MATERIALS AND METHODS: In a prospective study, demographic data and data related to previous SARS-CoV-2 infection, COVID-19 severity and vaccination status among whole blood donors were analysed, from February 10 to August 10, 2022, at the Blood Transfusion Institute of Vojvodina, Serbia. The detection and determination of the level of anti-SARS-CoV-2 IgG antibodies were performed using LIAISON® SARS-CoV-2 TrimericS IgG immunoassay. RESULTS: A total of 1190 blood donors were included, 24.5% were female and 75.5% were male while their average age was 41 years. Anti-SARS-CoV-2 antibody values ranged from 2.40 to 3120 BAU/ml with a mean value of 1354.56 BAU/ml. Statistical analysis showed that COVID-19 severity and vaccination status are linked with reactivity of anti-SARS-CoV-2 antibodies, while gender and age of voluntary blood donors are not related to the values of anti-SARS-CoV-2 antibodies. CONCLUSION: The values of anti-SARS-CoV-2 antibodies in voluntary blood donors in Serbia are kept relatively high, especially in blood donors who have overcome the severe COVID-19, as well as in donors who have been vaccinated against COVID-19. Further SARS-CoV-2 seroprevalence studies in our country are certainly still necessary so global strategies to fight against COVID-19 would be adequately evaluated.

An interesting case of isolated false-negative hepatitis B surface antigen in a blood donor.

BACKGROUND AND OBJECTIVES: An important requirement for a hepatitis B surface antigen (HBsAg) screening assay is reliable detection of HBsAg mutant forms, especially in blood donation. Here we investigate and describe the case of an isolated false-negative result of commercial serology HBsAg screening assay of a blood donor. MATERIALS AND METHODS: The current donation was routinely tested for HBsAg and hepatitis B virus (HBV) DNA in the mini-pool mode nucleic acid testing (MP-NAT of six samples), and further evaluated by individual donation ID-NAT. Finally, it was quantified and sequenced. All previous donations were found to have negative HBsAg and HBV DNA, as also the subsequent sample taken 3 months after the marked donation. RESULTS: The current donation of the 53-year-old unvaccinated female with 14 previous donations was initially HBsAg negative and HBV DNA (MP-NAT) positive. Further testing showed HBsAg positive using other HBV serological assays, antibodies to HBV core antigen immunoglobulin M positive and HBV DNA ID-NAT positive, and contained 200 IU/mL of HBV DNA. The implicated donation carried genotype D strains, subtype ayw2 (F83S, V96A, V190A, L193S, I195T, L213S, F220L). The mutations in three positions, namely amino acids T118A, P120T, and P127T, were proven subsequently. CONCLUSION: This unique mutation combination near the target epitope of one of the immunoassay monoclonals is a possible cause of the reduced analytical sensitivity of the serology assay.

Direct antiglobulin test positivity in Serbian blood donors in the era of gel card technology.

BACKGROUND AND OBJECTIVES: In the era of gel cards, we aimed to determine the incidence of a positive direct antiglobulin test (DAT) in a population of blood donors in Serbia and to compare results with the period when a conventional tube technique was used. MATERIALS AND METHODS: A retrospective study was conducted on 184,171 blood donors over 10 years (2012-2021). Positive DAT results initially were detected after positive result of the compatibility test. After a DAT had been initially performed on fresh blood samples, a control DAT was performed 6 months later. RESULTS: Using gel cards, we found a low incidence (0.09%) of DAT positivity among 55,254 female and 128,917 male blood donors, with no difference found in the occurrence of a positive DAT between them. Positive DAT moderately positively correlated with increasing age of blood donors, but without statistical significance. The vast majority of blood donors (98.86%) were IgG positive. All donors were in good health, did not take medication or had anaemia or haemolysis. During the period 1980-1989, when the test tube technique was used, we found 0.05% DAT-positive blood donors. CONCLUSION: The incidence of positive DAT results in Serbian blood donors is higher compared with that found using the previous test tube technique, but the incidence is consistent with the findings of other studies.

Personal Freedom and Public Responsibility: Remaining Questions after First Case of HIV Transmission via Blood Transfusion in North Serbia.

The reduction in the risk of transfusion-transmissible infections (including HIV infection) is an essential part of transfusion patient care. Here, we report the first incident of HIV transmission via transfusion in north Serbia due to blood donor dishonesty, and the failure of the laboratory screen tests to detect the presence of HIV particles in his blood. Infected blood products were distributed to two recipients, and HIV infection was confirmed in one. This incident finally led to the implementation of Nucleic Acid Amplification Technology as mandatory testing of blood donors for HIV infection in Serbia and raised many questions related to the responsibility and ethics of all the participants in the blood transfusion supply chain. There is a need for the implementation of modern and non-discriminative laws in Serbia in order to reduce transfusion-transmissible infections. In addition, transfusion institutes in Serbia need to be obliged to pursue the constant upgrade of their diagnostic capacities in order to prevent similar incidents and to provide the best possible care for blood donation recipients.

