How anti-c in a D- patient prompted lifesaving work between a transfusion service and a blood center reference laboratory.

This case report showcases an extraordinary collaboration to support the transfusion needs of a patient with a rare phenotype and long-standing anemia due to gastrointestinal bleeding. This report describes the Immunohematology Reference Laboratory testing and logistics of rare blood provision over an 11-year period, as well as a summary of the hematologic, gastroenterologic, and surgical interventions. This case illustrates how a strong collaboration among the clinical team, laboratory, blood center, and the rare donor community facilitated successful management of this patient's anemia until the patient could receive life-changing treatment.

Increased Intrauterine Transfusion Blood Volume Needed to Correct Fetal Anemia due to Placental Chorioangioma.

INTRODUCTION: To compare the blood volume transfused for fetal anemia in cases of placental chorioangioma versus red blood cell (RBC) alloimmunization in patients matched for gestational age (GA) and hydrops. METHODS: Study patients had intrauterine transfusions and were obtained from 3 sources: group (1) placental chorioangioma patients treated at our center (2016-2023); group (2) placental chorioangioma patients reported in the medical literature; and group (3) RBC alloimmunization patients treated for fetal anemia at our center (2016-2023) matched (2:1) to patients in groups 1 and 2 by GA at procedure and presence of hydrops. The expected volume (cc) of transfusion was calculated for all patients based on a formula commonly used for fetal anemia in cases of RBC alloimmunization that includes the GA at procedure, pre-transfusion hemoglobin, donor hemoglobin, and target hemoglobin. The ratio of the volume actually transfused to the expected volume was calculated for each group and for groups 1 and 2 combined; comparisons were made using nonparametric testing. RESULTS: By group, the patients studied included: (1) 7 treated chorioangioma patients, (2) 8 chorioangioma patients described in the literature, and (3) 30 matched RBC alloimmunization patients. The median (range) GA at procedure for groups 1, 2, and 3 was 29.6 (22.7-32.7), 27.0 (24.0-30.0), 28.4 (22.7-34.3) weeks. The median pre-procedure hemoglobin for each group was 8.5 (5.8-12.5), 6.7 (5.6-12.0), and 5.3 (2.2-10.7) g/dL, and the median post-procedure hemoglobin for each group was 12.9 (11.5-14.0), 12.7 (9.6-14.7), and 13.6 (8.0-15.7) g/dL. The median (range) ratio of the actual to the expected volume transfused for each group was 2.50 (1.79-8.33), 1.64 (1.11-3.85), and 1.10 (0.69-1.86) (p < 0.001). When groups 1 and 2 were combined, the median ratio was 1.89 (1.11-8.33), which remained statistically significant when compared to group 3 (p < 0.001). CONCLUSION: Intrauterine transfusion for fetal anemia in cases of large placental chorioangiomas appeared to require nearly twice the blood volume that was normally anticipated for cases of RBC alloimmunization, although the actual amount transfused varied widely.

Class switching is differentially regulated in RBC alloimmunization and vaccination.

BACKGROUND: Studies of human patients have shown that most anti-RBC alloantibodies are IgG1 or IgG3 subclasses, although it is unclear why transfused RBCs preferentially drive these subclasses over others. Though mouse models allow for the mechanistic exploration of class-switching, previous studies of RBC alloimmunization in mice have focused more on the total IgG response than the relative distribution, abundance, or mechanism of IgG subclass generation. Given this major gap, we compared the IgG subclass distribution generated in response to transfused RBCs relative to protein in alum vaccination, and determined the role of STAT6 in their generation. STUDY DESIGN AND METHODS: WT mice were either immunized with Alum/HEL-OVA or transfused with HOD RBCs and levels of anti-HEL IgG subtypes were measured using end-point dilution ELISAs. To study the role of STAT6 in IgG class-switching, we first generated and validated novel STAT6 KO mice using CRISPR/cas9 gene editing. STAT6 KO mice were then transfused with HOD RBCs or immunized with Alum/HEL-OVA, and IgG subclasses were quantified by ELISA. RESULTS: When compared with antibody responses to Alum/HEL-OVA, transfusion of HOD RBCs induced lower levels of IgG1, IgG2b, and IgG2c but similar levels of IgG3. Class switching to most IgG subtypes remained largely unaffected in STAT6 deficient mice in response to HOD RBC transfusion, with the one exception being IgG2b. In contrast, STAT6 deficient mice showed altered levels of all IgG subtypes following Alum vaccination. DISCUSSION: Our results show that anti-RBC class-switching occurs via alternate mechanisms when compared with the well-studied immunogen alum vaccination.

