Review of haemovigilance at the Rabat Regional Blood Transfusion Centre in Morocco (2017-2021).

Introduction: blood transfusion remains an essential therapeutic intervention, but the occurrence of transfusion reactions makes its administration even more complex. Vigilant reporting of such reactions by recipients of blood products is essential for effective haemovigilance. This study aimed to determine the frequency and nature of transfusion reactions. Methods: conducted over five years (2017-2021) at the Haemovigilance Department of the Rabat Regional Blood Transfusion Centre, this retrospective study exploited incident forms notified by health establishments and data from the regional blood transfusion centre's computer system. Results: from 1 January 2017 and 31 December 2021, the Rabat Regional Blood Transfusion Centre distributed 435,651 labile blood products to various healthcare establishments, which reported 191 transfusion reactions involving 191 patients. The median age of the patients was 44.3 years, with an overall cumulative incidence of transfusion reactions of 0.44 per 1000 labile blood products delivered. The predominant reactions were non-haemolytic febrile and allergic reactions, accounting for 41.36% and 35.60% respectively. Grade 1 reactions accounted for 87% of all reactions recorded. During the study period, three deaths were recorded, with ABO incompatibility and transfusion-related acute lung injury (TRALI) accounting for two and one case respectively. Transfusion reactions involving erythrocyte components were significantly more frequent than those involving platelet and plasma components. Conclusion: this study revealed a relatively low incidence of transfusion reactions (0.44%), dominated by non-haemolytic febrile and allergic reactions. Several levels of failure were identified, in particular under-reporting of reactions and inadequate training in transfusion practices and haemovigilance, as well as the need for an effective electronic transfusion reaction reporting system to facilitate reporting and identification of underlying problems and risk factors to improve the quality of transfusion care provided to patients.

Impact of the Pediatric ABO Policy Change on Listings, Transplants, and Outcomes for Children Younger Than 2 Years Listed for Heart Transplantation in the United States.

BACKGROUND: We assessed the impact of the liberalized ABO pediatric policy change on candidate characteristics and outcomes for children undergoing heart transplant (HT). METHODS AND RESULTS: Children <2 years undergoing HT with ABO strategy reported at listing and HT from December 2011 to November 2020 to the Scientific Registry of Transplant Recipients database were included. Characteristics at listing, HT, and outcomes during the waitlist and post-transplant were compared before the policy change (December 16, 2011 to July 6, 2016), and after the policy change (July 7, 2016 to November 30, 2020). The percentage of ABO-incompatible (ABOi) listings did not increase immediately after the policy change (P = .93); however, ABOi transplants increased by 18% (P < .0001). At listing, both before and after the policy change, ABOi candidates had higher urgency status, renal dysfunction, lower albumin, and required more cardiac support (intravenous inotropes, mechanical ventilation) than those listed ABO compatible (ABOc). On multivariable analysis, there were no differences in waitlist mortality between children listed as ABOi and ABOc before the policy change (adjusted hazard ratio [aHR] 0.80, 95% confidence interval [CI] 0.61-1.05, P = .10) or after the policy change (aHR 1.2, 95% CI 0.85-1.6, P = .33). Post-transplant graft survival was worse for ABOi transplanted children before the policy change (aHR 1.8, 95% CI 1.1-2.8, P = .014), but not significantly different after the policy change (aHR 0.94, 95% CI 0.61-1.4, P = .76). After the policy change, ABOi listed children had significantly shorter waitlist times (P < .05). CONCLUSIONS: The recent pediatric ABO policy change has significantly increased the percentage of ABOi transplantations and decreased waitlist times for children listed ABOi. This change in policy has resulted in broader applicability and actual performance of ABOi transplantation with equal access to ABOi or ABOc organs, and thus eliminated the potential disadvantage of only secondary allocation to ABOi recipients.

Incidence of acute haemolytic transfusion reaction among ABO-incompatible recipients transfused with A3 blood: A case series.