Tick-Borne Encephalitis Virus Seropositivity among Tick Infested Individuals in Serbia.

Tick-borne encephalitis (TBE), caused by the TBE virus (TBEV), is a life-threatening disease with clinical symptoms ranging from non-specific to severe inflammation of the central nervous system. Despite TBE is a notifiable disease in Serbia since 2004, there is no active TBE surveillance program for the serologic or molecular screening of TBEV infection in humans in the country. This prospective cohort study aimed to assess the TBEV exposure among tick-infested individuals in Serbia during the year 2020. A total of 113 individuals exposed to tick bites were recruited for the study and screened for anti-TBEV antibodies using a commercial indirect fluorescent antibody test (IFA) test. Blood samples from 50 healthy donors not exposed to tick bites were included as a control group. Most of the enrolled patients reported infestations with one tick, being I. ricinus the most frequent tick found in the participants. The TBEV seroprevalence was higher (13.27%, 15 total 113) in tick-infested individuals than in healthy donors (4%, 2 total 50), although the difference was not significant. Notably, male individuals exposed to tick bites showed five times higher relative risk (RR) of being TBEV-seropositive than healthy donors of the same gender (RR= 5.1, CI = 1.6-19; p = 0.007). None of the seropositive individuals developed clinical manifestations of TBE, but the first clinical-stage of Lyme borreliosis (i.e., erythema migrans) was detected in seven of them. Potential TBEV foci were identified in rural areas, mostly in proximity or within the Fruska Gora mountain. We conclude that the Serbian population is at high risk of TBEV exposure. Further epidemiological studies should focus on potential TBEV foci identified in this study. The implementation of active surveillance for TBEV might contribute to evaluating the potential negative impact of TBE in Serbia.

Shared Odds of Borrelia and Rabies Virus Exposure in Serbia.

Lyme borreliosis (LB) is the most common tick-borne disease in Serbia and other European countries. Rabies is a fatal zoonosis distributed worldwide and is caused by the rabies virus. Professionals at risk of rabies-including veterinarians, hunters, communal service workers, and forestry workers-overlap with some professions at a higher risk of exposure to tick bites and tick-borne pathogen infections. We hypothesized that individuals identified by the public health system as at risk of rabies virus infection, and consequently vaccinated against rabies virus, also share a higher likelihood of Borrelia exposure. To test our hypothesis, a case-control study was carried out during 2019 in Serbia to determine the seroprevalence of anti-Borrelia antibodies in two case groups (individuals at risk and vaccinated against rabies virus) and a control group (individuals without risk of rabies). Individuals vaccinated against rabies following either "pre-exposure protocol" (PrEP, n = 58) or "post-exposure protocol" (PEP, n = 42) were considered as rabies risk groups and healthy blood donors (n = 30) as the control group. The results showed higher Borrelia seroprevalence in PrEP (17.2%; 10/58) and PEP (19.0%; 8/42) groups compared with the control group (6.67%; 2/30). Furthermore, odds ratio (OR) analysis showed that risk of rabies (in either the PrEP (OR = 2.91) or PEP (OR = 3.29) groups) is associated with increased odds of being seropositive to Borrelia. However, the difference in Borrelia seroprevalence between groups was not statistically significant (Chi-square (χ²) test p > 0.05). The shared odds of LB and rabies exposure found in this study suggest that, in countries where both diseases occur, the common citizen can be at risk of both diseases when in a risky habitat. These findings are important to guide physicians in targeting high-risk groups, and diagnose LB, and to guide decision-makers in targeting control and prevention measures for both infections in risk areas.

Demographic and Clinical Factors Associated with Reactivity of Anti-SARS-CoV-2 Antibodies in Serbian Convalescent Plasma Donors.