The transfusion of non-prophylactically RH-KEL1 antigen-matched red blood cells is feasible in selected myelodysplastic syndrome and acute myeloid leukaemia patients.

BACKGROUND AND OBJECTIVES: Most myelodysplastic syndromes (MDS) patients become red blood cell (RBC) transfusion-dependent. Transfusing MDS patients with prophylactically RH-KEL1 antigen-matched (PAM) RBC units is recommended to avoid RBC allo-immunization. D+C-E-c+e+, D+C-E+c+e- and D+C+E-c-e+ phenotypes are infrequent among French blood donors. To preserve infrequent phenotype RBC units for patients other than MDS, and to manage frequent phenotype RBC unit stocks, we let, for 1 year, higher-risk non-immunized chronically transfused MDS and acute myeloid leukaemia (AML) patients receive RBC transfusions matched only for D. Our objectives were to evaluate the impact of non-PAM transfusions on the transfusion policy (which would be modified in case of RBC allo-immunization) for frequent and infrequent phenotypes patients and to estimate the number of infrequent phenotypes RBC units that could be redistributed to other patients. RESULTS: Ninety patients were enrolled. Thirty-five patients had infrequent phenotypes, nine received only PAM RBC (143 units) and 26 PAM and non-PAM RBC (415 and 532, respectively): none developed allo-immunization. Fifty-five patients had frequent RBC phenotypes, 34 received only PAM RBC (561 units) and three developed antibodies (2 non-RH-KEL1 and one anti-E); 21 received PAM and non-PAM RBC (436 and 109, respectively) and one developed allo-immunization (unknown specificity). Our strategy enabled us to preserve 532 infrequent phenotypes RBC units: 216 D+C-E-c+e+, 33 D+C-E+c+e- and 283 D+C+E-c-e+ units, representing 48.8% of the total number of RBC units received by infrequent phenotypes patients during the study period. CONCLUSION: Allowing the transfusion of non-PAM RBC in selected chronically transfused MDS and AML patients was feasible and enabled to redistribute infrequent phenotypes RBC units to other patients in need.

The lysophospholipid-binding molecule CD1D is not required for the alloimmunization response to fresh or stored RBCs in mice despite RBC storage driving alterations in lysophospholipids.

BACKGROUND: Despite the significant adverse clinical consequences of RBC alloimmunization, our understanding of the signals that induce immune responses to transfused RBCs remains incomplete. Though RBC storage has been shown to enhance alloimmunization in the hen egg lysozyme, ovalbumin, and human Duffy (HOD) RBC alloantigen mouse model, the molecular signals leading to immune activation in this system remain unclear. Given that the nonclassical major histocompatibility complex (MHC) Class I molecule CD1D can bind to multiple different lysophospholipids and direct immune activation, we hypothesized that storage of RBCs increases lysophospholipids known to bind CD1D, and further that recipient CD1D recognition of these altered lipids mediates storage-induced alloimmunization responses. STUDY DESIGN AND METHODS: We used a mass spectrometry-based approach to analyze the changes in lysophospholipids that are induced during storage of mouse RBCs. CD1D knockout (CD1D-KO) and wild-type (WT) control mice were transfused with stored HOD RBCs to measure the impact of CD1D deficiency on RBC alloimmunization. RESULTS: RBC storage results in alterations in multiple lysophospholipid species known to bind to CD1D and activate the immune system. Prior to transfusion, CD1D-deficient mice had lower baseline levels of polyclonal immunoglobulin (IgG) relative to WT mice. In response to stored RBC transfusion, CD1D-deficient mice generated similar levels of anti-HOD IgM and anti-HOD IgG. CONCLUSION: Although storage of RBCs leads to alteration of several lysophospholipids known to be capable of binding CD1D, storage-induced RBC alloimmunization responses are not impacted by recipient CD1D deficiency.