BACKGROUND AND OBJECTIVES: ABO antigens are among the most immunogenic, but the haemolytic risks of ABO incompatibilities involving a donor with a weak ABO phenotype are little documented. MATERIALS AND METHODS: This retrospective case series assessed the incidence of acute haemolytic transfusion reaction (AHTR) among ABO-incompatible recipients of A3 blood in Québec (Canada). Transfusion safety officers reported laboratory AHTR indicators measured ≤24 h pre- and post-transfusion. Because the AHTR case definition of Québec's Hemovigilance System (QHS) leaves significant room for clinical judgement, a two-step approach was used to assess potential cases: Step 1 consisted in a highly sensitive-but unspecific-initial screen that identified all candidate cases per QHS case definition, and Step 2 consisted in a detailed review of candidate cases by two haematologists. RESULTS: Nine donors initially typed as Group B (N = 1) or O (N = 8) were subsequently found to display an A3 B or A3 O phenotype. Eighty-one recipients received ABO-incompatible blood, including 53 (65.4%) with interpretable data. Of these, 29 (54.7%) were classified as candidate cases after Step 1. Following Step 2, no conclusive evidence of AHTR was found: Abnormal pre- versus post-transfusion changes appeared modest, within normal range, insufficient to ascertain AHTR, or were consistent with a pre-existing condition unrelated to AHTR. Two candidate cases had a QHS-reported transfusion reaction; both were unrelated to AHTR. CONCLUSION: In this case series, no conclusive evidence of serious AHTR was found among ABO-incompatible recipients who were inadvertently transfused with A3 blood.

Associations between ABO non-identical platelet transfusions and patient outcomes-A multicenter retrospective analysis.

BACKGROUND: Due to platelet availability limitations, platelet units ABO mismatched to recipients are often transfused. However, since platelets express ABO antigens and are collected in plasma which may contain ABO isohemagglutinins, it remains controversial as to whether ABO non-identical platelet transfusions could potentially pose harm and/or have reduced efficacy. STUDY DESIGN AND METHODS: The large 4-year publicly available Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) database was used to investigate patient outcomes associated with ABO non-identical platelet transfusions. Outcomes included mortality, sepsis, and subsequent platelet transfusion requirements. RESULTS: Following adjustment for possible confounding factors, no statistically significant association between ABO non-identical platelet transfusion and increased risk of mortality was observed in the overall cohort of 21,176 recipients. However, when analyzed by diagnostic category and recipient ABO group, associations with increased mortality for major mismatched transfusions were noted in two of eight subpopulations. Hematology/Oncology blood group A and B recipients (but not group O) showed a Hazard Ratio (HR) of 1.29 (95%CI: 1.03-1.62) and intracerebral hemorrhage group O recipients (but not groups A and B) showed a HR of 1.75 (95%CI: 1.10-2.80). Major mismatched transfusions were associated with increased odds of receiving additional platelet transfusion each post-transfusion day (through day 5) regardless of the recipient blood group. DISCUSSION: We suggest that prospective studies are needed to determine if specific patient populations would benefit from receiving ABO identical platelet units. Our findings indicate that ABO-identical platelet products minimize patient exposure to additional platelet doses.

A cross-sectional study of haemolytic disease of the newborn in Uganda.

BACKGROUND AND OBJECTIVES: Haemolytic disease of the newborn (HDN) is an immune haemolytic anaemia from maternal alloantibodies. Rh immunoglobulin (RhIg) prophylaxis can prevent alloimmunization to the D antigen. However, RhIg is not universally available in Uganda. ABO incompatibility also causes HDN. We determined the prevalence of HDN among newborn infants with jaundice in Uganda. MATERIALS AND METHODS: We conducted a prospective cross-sectional study at Kawempe National Referral Hospital, Kampala, Uganda. Infants aged 0-14 days with neonatal jaundice (or total bilirubin >50 µmol/L) were enrolled. Clinical evaluation and laboratory testing, including ABO, RhD typing and maternal antibody screen, were performed. RESULTS: A total of 466 babies were enrolled. The mean (SD) age was 3.4 (1.5) days. Of newborn babies with jaundice, 17.2% (80/466) had HDN. Babies with HDN had lower haemoglobin (SD); 15.7 (2.7) compared with those without HDN; 16.4 (2.4) g/dL, p = 0.016; and a higher bilirubin (interquartile range); 241 (200-318) compared with those without HDN; 219 (191-263) µmol/L, p < 0.001. One baby had anti-D HDN, while 46/466 had HDN from an ABO incompatibility (anti-A 43.5% and anti-B 56.5%); 82% of babies with HDN also had suspected neonatal sepsis or birth asphyxia. About 79.2% (57/72) of mothers did not have ABO/Rh blood group performed antenatally. All infants with HDN survived except one. CONCLUSION: Among newborn infants with jaundice, HDN is not rare. The majority is due to ABO HDN affecting group A and group B babies equally. Ensuring routine ABO/Rh grouping for all pregnant women is an area for improvement.

