Antibody Screening Research Articles

A protocol for pretreatment testing for antibodies to galactose-alpha-1,3-galactose to mitigate the risk of cetuximab hypersensitivity reactions.

115 Background: Cetuximab has been shown to improve survival in patients with KRAS wildtype metastatic colorectal cancer. However, high rates of hypersensitivity reactions (HSRs) limit its use, with HSR rates up to 10-20%. A major driver of cetuximab HSR is from pre-formed antibody response to galactose-1,3-alpha-galactose (alpha-gal). Evidence from retrospective studies supports alpha-gal pre-screening in this setting. We are the first to report on the impact of prospective alpha-gal antibody screening on cetuximab HSR. Methods: Records were reviewed across three medical oncology centres that have adopted alpha-gal antibody screening measures. Data for patients with metastatic colorectal cancer treated with cetuximab were retrieved. All centres assessed alpha-gal antibody status using the ImmunoCAP ELISA assay. Due to lack of a shared screening approach across study sites, a pre-determined protocol was retrospectively applied to all cases. This protocol allowed cetuximab administration if alpha-gal levels were ≤0.1 kUA/L, but prohibited it if alpha-gal levels were >0.1 kUA/L in favour of panitumumab administration. Patients were allocated to either the Protocol Applied or Protocol Not Applied cohorts based on protocol requirements being met. The primary outcome between these patient groups was the incidence of cetuximab HSRs. Results: Of 254 assessable patients, 39 underwent the pre-treatment screening protocol. Of the Protocol Applied group, 3% (n=1/38) experienced a cetuximab HSR compared to 16% (n=35/215) in the Protocol Not Applied group (Odds ratio (OR) 7.16; 95% CI 1.13–299.61, p =0.02). Patients with alpha-gal antibody titres >0.1 kUA/L were more likely to experience a cetuximab HSR (OR 69.71; 95% CI 5.18–4296.81, p =0.0001). Conclusions: Pre-treatment screening for alpha-gal antibodies significantly reduces the incidence of cetuximab HSRs. A testing threshold of 0.1 kUA/L is effective in identifying patients at risk. Implementing this protocol can improve the safety of cetuximab therapy in high-risk populations.

P-2203. High Rate of False Positives in Military Blood Donors Screening Positive for Hepatitis C Virus

Abstract Background While the overall rates of Hepatitis C virus (HCV) in military populations are low, positive post-donation screening represents the second most common indication for post-donation infectious deferrals in military blood donors. All donors who screen positive are permanently deferred from blood donation, regardless of follow-up testing in clinical laboratories. There is limited data on the follow-up evaluation of these blood donors. This study describes the confirmatory testing, access to appropriate subspecialty care, and treatment of blood donors who screened positive for HCV at a large military blood bank. Methods All military blood donors between 2017-2023 at the Armed Service Blood Bank Center-San Antonio were screened for HCV by both antibody tests and nucleic acid tests, with positive antibody screening tests confirmed with an enzyme-linked immunosorbent assay (ELISA). Donors who screened positive had their medical charts reviewed to determine demographic information, follow-up evaluation, and treatment rates. On follow-up clinical diagnostic tests, patients with positive antibodies were determined to true positives (TP) and those with negative antibodies were determined to be FP. Results Of the 100,182 blood donors during the study period, 37 (0.04%) screened positive for HCV, of which follow-up information was available for 27 (73%). Of these 27, only 12 (44%) of donors were found to be TP. TP donors were more likely to be older (median 22 [20-29.5] vs. 20 [18-22], p=0.05) and have higher rates of positive nucleic acid testing (58% vs. 0%, p=0.001) after blood donation (Table 1). There was no difference in linkage to both primary and subspecialty care for TP and FP (Table 2). Of the TP, 7 (58%) were viremic, 3 (43%) of which received anti-viral therapy and 4 (57%) were administratively separated. Conclusion While HCV is one of the most common infectious reasons for military service members who donate blood to be deferred from future donations, most positive screenings were FP. Future efforts should be made to re-enter these patients with FP screening tests back into the donor pool. Disclosures All Authors: No reported disclosures