Passive immunotherapy with convalescent COVID-19 plasma (CCP) is used as a therapeutic procedure in many countries, including Serbia. In this study, we analyzed the association between demographic factors, COVID-19 severity and the reactivity of anti-SARS-CoV-2 antibodies (Abs) in Serbian CCP donors. Individuals (n = 468) recovered from confirmed SARS-CoV-2 infection, and who were willing to donate their plasma for passive immunization of COVID-19 patients were enrolled in the study. Plasma samples were tested for the presence of IgG reactive to SARS-CoV-2 spike glycoprotein (S1) and nucleocapsid antigens. Individuals were characterized according to age, gender, comorbidities, COVID-19 severity, ABO blood type and RhD factor. Total of 420 candidates (420/468; 89.74%) reached the levels of anti-SARS-CoV-2 IgG that qualified them for inclusion in CCP donation program. Further statistical analysis showed that male individuals (p = 0.034), older age groups (p < 0.001), existence of hypertension (p = 0.008), and severe COVID-19 (p = 0.000) are linked with higher levels of anti-SARS-CoV-2 Abs. These findings will guide the selection of CCP donors in Serbia. Further studies need to be conducted to assess the neutralization potency and clinical efficiency of CCP collected from Serbian donors with high anti-SARS-CoV-2 IgG reactivity.

Assessing donor suitability for blood donation: Utility of Geenius HIV 1/2 confirmatory assay.

BACKGROUND: Blood donor care and blood safety require a quick and accurate decision on the presence or absence of Human Immunodeficiency Virus (HIV) infection, based on the proper selection of blood donors, serological and molecular HIV testing as well as western blot test. The aim was investigating the possibility of inclusion of Geenius HIV 1/2 Confirmatory Assay in blood donor testing algorithm in order to shorten test time and decrease the number of indeterminate results. METHODS: A total of 75 archived serum/plasma samples were tested. Their previous serological and molecular HIV results were: 3 negative samples, 7 positive samples, 65 serological indeterminate or positive but confirmatory testing and NAT negative samples. RESULTS: Geenius assay confirmed the presence of antibodies in all blood donors with HIV positive serology and Nucleic Acid Testing (NAT). HIV-1 gp160 and gp41 antibodies were detected in these donors, while p31 and p24 antibodies were not detected in two and three donors, respectively. HIV-2 antibodies gp36 and gp140 were not found. Blood donor with HIV indeterminate or positive serology but negative confirmatory testing and NAT, were negative in Geenius assay. Conclusion The results obtained are consistent with western blot results. The assay proved simple and quick to perform. Studies have confirmed the possibility of introducing Bio-Rad Geenius into a routine blood donor testing protocol.

Exchange Transfusion for Severe Neonatal Hyperbilirubinemia: 17 Years' Experience from Vojvodina, Serbia.

This study aimed to evaluate the frequency of the main risk factors for severe neonatal hyperbilirubinemia, to determine the incidence of exchange transfusion (ET) in the Autonomous Province of Vojvodina (the northern part of Serbia) and to describe the experience with ET performed in premature and term infants during the past 17 years. We performed a retrospective data analysis of 398 newborn infants who underwent a double volume ET from 1997 to 2013. During the 17 year study period, a decreasing incidence of ET, expressed per thousand newborns, was observed. A total of 468 double volume ET were performed: 328 (82.4 %) infants had one treatment and 70 (17.6 %) had repeated treatments. A total of 262,830 mLs of blood were transfused, an average of 660 mLs per child. There were 221 male and 177 female infants, with a sex ratio 1.25:1. The frequencies of risk factors for developing hyperbilirubinemia were as follows: (1) 38 % RhD incompatibility; (2) 38 % ABO incompatibility (26 % group A infant of group O mother, 12 % group B infant of group O mother); (3) 7 % low birth weight/preterm birth; (4) 17 % other factors. Risk factors for neurotoxicity were identified in 56.3 % of infants. No deaths or complications were reported arising from the treatment. ABO and Rh incompatibilities were found to be the main risk factors for severe neonatal hyperbilirubinemia in Vojvodina. Exchange transfusion, used as therapy for severe hyperbilirubinemia, trended downwards over the period of this study.

[Improving blood safety: errors management in transfusion medicine].

INTRODUCTION: The concept of blood safety includes the entire transfusion chain starting with the collection of blood from the blood donor, and ending with blood transfusion to the patient. The concept involves quality management system as the systematic monitoring of adverse reactions and incidents regarding the blood donor or patient. Monitoring of near-miss errors show the critical points in the working process and increase transfusion safety. OBJECTIVE: The aim of the study was to present the analysis results of adverse and unexpected events in transfusion practice with a potential risk to the health of blood donors and patients. METHODS: One-year retrospective study was based on the collection, analysis and interpretation of written reports on medical errors in the Blood Transfusion Institute of Vojvodina. RESULTS: Errors were distributed according to the type, frequency and part of the working process where they occurred. Possible causes and corrective actions were described for each error. The study showed that there were not errors with potential health consequences for the blood donor/patient. Errors with potentially damaging consequences for patients were detected throughout the entire transfusion chain. Most of the errors were identified in the preanalytical phase. The human factor was responsible for the largest number of errors. CONCLUSION: Error reporting system has an important role in the error management and the reduction of transfusion-related risk of adverse events and incidents. The ongoing analysis reveals the strengths and weaknesses of the entire process and indicates the necessary changes. Errors in transfusion medicine can be avoided in a large percentage and prevention is cost-effective, systematic and applicable.