Postoperative Outcomes in Infants Undergoing ABO-incompatible Heart Transplantation in the United States.

BACKGROUND: ABO-incompatible heart transplant is a method to increase the infant donor pool. However data on long-term survival and rejection after ABO-incompatible heart transplant in recent era are limited. METHODS: The United Network for Organ Sharing database was queried for infant heart transplants performed from January 2008 to March 2020. Patient demographics and known risk factors for posttransplant mortality were collected. Statistical analysis using Bayesian additive regression trees was performed to evaluate the association of ABO incompatibility and overall survival, graft survival, acute rejection episodes, and length of stay. RESULTS: Of 1368 included infants (age < 1 year), 280 (20.47%) were ABO incompatible. ABO incompatibility was not associated with increased all-cause mortality, acute rejection episodes, or length of stay, whereas extracorporeal membrane oxygenation and intubation status of the recipient at the time of transplantation were associated with increased all-cause mortality and graft failure. Idiopathic cardiomyopathy was associated with a decreased likelihood of posttransplant all-cause mortality. One-, 5-, and 10-year survival rates among compatible vs incompatible transplants were estimated to be 90% vs 88%, 82% vs 79%, and 77% vs 73%, respectively. CONCLUSIONS: ABO-incompatible infant heart transplant does not affect posttransplant survival, incidence of rejection, or postoperative length of stay. Therefore it remains a viable and important strategy to increase the infant donor pool.

Optimizing transfusion management of multiple myeloma patients receiving daratumumab-based regimens.

BACKGROUND: Daratumumab, a human anti-CD38 monoclonal antibody used to treat multiple myeloma, interferes with pretransfusion testing and can mask alloantibodies. Incidence of alloimmunization in patients on daratumumab has not been well characterized, and optimal transfusion guidelines regarding prophylactic antigen matching, accounting for both patient safety and efficiency, have not been well established for these patients. METHODS: Records of patients who received daratumumab between January 1, 2014 and July 2, 2019 were reviewed. Daratumumab interference with pretransfusion testing was managed by testing with reagent red blood cells (RBCs) treated with 0.2 M dithiothreitol. When daratumumab was present during antibody testing, patients were transfused with RBC units prophylactically matched for D, C, c, E, e, and K antigens per hospital policy. RESULTS: Out of 90 patients identified, 52 received a total of 638 RBC transfusions (average of 12.3 units per patient, SD 17.2, range 1-105, median 5 among those transfused). Alloantibodies existing before daratumumab initiation were identified in seven patients. No new alloantibodies were detected in any patients after starting daratumumab treatment. CONCLUSIONS: The incidence of alloimmunization in patients receiving daratumumab is low. Whether this is due to the effect of daratumumab, underlying pathophysiology, or other factors, is unknown. Because these patients require a large number of RBC transfusions overall and have little observed alloimmunization, phenotype matching (beyond RhD) may be unnecessary. Since the use of dithiothreitol cannot rule out the presence of anti-K, we recommend transfusion of ABO-compatible units, prophylactically matched for the D and K antigens only.

Accuracy of a point-of-care major crossmatch test and risk factors for major crossmatch incompatibility in cats.

Major crossmatch testing can help identify immunologic incompatibilities between blood donors and recipients; however, there are limited studies describing the accuracy of point-of-care crossmatch tests. The first aim of this study was to determine if a gel-based, point-of-care major crossmatch method (GEL-CM), without antiglobulin-enhancement, could accurately detect compatible and incompatible donor-recipient pairings, using an antiglobulin-enhanced laboratory-based major crossmatch method (LAB-CM) as the reference standard. The second aim was to describe the incidence of, and risk factors for, major crossmatch incompatibility in cats. Nineteen previously-transfused cats and 32 transfusion-naïve cats, representing 132 unique donor-recipient pairings, were included in this study. Both LAB-CM and GEL-CM tests were performed for most parings. There was poor agreement between the LAB-CM and GEL-CM results (kappa = 0.111; 95% confidence interval [CI], -0.093 to 0.314). Transfusion-naïve cats had incompatibility rates of 3% and 6% using LAB-CM and GEL-CM, respectively; previously-transfused cats had incompatibility rates of 32% and 26% using LAB-CM and GEL-CM, respectively. History of previous transfusion was the only identified cat risk factor for an incompatible LAB-CM (odds ratio [OR], 31.0; 95% CI, 3.77-254.98; P = 0.0019) and GEL-CM (OR, 5.7; 95% CI, 1.72-19.20; P = 0.0054). Further studies are needed to determine if GEL-CM can detect clinically-relevant immunologic incompatibilities that would result in transfusion reactions. Major crossmatch testing is of greater importance in cats that have previously received a transfusion.