P-162. Estimating the Seroprevalence of HTLV-1 in Pregnant Peruvian Women Based on Blood Bank Markers: a Road to Elimination of Mother-to-Child Transmission of HTLV-1

Abstract Background The prevention of mother-to-child transmission (PMTCT) of human T-cell lymphotropic virus type 1 (HTLV-1) is a top priority for HTLV-endemic countries due to its chronicity, lack of treatment and association with the aggressive adult T cell leukemia/lymphoma in comparison to other routes of infection. As of 2024, Japan, Brazil and Chile are few of the countries with national policies regarding antenatal screening. Peru, also an endemic country with around 150,000 to 450,000 HTLV-1 carriers, has limited data in pregnant women and does not have any PMTCT policy in place. By contrast, HTLV-1/2 antibody screening of blood donations has been endorsed since 1997 and national data are available. We aim to leverage these data to estimate the prevalence of HTLV-1 in pregnant women as a first step towards development and implementation of a PMTCT policy in Peru. Figure 1 Estimation of number of HTLV-1 infected pregnant women and HTLV-1 seroprevalence in pregnant women in Peru (2017) Methods This was an ecological study using public-use data from the Peruvian Bulletin on Blood Supply 2015-2020, the 2017 National Census, the 2017 Demographic and Health Survey (DHS) and the National Registry. The unit of analysis was Peru and its subregions in the year of 2017. To estimate the number of infected women of reproductive age (WRA, 15-49 years), we used census data and a calculated percentage of HTLV-1/2 reactive blood units for this group based on a weighted factor by sex and age (Figure 1, Table 1). Using the DHS percentage of WRA currently pregnant, we estimated the number of infected pregnant women. To obtain the HTLV-1 prevalence for this group, we used the number of life births adjusted for a 9-month period (0.75) as the denominator. Calculation of weighted factor for HTLV-1/2 seroprevalence by age and sex based on local blood bank data Results A total of 359,458 blood units were screened and 2,809 were reactive for HTLV-1/2 (0.78%) (Figure 2). We estimated between 68,456 to 72,978 HTLV-1 carriers who were WRA, of whom 2,463 to 2,773 were pregnant (Figure 3). This is comparable to rates in Japan and Brazil. Our estimated HTLV-1 seroprevalence in pregnant women was 0.61% for the entire country. Number and percentage of HTLV-1/2 reactive blood units in 2017 by departments of Peru Conclusion Our findings could help guide future strategies for PMTCT, such as universal antenatal screening and assessing the feasibility of formula supplementation for infants born to HTLV-1 positive mothers. Our limitations included the use of one-year data, HTLV-1/2 false-positives in blood donors and not using inverse probability weighting. Estimated number and percentage of HTLV-1 infected pregnant women in 2017 by Departments of Peru Disclosures All Authors: No reported disclosures

P-2359. CLEAR Hepatitis C – Development and impact of a regional collaborative to facilitate identification and treatment of patients with Hepatitis C

Abstract Background Despite advancements in therapy, hepatitis C continues to significantly impact public health and individual patients. Untreated hepatitis C can lead to liver failure and death. The introduction of oral therapies provides an opportunity to cure patients’ hepatitis C and limit the spread. However, challenges persist in the identification of patients, access to specialists trained in the treatment of hepatitis C and the medication therapy costs. FirstHealth of the Carolinas (FHC) developed partnerships and care pathways within our regional medication community including employed and non-employed physician practices. The principles of the care pathway were, CLEAR Hepatitis C (Figure 1). The purpose of our study was to evaluate the outcomes associated with a comprehensive regional approach to identification and treatment of patients with hepatitis C. CLEAR Hepatitis C acronym Outlines care pathway developed for the treatment of hepatitis C Methods A retrospective study was conducted at FHC reviewing outcomes associated with the CLEAR Hepatitis C initiative undertaken from September 2023 through April 2024. Data evaluated included: hepatitis C antibody screens conducted by primary care providers, Infectious Disease clinic referrals for hepatitis C treatment, oral therapies prescribed by Infectious Disease providers, patients assisted with medication therapy by specialty pharmacists and pharmacy technicians and patients receiving a curative diagnosis. CLEAR Hepatitis Results Results associated with each step of the care pathway. Results Primary care provider education and promotion of CLEAR Hepatitis C initiative commenced in November 2023. Comparing the fourth month periods of September-December of 2023 to January-April 2024: the total hepatitis C antibody screens conducted increased from 1169 to 1514 (p < 0.05); Infectious Disease clinic visits with a primary diagnosis of hepatitis C increased from 7 to 18; Prescriptions from Infectious Disease providers increased from 9 to 19; Patients assisted with medication access increased from 6 to 15. During the study period, 4 patients received a curative diagnosis. An additional 8 patients have completed treatment and are awaiting confirmatory lab testing (Figure 2). Conclusion Development of a collaborative, integrated hepatitis C care pathway within our regional medical community successfully increased the number of patients identified and treated for hepatitis C in our region. Disclosures All Authors: No reported disclosures

