Anti Antibody Research Articles

A rare presentation of severe alloimmune hemolytic disease of newborn pertaining to minor blood group ‘c’ incompatibility: a case report and review of literature

Hyperbilirubinemia is one of the most widely seen causes of neonatal morbidity. Haemolytic disease of fetus and newborn is caused by maternal alloantibodies to the fetal RBCs. It is responsible for incompatibility between maternal and fetal blood groups, which results in destruction of fetal red blood cells causing hyperbilirubinemia. ABO and Rh incompatibility are the most common causes of severe indirect hyperbilirubinemia. Besides ABO and Rh isoimmunization, minor blood group incompatibilities such as anti-Kell, anti-C, anti-c, anti-E, anti MNS, Duffy, KIDD, P, Lutheran and Lewis have also been identified as causes of severe neonatal jaundice with an incidence of 385/1,00,000 live births in South-East Asia. We, hereby report a rare case of a full term 2.2 kg newborn presented with severe anemia with reticulocytosis and neonatal hyperbilirubinemia at second hour of life. In view of strongly positive DCT and no Rh negative or ABO setting, minor blood group incompatibility screening test was performed in the mother which revealed presence of multiple alloantibodies; however, the red cell phenotyping confirmed the presence of anti-c antibodies in maternal sera responsible for neonatal alloimmune haemolytic anemia. The baby was offered intensive phototherapy with intravenous immunoglobulin.

Biomarkers of transfusion transmitted occult hepatitis Bvirus infection: Where are we and what next?

Blood transfusion is a vital procedure, where transfusion-transmitted infection of hepatitis B virus (HBV) remains an important issue, especially from blood donors with occult hepatitis B virus infection (OBI). Occult hepatitis B virus infection is a complex entity to detect using surrogate blood biomarkers for intrahepatic viral transcriptional activity, requiring a continually refined battery of tests utilised for screening. This review aims to critically evaluate the latest advances in the current blood biomarkers to guide the identification of OBI donors and discuss novel HBV markers that could be introduced in future diagnostic practice. Challenges in detecting low HBV surface antigen levels, mutants, and complexes necessitate ultrasensitive multivalent dissociation assays, whilst HBV DNA testing requires improved sensitivity but worsens inaccessibility. Anti-core antibody assays defer almost all potentially infectious donations but have low specificity, and titres of anti-surface antibodies that prevent infectivity are poorly defined with suboptimal sensitivity. The challenges associated with these traditional blood HBV markers create an urgent need for alternative biomarkers that would help us better understand the OBI. Emerging viral biomarkers, such as pre-genomic RNA and HBV core-related antigen, immunological HBV biomarkers of T-cell reactivity and cytokine levels, and host biomarkers of microRNA and human leucocyte antigen molecules, present potential advances to gauge intrahepatic activity more accurately. Further studies on these markers may uncover an optimal diagnostic algorithm for OBI using quantification of various novel and traditional blood HBV markers. Addressing critical knowledge gaps identified in this review would decrease the residual risk of transfusion-transmitted HBV infection without compromising the sustainability of blood supplies.

Demographic and Clinical Factors Associated With SARS-CoV-2 Spike 1 Antibody Response Among Vaccinated US Adults: the C4R Study.

This study investigates correlates of anti-S1 antibody response following COVID-19 vaccination in a U.S. population-based meta-cohort of adults participating in longstanding NIH-funded cohort studies. Anti-S1 antibodies were measured from dried blood spots collected between February 2021-August 2022 using Luminex-based microsphere immunoassays. Of 6245 participants, mean age was 73 years (range, 21-100), 58% were female, and 76% were non-Hispanic White. Nearly 52% of participants received the BNT162b2 vaccine and 48% received the mRNA-1273 vaccine. Lower anti-S1 antibody levels are associated with age of 65 years or older, male sex, higher body mass index, smoking, diabetes, COPD and receipt of BNT16b2 vaccine (vs mRNA-1273). Participants with a prior infection, particularly those with a history of hospitalized illness, have higher anti-S1 antibody levels. These results suggest that adults with certain socio-demographic and clinical characteristics may have less robust antibody responses to COVID-19 vaccination and could be prioritized for more frequent re-vaccination.