Variation of anti-A and anti-B titers in group O potential blood donors: A pilot study.

BACKGROUND: Resuscitation with fresh whole blood is vital to preserving life on the battlefield. Transfusing low titer O whole blood (LTOWB), defined as anti-A and anti-B titer levels of <1:256, is safe because LTOWB alleviates the risk for hemolytic transfusion reactions. Because of possible variations in titer levels over time, a study was needed using US Navy and Marine Corps personnel to assess how these titers change across two assessments. METHODS: Retrospective data from group O marines and sailors (M = 25 years of age; range, 19-35 years) stationed in the San Diego region were acquired from the Armed Services Blood Program and the Composite Health Care System. Of 972 group O donors between January 2016 and November 2019, 55 donors with 2 samples were identified (N = 55). Analysis included contrasting rates of high (≥1:256) and low (<1:256) anti-A and anti-B titers on the initial and second blood tests, along with the time between testings. RESULTS: The average time between testing was 332 days (range, 35-1,121 days), which far exceeded the recommended 90-day interval (p < 0.00001). Only 45% met the 90-day recommendation. Titer status changed frequently, from low to high (anti-A, 18%; anti-B, 13%; LTOWB to not LTOWB, 21%) or from high to low (anti-A, 62%; anti-B, 78%; not LTOWB to LTOWB, 62%). CONCLUSIONS: Anti-A and anti-B titers change frequently enough to warrant testing immediately before deployment and even during deployment. The observed time elapsed between testing is unacceptably long. The present pilot study provides a foundation for a larger formal study to more fully characterize titer changes over repeated testing. LEVEL OF EVIDENCE: Diagnostic test, level IV.

Modelling suggests ABO histo-incompatibility may substantially reduce SARS-CoV-2 transmission.

Several independent datasets suggest blood type A is over-represented and type O under-represented among COVID-19 patients. However, blood group antigens appear not to be conventional susceptibility factors in that they do not affect disease severity, and the relative risk to non-O individuals is attenuated when population prevalence is high. Here, I model a scenario in which ABO transfusion incompatibility reduces the chance of a patient transmitting the virus to an incompatible recipient - thus in Western populations type A and AB individuals are "super-recipients" while type O individuals are "super-spreaders". This results in an offset in the timing of the epidemic among individuals of different blood types, and an increased relative risk to type A/AB patients that is most pronounced during early stages of the epidemic. However, once the majority of any given population is infected, the relative risk to each blood type approaches unity. Published data on COVID-19 prevalence from regions in the early stages of the SARS-CoV-2 epidemic suggests that if this model holds true, ABO incompatibility reduces virus transmissibility by at least 60 %. Exploring the implications of this model for vaccination strategies shows that paradoxically, targeted vaccination of either high-susceptibility type A/AB or "super-spreader" type O individuals is less effective than random vaccination at blocking community spread of the virus. Instead, the key is to maintain blood type diversity among the remaining susceptible individuals. Given the good agreement between this model and observational data on disease prevalence, the underlying biochemistry urgently requires experimental investigation.

ABO blood group relationships to kidney transplant recipient and graft outcomes.