Association between renal failure and red blood cell alloimmunization among newly transfused patients.

BACKGROUND: Renal failure and renal replacement therapy (RRT) affect the immune system and could therefore modulate red blood cell (RBC) alloimmunization after transfusion. STUDY DESIGN AND METHODS: We performed a nationwide multicenter case-control study within a source population of newly transfused patients between 2005 and 2015. Using conditional multivariate logistic regression, we compared first-time transfusion-induced RBC alloantibody formers (N = 505) with two nonalloimmunized recipients with similar transfusion burden (N = 1010). RESULTS: Renal failure was observed in 17% of the control and 13% of the case patients. A total of 41% of the control patients and 34% of case patients underwent acute RRT. Renal failure without RRT was associated with lower alloimmunization risks after blood transfusion (moderate renal failure: adjusted relative rate [RR], 0.82 [95% confidence interval (CI), 0.67-1.01]); severe renal failure, adjusted RR, 0.76 [95% CI, 0.55-1.05]). With severe renal failure patients mainly receiving RRT, the lowest alloimmunization risk was found in particularly these patients [adjusted RR 0.48 (95% CI 0.39-0.58)]. This was similar for patients receiving RRT for acute or chronic renal failure (adjusted RR, 0.59 [95% CI, 0.46-0.75]); and adjusted RR, 0.62 [95% CI 0.45-0.88], respectively). CONCLUSION: These findings are indicative of a weakened humoral response in acute as well as chronic renal failure, which appeared to be most pronounced when treated with RRT. Future research should focus on how renal failure and RRT mechanistically modulate RBC alloimmunization.

Characterization of circulating and cultured Tfh-like cells in sickle cell disease in relation to red blood cell alloimmunization status.

BACKGROUND: People living with sickle cell disease (SCD) are prone to red blood cell (RBC) alloimmunization. We hypothesized that subjects with alloantibodies (responders) would have differences in circulating T-follicular helper (Tfh)-like cells compared to subjects without alloantibodies (non-responders). MATERIALS AND METHODS: Peripheral blood mononuclear cells were collected from 28 subjects, including those with SCD and controls. Circulating CD4 T-cell subsets were first evaluated at baseline. CD4 T-cell subsets were also evaluated after naïve CD4 T-cells were differentiated into Tfh-like cells following in vitro culture with CD3/CD28 beads, IL-7, IL-12, and Activin A. Transfusion and alloantibody histories were extracted from the electronic medical record. RESULTS: Non-responders had a lower percentage of CD45RA negative Tmemory cells than responders or controls (p<0.05). Notably, there were no differences in circulating Tfh-like cells between any group. However, naïve CD4 T-cells from subjects with SCD were more likely to express CXCR5 after in vitro culture than cells from controls. After culture, CXCR5 expressing cells from responders were more likely to express PD1 and ICOS (16.43 %, sd. 20.23) compared to non-responders (3.69 %, s.d. 3.09) or controls (2.78 %, s.d. 2.04). DISCUSSION: The tendency for naïve CD4 T-cells from responders to differentiate into Tfh-like cells after in vitro culture may suggest these cells are prepared to assist B-cells with antibody production regardless of antigen specificity. Further studies are needed, but it is possible that these results may explain why some responders form RBC alloantibodies with multiple specificities, in addition to RBC autoantibodies and HLA alloantibodies.

Immunological principle of development of red blood cell alloimmunization in pregnancy, hemolytic disease of the fetus and prevention of RhD alloimmunization in RhD negative women.