P-30 ROLE OF PLASMAPHERESIS IN TREATING A RARE CASE OF EXOGENOUS INSULIN ANTIBODY SYNDROME (EIAS) IN A YOUNG PATIENT WITH TYPE 1 DIABETES MELLITUS IN BABYLON GOVERNORATE: A CASE REPORT

Abstract Clinical Case A 17-year old female patient who was diagnosed with type 1 diabetes mellitus (DM) seven years ago, and she had continuously very high blood glucose readings with recurrent admissions to the emergency unit due to attacks of DKA. In addition to a planned diet, she was on more than 250 units of insulin per day (while her weight was 75 kilograms). She was initially on human insulin in the form of twice NPH insulin injections, and pre-meal regular insulin injections, in addition to repeated regular insulin correction doses without any reduction of her blood glucose. Then she was shifted to insulin analogues (to eliminate the possibility of insulin immunogenicity which have been encountered with the use of human insulin), in form of basal insulin Glargine OD, plus pre-meal rapid acting insulin Glulisine without any noticeable response. Continuous switching of her injection sites, with an in-hospital observed insulin injections (to avoid noncompliance), even the use of intravenous route did not help to achieve a glycemic control. Later on, metformin 1000 mg XR BID was added to her daily treatment without any benefit. A screen of anti-insulin antibodies was done and found to be elevated (which should be negative after all these years after her initial diabetes diagnosis). A presumptive diagnosis of EIAS (Exogenous Insulin Antibody Syndrome) was put. A small dose of steroids was administered with close observation (to avoid exacerbation ketosis) without any improvement. Then Cellcept (Mycophenolate mofetil), an immune modulator was added at a dose of 500 mg BID and increased 48 hrs. later to 1000 mg BID and resulted in a minimal reduction of her blood glucose levels. Finally the decision of plasmapheresis was made and an informed consent was obtained from the family after explaining the condition. A good response was recorded after the 1st session, with a minimal decrease of her total daily insulin doses. Later on, an additional excellent response was received during the next 2 sessions with a rapid decline of her glucose readings and her total daily insulin doses. She had recurrent attacks of hypoglycemia during her third and last plasmapheresis session. Her total daily dose of insulin was successfully reduced by more than 50%, and her general condition was improved noticeably without any recorded adverse reactions, as shown in the blood glucose logbook photos attached below.Figure 1:Glucose logbook after the 3rd and last session of Plasmapheresis Table 1:Response parameters to three sessions plasampheresis therapy

Clinical characteristics and cause analysis of false-positive results in treponemal testing among patients