INTRODUCTION: Certain ABO blood types have been linked to cardiovascular disease, infection and cancers. The effect of recipient ABO blood group on patient and graft survival has not been studied in ABO-matched kidney transplantation. This study aims to determine the association between kidney transplant recipient ABO blood groups with patient and graft survival in Australian and New Zealand. METHODS: All Australian and New Zealand transplant recipients who received ABO-compatible primary kidney transplants between 1995-2016 were analysed using a de-identified dataset from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. Primary analysis was undertaken of recipient ABO blood group O versus non-O blood groups. The primary outcome was patient survival post kidney transplantation and the secondary outcome was death censored graft survival. Recipient age at first transplant, gender, ethnicity, body mass index, smoking status, vascular disease, presence of diabetes mellitus, chronic lung disease, primary kidney disease, donor source, donor age and gender, and era of transplants were included in the multivariate model as confounders. RESULTS AND CONCLUSIONS: On analysis of 15,523 kidney transplant recipients, blood group O was not associated with patient survival (hazard ratio (HR) 0.96, 95% confidence interval (CI) 0.89-1.04) nor death censored graft survival (HR 0.97, 95% CI 0.89-1.05) compared to non-blood group O recipients. Competing risks analyses showed an increased risk of cancer-related mortality in blood group O recipients on univariate analyses (HR 1.18, 95% CI 1.01-1.37) however, this became insignificant on multivariate analyses. On secondary analyses, recipient blood group AB (4.11% participants) was associated with inferior death censored graft survival compared to those with blood group O (HR 1.24, 95% CI 1.02-1.50). Although recipient ABO blood groups were not associated with patient nor graft survival, differences in cause-specific mortality between individual blood groups cannot be excluded based on current analyses.

[Frequency and titration of hemolytic activity of anti-A and anti-B antibodies in mothers of children with jaundice in Yaoundé, Cameroon]. / Fréquence et titrage des hémolysines anti-A et anti-B chez les mères d'enfants ictériques à Yaoundé, Cameroun.

INTRODUCTION: The alloimmunization of the ABO blood group system is involved in neonatal jaundice with a considerable overall prevalence. The role of ABO incompatibility is relatively little known. The purpose of this study was to investigate neonatal jaundice due to feto-maternal ABO incompatibilities and to determine the link between the hemolysins value in the mother and the degree of jaundice observed in the infant. METHODS: We conducted a cross-sectional study from June to November 2015. The study population was exclusively composed of moms who were blood type O with children who were a different blood type hospitalized in the Department of Neonatology at the Reference Hospital in the city of Yaoundé. Statistical analyses were performed using the GraphPadPrism 6 software with a confidence interval of 95%. RESULTS: Hemolysins frequency was of 20.58% (7/34) and anti-A hemolysin was the most common type (85.7%; 6/7). The new-born who had blood type B had a greater concentration of bilirubin levels compared to those of the AB group (p = 0.01). Multiparity was not associated with the presence of hemolysin (p = 0.8) as well as blood type of the infant was not associated with the occurrence of the hemolysins in the mother (p = 0.5). CONCLUSION: Early neonatal jaundice or protracted neonatal jaundice are also caused by hemolysins anti-A and anti-B derived from the allo-ABO immunization. A study on a larger sample is recommended for better assessment.

The management and outcomes of ABO-incompatible pediatric liver transplantation: Experience of a single Chinese center.

BACKGROUND: To investigate the safety of using ABO incompatible (ABO-i) liver grafts in pediatric patients under our prophylactic strategies. METHODS: A total number of 544 pediatric liver transplantations between January 2013 and December 2017 performed in Organ Transplant Center, Tianjin First Central Hospital were included in this study. The recipients were divided into 3 groups based on the compatibility of donor-recipient blood type matching (ABO-identical group, n = 352, ABO-compatible group, n = 121 and ABO-incompatible group, n = 71). Recipient characteristics, perioperative data, postoperative complications and recipient survival rate were compared. The recipient outcomes between living-related and non-living-related ABO-incompatible liver graft recipients were also compared. RESULTS: The median follow-up time in three groups were 3.4 (1.8, 6.4) years, 3.2 (1.8, 6.1) years and 2.8 (1.8, 6.2) years, without statistical difference. The cumulative 1-year and 3-year graft survival rate were 94.3% and 94.0% in ABO-id group, 93.1% and 93.1% in ABO-c group and 97.1% and 97.1% in ABO-i group. The cumulative 1-year and 3-year recipient survival rate were 96.1% and 95.5% in ABO-id group, 94.8% and 94.8% in ABO-c group and 97.1% and 97.1% in ABO-i group, respectively. No significant difference was seen among three groups. The recipient characteristics and perioperative data were similar among three groups. The recipients in ABO-i group showed significantly lower incidence of portal vein stenosis. Apart from that, three groups shared equal incidence of other surgical complications and acute rejection. Among ABO-i liver graft recipients, the cumulative 1-year and 3-year recipient survival rate were 98.2% and 98.2% in living donor liver transplant (LDLT) recipients and 92.9% and 92.9% in deceased donor liver transplant (DDLT) recipients, without significant difference. The incidence of hepatic artery thrombosis was significantly higher in DDLT group compared with LDLT group, while the other complications were similar between two groups. CONCLUSION: Our data revealed that the application of ABO-i liver grafts in pediatric liver transplantation under rational peri-operative management strategy is a safe measure to increase donor availability for pediatric patients in Chinese population. LEVELS OF EVIDENCE: III.