[The importance of immunohematology testing in the neonatal period].

INTRODUCTION: In order to diagnose hemolytic disease of the newborn it is necessary to determine ABO/Rh blood group, direct antiglobulin test and indirect antiglobulin test in newborns as well as ABO/Rh and indirect antiglobulin test in their mothers due to a possible incompatibility between the blood types of the mother and her baby. The study was aimed at reviewing and analyzing the results of screening of the newborns and pregnant women on the territory of South Backa District during 2011, as well as at estimating the necessity to give blood transfusion to the newborns in the same period. MATERIAL AND METHODS: Data obtained from the information system and protocol of the Institute for Blood Transfusion of Vojvodina were used in a retrospective analysis of screening of newborns and pregnant women. RESULTS: Blood samples taken from 3313 newborns were tested and the following distribution of the ABO blood types was recorded: O in 45.6%, A in 35%, B in 15.9%, AB in 3.5%; 78.9%, newborns were found to be D-positive, 21.1% were D-negative. The direct antiglobulin test was positive in 165 (4.9%) cases, it was weakly positive +/- in 85 (51.5%), positive 1+ in 45 (27.3%), positive 2+ in 17 (10.3%), positive 3+ in 12 (7.3%), positive 4+ in 6 (3.6%). In all cases, the monospecific direct antiglobulin test was positive with IgG antibodies. Of four newborns with positive direct antiglobulin test who required exchange blood transfusion, two had RhD incompatibility and two had ABO incompatibility. Blood samples of 3429 (100%) women were tested and 36 (1.05%) were actively immunized: 23 (0.67%) to RhD antigen, 8 (0.23%) to blood group antigens other than ABH and Rh, specificity could not be determined in 5 (0.15%). Anti-D antibodies were found in 19 (0.55%) pregnant women, in two (0.06%) cases newborns required exchange blood transfusion. CONCLUSION: Testing neonates and pregnant women contributes to the detection of blood type incompatibility between the mother and her child; it provides an opportunity for clinicians to implement the adequate prevention of RhD alloimmunization as well as to make timely diagnosis and to introduce treatment of hemolytic disease in newborns.

[Rare blood donors with irregular antibodies].

INTRODUCTION: Blood groups are inherited biological characteristics that do not change throughout life in healthy people. Blood groups represent antigens found on the surface of red blood cells. Kell blood group system consists of 31 antigens. Kell antigen (K) is present in 0.2% of the population (the rare blood group). Cellano antigen is present in more than 99% (the high-frequency antigen). These antigens have a distinct ability to cause an immune response in the people after blood transfusion or pregnancy who, otherwise, did not have them before. CASE REPORT: This paper presents a blood donor with a rare blood group, who was found to have an irregular antibody against red blood cells by indirect antiglobulin test. Further testing determined the specificity of antibody to be anti-Cellano. The detected antibody was found in high titers (1024) with erythrocyte phenotype Kell-Cellano+. The blood donor was found to have a rare blood group KellKell. This donor was excluded from further blood donation. It is difficult to find compatible blood for a person who has developed an antibody to the high-frequency antigen. The donor's family members were tested and Cellano antigen was detected in her husband and child. A potential blood donor was not found among the family members. There was only one blood donor in the Register of blood donors who was compatible in the ABO and Kell blood group system. CONCLUSION: For the successful management of blood transfusion it is necessary to establish a unified national register of donors of rare blood groups and cooperate with the International Blood Group Reference Laboratory in Bristol with the database that registers donors of rare blood groups from around the world.

[Transfusion management of patients with red blood cell antibodies]. / Transfuziolosko zbrinjavanje bolesnika sa eritrocitnim antitelima.