Phenotyping of Rh and Kell blood group antigen in thalassemia and its impact on alloimmunization in a tertiary care hospital

Objectives: Alloimmunization to red cell antigens is a dreaded complication in multitransfused patients, leading to difficulty in obtaining compatible red blood cell units and development of delayed hemolytic transfusion reactions. The objective of this study was to assess the impact of partial matched phenotype blood (for RhD, C, c, E, e, and Kell antigens) on alloimmunization in thalassemics versus non-phenotype matched blood (ABO & RhD). Materials and Methods: This cross-sectional study was conducted over a period of two years where 250 patients with thalassemias were enrolled. They were divided into two groups, patients in Group I (n = 180) who received partial matched phenotype blood since initiation of transfusion therapy and those in Group II (n = 70) subjects who received usual matched blood. Statistical analysis: All statistical calculations were done using statistical package for the social sciences (SPSS) 21 version. Data were described in terms of range, median (interquartile range [IQR]), frequencies, etc. Results: The median (IQR) age of the study population was 12 (7–18) years (range 6 months–36 years). The most common Rh antibodies were anti-D (2.85%), anti-E (2.85%), anti-C (1.42%), and anti-c (1.42%), and Kell antibodies were (7.1%). It was seen that chances of developing autoantibodies (37% vs. 5%), alloantibodies 11 (15.7% vs. 0%), and transfusion reactions 25 (35.7% vs. 3.3%) were more in Group II subjects as compared to Group I. A significant difference was seen with febrile non-hemolytic transfusion reactions in between two groups 0.001 (95% confidence interval 2.98–65.73). Conclusions: Patients with thalassemia should be typed for RhD (C, c, E, and e) and Kell antigen before initiation of transfusion, which will help in reducing the rate of alloimmunization, autoimmunization, and frequency of transfusion and will improve the overall survival rate in thalassemia.

Emergence of additional anti-C with amplification of anti-D titer post-Rh-Kell phenotype-matched intrauterine transfusions in severe hemolytic disease of fetus

Abstract Transplacental ultrasound-guided intrauterine transfusion (IUT) acts as a lifesaving therapy to prevent fetal anemia or even to reverse fetal hydrops. IUTs are generally initiated after 22–24 weeks of gestation and repeated every 2–4-week period of gestation. Although Rh-Kell phenotype-matched, fresh irradiated leukoreduced donor-packed red cells help to increase fetal hemoglobin level, this invasive procedure can increase fetal complications by fetomaternal hemorrhage. Women receiving IUTs are noted to be high allo-responders to red cell antigens, which can cause enhanced antibody titer or the formation of additional antibodies which might complicate future pregnancies. Hereby, we are reporting the case of a multiparous woman who underwent three sessions of IUTs between 24 weeks and 31+-week period of gestation and developed an additional anti-C antibody which was incidentally detected during compatibility testing at 34 weeks, along with raised anti-D immunoglobulin G titer of 1024 from initial titer of 128.

Synergistic impact of N-antigenemia profiled by a rapid antigen test and low anti-S1 antibodies on the risk of hospitalization in COVID-19

ObjectivesIdentifying patients with COVID-19 who are at risk of poor evolution is key to early decide on their hospitalization. We evaluated the combined impact of nucleocapsid (N)-antigenemia profiled by a rapid test and antibodies against the S1 subunit of the SARS-CoV S protein (S1) on the hospitalization risk of patients with COVID-19. MethodsN-antigenemia and anti-S1 antibodies were profiled at admission to the emergency department in 146 patients with COVID-19 using the Panbio® antigen Rapid Test and the SARS-CoV-2 immunoglobulin G II Quant/SARS-CoV-2 immunoglobulin G assay from Abbott. A multivariable analysis was used to evaluate the impact of these factors on hospitalization. ResultsPatients with a positive N-antigen test in plasma and anti-S1 levels <2821 arbitrary units/mL needed hospitalization more frequently (20 of 23, 87%). A total of 20 of 71 (28.2%) of those showing a negative N-antigen test and anti-S1 ≥2821 arbitrary units/mL were hospitalized for 18 of 52 (34.6%) of the patients with only one of these conditions. Patients with a positive N-antigen test and low antibody levels showed an odds ratio, 95% confidence interval, and P-value for hospitalization of 18.21, 2.74-121.18, and 0.003, respectively, and exhibited the highest mortality (30.4%). ConclusionsSimultaneous profiling of a rapid N-antigen test in plasma and anti-S1 levels could help to early identify patients with COVID-19 needing hospitalization.

