Red Cell Surface Research Articles

Distribution of ABO and Rhesus Blood Groups among Blood Donor Attending Transfusion Medicine Department of Chattagram Maa-O-Shishu Hospital Medical College

Introduction: The ABO blood group system was the first human blood group system to be discovered by Karl Landsteiner in 1900. Next to ABO, Rhesus system the second most significant blood group system. Blood group is applied to the genetically determined antigen which can be detected on the red cell surface of an individual by specific antibody. The aim of this study to examine the distribution patterns of ABO and Rh-D blood group among the blood donor attending at Transfusion Medicine Department in CMOSH. It is helpful to increase social awareness among the population and maintain safe blood transfusion to patient. Materials and methods: It was a cross sectional study conducted in the Department of Transfusion Medicine,Chattagram Maa O Shishu Hospital Medical College, from January to December 2022. After proper ethical consideration a total of 7,289 blood donors were included in this study. ABO and Rh blood groupings were carried out in our blood bank by standard tile techniques. Results: Among 7,289 blood donors male blood donors were 6,936(95.15%), female blood donors were 353(4.84%).2,775 (38.07%) blood donor were identified as having blood group B while 2,185 (29.97%) were blood group O, 1702( 23.35%) and 627(8.6%)were blood group A and AB respectively. Rh-D positive were 6,960(95.48%) and Rh-D negative were 329(4.51%). Conclusion: The knowledge of ABO and Rhesus D blood group is important in blood transfusion service.Study of blood grouping not only generates a simple database but also create a great social awareness about self-blood grouping and safe blood transfusion among the population of a country. Chatt Maa Shi Hosp Med Coll J; Vol.23 (1); January 2024; Page 52-55

Proteomic Identification and Functional Analysis of Babesia microti Reveals Heparin-Binding Proteins.

Glycosaminoglycan (GAG) molecules on the surface of red blood cells play an important regulatory role in the invasion of merozoites of apicomplexan protozoa. Heparan sulfate, a type of GAG molecule, has been identified as an important receptor facilitating the invasion of red blood cells by these parasites. Proteins in the parasite that exhibit strong affinity for heparin may play a pivotal role in this invasion process. This study aims to use proteomics to identify Babesia microti proteins with high binding affinity to heparin. Bioinformatics was utilized to analyze the subcellular localization and biological functions of these proteins. Candidate genes encoding proteins with strong heparin affinity will be expressed in a prokaryotic system to produce recombinant proteins. The interaction between these recombinant proteins and heparin will be characterized through heparin-binding experiments and other methods. Initially, a mouse model of B. microti was established and high-density B. microti were obtained. Heparin affinity chromatography was then used to purify natural B. microti proteins that can bind to heparin, identifying 186 B. microti proteins via ESI-MS that specifically interact with heparin. Further studies were carried out to analyze those specific proteins with unique peptide segments of two or more, yielding 15 B. microti proteins, most of which are cell surface proteins and secretory proteins. Based on mass spectrometry identification and subsequent analyses, BMSA5-1-1, B. microti peptidyl-prolyl cis-trans isomerase (BmPPIase), and chaperonin were selected for further study due to their potential impact on the invasion of red blood cells by B. microti. These candidate proteins were expressed as recombinant proteins using a prokaryotic expression system. In vitro heparin-binding assays demonstrated that these recombinant proteins specifically bind to heparin. Notably, BmPPIase and chaperonin recombinant proteins exhibited activity in specific heparin binding. Molecular interaction studies further confirmed the strong interaction between BmPPIase and heparin. In conclusion, this study used proteomic methods to identify 186 specific B. microti proteins with specific binding affinity to heparin, providing in-depth analysis of 15 key proteins. The findings confirmed that BmPPIase and chaperonin specifically bind to heparin, with molecular interaction experiments substantiating the strong interaction between BmPPIase and heparin.

Plasmodium falciparum surf4.1 in clinical isolates: From genetic variation and variant diversity to in silico design immunopeptides for vaccine development.