Background Currently, there is a dearth of systematic research data on the phenomenon of false-positive reactions in treponemal tests. The aim of this study is to analyze the clinical characteristics and influencing factors associated with false-positive treponemal tests in patients, so as to enhance the diagnostic accuracy of syphilis and mitigate misdiagnosis-induced incorrect treatment. Methods From January 2017 to December 2023, a total of 759 cases with false-positive results for treponema were screened for blood transfusion, surgery, or other medical interventions at Jinling hospital. The demographic, clinical, and laboratory characteristics of patients were retrospectively analyzed to identify the risk factors associated with false-positive reactions in treponemal antibody screening. Results The results indicated that individuals under 18 years old, over 45 years old and males exhibited a higher false-positive rate for treponemal tests (p < 0.001). The false-positive rates of treponema were found to be higher in the fields of pediatrics, nephrology, and internal medicine (p < 0.05). There was no difference observed in ABO blood group distribution (p > 0.05). .Furthermore, the levels of treponema antibody and coagulation function were found to be associated with the occurrence of false-positive syphilis test results. Multivariate logistic regression analysis indicated that ≤18 years, ≥45 years, male were independent risk factors (p < 0.01). Conclusion This study demonstrates that the false-positive rate of treponemal tests can be increased by factors such as age, gender, immune diseases, and coagulation disorders. The treponemal antibodies titer level is a valuable reference for assessing false-positive results. To enhance the accuracy of syphilis diagnosis, multiple risk factors should be considered when interpreting results from treponemal tests.

Cryofibrinogenemia as a cause of ABO forward/reverse discrepancy and positive antibody screen result.

Cryofibrinogenemia as a cause of ABO forward/reverse discrepancy and positive antibody screen result.

A whistleblower direct antiglobulin test in chronic kidney disease: An interesting case of occult autoimmune hemolytic anemia in an undiagnosed lymphoma with pure red cell aplasia

Abstract A 67-year-old male, presented with urosepsis, severe anemia, advancing azotemia requiring blood transfusion. Patient grouped as O RhD positive. Antibody screening was pan-positive (4+). Similar strong pan-positivity seen on antibody identification with extended cell panel. DAT was 4+ positive for IgG and negative for complement C3. Repeated identification with eluate also showed pan-positive (4+) reaction. Serum haptoglobin markedly reduced. Bone marrow aspirate suggested pure red cell aplasia with suspicion of parvovirus-related changes. Bone marrow biopsy suggested T-cell lymphoproliferative disorder. Immunophenotyping elucidated a suspicious clone of CD7-negative T-cells with CD4 restriction. Histopathological examination revealed angioimmunoblastic T-cell lymphoma (AITL) with bystander Epstein–Barr virus-driven large B-cells. Owing to rarity and nonspecific symptoms, diagnosis of AITL is often challenging. Antibody screen acted as a whistleblower for an undiagnosed aggressive lymphoma. Thus, it will be prudent to look beyond the obvious in complex cases, and a detailed workup will help put together all parts of the jigsaw puzzle.

A single droplet dispensing system for high-throughput screening and reliable recovery of rare events.

Microfluidic droplet sorting has emerged as a powerful technique for a broad spectrum of biomedical applications ranging from single cell analysis to high-throughput drug screening, biomarker detection and tissue engineering. However, the controlled and reliable retrieval of selected droplets for further off-chip analysis and processing is a significant challenge in droplet sorting, particularly in high-throughput applications with low expected hit rates. In this study, we present a microfluidic platform capable of sorting and dispensing individual droplets with minimal loss rates. We demonstrate our direct transfer mechanism by placing selected droplets containing hybridoma cells into microwells, eliminating the need for manual and often lossy handling steps. Sorted droplets are dispensed via a novel 3D-printed dispensing nozzle, enabling precise and controlled placement of selected single droplets into individual wells without affecting the microfluidic sorting flow. The sorting and transfer process is monitored in real time, which provides feedback and quality control of the entire workflow. Our integrated microfluidic system holds great potential for applications requiring high-throughput droplet sorting with minimal sample loss and precise dispensing into microwells, such as screening for therapeutical antibodies or monoclonal cells.

Clinical and laboratory characteristics of Sjögren's syndrome-associated autoimmune liver disease: a real-world, 10-year retrospective study.