Clinical and immunological outcomes of SARS-CoV-2-infected vaccine responders, vaccine non-responders, and unvaccinated patients evaluated for neutralizing monoclonal antibody treatment at a single German tertiary care center: a retrospective cohort study with prospective follow-up

PurposeThis study assessed the clinical and immunological outcomes of SARS-CoV-2-infected patients with risk factors for severe disease depending on their immunological status.MethodsIn this retrospective study with single follow-up visit, clinical outcome and humoral immunity was monitored in SARS-CoV-2 infected patients at risk. The results were compared based on the patients’ initial immunological status: unvaccinated (UV), patients who did not develop neutralizing antibodies after vaccination (vaccine non-responders, VNR), and patients who expressed neutralizing antibodies after vaccination (vaccine responders, VR). Patients who lacked neutralizing antibodies (VNR and UV) were treated with nMABs.ResultsIn total, 113 patients at risk of severe COVID-19 consented to participate in the study. VR and UV were not admitted to the hospital. During the observation period, UVs had the highest rate of SARS-CoV-2 re-infections. Three of 41 VNRs (7.3%) were hospitalized due to severe COVID-19, with two of them having undergone iatrogenic B-cell depletion. The humoral immune response after infection was significantly lower in the VNR group than in the VR group in terms of anti-N, anti-receptor-binding domain (RBD), anti-S antibody titers, and anti-S antibody avidity. In a sub-analysis of VNR, B cell-deficient non-responders had significantly lower levels of anti-N antibodies and anti-S avidity after infection than other VNRs.ConclusionVNR, particularly B-cell-depleted VNR, remained at risk of hospitalization due to COVID-19. In the VR group, however, no clinical complications or severe disease were observed, despite not receiving nMAbs. Tailoring the administration of nMABs according to patient vaccination and immunological status may be advisable.

First exploration of the on-treatment changes in tumor and organ uptake of a radiolabeled anti PD-L1 antibody during chemoradiotherapy in patients with non-small cell lung cancer using whole body PET

BackgroundIn patients with locally advanced unresectable non-small cell lung cancer (NSCLC), durvalumab, an anti-programmed cell death ligand-1 (PD-L1) antibody, has shown improved overall survival when used as consolidation therapy following...

Age dependent discrepancy between SARS-CoV-2 anti-nucleoprotein antibody and anti-RBD spike protein antibody in children reflects vaccine coverage

BackgroundCOVID-19 has become widespread in Japanese children. However, the impact of varying immunization coverage on the seroprevalence of SARS-CoV-2 in children is unknown. MethodsWe examined the SARS-CoV-2 antibody in children aged 0 to 18 who were hospitalized at a university hospital from June 2020 through May 2023. The SARS-CoV-2 anti-nucleoprotein (N) antibody and anti-RBD spike (S) protein antibody was measured. ResultsA total of 586 cases were enrolled. The median age was 4 years old (interquartile range 1–9), and 362 (61.8 %) were male. The seroprevalence of anti-S antibodies gradually increased from October 2021 and reached 60 percent by early 2023. The anti-N antibody increased starting in January 2022 and reached 50 percent in May 2023. There was a discrepancy in the seroprevalence of anti-S and N antibodies in children 0 years of age or 12 years and older until the fall of 2022. This discrepancy was minimal for children 1–4 years of age and relatively small in the 5–11-year-old group. DiscussionThe data suggests that approximately half of the children in our cohort had been infected with SARS-CoV-2 by May 2023. The discrepancy in seropositivity between the anti-S and N antibodies corresponded to the reported vaccine uptake of each target age group, which suggested protective effects of immunization. However, this effect appeared to diminish after early 2023. ConclusionAge dependent discrepancy between SARS-CoV-2 anti-N and anti-S antibody in children reflected differences in vaccine coverage.

ABO Blood System: Biosynthesis of Agglutinogenic Alkaline and Non-Agglutinogenic Acid Glycotopes of A and B Antigens at Different pHs of the Culture Medium.