A current era analysis of ABO incompatible listing practice and impact on outcomes in young children requiring heart transplantation.

BACKGROUND: Heart transplantation from ABO incompatible (ABOi) donors has evolved into a progressively accepted therapy in young children. We assessed the recent practice of ABOi listing impact on waitlist and post-transplant outcomes. METHODS: Using the Pediatric Heart Transplant Society registry, we compared clinical presentation, waitlist parameters, and post-transplant survival of children < 2 years of age listed for ABOi vs ABO compatible (ABOc) heart transplant between January 2010 and June 2018 with sub-analysis of blood group O recipients. RESULTS: Among 2,039 patients, ABOi listing increased significantly with time from 49% (2010) to 72% (2017). ABOi-listed patients had lower age and body surface area, and higher proportion of congenital heart disease, mechanical ventilation, and high urgency status (all p < 0.01). Use of mechanical circulatory support was similar between groups. Of 1,288 patients reaching transplant, 239 (18.6%) received an ABOi organ (15%-40%/year). Death while waiting, removal from the waitlist, and waitlist survival were similar between groups. Time to transplant was significantly shorter for ABOi listing in blood group O patients (p < 0.02), approaching significance (p = 0.057) for all blood groups. Post-transplant survival was similar except for lower survival of patients listed ABOc but transplanted ABOi. These patients showed increasing need for mechanical circulatory support and high urgency listing while waiting. CONCLUSIONS: In the current era, primary listing for ABOi heart transplant has become routine for the majority of children < 2 years old, resulting in shorter waitlist time, especially in blood group O. Post-transplant survival is similar despite ABOi-listed children still showing a higher risk profile.

ABO hemolytic disease of newborn : Does newborn's blood group a risk factor?

BACKGROUND: Due to the marked decline of maternal-fetal rhesus incompatibility, ABO alloimmunization has become the leading cause of the newborn hemolytic disease. It is estimated that 15-25 % of all pregnancies are concerned by ABO incompatibility. AIM: Neonatal blood group B seems to be more predisposing to acute hemolysis and severe hyperbilirubinemia. We propose to find if the newborn's blood group B represents a risk factor for severe hemolysis and/or severe hyperbilirubinemia. METHODS: We conducted a comparative study in the pediatrics department "B" of the Children Hospital of Tunis. We collected retrospectively the medical files of the newborn hospitalized for ABO alloimmunization (January 2011 - March 2014), then we compared two groups, OA group with OA alloimmunization and OB group with OB alloimmunization. A significant threshold was fixed to 0.05. RESULTS: We collected 98 cases of newborn ABO hemolytic disease. Both groups, OA and OB, were similar for the onset of jaundice, age of hospitalization, initial hemoglobin and indirect bilirubin levels. There were no statistically significant difference in the severity of hyperbilirubinemia and the use of exchange transfusion for the two groups. However, transfusion was statistically more frequent in the OB group compared to OA group (81.6‰ vs 10.2‰, p = 0,039, OR=2.9, 95% IC (1.1 - 7.8)). CONCLUSION: OB alloimmunization seems to induce more active hemolysis than OA one, with no difference for severe hyperbilirubinemia in both groups.