SURFINs protein family expressed on surface of both infected red blood cell and merozoite surface making them as interesting vaccine candidate for erythrocytic stage of malaria infection. In this study, we analyze genetic variation of Pfsurf4.1 gene, copy number variation, and frequency of SURFIN4.1 variants of P. falciparum in clinical isolates. In addition, secondary structure prediction and immunoinformatic were employed to identify immunogenic epitopes in humoral response as proposed vaccine candidates. Overall, our data demonstrate extensive polymorphism of SURFIN4.1 in both genetic and protein level. The surf4.1 gene showed extensive genetic variation with total of 447 polymorphic sites with maximum of three variants as well as singlet/triplet bases indels and mini/microsatellites in the coding sequence. The exon1 encoding extracellular region exhibited higher variation compared to exon2 which coding for intracellular domain. Interestingly, selective pressure was detected on both extracellular region (Var1 and Var2) as well as intracellular region (WRD2 and WRD3). Importantly, extensive full gene analysis suggests adenosine insertion at three key points nucleotide bases (nt 2409/2410, 3809/3810, and 4439/4440) of exon2 could lead to frameshift mutation resulted in four different SURFIN4.1 variants (TMs, WD1, WD2 and WD3). The SURFIN4.1 variant TMs was the most observed type with 67% frequency (51/76). Along with more than one copy number of surf4.1 gene was observed with frequency of 13% (9/70). Despite substantial polymorphism, analysis of relatedness within P. falciparum population using full coding sequence was able to group SURFIN4.1 protein into five distinct clades and reduced into four clades when using only exon1 coding sequence. Also, predicted secondary structure revealed conserved structure of five helix domains of extracellular region which similar among four SURFIN4.1 variant types. In addition, in silico design eight immunopeptides derived from SURFIN4.1, four of which are highly conserved and four of dimorphic epitopes, as potential vaccine candidates.

Low‐Intensity Focused Ultrasound‐Responsive Nanobubbles Enhance Thrombus Targeting and Penetration for Highly Effective Thrombolytic Therapy

Owing to the short half‐life, restricted targeting capability, and high bleeding risk associated with thrombolytic drugs, safe and effective thrombolytic therapy remains challenging. Based on the natural targeting and immune escape functions of platelets during thrombosis, spatiotemporally controlled nanobubbles (PAF@M) are developed to specifically target thrombus sites. These nanobubbles are designed by loading an air core of perfluoropentane (PFP) and l‐arginine within a poly(lactic‐co‐glycolic acid) shell and coating it with a platelet membrane. Under stimulation with low‐intensity focused ultrasound (LIFU), physical shear stress promotes deep penetration of the nanobubbles into the thrombus. Moreover, the liquid–gas phase transition of PFP and the release of nitric oxide synergistically enhance ultrasonic cavitation to disrupt the thrombus structure. In terms of mechanism, these gas molecules induce acoustic pore action to disrupt the fibrin network structure, loosening the interior of the thrombus, and act specifically on the surfaces of red blood cells and activated platelets, launching a comprehensive attack on the thrombus. It is believed that PAF@M nanobubbles will delay the progression of thrombosis and achieve safe and highly effective thrombolytic therapy. This simple LIFU response principle has the potential to be a safer and more effective alternative to current pharmaceutical approaches.

Genetic analysis of a blood donor with combined FUT1 and ABO dual blood group gene variants resulting in para-Bombay and A2 subtype blood types and a literature review