The biosynthesis of agglutinogenic and adsorbing groups A and B glycotopes of the erythrocyte's membrane is mediated by the activity of specific glycosyltransferases. This study aimed to assess the nature of the biosynthesis of A and B antigenic glycotopes, depending on the pH of the medium during the cultivation of erythrocytes, and the antigenic (transferase) characteristics of the donor serum of the other group. Monoclonal antibodies (Mabs) were obtained from IGBRL under Program IV of the International Workshop on Monoclonal Antibodies and Red Blood Cell Antigens. Biosynthesis was performed using erythrocytes, fresh serum, medium 199, and an antibiotic solution. The agglutinogenic characteristics of 11 out of 33 samples changed by the end of the cultivation period due to the acquisition of additional agglutinogen corresponding to the donor serum. None of the samples lost their inherent agglutinogen due to its absence in the donor serum. Four of six samples of O(I) erythrocytes acquired the ability to be agglutinated by anti-A reagents, especially by the polyclonal anti-A, and the manifestation of agglutination depended on the reaction time. Two of the three samples with initial A(II) agglutinogenic specificity added to the donor serum with Bc'+ characteristic of the erythrocytes acquired this characteristic. However, none of the five A(II)Ac'+ samples cultured in the serum of Ac'-O(I)Ac'-Bc'+ and O(I)Ac'-Bc'- donors lost their inherent earlier Ac'+ characteristic. The investigation of the inhibitory ability of alkaline and acidic glycoconjugates isolated from membranes revealed that alkaline Alp-00 and Alp-1 glycotopes isolated from glycolipids had the highest inhibitory activity, and the degree of inhibition of polyclonal anti-A antibodies was even higher than that of monovalent BRIC-131. This study showed the possibility of the biosynthesis of specific non-agglutinogenic A and B glycotopes under the influence of a different group's serum as a source of the corresponding transferase.

High-level expression of anti FLAG tag antibody in plants

Plant bioreactor is a new production platform for expression of recombinant protein, which is one of the cores of molecular farming. In this study, the anti DYKDDDDK (FLAG) antibody was recombinantly expressed in tobacco (Nicotiana benthamiana) and purified. FLAG antibody with high affinity was obtained after immunizing mice for several times and its sequence was determined. Based on this, virus vectors expressing heavy chain (HC) and light chain (LC) inoculated into Nicotiana benthamiana leaves by using Agrobacterium-mediated delivery. Accumulation of the HC and LC was analyzed by SDS/PAGE followed by Western blotting probed with specific antibodies from 2 to 9 days postinfiltration (dpi). Accumulation of the FLAG antibody displayed at 3 dpi, and reached a maximum at 5 dpi. It was estimated that 66 mg of antibody per kilogram of fresh leaves could be obtained. After separation and purification, the antibody was concentrated to 1 mg/mL. The 1:10 000 diluted antibody can probe with 1 ng/mL FLAG fused antigen well, indicating the high affinity of the FLAG antibody produced in plants. In conclusion, the plant bioreactor is able to produce high affinity FLAG antibodies, with the characteristics of simplicity, low cost and highly added value, which contains enormous potential for the rapid and abundant biosynthesis of antibodies.

Organ preservation with durvalumab-based immunotherapy in combination with chemoradiation as definitive therapy for early stage, cT1, and cT2N0 esophageal adenocarcinoma with indication for radical surgery: A prospective, multicenter study of the FLOT-AIO Gastric Cancer Group (IKF-t057/PRESTO trial).