Isoantibodies, prevalence and risk factors in two hospitals in Mexico / Isoanticuerpos, prevalencia y factores de riesgo en dos hospitales de México

Background: Erythrocyte isoimmunization or alloimmunization is a late complication of transfusion, in which antibodies against erythrocyte antigens other than the ABO system are developed. Its prevalence is variable, groups of patients with low prevalence (2%) and others of high risk with more than 50% have been described. These antibodies can have serious clinical repercussions in transfused patients. Objective: To know the prevalence of erythrocyte isoimmunization, the risk factors for its development and the types of antibodies developed in the user population of two hospitals in Mexico. Methods: Retrospective study. The database of the Blood Bank and the Transfusion Service of two hospitals was analyzed for the search of transfused patients who developed isoantibodies from 2012 to 2016, analyzing their background to determine the risk factors, prevalence and type of antibodies. Results: An isoimmunization prevalence of 0.97% was found in 5 years; the main antibodies found were: anti-E, anti-K, anti-C, anti-Dia, anti-c, anti-D and anti-Fya. The associated risk factors for the development of isoimmunization were: transfusion history, pregnancy and female sex, as a finding it was found that group O is a protective factor. Conclusions: Erythrocyte alloimmunization in the population studied corresponded to a low prevalence. The main antibodies found were against Rh, Kell and Diego system antigens, with a different distribution than published in other international series. No previous report was found about the finding on group O as a protective factor for isoimmunization.

Introducción: la isoinmunización o aloinmunización eritrocitaria es una complicación tardía de la transfusión, en la cual se desarrollan anticuerpos contra antígenos eritrocitarios diferentes al sistema ABO. Su prevalencia es variable, se han descrito grupos de pacientes con baja prevalencia (2%) y otros de alto riesgo con más del 50%. Estos anticuerpos pueden tener repercusiones clínicas graves en los pacientes transfundidos. Objetivo: conocer la prevalencia de la isoinmunización eritrocitaria, los factores de riesgo para su desarrollo y los tipos de anticuerpos desarrollados en la población usuaria de dos hospitales en México. Métodos: estudio retrospectivo. Se analizó la base de datos del banco de sangre y del servicio de transfusión de dos hospitales para la búsqueda de pacientes transfundidos que desarrollaron isoanticuerpos del año 2012 al 2016, analizando sus antecedentes para determinar los factores de riesgo, prevalencia y tipo de anticuerpos. Resultados: se encontró una prevalencia de isoinmunización del 0.97% en 5 años; los principales anticuerpos encontrados fueron: anti-E, anti-K, anti-C, anti-Dia, anti-c, anti-D y anti-Fya. Los factores de riesgo asociados para el desarrollo de isoinmunización fueron: antecedentes transfusionales, embarazo y el sexo femenino, como hallazgo se encontró que el grupo O es un factor protector. Conclusiones: la aloinmunización eritrocitaria en la población estudiada correspondió a una prevalencia baja. Los principales anticuerpos encontrados fueron contra antígenos del sistema Rh, Kell y Diego, con una distribución diferente a lo publicado en otras series internacionales. No se encontró reporte previo acerca del hallazgo sobre el grupo O como factor protector para isoinmunización.

Adverse transfusion reactions in transfused children.

Transfusion in paediatrics requires specific guidelines, because child physiology and pathology differ significantly as compared to adults. Adverse transfusion reactions in transfused children also vary in type and frequency, but there is a better understanding of these reactions in adults than in children. However, for the most frequent adverse transfusion reactions, the overall prevalence is higher in children than in adults, with the exception of post-transfusion red blood cell alloimmunisation, which is lower, excluding patients with haemoglobinopathies. In several studies, allergic reactions were the most frequently reported adverse transfusion reaction in paediatrics, and the platelet concentrate the most frequently implicated blood product. Early diagnosis of certain adverse transfusion reactions such as haemosiderosis, is essential in order to initiate the best therapy and obtain a good clinical outcome. The prevention of adverse transfusion reactions in children is required, but needs further clinical studies in paediatrics. Lastly, changes in technology, policy and clinical practices will improve transfusion safety in children.

Safety issues related to the electronic cross-matching of blood in mainland China: A prospective cohort study involving cross-matching of 40,228 blood samples.