To investigate the serological and molecular genetic characteristics of a voluntary blood donor with combined FUT1 and ABO blood group gene variants causing para-Bombay and A2 subtype, and to review relevant literature on para-Bombay blood types carrying alleles such as FUT101W.37 and FUT101W.23. A blood donor with para-Bombay and A2 subtype who participated in voluntary blood donation at the Dongguan Blood Center in August 2023 was selected as the study subject. Serological tests were performed to identify the ABO blood group, Lewis blood group antigens, and unexpected serum antibodies in the donor. Adsorption-elution test was conducted to detect trace antibodies in the blood donor's plasma to trace the A, B and H antigens on the red blood cell surface. Sanger sequencing was carried out to analyze the sequences of the FUT1 and ABO genes. Using keywords such as "para-Bombay" "FUT1*01W.37" and "FUT1*01W.23" both in Chinese and English, relevant literature on para-Bombay blood type subjects carrying FUT1*01W.37 and FUT1*01W.23 alleles was retrieved from the CNKI, Wanfang Data Knowledge Service Platform, and PubMed databases, and the retrieval time was set as from the establishment of database to December 2022. This study has been approved by the Ethics Committee of Dongguan Blood Center (No. 2022005), and informed consent of blood donation was obtained from the blood donor. Serological testing of the blood donor revealed inconsistent results between forward and reverse ABO blood typing, negative H antigen on the red blood cell surface, Le(a-b+) secretor type for Lewis blood group, and unexpected anti-H antibodies in the plasma, indicating a suspected para-Bombay type. Absorption-elution test suggested the blood type of the blood donor to be para-Bombay and A subtype. Sanger sequencing showed that the donor has harbored homozygous FUT1*(c.35T+c.803A)/(c.35T+c.803A) variant, with the FUT1*(c.35T+c.803A) allele containing a dual nucleotide variant unrecorded by the International Society of Blood Transfusion (ISBT) FUT1 gene variant database, which was similar to the weakly functional allele of FUT101W. 37(c.803G>A) as recorded by the ISBT database. The ABO genotype was heterozygous ABOA2.05/O.01.02. Combining the results of serological and genetic testing, the blood type of the blood donor was determined to be para-Bombay and A2 subtypes. Literature review has identified a pregnant women from Qingdao carrying the FUT1*01W.37 allele and 2 individuals carrying a heterozygous FUT1*01W.23 allele. This study has discovered a blood donor with coexisting para-Bombay and ABO subtype blood groups. Based on the characteristics of red blood cell surface antigens, the FUT1*01W.37 as classified as an FUT1 null allele.

Prevalence of ABH(O) Blood Group Secretors Among Indigenous Population of Shillong: A Cross-Sectional Study.

Background ABH antigens on the surface of red blood cells form Type A, B, AB, and O blood groups. These antigens are also found in body secretions like serum, gastric juices, ovarian cyst fluid, semen, amniotic fluid, sweat, urine, tears, bile, and saliva (except cerebrospinal fluid). People who have these antigens in their body fluids are called secretors. Purpose This study was conductedto find out the prevalence of salivary secretor status among the adult local indigenous population of Shillong, India. Method Unstimulated saliva was collected and processed from 250 apparently healthy adults, determined its secretor status using the absorption-inhibition method, and then analyzed using the Chi-square test to find its association with age, sex, tribe, and blood groups. Results The study found a prevalence of salivary secretor status of 57.2% (n=143), with a slight female predominance of 57.7% (n=64) over males (56.8%, n=79). The highest percentage was found in individuals aged 71-80 (68.8%, n=16), while the least in people aged 18-30 (48.2%, n=40). Khasi tribes had the highest incidence (64.2%, n=88), followed by Garo (55%, n=22), and least in Jaintia tribes (45.2%, n=33). O-blood group individuals had the highest percentage (71%, n=22), while AB-blood group individuals had the least (46%, n=23). We observed a statistically significantcorrelation of salivary secretor status with the blood group and tribe of the individuals but not with their sex and age. Conclusion Saliva can be found on various items in medicolegal cases like robberies, rapes, and hangings, but blood stains may not always be present. Saliva can be used to determine blood groups, potentially aiding in resolving claims of parentage, immigration, kidnapped children, disputed paternity, or identifying victims in mass disasters. ABO(H) determination from body fluids, especially saliva, has been used in forensic investigations before DNA technology. Currently, this can be an initial screening method because DNA methodology is not often available in laboratories in India.

Ticks and hemoplasma screening in dromedary camels (Camelus dromedarius) from Somalia.