DESIGN: Review article. SETTING: Department of Obstetrics and Gynecology, Palacky University Olomouc, Faculty of Medicine and Dentistry, University Hospital Olomouc. Methods, results: Every person exposed to a foreign red blood cell antigen (erythrocyte antigen) develops an antibody. If the contact with a foreign erythrocyte antigen occurs during pregnancy, the erythrocyte alloimmunization of the pregnant woman develops and, due to antibodies crossing through the placenta also Haemolytic disease of the foetus and newborn (HDFN) can occur. Antibodies are made by pregnant woman's immune system and their quantity and quality depend on many factors. Their function is to eliminate foetal "foreign" erythrocytes. Ways of elimination of antibody-labelled foetal erythrocytes are the same in the bloodstream of pregnant women and foetuses/newborns and their principle is type II hypersensitivity (cytotoxic), according to the Coombs and Gell classification. Severe forms of HDFN can lead to increased perinatal morbidity and mortality. Prevention of the development of RhD alloimmunization and severe forms of HDFN is based on the administration of polyclonal immunoglobulin (Ig) G anti-D in all potentially sensitizing events. It is assumed that the mechanism of anti-D IgG action is based on the rapid removal of the antigen by antibody overflow, and on antibody mediated immune suppression (AMIS). However, the exact immunological principle is not fully known yet. CONCLUSION: This article describes the development of irregular antibodies, methods of foetal erythrocytes destruction and the mechanism of prevention of anti-D immunoglobulin from the immunological point of view.

How shall we transfuse Hippolyta?

The US Department of Defense recently made the decision to open direct ground combat roles to women. Blood product transfusion is an essential component of the US Military guidelines for tactical combat casualty care and damage control resuscitation, but blood transfusion carries with it the specific side effect of alloimmunization-a uniquely significant side effect for young women who may desire subsequent pregnancies. Presently to be considered are the changes that may need to be made to blood transfusion in the setting of battlefield medicine to optimally care for combat-injured women, as a majority of the existing data regarding the risks of transfusion in the trauma setting involve predominantly men. This article delves into the possibility of a new cohort of women at risk for hemolytic disease of the fetus and newborn, the need for women's health professionals to appropriately counsel women considering serving in direct ground combat roles about this specific risk, and the appropriate steps that should be considered to provide these women optimal medical care.

Prevalence and risk factors for red blood cell alloimmunization in 175 children with sickle cell disease in a French university hospital reference centre.

Patients with sickle cell disease (SCD) show a high prevalence of red blood cell (RBC) alloimmunization, but few studies have focused on children. We aimed to study the prevalence and risk factors of RBC alloimmunization in SCD children. We retrospectively analysed the medical and transfusion files for 245 SCD children hospitalized in our centre in 2014 and included 175 patients who had received at least one RBC unit in their lifetime. The main clinical and immuno-haematological characteristics of alloimmunized and non-alloimmunized patients were compared. The prevalence of alloimmunization was 13·7% [95% confidence interval (CI) (8·6-18·6)], and 7·4% [95% CI (3·5-11·3)] after excluding the probable irregular natural antibodies (anti-M, anti-Lea , anti-Leb , anti-Lex ). Main risk factors for alloimmunization were increased number of RBC units received (median of 65 vs. 10 units per patient; P = 0·01) and the presence of one or more red cell autoantibodies (46·2% vs. 4·7%; P < 0·0001). The alloimmunization rate was higher for episodically transfused than chronically transfused patients (1·43 vs. 0·24/100 units received; P < 0·001). The presence of red cell autoantibodies appears to be a major risk factor for alloimmunization in SCD children and could justify specific transfusion guidelines.

Red blood cell alloimmunization is influenced by recipient inflammatory state at time of transfusion in patients with sickle cell disease.