INTRODUCTION: Red blood cell antibodies may cause a positive result of pre-transfusion blood compatibility testing (crossmatch test). It can be a problem to provide suitable blood units for patients with clinically significant antibodies to high-frequency antigens as well as for those with multiple alloantibody specificities. This study was aimed at identifying transfused patients in the population of South-Backa who had developed clinically significant red blood cell alloantibodies. MATERIAL AND METHODS: We analyzed the records of crossmatch results and antibody screening performed at the Blood Transfusion Institute of Vojvodina during 2012. RESULTS: Antibodies were found in 103 patients: A) 63 patients with single antibodies: 1) 16 with antibodies of unknown specificity (3 autoantibodies, 13 alloantibodies); 2) 39 with clinically significant antibodies (23 from Rh system (2 anti-C, 2 anti-D, 12 anti-E, 7 anti-c), 4 anti-K, 3 anti-Fya, 7 anti-Jka, 2 anti-S); 3) 8 with usually not significant antibodies (6 anti-M, 1 anti-Al, 1 antiC); B) 40 patients developed multiple antibodies: 1) all patients had at least one clinically significant antibody from various blood group system (44 Rh, 13 Kell, 7 Kidd, 7 MNSs (S, s)); 2) 3 patients had usually not significant antibodies (1 Lewis, 2 Lutheran); 3) 3 patients occasionally had clinically significant antibody (3 anti-Ytd4) 3 patients had antibodies of unknown specificity (2 autoantibodies, lalloantibody). Antibodies detected in the majority of patients (65-63.1%) had a specificity of Rh and/or the Kell system. CONCLUSIONS: The main goal of pre-transfusion blood compatibility testing is to detect clinically significant antibodies. The provision of antigen negative blood units for those patients is a special challenge for blood establishments. Database with a sufficient number of typed blood donors can help to resolve this problem.

[Transfusion management of patients with alloanti-Gerbich antibodies: case report].

INTRODUCTION: Transfusion management of patients who are alloimmunized against high-prevalence erythrocyte antigens is often problematic. Strategy management depends, not only on the specific clinical circumstances of the patient, but also on the acceptable time frame. In patients without clinically significant antibody incompatible transfusion it may be less harmful than delaying medical intervention. CASE OUTLINE: We report a 57-year-old female from Libya, blood group O, RhD-positive, who was treated at the Institute of Cardiovascular Diseases of Vojvodina. At the Blood Transfusion Institute of Vojvodina, during pretransfusion testing an IgG alloantibody of unknown specificity was determined. A total of 200 blood units (O, RhD-positive) were crossmatched, but positive reactions indicating that the donor units were incompatible for that specific patient. By testing the patient's family members in Tripoli, six compatible blood units were found and applied during and after surgery. Due to the deterioration of the patient's condition a rapid transfusion was required; however cross-match compatible blood was not available. After a biological cross-match to predict the clinical significance of this antibody, 12 units of erythrocytes with the lowest positive cross-match reactions, were transfused to the patient without any adverse effects. Good tolerance of the units suggested that the present antibodies were not clinically significant. Later on, a rare alloantibody directed to the high frequency Gerbich blood group antigens was identified by the Foundation Central Laboratory, Blood Transfusion Service in Bern, Switzerland. CONCLUSION: In cases of emergency patients with alloantibodies against high frequency Gerbich, when autologous or compatible alogenous transfusion is unavailable, blood with the lowest positive cross-match reaction could be transfused if the biological cross-match is negative. Formation of a national register of donors with rare blood groups and their connection with international registers is of crucial significance in the management of patients requiring antigen negative blood otherwise unavailable from routine blood banks.

[Risk factors for syphilis infection in the South Backa blood donor population].

INTRODUCTION: Syphilis is one of infectious diseases that can be transmitted by blood transfusion. Determining the frequency of syphilis among blood donors and the relevant risk factors is an important aspect of safe blood transfusion. OBJECTIVE: To determine the frequency and the trend of syphilis infection among blood donors in South Backa Region, to classify the confirmed infection and to describe demographic characteristics of seropositive blood donors and their risk factors. METHODS: This retrospective study analyzed results of routine EIA syphilis screening and blood donor data from South Backa Region between 2004 and 2008. RESULTS: Thirteen out of 153,431 tested blood units were confirmed as syphilis-infected.The study found that the overall frequency of infection was 8.47 per 100,000 blood donations, with a trend increase of 2.4%; there was a statistically significant (p < 0.001) higher frequency among first-time blood donors (51.93/100,000) than regular ones (2.84/100 000). The highest prevalence was noted in donors aged over 45 years. All cases were classified as past syphilis infections. Post-donation interviews revealed exposure risk in 69.23% of the donors. CONCLUSION: A higher frequency of past infections detected in older donors is probably due to a higher prevalence and incidence of syphilis in the past. Further continual epidemiologic follow-up of syphilis in blood donors is crucial in obtaining safe blood.