To investigate the clinical and laboratory features of Sjögren's syndrome-associated autoimmune liver disease (SS-ALD) patients and identify potential risk and prognostic factors. SS patients with or without ALD, who visited Tongji Hospital between the years 2011 and 2021 and met the 2012 American College of Rheumatology (ACR) classification criteria for Sjögren's syndrome, were retrospectively enrolled. The clinical and laboratory data of the enrolled patients, including autoimmune antibodies, were collected and analyzed with principal component analysis, correlation analysis, LASSO regression, and Cox regression. A total of 117 SS-ALD patients were confirmed out of 568 SS patients. Compared to SS-non-ALD patients (n = 451), SS-ALD patients exhibited more severe involvement of the hepatic and hematologic systems, albeit with less pronounced typical SS symptoms. Disease activity was higher in SS-ALD patients, as indicated by elevated ESR, CRP, and IL-6 levels, particularly in the SS-overlap subgroup. Furthermore, SS-AIH patients without AIH-specific autoantibody testing or with negative testing results had higher AST and ALT levels than those who were autoantibody-positive. Our predictive model, incorporating IgG, IgM, AST, GGT, ALT, and C4, effectively identified ALD complications in SS patients, achieving an AUC of 0.924. Additionally, a grimmer prognosis was associated with higher baseline AST and ALT levels. SS-ALD patients often manifest with an insidious onset and atypical SS symptoms, yet frequently exhibit severe systemic involvement, intense inflammatory and immune responses, and a poor prognosis. To improve the clinical outcomes in SS-ALD patients, regular monitoring, early identification, and active treatment should be applied. Key Points • The study provided a detailed profile of clinical and laboratory features of SS-ALD and SS-non-ALD patients, contributing to a predictive model of ALD complications in SS patients • SS-ALD patients manifested with an insidious onset but exhibited severe systemic involvement, robust inflammatory and immune responses, and poor prognosis • SS-AIH patients without available testing for AIH-specific autoantibodies or with negative results demonstrated worse liver function, thus routine screening for autoimmune liver antibodies is recommended in SS patients • More severe baseline liver function status was associated with poorer therapeutic responses to routine medications, so early detection and timely intervention are essential for SS patients.

Prevalence of Hepatitis C Virus Among Hospitalized Patients in a Tertiary Hospital in Italy: The Basis for a National Screening Assessment Model?

Free-of-charge hepatitis C virus antibody (HCV Ab) screening in some key populations and in 1969-1989 birth cohorts have been funded in Italy as the first step in confirming diagnosis in individuals who may be unaware of their infection. The purpose of this study is to leverage existing in-hospital routine screening data to better understand the distribution of HCV. A retrospective study of hospitalized patients (PTs) tested for HCV Ab for 5 years (from January 2017 to December 2022) in San Raffaele hospital was conducted according to age categories: birth year group before 1947 (patients older than 76 years old), birth year group 1947-1968, birth year group 1969-1989, and two other groups with birth year groups 1990-2000 and 2001-2022 (with patients younger than 33 years old) using the TriNetX platform. Among the 42,805 in-hospital PTs tested, 1297 (3.03%) were HCV Ab positive. The prevalence of HCV Ab was greater in PTs over the age of 76 (5.3%), whereas it was lower in the youngest birth year cohort (2000-2022, 0.16%). Among 1297 HCV Ab positive PTs, only 198 (15.3%) were tested for the presence of HCV RNA. The birth cohort 1969-1989 had a modest seroprevalence (1.5%), yet they were the most affected age group, with 44.4% being HCV RNA positive. The in-hospital HCV screening including birth year cohort 1947-1989 could be a more valuable option compared to the screening for birth year group 1969-1989 in the general population.

Incidence and Outcome of Hepatitis D Virus Infection in People With Human Immunodeficiency Virus (HIV) and Hepatitis B Virus Coinfection in the Era of Tenofovir-Containing Antiretroviral Therapy