Hemotropic mycoplasmas (hemoplasmas) are small pleomorphic bacteria that parasitize the surface of red blood cells of mammals. Hemoplasmas have been described in different species from the Camelidae Family, such as llamas and alpacas (South American camelids), but data on dromedary camels (Camelus dromedarius) are limited to a few reports. Somalia has one of the world's largest dromedary camel populations, and studies on hemoplasmas and tick-borne pathogens are lacking. Accordingly, this study aimed to screen dromedaries from Somalia for hemoplasmas by PCR-based assays. A total of 155 dromedary camel blood samples from 2 different areas of Mogadishu (n = 104) and the Lower Shabelle Region (n = 51) of the country were collected. All blood DNA samples were screened for hemoplasmas using a SYBR Green Universal Real-Time PCR (qPCR), nested PCR (nPCR), and conventional PCR (cPCR) assays targeting the 16S rRNA gene of hemoplasmas. Five out of 155 animals (3.23%; 95% confidence interval [CI]: 1.39-7.33%) were positive for hemoplasmas. A total of 346 (228 M, 117 F, and 1 nymph) ticks were collected from 79/155 (50.9%; 95% CI: 42.8-59.1%) dromedary camels with a mean of 4.4 ticks per animal. Ticks were identified as Rhipicephalus pulchellus (174/346; 50.3%), Hyalomma dromedarii (103/346; 29.8%), Hyalomma rufipes (35/346; 10.1%), Hyalomma marginatum (16/346; 4.6%), Rhipicephalus humeralis (14/346; 4.0%), Amblyomma lepidum (2/346; 0.6%), Amblyomma gemma (1/346; 0.3%), and Ornithodoros sp. (1/185; 0.5). This is the first study on the molecular screening for hemoplasmas in dromedary camels from Somalia and the first report of A. lepidum and R. humeralis in Somali dromedary camels.

Hydrogen Peroxide increased High Mannose N-glycans on the Red Blood Cell Surface; Mechanistic insights and Functional Implications

Hydrogen Peroxide increased High Mannose N-glycans on the Red Blood Cell Surface; Mechanistic insights and Functional Implications

Red Blood Cell (RBC) Antigen Confirmation Workflow – A Positive Impact at an Academic Medical Center

Abstract Introduction/Objective Introduction: Blood group antigens, present on the surface of red blood cells (RBCs), play a crucial role in transfusion medicine. These antigens are recognized serologically and form the basis of RBC phenotyping. Understanding the significance of antigen-negative RBCs is essential for mitigating the risk of hemolytic transfusion reactions and hemolytic disease of the fetus and newborn (HDFN). This study aims to assess the impact of implementing a new RBC antigen confirmation workflow on transfusion service efficiency and patient outcomes. Methods/Case Report Method: The study involved collaboration between our Transfusion Services Department (TS), the Blood Center supplier, and the Apheresis department. A comprehensive review of historical practices and FDA recommendations regarding RBC antigen labeling was conducted. Changes were implemented to streamline antigen confirmation testing and labeling processes. The impact on TS workload, turnaround time, and patient care metrics was evaluated. Results (if a Case Study enter NA) Results: Implementation of the new RBC antigen confirmation workflow led to a significant reduction in antigen confirmation tests performed by TS, with a 607% decrease observed from 2020 to 2023. Concurrently, the workload for reference lab workups increased by 337% over the same period. This shift in workload distribution allowed TS staff to focus more on patient reference workup cases and case review. The improved workflow efficiency resulted in enhanced turnaround times for providing patients with antigen-negative RBCs, ultimately improving the patient experience. Conclusion Conclusion: The adoption of the new RBC antigen confirmation workflow has resulted in compliance with FDA labeling requirements, efficient utilization of TS staff resources, and decreased turnaround times for blood delivery. These improvements have positively impacted patient care by ensuring timely access to compatible blood products. Future steps include developing reports to track turnaround time for patients with special blood product needs and continuing collaboration with the blood supplier and the Apheresis department to optimize inventory management and transfusion processes.