Sickle cell disease (SCD) patients are at increased risk of red blood cell (RBC) alloimmunization. Recipient inflammatory state at time of transfusion has been shown to regulate alloimmunization in murine models, but evidence is lacking in SCD patients. We retrospectively studied a cohort of alloimmunized SCD patients to determine the influence of pro-inflammatory SCD-related complications at time of transfusion on alloimmunization. For each transfusion, the presence of pro-inflammatory state, degree of RBC antigen matching, unit age, storage solution and alloantibody detection date were ascertained. Transfusion-associated pro-inflammatory events were compared between transfusions resulting and not resulting in new alloantibodies. Univariate analysis and multivariate logistic regression were performed. Fifty-two patients received 3166 pre-storage leuco-reduced transfusions of which 128 resulted in alloantibodies. Transfusions during inflammatory events were associated with increased alloantibody risk on univariate and multivariate analysis; acute chest syndrome and vaso-occlusive crisis showed strongest associations with alloimmunization. Increased antigen matching demonstrated a protective effect on alloimmunization (univariate and multivariate analysis). Although an association was seen between citrate-phosphate-dextrose (adenine) stored units and alloimmunization on univariate analysis, no effect was found on multivariate analysis. Identifying recipient pro-inflammatory states at time of transfusion that promote alloimmunization can impact RBC unit selection decisions for SCD patients at risk for alloimmunization.

Effect of delayed cord clamping on red blood cell alloimmunization: a retrospective cohort study.

BACKGROUND: Although delayed cord clamping has well-known benefits for preterm and term neonates, it has been inadequately assessed in alloimmunized neonates. OBJECTIVE: This study aimed to evaluate the benefits and risks of delayed cord clamping in alloimmunized neonates. STUDY DESIGN: This was a retrospective comparative pre-post cohort study conducted from 2003 to 2018 in a tertiary care center in France. All living singleton neonates whose mothers were followed up for red blood cell alloimmunization during gestation and confirmed at birth (N=224) were included. Neonates were either exposed to immediate (n=125) or delayed cord clamping (n=99). Our main outcome was the time from birth to first exchange transfusions and/or transfusions. Secondary outcomes were hemoglobin level at birth, rate of exchange transfusion, number of postnatal transfusions, maximum bilirubin level, and number of phototherapy hours. RESULTS: Hemoglobin at birth was significantly higher in case of delayed cord clamping (mean difference, 1.7 g/dL; 95% confidence interval, 0.7-2.8). Among infants treated with exchange transfusion or transfusion, the time to initial treatment was higher in case of delayed cord clamping (median difference, 8 days; rate ratio, 1.51; 95% confidence interval, 1.09-2.10). There were no significant differences in the need for exchange transfusion, the number of transfusions, the maximum total bilirubin level, nor the number of phototherapy hours. In the subgroup analysis of neonates needing intrauterine transfusion during pregnancy (ie, severe alloimmunization), neonates had a lower rate of exchange transfusion in case of delayed cord clamping (odds ratio, 0.36; 95% confidence interval, 0.15-0.82). CONCLUSION: Our results indicate a benefit of delayed cord clamping in alloimmunization, regardless of pathology severity, without increased risk of jaundice.

Red Blood Cell Alloimmunization in Pediatric group with Beta Thalassemia: A Five-Year Experience.

Beta-thalassemia is one of the most frequently occurring hematological disorders in [Removed for blinded peer-review]. Regular blood transfusion is required in almost all cases for management. However, this is associated with significant major complications like red blood cell (RBC) alloimmunization. This retrospective cross-sectional is conducted to evaluate the RBC alloimmunization frequency in children with beta-thalassemia aged between 6 months and 16 years in [Removed for blinded peer-review]. Antibody screening was performed using the Dia clon3 cell antigen panel. If the screening came back positive, a detailed panel was created for the identification of specific antibody. In our sample, the frequency of RBC alloimmunization was found in 22 (26.19%) patients. Of these 22 patients, the Rhesus system was found in most patients 17 (77.3%), followed by Kell 5 (22.7%). RBC alloimmunization was significantly associated with a family history of a blood disorder and splenectomy.

Maternal bleeding complications in pregnancies affected by red blood cell alloimmunization.