Abstract Background Tenofovir-containing antiretroviral therapy (ART) improves survival in hepatitis B virus (HBV)–coinfected people with HIV (PWH). We investigated the incidence of hepatitis D virus (HDV) infection and its clinical impact in HBV-coinfected PWH in the era of tenofovir-containing ART. Methods Between 2011 and 2022, HBV-coinfected PWH were included and followed until December 2023. Anti-HDV antibody screening was performed using sequentially archived blood samples. Timing of incident HDV infection was estimated as the midpoint between the last timepoint of anti–HDV-negative samples and the first timepoint of anti–HDV-positive samples. Differences in survival and liver-related outcomes between HDV-infected and -uninfected PWH were analyzed. Results 534 HBV-coinfected PWH were included; 36 (6.7%) tested HDV-seropositive at baseline. During 3987.78 person-years of follow-up (PYFU), 50 (10.0%) of 498 anti–HDV-negative PWH seroconverted for HDV, with an overall incidence rate of 12.54 per 1000 PYFU; 88.0% (44/50) of HDV seroconverters were men who have sex with men. After a median follow-up of 10.2 years (84.7% of the follow-up period covered by tenofovir-containing ART), all-cause mortality was 4.7% (25/534). PWH with HDV had significantly higher rates of liver-related mortality (3.5% vs 0.4%, P = .032), cirrhosis (11.3% vs 3.6%, P = .008), and hepatitis flare (28.2% vs 14.2%, P = .001) than HDV-uninfected PWH. In multivariate Cox analysis, HDV infection was associated with liver-related mortality (adjusted HR, 9.696; 95% CI, 1.284–73.222, P = .028). Risk of hepatocellular carcinoma was similar for HDV-infected and HDV-uninfected PWH. Conclusions HBV-coinfected PWH remain at risk of HDV superinfection and HDV infection is associated with liver-related death in the era of tenofovir-containing ART.

A comparative study evaluating three line immunoassays available for serodiagnosis of equine Lyme borreliosis: Detection of Borrelia burgdorferi sensu lato-specific antibodies in serum samples of vaccinated and non-vaccinated horses

Diagnosis of equine Lyme borreliosis (LB), an infection caused by members of the Borrelia burgdorferi sensu lato complex (Bbsl), is challenging due to the nonspecific clinical signs of the disease and due to the variety of non-standardized serological tests. Specific vaccine-induced antibodies against LB, providing an effective protection against the infection, complicate the issue further. The standard for the detection of specific antibodies against Bbsl is a two-tier test system based on an enzyme-linked immunosorbent assay (ELISA) or indirect fluorescent antibody test (IFA) for antibody screening combined with a qualitative, highly specific immunoassay (e. g. line immunoassay (LIA)) for confirmation. In this study, three LIAs available for detection of antibodies in equine serum samples were evaluated and compared. A total of 393 serum samples of 131 horses with known serostatus were used. It included groups of non-vaccinated horses, immunized horses (vaccinations against LB on days 0 and 14), and horses that had received an initial immunization plus an additional booster on day 180. Sera were collected on days 0, 135 and 210 of the study. Results were compared considering the tests’ sensitivity, specificity, diagnostic outcome, and the operability of each test. Agreements of the diagnostic results among the LIAs were calculated for overall test results and single antigen-antibody-complex signal results. They are presented as inter-rater agreement and statistic reliability, represented by the Fleiss’ kappa coefficient. Agreement scores ranged from poor to moderate depending on group and time-point of blood sample collection. Depending on LIA used, deficiencies were observed in the form of non-sufficient sensitivity of antigen signals on the LIA strips (especially for outer surface protein A (OspA) or variable major protein like sequence expressed (VlsE)) or as an inappropriate test interpretation of the OspA signal. Operability of the three LIAs was equally user-friendly with minor variations. In two LIAs, test-evaluation was simplified by a supplied scanner and evaluation software. To improve functionality of available LIAs for equine serum samples it is advisable to adjust sensitivity and specificity of single test antigen signals and establish appropriate evaluation protocols.

Screening of Antibodies Against Leptospiral Hardjo Among Bovine Species of Nawalpur, Tanahun and Gorkha Districts of Nepal