Genetic and mechanistic evaluation of an individual with para-Bombay phenotype associated with a compound heterozygote comprising two novel FUT1 variants.

As is well documented, the para-Bombay phenotype is typically characterized by the reduction or absence of ABH antigens on red blood cells but the presence of corresponding antigens in saliva. Herein, the underlying molecular mechanism of an individual with para-Bombay AB phenotype combined with two novel variants of the FUT1 gene was investigated. ABH antigens and antibodies were detected in the serum of the proband using conventional serological methods. The coding region nucleotides of the ABO, FUT1, and FUT2 genes were directly sequenced by polymerase chain reaction. Moreover, the FUT1 haploid type in the proband was analyzed by TA clone sequencing. The 3D structure of wild-type and mutant fucosyltransferases were simulated and analyzed using Phyre2 and Pymol software. Lastly, the effect of missense substitution on the function of fucosyltransferase was predicted by the Polymorphism Phenotyping algorithm (PolyPhen-2) and MutationTaster. ABH antigens were noted to be absent on the surface of red blood cells of the proband. The ABO genotype was ABO*A1.02/ABO*B.01, while the FUT2 genotype was FUT2*01/FUT2*c.357T. Interestingly, two novel missense variants (c.289G>A, p.Ala97Thr and c.575G>C, p.Arg192Pro) and one synonymous SNP (c.840G>A) were identified in the FUT1 gene. Furthermore, c.289G>A was detected in one haploid type, whereas c.575G>C and c.840G>A were discovered in another haploid type. Meanwhile, in silico analysis revealed that amino acid substitution caused by missense variants altered the partial spatial structure of the α-helices where residues 97 and 298 were located using 3D homology modeling software. Finally, both missense variants were defined as probably damaging based on PolyPhen-2 prediction. Two novel FUT1 variants were identified in a Chinese individual with para-Bombay AB phenotype, which can expand our understanding of the molecular mechanism underlying the para-Bombay phenotype and contribute to improving the safety of blood transfusion.

A rare case of ABO grouping discrepancy due to probable blood group switching which presented as lost antigens detectable only with indigenous reagents in less sensitive platforms compared to highly sensitive automated platforms using non indigenous reagents

Abstract: Blood group switching in the form of loss or diminished expression of RBC antigens has been reported in malignancies and infections. Blood group antigens are present on the red cell surface. ABO blood group system is the most clinically significant system. Some cases can present as grouping discrepancy. Here we present a rare case of ABO grouping discrepancy due to probable blood group switching which presented as lost antigens detectable only with indigenous reagents in less sensitive platforms compared to highly sensitive automated platforms using non indigenous reagents. 66 year old female whose historic blood group was A Rh D positive with history of uneventful transfusion of 2 units of A Rh D positive packed red cell one and half years back now presented with mycoplasma pneumonia and acute pulmonary edema. On routine complete blood count testing her hemoglobin was 3.6 gm%, request send to blood bank for pretransfusion testing. Testing performed via conventional tube technique and ABO blood group discrepancy was noted with forward grouping turned to be A Rh D positive (positive reaction with anti A1 lectin) and on reverse grouping 3+ reactions was observed in both A and B cell giving a picture of O blood group. Blood grouping was performed in different platforms including fully automated, semi automated and manual using commercially available antisera and human plasma as a source of anti A, anti B antibodies for forward grouping. The antisera used in automated platforms are non indigenous and that for manual are indigenous. Discrepancy was noted (Forward A and Reverse O) in CTT with commercially available antisera and human plasma as reagents for forward grouping .The same discrepancy was noted with CAT in neutral card with commercially available antisera for manual grouping. But when grouping performed with Column Agglutination Technology using matrix grouping gel card the discrepancy was resolved reporting the blood group as O. For further confirmation we repeated the blood grouping in another fully automated platform, SPRCA Technology (Immucore NEOIRIS) and in that also no discrepancy noted giving a picture of O group. This patient probably had undergone a blood group switching from A to O by losing some but not all A epitopes and started anti A antibody production. Some A epitopes which were not lost had been picked up by the commercially available antisera intended for manual grouping. These antisera are indigenous in origin. Also when human plasma was used as source of antibodies the A epitopes which were not lost were detected. But when grouping was done with non-indigenous antisera in both manual and automatic platform the A epitopes were not detected. This case points towards the relevance of incorporating indigenous antisera in automated platforms.