TPS431 Background: The outcome of patients (pts) with adenocarcinomas of stomach and esophagogastric junction (GEJ) remains unsatisfactory (5-year survival rates of 24-84%), whereby surgical resection is considered as cornerstone of the curative treatment for pts with early stage esophageal adenocarcinoma (EGA), however, it is associated with mortality, morbidity and an impact on the patient’s quality of life. Recent investigations showed that in locally advanced stage EGA surgery with neoadjuvant chemoradiotherapy (CROSS trial) is beneficial over surgery alone. Further benefit was achieved for locally advanced EGA by perioperative treatment with FLOT acc. to FLOT4- trial data. Immuno-oncology (IO) therapy by using checkpoint inhibitors is approved in the palliative and adjuvant EGA situation. In this trial we aim for the organ preservation treatment of EGA pts with a combination of the anti PD-L1 antibody durvalumab- FLOT - and chemoradio-therapy. Methods: This is a multicenter, single arm, open-label, phase II trial including a total of 32 pts with T1-T2N0 EGA (including GEJ) with indication for radical surgery. Enrolled pts will receive immunotherapy with durvalumab (1500 mg Q4W) in parallel to 2 cycles FLOT (50 mg/m2 docetaxel, 85 mg/m2 oxaliplatin, 200 mg/m2 calcium folinate and 2600 mg/m2 5FU, Q2W) induction followed by 3 cycles of mFOLFOX (85 mg/m2 oxaliplatin, 200 mg/m2 calcium folinate, 400 mg/m2 5FU bolus and 1600 mg/m2 5FU over 48h, Q2W) plus concomitant radiation (25 daily fractions with 2.0 Gy = Σ50Gy). 8 weeks after last treatment, pts will undergo tumor assessment by esophagogastroduodenoscopy with biopsies, endoscopic ultrasonography, and CT- or MRI-scans. Surgical resection would be offered only to pts in whom a locoregional persistence is confirmed. Pts with complete remission will enter the maintenance phase and will receive durvalumab monotherapy (1500 mg, Q4W) for a maximum of 12 cycles accompanied by regular tumor re-evaluation. Primary endpoint is the rate of cCR/pCR at time of re-evaluation. Secondary endpoints include rate of cCR/pCR at 1, 2 and 3 years, rate of salvage surgery, 90 day and 1 year mortality after start of treatment, safety and quality of life. In this exploratory trial a cCR/pCR rate of ≥75% would indicate that the study treatment should be further investigated, whereas a rate &lt; 55% indicates no further investigation. First patient was enrolled on 2023-08-28. Currently one patient is recruited. Clinical trial information: NCT05713838 .

Timing of Maternal COVID-19 Vaccine and Antibody Concentrations in Infants Born Preterm

COVID-19 vaccine-derived antibodies in pregnant people may protect infants from severe infection in the first 6 months of life via transplacental antibody transfer. Few data exist on maternally derived SARS-CoV-2 antibodies in preterm compared with full-term infants in association with vaccination timing. To compare SARS-CoV-2 anti-Spike (anti-S) antibody levels in preterm and full-term infants in the context of vaccine dose timing before delivery. This prospective cohort study enrolled pregnant individuals and collected paired maternal and cord blood samples at delivery at the University of Washington between February 1, 2021, and January 31, 2023. Participants who had received at least 2 doses of a messenger RNA COVID-19 vaccine before delivery and did not have a history of prior COVID-19 infection or detectable anti-SARS-CoV-2 nucleocapsid antibodies were included. Timing of the last vaccine dose and preterm or full-term gestational age at delivery. Paired maternal and cord samples were tested for anti-S antibody, and linear regression was used to evaluate associations between preterm delivery and anti-S antibody levels. Covariates included timing of last dose, number of doses, insurance status, and immunosuppressing medications. A total of 220 participants (median [IQR] age, 34 [32-37] years; 212 [96.4%] female) with 36 preterm and 184 full-term deliveries were studied. Before delivery, 121 persons received 2 vaccine doses and 99 persons received 3 or more vaccine doses. The geometric mean concentration of maternal anti-S antibodies was 674 (95% CI, 577-787) after 2 doses and 8159 (95% CI, 6636-10 032) after 3 or more doses (P < .001). The cord anti-S antibody geometric mean concentration was 1000 (95% CI, 874-1144) after 2 doses and 9992 (95% CI, 8381-11 914) after 3 or more doses (P < .001). After adjustment for vaccine timing and number of doses before delivery, no association was found between preterm delivery and cord anti-S antibody levels (β = 0.44; 95% CI, -0.06 to 0.94). In this prospective cohort study of pregnant individuals with preterm and full-term deliveries, receipt of 3 or more compared with 2 doses of COVID-19 vaccine before delivery resulted in 10-fold higher cord anti-S antibody levels. Maternal antibody concentration appeared more important than delivery gestational age in determining cord anti-S antibody levels. The number of doses and timing considerations for COVID-19 vaccine in pregnancy should include individuals at risk for preterm delivery.

Primary Biliary Cholangitis in Men: A Rare and Particular Presentation (About 2 Cases and Review of the Literature)

Primary biliary cholangitis (PBC) is a rare etiology of cholestatic jaundice in men. We report two rare cases of PBC in men revealed by chronic cholestasis (jaundice, pruritus, dark urine, discolored stools, ALP greater than 1.5 times the upper limit and GGT greater than 3 times the upper limit). The first case had positive anti-mitochondria type 2 antibodies, while in the second case they were negative with positive anti gp-210 antibodies. The histological study of liver biopsies in the first case confirmed PBC. The second case was diagnosed at the stage of cirrhosis.