Introduction: Leptospirosis, a bacterial zoonosis, can affect livestock species with considerable losses especially cattle and buffalo. Leptospira interrogans serovar hardjo is known to be associated with reproductive disorders in bovines. Information on the seroprevalence of antibodies against this serogroup in this territory is important in managing risks and instituting control measures for the area, such as Nepal since these diseases could be overlooked due to the absence of some surveillance practices. The aim of the study was to investigate the seroprevalence of Leptospira interrogans serovar hardjo antibodies among cattle and buffalo from Nawalpur, Tanahun and Gorkha districts of Nepal in order to evaluate the extent of the disease and its effect on cattle. Methods: A total of blood samples were collected aseptically using purposive sampling from cattle and buffalo in the study area 174. These samples were analyzed serologically using PrioCHECK®L.hardjo Ab ELISA kit for antibodies to Leptospira interrogans serovar hardjo. Results: The serological analysis indicated that the seroprevalence was 1.149% which points out the existence of a natural infection in cattle and buffalo reared without any immunization against leptospirosis. Geographical factors, especially region, combined with other factors like low immunogenicity of their vaccines offered to the animals, might explain the low level seroprevalence of the disease. Conclusion: This current study has highlighted the natural occurrence of the leptospires in the hardjo serovar in cattle and buffalo within the study region. The above studies bring out the necessity for active programs for control and preventative measures to restraints leptospirosis disease among the cattle as the disease prevalence designates low seroprevalence rate.

Alloantibody Identification: The Importance of Temperature, Strength Reaction and Enzymes-A Practical Approach.

Red blood cell (RBC) alloimmunization and antibodies formation against non-self antigens on red cells may occur after blood transfusion, pregnancies or other exposures. The RBC alloimmunization rate varies from 2% to 6% according to recent studies. The antibody screen is performed to identify or confirm the presence of antibodies in patient's serum or plasma, as a preoperative or pretransfusion test. The antibody identification process and major crossmatch are critical steps of risk management in transfusion medicine. The aim of this article is to describe a flow chart of the antibody identification. I report three educational examples of case studies associated with the negative direct antiglobulin test and clinically significant single and multiple alloantibodies using the gel method, Anti-M, Anti-c and Anti-E, Anti-Jka and Anti-s. Furthermore, I provide a critical analysis of the current literature on the topic. The flow chart of the antibody identification may simplify the process and possibly reduce errors in routine workflow.

Acute hemorrhagic leukoencephalitis with a positive transfusion-related antibody screening test

Acute hemorrhagic leukoencephalitis with a positive transfusion-related antibody screening test

PREVALENCE AND RISK FACTORS OF HEPATITIS C INFECTION AMONG PREGNANT WOMEN IN ILORIN, KWARA STATE, NIGERIA

Hepatitis C virus (HCV) poses a significant risk to the well-being of pregnant women and their offspring with about 1.5 million new infections occurring annually. The data on the prevalence and associated risk factors among pregnant women in Nigeria remains limited. This study therefore aimed to determine the prevalence and associated risk factors of hepatitis C infection among pregnant women in Ilorin, Kwara State, Nigeria. This cross-sectional study enrolled 180 eligible pregnant women who visited and received antenatal care at Cottage and Civil Service Hospitals in Ilorin, Nigeria between November 2021 and January 2022. Demographic and clinical data were collected using a structured questionnaire while the antibody screening was via Enzyme-Linked Immunosorbent Assay (ELISA). The data were analyzed with IBM SPSS version 26 at p&lt;0.05 significant level. Of the 180 pregnant women, 8 (4.4%) were positive for HCV. The highest proportion of HCV positivity was recorded among women aged 20-30 years (75%), those with tertiary education (100%), Civil Servants (100%), married women (100%), and those in the second trimester gestational age (100%). Furthermore, 87.5% of HCV-positive patients had a history of blood transfusion and 62.5% reported scarification. However, no significant statistical association was recorded between demographic characteristics, risk factors, and HCV seropositivity (p ˃ 0.05). Although the prevalence of active HCV infection among pregnant women in Ilorin was low, the outcome underscores the importance of routine screening of pregnant women for HCV to prevent maternal and neonatal complications in line with Sustainable Development Goal 3 on good health and wellbeing. This warrants further research for comprehensive data on HCV prevalence among pregnant women across Nigeria.

Transfusing selected RhD negative patients with RhD positive packed red cell concentrates resulted in lower frequency of anti-D development and saved almost two thousand RhD negative concentrates during 5 years.