OBJECTIVE: To investigate whether women with red blood cell (RBC)1 alloimmunization are more likely to experience bleeding complications during pregnancy or delivery than women without RBC alloimmunization. STUDY DESIGN: Retrospective study involving all singleton pregnancies affected by RBC alloimmunization and without pre-existing maternal bleeding disorders or placenta previa, from 1 July 1999 to 30 June 2019 ("cases"). Only bleedings not related to invasive procedures (amnio- or cordocenteses) were included. Patients who were already at increased risk of pre- or perinatal bleeding due to their medical history (pre-existing bleeding disorders, antithrombotic therapy), or known obstetrics parameters (placental abnormalities etc.) were not included a priori. Cases were compared to controls without RBC alloimmunization, matched for maternal age and body mass index, from the same tertiary referral center in Austria. RESULTS: 130 cases were compared to 130 controls. Cases had significantly more previous pregnancies and miscarriages and their newborns had lower birthweight and were more often transferred to the intensive care unit than newborns of controls. 18/130 (13.8%) cases, compared to 8/130 (6.2%) controls experienced any bleeding during pregnancy or delivery (p = 0.061). Bleeding most often happened during the third trimester (cases: 4.6% vs. controls 0.8%, p = 0.12) and during or after delivery (cases: 7.7% vs. controls: 4.6%, p = 0.168). Binary logistic regression for the prediction of any bleeding complication during pregnancy, delivery or postpartum revealed immunization against RBC antigens as the only independent contributor (p = 0.04). Age, smoking, or previous obstetric history had no influence on the likelihood of maternal bleeding complications. Neither RBC antibody specificity nor titers were predictive of maternal bleeding during pregnancy or delivery. CONCLUSION: Pregnancies affected by RBC alloimmunization might be at increased risk of maternal bleeding complications during pregnancy and delivery.

[Red blood cell alloimmunization among polytransfused patients in the National Hospital and University Center of Cotonou: about 51 cases]. / Allo-immunisation anti-érythrocytaire chez les polytransfusés au Centre National Hospitalier Universitaire de Cotonou: à propos de 51 cas.

Blood transfusion is a medical procedure used to treat patients with labile blood product. Each transfusion of globular concentrate exposes recipients to the risk of red blood cell alloimmunization. The test for red cell antibodies (RCA) ensures the immunohaematological safety of transfused patients. In Benin, this test is not performed in a systematic way or included either in the pre-transfusion or in the post-transfusion tests. The purpose of this study is to determine the presence of red cell antibodies among polytransfused patients. RCA was performed using indirect antiglobulin test on gel-filtration in 51 polytransfused patients including 26 selected in the Department of Hematology and 25 in the Department of Nephrology at the National Hospital and University Center of Cotonou. After phenotyping alloimmunized patients, tests for detecting signs of hemolysis were performed. Clinical data as well as those on transfusion were collected from transfusion registries and medical records. The prevalence of alloimmunization in our study population was 13.73%. The antibodies identified had the following characteristics: association of anti-RH1 and anti-RH3, anti LE1, association of anti-RH3 and anti-FY1. Alloantibodies were more frequent in patients who had received more than 15 packed red blood cells. Laboratory tests showed signs of hemolysis in one alloimmunized patient. There was no correlation between age, sex, clinical diagnosis and the occurrence of red blood cell alloimmunization. The test for red cell antibodies should be systematically performed in polytransfused patients in order to ensure better transfusion recipient safety in Benin.

Two Reliable Methodical Approaches for Non-Invasive RHD Genotyping of a Fetus from Maternal Plasma.

Noninvasive fetal RHD genotyping is an important tool for predicting RhD incompatibility between a pregnant woman and a fetus. This study aimed to assess a methodological approach other than the commonly used one for noninvasive fetal RHD genotyping on a representative set of RhD-negative pregnant women. The methodology must be accurate, reliable, and broadly available for implementation into routine clinical practice. A total of 337 RhD-negative pregnant women from the Czech Republic region were tested in this study. The fetal RHD genotype was assessed using two methods: real-time PCR and endpoint quantitative fluorescent (QF) PCR. We used exon-7-specific primers from the RHD gene, along with internal controls. Plasma samples were analyzed and measured in four/two parallel reactions to determine the accuracy of the RHD genotyping. The RHD genotype was verified using DNA analysis from a newborn buccal swab. Both methods showed an excellent ability to predict the RHD genotype. Real-time PCR achieved its greatest accuracy of 98.6% (97.1% sensitivity and 100% specificity (95% CI)) if all four PCRs were positive/negative. The QF PCR method also achieved its greatest accuracy of 99.4% (100% sensitivity and 98.6% specificity (95% CI)) if all the measurements were positive/negative. Both real-time PCR and QF PCR were reliable methods for precisely assessing the fetal RHD allele from the plasma of RhD-negative pregnant women.