Mast Cell-Targeting Therapies in Mast Cell Activation Syndromes.

Provide an overview of the expanding landscape of mast cell (MC)-targeting treatments in mast cell activation syndromes (MCAS). Tyrosine-kinase inhibitors (TKIs) targeting wild-type and mutated KIT can efficiently induce MC depletion. Avapritinib and midostaurin can also temper IgE-mediated degranulation. Avapritinib has been recently approved by the FDA for the treatment of indolent systemic mastocytosis (ISM). Targeting activation pathways and inhibitory receptors is a promising therapeutic frontier. Recently, the anti Siglec-8 antibody lirentelimab showed promising results in ISM. MCAS is a heterogeneous disorder demanding a personalized therapeutic approach and, especially when presenting as anaphylaxis, has not been formally captured as outcome in prospective clinical trials with TKI. Long-term safety of TKI needs to be addressed. New drugs under investigation in diseasesin which non-neoplastic MCs play a pivotal role can provide important inputs to identify new efficient and safe treatments for MCAS.

The development of an electrochemical immunosensor utilizing chicken IgY anti-spike antibody for the detection of SARS-CoV-2

This paper introduces a novel approach for detecting the SARS-CoV-2 recombinant spike protein combining a label free electrochemical impedimetric immunosensor with the use of purified chicken IgY antibodies. The sensor employs three electrodes and is functionalized with an anti-S IgY antibody, ELISA and immunoblot assays confirmed the positive response of chicken immunized with SARS-CoV2 S antigen. The developed immunosensor is effective in detecting SARS-CoV-2 in nasopharyngeal clinical samples from suspected cases. The key advantage of this biosensor is its remarkable sensitivity, and its capability of detecting very low concentrations of the target analyte, with a detection limit of 5.65 pg/mL. This attribute makes it highly suitable for practical point-of-care (POC) applications, particularly in low analyte count clinical scenarios, without requiring amplification. Furthermore, the biosensor has a wide dynamic range of detection, spanning from 11.56 to 740 ng/mL, which makes it applicable for sample analysis in a typical clinical setting.

A Rare Case of Pregnancy-induced Anti-D, Anti-C, and Anti-G Antibodies

ABSTRACT A 39-year-old female with breast carcinoma presented with complaints of menorrhagia and weakness. At current admission, her hemoglobin was 6.2 g/dL, and a requisition for packed red blood cells (PRBCs) was sent to the blood center. There was no previous history of transfusions, and the last pregnancy was 11 years ago. During the immunohematological (IH) workup, she was typed as O, ccdee, with an extra reaction in reverse grouping. Her antibody screening was positive, followed by the antibody identification, which was suggestive of anti-D and anti-C antibodies. The “Rhesus G” is an immunogenic antigen that is present on red cells that are D- and/or C-positive. Therefore, it is essential to determine the possibility of the presence of an anti-G antibody in the patient since anti-G appears as anti-D + anti-C serologically. In our case, a series of IH tests were performed, which ultimately led to the detection of all three antibodies: anti-D, anti-C, and anti-G. The patient’s husband and both children were typed as A, CcDee. Hence, her alloantibodies were most probably pregnancy induced, and since antibodies to the Rhesus system have a poor evanescence phenomenon, they are persisting to date. She was safely transfused with two units of O, ccdee PRBCs, and a special blood group card was provided to ensure that she always receives transfusions with phenotype-matched red cells in the future to avoid further alloimmunization.

Anti-S Antibodies Against SARS-CoV-2 Infection Among Four Types of Vaccines in Malaysia.

Monitoring SARS-CoV-2 antibody levels can provide insights into a person's immunity to COVID-19 and inform decisions about vaccination and public health measures. Anti-S may be useful as an indicator of an effective immune response. Thus, we conducted this study that aimed to determine the immune response of anti-S antibodies against SARS-CoV-2 for all the vaccine types over time among adult recipients in Malaysia and to determine the associated factors. This study was a cohort that recruited 2513 respondents aged 18 years and above from June to December 2021. Each participant was followed-up for 1-year period from the initial vaccine dose (baseline). We found that the anti-S antibody generally increased for all vaccine types and peaked at two weeks after the second dose vaccination, with Pfizer recipients having the highest median of 100 (100.00-100.00). During the third-month follow-up, the seropositivity of anti-S antibody and the median level decreased for all vaccines. We found that type of vaccines, comorbid status, infection, and booster status were significantly associated with the anti-S antibody level after one year.