Molecular mechanism of distinct chemokine engagement and functional divergence of the human Duffy antigen receptor

The Duffy antigen receptor is a seven-transmembrane (7TM) protein expressed primarily at the surface of red blood cells and displays strikingly promiscuous binding to multiple inflammatory and homeostatic chemokines. It serves as the basis of the Duffy blood group system in humans and also acts as the primary attachment site for malarial parasite Plasmodium vivax and pore-forming toxins secreted by Staphylococcus aureus. Here, we comprehensively profile transducer coupling of this receptor, discover potential non-canonical signaling pathways, and determine the cryoelectron microscopy (cryo-EM) structure in complex with the chemokine CCL7. The structure reveals a distinct binding mode of chemokines, as reflected by relatively superficial binding and a partially formed orthosteric binding pocket. We also observe a dramatic shortening of TM5 and 6 on the intracellular side, which precludes the formation of the docking site for canonical signal transducers, thereby providing a possible explanation for the distinct pharmacological and functional phenotype of this receptor.

Molecular Diagnosis of Mycoplasma haemofelis and ‘Candidatus Mycoplasma haemominutum’ in Domestic Feline: A Case Report

The aim of this work was to report the molecular diagnosis of Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in a domestic feline. Mycoplasma spp. are pleomorphic bacteria that parasitize the surface of red blood cells in several domestic species, mainly cats, being responsible for feline mycoplasmosis, which can cause hemolytic anemia. Cats can become infected through blood transfusions, social interactions via fights and flea bites. In this report, the patient exhibited in the clinical exam, pale and icteric mucous membranes, and enlargement of the popliteal and submandibular lymph nodes. Based on the symptoms presented, a blood sample was collected to search for hemoparasites using blood smears and also molecular examination by polymerase chain reaction (PCR). The blood smear revealed inclusions characteristic of Mycoplasma spp. Observed in red blood cells, and the diagnosis of mycoplasmosis was confirmed by PCR. This report highlights the importance of screening for hemoparasites in the feline clinical routine, with molecular tests being the most recommended due to their high sensitivity and specificity.

Determination of ABO blood group based on secretors or non-secretors analysis in body fluids

Criminal acts often leave traces analyzed by law enforcement, especially by the Indonesian National Police (POLRI). Sometimes, various items were found and analyzed to link the victim and the perpetrator. Blood, the most abundant body fluid, found in crime scenes, consists of cellular and liquid elements. The forensic focuses on red blood, which can be wet or dried at the crime scene. Sometimes, there was no blood or bloodstains found, but objects related to other body fluids, such as: condoms, toothbrushes, the mouth of glass cups, straws, etc, could be found. Blood group analysis could still be carried out based on secretor gene (Se) considering that 80% of the population was of the secretor group. There are two chromosomes related to blood regulation, namely: chromosomes no. 9 and 19. The former relates to the ABO blood group and the latter relates to the secretory phenotype. The basic principle of secretors was antigens found on the surface of red blood cells and all body fluids, except cerebrospinal fluid. The pattern of inheritance on chromosomes 9 and 19 is based on the probability law by Mendell. It stated that all of genotypes (homozygous dominant-recessive or heterozygous) would be passed on to their offspring.