The Blood Bank at Oslo University Hospital implements restrictions when the stocks of blood groups O and A RhD negative packed red blood cell concentrates (PRBCCs) drop below 60 units due to high demand and low donor availability. Restrictions entail transfusing RhD negative male patients and women >50 years with RhD positive units, to provide RhD negative units to those who should not receive RhD positive units. Earlier studies have reported that up to 50% of RhD negative patients developed anti-D after RhD positive blood transfusion. We aimed to investigate the rate of anti-D alloimmunization using this restriction strategy in our population. This retrospective study was performed at Oslo University Hospital between 2006 and 2011. Antibody screen results were included throughout 2019 for the patients readmitted to the hospital. 607 RhD negative mostly cancer patients and patients having surgery for cardiovascular conditions received 1926 RhD positive PRBCCs. Post-transfusion antibody screen was available for 401 patients (66.1%), and 76 patients (22.2%) developed anti-D. In 15 of the 76 patients (19.7%), anti-D became evanescent in the follow-up. The proportion of anti-D immunisation in RhD negative patients receiving RhD positive PRBCCs in this study was consistent with findings from other reports. To our knowledge, this is the first study reporting a high proportion of evanescence of anti-D. Transfusing selected RhD negative patients with RhD positive PRBCCs when RhD negative stocks are low, contributed saving 1926 RhD negative PRBCCs during the study period of 64 months.

HEV Infection in Beta-Thalassemia Patients.

Thalassemia is an inherited hematological disorder characterized by a decrease in the synthesis of or absence of one or more globin chains. Hepatitis E virus (HEV) is a major cause of acute viral hepatitis, constituting a major global health burden and emerging as a critical public health concern. HEV infection is mainly transmitted via the fecal-oral route; however, parenteral transmission through blood components has been reported in both developing and developed countries. Although HEV infection is typically self-limiting, immunocompromised individuals, patients with chronic liver disease, and thalassemic patients are at a heightened risk of contracting the infection and may develop chronic hepatitis and life-threatening complications that require treatment. The reported prevalence rates of HEV in thalassemia patients vary significantly by country. Age, gender, residential area, and the cumulative amount of blood transfusions received have been identified as associated risk factors for HEV infection. In order to enhance blood safety and ensure the protection of vulnerable patient populations, such as thalassemia patients, several countries have introduced universal or targeted HEV screening policies in blood donations. Other preventive measures include vigilant monitoring of thalassemic patients and screening for anti-HEV antibodies. The aim of this review is to explore the prevalence, risk factors, clinical impact and management of HEV infection in patients with thalassemia.

Virus neutralization test for confirmation of ELISA-positive SARS-CoV-2 antibodies in dogs.

Constant antigenic changes, new variants and easy transmission of SARS-CoV-2 virus should acquire greater zoonotic attention and need to remain alert. In this retrospective study the aim was to analyze seropositivity to SARS-CoV-2 in dogs by commercial ELISA. The Virus neutralization test (VNT) was modified for the purpose of confirmation of SARS-CoV-2 antibodies in ELISA-positive dog sera. The sera were collected from 204 dogs from different veterinary clinics across Vojvodina Province, Serbia, during COVID-19 pandemic. For the screening of antibodies a commercial double multi-species antigen ELISA was used, followed by the VNT modified with SARS-CoV-2 as a confirmatory test. VNT was modified as "one step" test using local isolate of SARS-CoV-2 and the results were checked by cytopathic effect in cell culture on the 96-well microtiter plate. Obtained data have shown that 9 out of 204 dogs were positive by ELISA (4.4%), while 2 (0.97%) sera were doubtful. VNT confirmed 9 positive dogs, but 2 doubtful samples were negative, exhibiting the seroconversion to SARS-CoV-2 in 4.4% dogs from Vojvodina region during pandemic of COVID-19. VNT with SARS-CoV-2 helped to elucidate ELISA ambiguous results. The occurrence of antibodies to SARS-CoV-2 in dogs in this study during COVID-19 pandemic suggested the possibility of viral transmission to dogs, implicating the potential for zoonotic transmission. This was the first research on seroconversion to SARS-CoV-2 in dogs from the Province of Vojvodina, the northernmost part of Serbia.