Analysis of red blood cell alloimmunization among inpatients: 104 588 cases / 中国输血杂志

【Objective】 To analyze the yield, specificity and detection time of red blood cell(RBC)alloimmunization in 104 588 inpatients. 【Methods】 The clinical information of patients who underwent at least one antibody screening in our hospital from November 2017 to December 2019 was retrospectively analyzed. The demographic characteristics, transfusion history, pregnancy history and antibody screening results of patients were collected. The RBC alloantibody yield, specificity and detection time were analyzed, and differences of transfusion units and frequency between patients with and without alloimmunization were compared. 【Results】 Eight hundred cases of alloantibodies with clinical significance were detected in blood samples of 723 patients, with a positive rate of 0.7% (723/104 588). The incidence rate of alloimmunization in females was higher than that in males (0.9% vs 0.5%, P<0.05). Rh alloantibodies accounted for 76.4%(611/800), of which 61.4%(375/611)were anti-E. Transfusion units and frequency of patients with alloimmunity were higher than those without(median: 6.0 vs 4.0, P<0.05; 4.0 vs 2.0, P<0.05, respectively). And 67.5% of RBC alloantibodies were detected within 6 months, with the median (IQR) detection time of 97.0 (22.5-247.0) days. 【Conclusion】 Routine antibody screening should be performed before transfusion in order to reduce the occurrence of adverse reactions, and Rh typing transfusion with compatible crossmatch should be performed if necessary.

Red blood cell alloimmunization in multi-transfused patients with chronic kidney disease in Port Harcourt, South-South Nigeria.

BACKGROUND: Serological safety is an integral part of overall safety for blood banks. OBJECTIVES: The aim of the study was to determine the prevalence and specificities of red blood cell alloimmunization in multi-transfused patients with chronic kidney disease (CKD). METHODS: A cross-sectional case-control study carried out at the University of Port Harcourt Teaching Hospital in which 186 patients with CKD were enrolled consecutively, 124 had received multiple transfusions (more than one unit of blood in one month, or at least 10 units within 3 months), while 62 had never been transfused. Antibody screen test was performed by the gel agglutination technique. RBC antibody identification was performed on the sera of those that tested positive to antibody screening test. RESULTS: Out of the 124 multi-transfused patients (total of 789 transfusions), 4 (3.2%) were alloimmunised. The alloimmunised patients received a higher mean number of 17.5 ± 12 blood units, compared to 6 ± 6 units by the non-alloimmunised multi-transfused patient (p= <0.001). Six clinically significant alloantibodies were identified with all of the alloimmunised patients forming more than one antibody. Anti-E was detected in all alloimmunised patients. CONCLUSION: The prevalence of RBC alloimmunisation in multi-transfused CKD patients was 3.2% with anti-E being the most frequently identified antibody.

Differential Intrasplenic Migration of Dendritic Cell Subsets Tailors Adaptive Immunity.

Evidence suggests that distinct splenic dendritic cell (DC) subsets activate either CD4+ or CD8+ T cells in vivo. This bias has been partially ascribed to differential antigen presentation; however, all DC subsets can activate both T cell lineages in vitro. Therefore, we tested whether the organization of DC and T cell subsets in the spleen dictated this preference. We discovered that CD4+ and CD8+ T cells segregated within splenic T cell zones prior to immunization. After intravenous immunization, the two major conventional DC populations, distinguished by 33D1 and XCR1 staining, migrated into separate regions of the T cell zone: 33D1+ DCs migrated into the CD4+ T cell area, whereas XCR1+ DCs migrated into the CD8+ T cell area. Thus, the post-immunization location of each DC subset correlated with the T cell lineage it preferentially primes. Preventing this co-localization selectively impaired either CD4+ or CD8+ T cell immunity to blood-borne antigens.