Although the electronic cross-matching of blood has been widely applied in some developed countries and regions, concern over the risk of undetected red blood cell (RBC) antibodies has limited its application in mainland China.This study was performed to explore the missed detection rate of RBC antibodies in a Chinese population from 2011 to 2016. If the results of 2 consecutive tests of ABO/RhD blood group identification were consistent and antibody screening results were negative, electronic cross-matching of the blood was performed. In addition, traditional serological cross-matching of blood (polybrene method) and a parallel experiment for electronic cross-matching of blood were performed to analyze the missed detection of unexpected RBC antibodies in blood donors and recipients.Using the polybrene method, 40,228 blood samples were tested by parallel traditional serological cross-matching of blood; among these samples, blood compatibility was found in 40,222 cases, primary incompatibility (incompatibility of the donor's erythrocytes with the recipient's serum) was found in 6 cases, and no secondary incompatibility was found. Identification of antibody specificity was performed using panel cells, and all unexpected RBC antibodies were confirmed as anti-Mur alloantibodies in the MNS system.Further improvements in the erythrocyte antigenic spectrum, especially the Mur antigen in Asian populations, are expected to ensure the safety of implementing electronic cross-matching in China.

Red Blood Cell Alloimmunization in Transfused Patients With Sickle Cell Disease in Sub-Saharan Africa; a Systematic Review and Meta-Analysis.

Sickle cell disease (SCD) is the most common monogenic disorder in sub-Saharan Africa (SSA). Blood transfusion to increase the oxygen carrying capacity of blood is vital in the management of many patients with SCD. However, red blood cell (RBC) alloimmunization is a major challenge to transfusions in these patients. Commonly in SSA, pretransfusion tests only involve ABO D grouping and compatibility without RBC antibody testing. Data on the frequency of RBC alloimmunization in patients with SCD in SSA are limited. We performed a systematic review and meta-analysis on available data on alloimmunization in transfused patients with SCD to determine the published prevalence of RBC alloimmunization in SCD patients in SSA. Six databases were systematically searched to identify relevant studies, without year or language restrictions. In all, 249 articles were identified and 15 met our selection criteria. The overall proportion of alloimmunization was 7.4 (95% confidence interval: 5.1-10.0) per 100 transfused patients. Antibodies against E, D, C, and K antigens accounted for almost half of antibody specificities, and antibodies to low- and high-frequency antigens were also common and represented almost 30% (20% to low-frequency antigens and 9% to high-frequency antigens) of specificities. Heterogeneity between studies was moderate, and meta-analysis found region of Africa as the major contributor to the heterogeneity. We also observed inconsistencies across studies in reporting of factors that may influence alloimmunization. This review provides an overview of the extent of the alloimmunization problem in SSA and provides a baseline against which to compare the effect of any interventions to reduce the alloimmunization risk.

[Severe hyperbilirubinemia in newborns, risk factors and neurological outcomes]. / Hiperbilirrubinemia severa en Recién Nacidos, factores de riesgo y secuelas neurológicas.

INTRODUCTION: Hyperbilirubinemia is highly prevalent in newborns, with risk of neurological invol vement with bilirubinemia higher than 20 to 25 mg/dl. This progression is preventable with early de tection and treatment. OBJECTIVE: To describe the incidence and associated factors in hospitalized pa tients with hyperbilirubinemia higher than 20 mg/dl, and the follow-up of symptomatic cases during hospitalization. PATIENTS AND METHOD: Retrospective study of patients with severe hyperbilirubine mia, between 2013 and 2016. Risk factors were evaluated, stratifying by bilirubin level, admission age, and gestational age. The data were compared with Fisher's exact test, chi-square test, and relative risk (RR) in an Excel database, with an alpha error of p <0.05. The data were obtained from the electronic discharge summary and the medical record of secondary level follow-up. RESULTS: During the studied period, out of 25,288 live newborns (NB), 593 were hospitalized due to hyperbilirubinemia higher than 20 mg/dl, one per each 42 live NB; and 59 with bilirubinemia higher than 25 mg/dl, one per each 428 live NB. Hyperbilirubinemia was more frequent in males, with RR 1.22 (95% CI 1.04-1.44), and in late preterm newborns, with RR 2.39 (95% CI 1.96-2.93) compared with term NB. In those admitted with more than four days, the main associated factor was excessive weight loss, whereas in the first three days was classic group incompatibility. Three of ten cases with acute encephalopathy persisted with neurological involvement, which means 11.8 per 100,000 live births. CONCLUSIONS: The main risk factors for developing severe hyperbilirubinemia were prematurity, excessive weight loss, classic group incompatibility, and male sex. These findings allow to focus attention on risk groups and decrease the probability of neurological damage.