Effects of Breed on the Morphometric Parameters of Erythrocytes in Horses

Various factors have a distinct impact on the quantity and dimensions of red blood cells across diverse animal species. These factors encompass age, sex, elevation, time of year, and lineage. The present study aimed to evaluate the influence of breed on the morphometric parameters of red blood cells in horses. To examine the impact of various horse breeds on the diameter, circumference, and surface area of red blood cells, blood samples were obtained from a total of 90 healthy horses. These horses belonged to three different breeds, including Arab Thoroughbred, English Thoroughbred, and Barbe. Each breed consisted of 30 individuals, with an equal distribution of males and females. The collected blood specimens were then divided into two separate batches for further analysis. The age range of all horses included in the study was between 5 and 12 years old. Smears were made and stained using the May-Grünwald Giemsa technique. The morphometric measurements were performed while using the OPTIKATM Vision Pro special software. The obtained results showed that there were no significant differences in the red blood cell diameters across different horse breeds. However, this factor appears to influence significantly both the circumference and surface area of erythrocytes. Specifically, the circumference and surface of Barbe red blood cells were highly smaller than both Arabian and English purebred horses. The present study demonstrated that the circumference and surface of red blood cells appear to be more indicative and representative in detecting variations in the erythrocyte morphometry between different horse breeds.

Characterization of Blood Group Variants in an Omani Population by Comparison of Whole Genome Sequencing and Serology.

Although blood group variation was first described over a century ago, our understanding of the genetic variation affecting antigenic expression on the red blood cell surface in many populations is lacking. This deficit limits the ability to accurately type patients, especially as serological testing is not available for all described blood groups, and targeted genotyping panels may lack rare or population-specific variants. Here, we perform serological assays across 24 antigens and whole genome sequencing on 100 Omanis, a population underrepresented in genomic databases. We inferred blood group phenotypes using the most commonly typed genetic variants. The comparison of serological to inferred phenotypes resulted in an average concordance of 96.9%. Among the 22 discordances, we identify seven known variants in four blood groups that, to our knowledge, have not been previously reported in Omanis. Incorporating these variants for phenotype inference, concordance increases to 98.8%. Additionally, we describe five candidate variants in the Lewis, Lutheran, MNS, and P1 blood groups that may affect antigenic expression, although further functional confirmation is required. Notably, we identify several blood group alleles most common in African populations, likely introduced to Oman by gene flow over the last thousand years. These findings highlight the need to evaluate individual populations and their population history when considering variants to include in genotype panels for blood group typing. This research will inform future work in blood banks and transfusion services.

Insight Into Aetiology and Severity of Hemolysis Associated with Immunoproteins on Red Cell Surface in Direct Antiglobulin Test Positive Auto-immune Hemolytic Anemia

Insight Into Aetiology and Severity of Hemolysis Associated with Immunoproteins on Red Cell Surface in Direct Antiglobulin Test Positive Auto-immune Hemolytic Anemia

Investigating the Relationship between Electrolyte Levels and ABO Blood Groups: Prospects for Customized Medicine

Human ABO blood type antigens exhibit alternative phenotypes and genetically derived glycoconjugate structures that are located on the red cell surface which play an active role in the cells' physiology and pathology. This study was carried out to evaluate the electrolytes, urea and creatinine of individuals with different ABO blood groups in Ekpoma. A total of one hundred (100) samples were used in this study. Electrolytes was estimated using ion selective electrode, urea was estimated using Berthelot method, while creatinine was estimated using Jaffe’s method. The results were presented in tables as mean ± standard deviation. Statistical analysis was done using one-way analysis of variance (ANOVA) and the student’s t-test. Significant difference was accepted at p<0.05. The results obtained showed that Sodium (Na) (mmol/L) was significantly higher (p<0.05) in subjects with blood group O (136.72±1.22) and blood group A (136.00±1.36) when compared with blood group B (134.56±2.56). Potassium (K) (mmol/L) was non-significantly higher (p>0.05) in blood group A (3.62±0.29), followed by blood group O (3.59±0.18) and least in blood group B (3.51±0.22). Bicarbonate (HCO3) (mmol/L) was non-significantly higher (p>0.05) in blood group A (21.17±1.76), followed by blood group O (20.67±1.09) and least in blood group B (20.52±0.91). Chloride (Cl) (mmol/L) was non-significantly higher in blood group O (103.20±1.81) followed by blood group A (102.10±2.35) and least in blood group B (101.60±3.58). Furthermore, Urea (mg/dl) was non-significantly higher (p>0.05) in blood group O (23.20±4.57), followed by blood group A (21.48±4.15) and least in blood group B (20.76±5.15). Similarly, Creatinine (mg/dl) was non-significantly higher in blood group O (0.65±0.15), followed by blood group A (0.63±0.12) and least in blood group B (0.62±0.15). In conclusion, electrolytes, urea and creatinine were higher in blood group A and O compared with blood group B. With respect to gender, Na, HCO3, Cl, Urea and Creatinine were significantly higher in male subjects compared with female subjects. There was no significant difference in electrolytes, urea and creatinine of the subjects with respect to age (p>0.05). Further studies should be carried out to understand the mechanism behind increase in electrolytes, urea and creatinine in certain blood group compared with others.