Surface antigen serocleared hepatitis B virus infection increases the risk of mixed cryoglobulinemia vasculitis in male patients with chronic hepatitis C.

Mixed cryoglobulinemia vasculitis (MCV) is caused in ~90% of cases by chronic hepatitis C virus (HCVposMCV) and more rarely by hepatitis B virus (HBV) infection, or apparently noninfectious. HCVposMCV develops in only ~5% of patients with chronic hepatitis C (CHC), but risk factors other than female gender have not been identified so far. We conducted a retrospective case control study investigating whether past active HBV infection, defined by hepatitis B surface antigen (HBsAg) seroclearance and anti-core antibody (HBcAb) positivity, could be a risk factor for developing HCVposMCV. The prevalence of HBsAg seroclearance was 48% within 123 HCVposMCV patients and 29% within 257 CHC patients (p=0.0003). Multiple logistic regression including as variables gender, birth year, age at HBV testing, cirrhosis, and hepatocellular carcinoma, confirmed an association of HBsAg seroclearance with HCVposMCV [adjusted odds ratio (OR) 2.82, 95% confidence interval (95% CI) 1.73-4.59, p<0.0001]. Stratification by gender, however, showed that HBsAg seroclearance was associated with HCVposMCV in male [OR 4.63, 95% CI 2.27-9.48, p<0.0001] and not in female patients [OR 1.85, 95% 95% CI 0.94-3.66, p=0.076]. HBsAg seroclearance, and more likely occult HBV infection, is an independent risk factor for HCVposMCV in male CHC patients.

Estimation of ABO Anti-A and Anti-B Agglutinin Titers among Blood Donors at a Tertiary Care Referral Teaching Hospital Blood Centre in Southern India: A Cross-sectional Study

Introduction: Transfusion of blood Group O and its components with high ABO antibody titers to non O recipients has been shown to cause acute transfusion reactions, especially in platelet transfusions, as platelets contain significant amounts of ABO antigen on their surface as well as Anti-ABO alloisogglutinins in plasma. Aim: To estimate the ABO Anti-A and Anti-B agglutinin titers among blood donors at a tertiary care referral teaching hospital blood centre. Materials and Methods: This cross-sectional observational study was conducted at the Immunohaematology laboratory of the Department of Transfusion Medicine, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India, from March 2021 to June 2022. All blood donors presenting to the blood centre were screened for eligibility for blood donation. Donors who fulfilled the eligibility criteria as per the Drugs and Cosmetics Act, 1940, and Rules, 1945 were included. Anti-A and Anti-B titers were determined by the conventional tube method with dilutions of 1 in 2, 1 in 4, 1 in 8, 1 in 16, 1 in 32, 1 in 64, 1 in 128, 1 in 256, 1 in 512, and 1 in 1024. A titer of &lt;64 was considered as a low titer, while a titer of &gt;64 was considered as a high titer. Results: A total of 399 donors were included in the study, with 393 (98.5%) being males and 6 (1.5%) being females. The mean age of the study population was 28.49 years. Among blood group A, the percentage of individuals with an IgM anti-B titer of &lt;64 was 85.44% (88) and &gt;64 was 14.56% (15), whereas in blood group B, IgM anti-A titers of &lt;64 were 65.5% (93) and &gt;64 were 34.5% (49). In blood group O, the percentage of individuals with &lt;64 and &gt;64 titers of IgM anti-A were 52.60% (81) and 47.40% (73), respectively, whereas for anti-B, &lt;64 and &gt;64 titers were 77.92% (120) and 22.08% (34), respectively. Conclusion: It is recommended that a database be maintained in all institutes by estimating antibody titers for every A, B, O blood group donors. Whole blood or platelets from group O donors with IgM Anti-A and Anti-B antibody titers &lt;64 can only be transfused across the ABO barrier. As the majority of group A donors had titers &lt;64, group A platelets may be transfused across the ABO barrier in emergency situations.