Plasmodium vivax spleen-dependent protein 1 and its role in extracellular vesicles-mediated intrasplenic infections.

Recent studies indicate that human spleen contains over 95% of the total parasite biomass during chronic asymptomatic infections caused by Plasmodium vivax. Previous studies have demonstrated that extracellular vesicles (EVs) secreted from infected reticulocytes facilitate binding to human spleen fibroblasts (hSFs) and identified parasite genes whose expression was dependent on an intact spleen. Here, we characterize the P. vivax spleen-dependent hypothetical gene (PVX_114580). Using CRISPR/Cas9, PVX_114580 was integrated into P. falciparum 3D7 genome and expressed during asexual stages. Immunofluorescence analysis demonstrated that the protein, which we named P. vivax Spleen-Dependent Protein 1 (PvSDP1), was located at the surface of infected red blood cells in the transgenic line and this localization was later confirmed in natural infections. Plasma-derived EVs from P. vivax-infected individuals (PvEVs) significantly increased cytoadherence of 3D7_PvSDP1 transgenic line to hSFs and this binding was inhibited by anti-PvSDP1 antibodies. Single-cell RNAseq of PvEVs-treated hSFs revealed increased expression of adhesion-related genes. These findings demonstrate the importance of parasite spleen-dependent genes and EVs from natural infections in the formation of intrasplenic niches in P. vivax, a major challenge for malaria elimination.

RHD Genotyping to Resolve Weak and Discrepant RHD Phenotypes: The “Serenissima” Experience

Background: A considerable number of RHD alleles responsible for weak and partial D phenotypes have been identified. Serological determination of these phenotypes is often doubtful and makes genetic analysis of RHD gene highly desirable in transfusion recipients and pregnant women. Aim: We report the experience of Mestre Blood Bank in analysis of the RHD gene in six years from 2018 to 2023. Methods: Subjects for RHD gene analysis were selected for presence of a serological weak D phenotype, defined as reactivity of RBCs with an anti-D reagent giving no or weak (≤2+) score in initial testing but agglutinating moderately or strongly with anti human globulin (AHG). These samples were selected for genotyping using the microarray-based method Bead-Chip supplied by Werfen. Results: From 2018 to 2023, we selected, for RHD gene analysis, 555 subject with D weak phenotype; 86 subjects (15.5%) were D positive and 56 (10.1%) were D negative, without variant, in 413 subjects a D weak or a D variant was observed. Discussion: Many serological weak D phenotypes are associated to RHD gene mutations leading to one or more amino acids substitutions in the RhD protein predicted to be within or below the RBC membrane, causing decreased antigen expression on the red cell surface. Prevalence of serological weak D phenotypes varies by race and ethnicity. Serological weak D phenotypes are the most common D variants detected in Caucasians (0.2%-1.0%). The majority, as in our series, are associated with weak D type 1, 2 or 3. Our data confirmed a high prevalence of weak D type 1 and type 2, but we observed a high prevalence of type 11 and 15 and of the uncommon type 18 too. The most common partial D phenotypes in Europe are DNB, DVI, and DVII. Our data confirmed a high prevalence of D partial type VI. Studies indicate that D partial transfusion recipients are at risk of forming alloanti-D when exposed to conventional RhD-positive blood units.