Red blood cell alloantibodies in paediatric transfusion in sub-Saharan Africa: A new cohort and literature review

Red cell specifications for blood group matching in patients with haemoglobinopathies: An updated systematic review and clinical practice guideline from the International Collaboration for Transfusion Medicine Guidelines

Red blood cell (RBC) antigen matching beyond ABO and RhD is commonly recommended for patients with sickle cell disease (SCD) and thalassaemia. We present an updated systematic literature review to inform evidence-based guidelines on RBC matching. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool was used to develop recommendations. Six new observational studies (4 prospective, 2 retrospective) were identified. The six studies reported on 583 patients in total, including cross-over designs, with sample sizes from 10 to 343. Studies were heterogeneous, utilising varying degrees of RBC matching and different definitions for 'extended' matching. All reported on alloimmunisation. One study reported on molecular matching. The reported prevalence of alloimmunisation using limited matching was 0%-50% and with extended matching was 0%-24%. Eighty-two patients were alloimmunised before study entry. The risk of bias across studies was moderate to critical. The guideline panel recommends that ABO, RhDCcEe, and K-compatible RBCs are selected for individuals with SCD and thalassaemia, even in the absence of alloantibodies, and that RBCs which are antigen-negative to already existing clinically significant antibodies are chosen. There is a need for comparative research to define the benefit, impact, cost-effectiveness, and feasibility of extended RBC matching strategies to prevent alloimmunisation.

Improvement of blood transfusion safety using the chemiluminescence technique for viral marker screening of blood donors in sub Saharan Africa

INTRODUCTION

Sub-Saharan Africa struggles continuously with insufficient resources and inadequate infrastructure that hinder the establishment of a safer blood supply despite improvements in transfusion safety over recent decades. This study aimed to evaluate the impact of the chemiluminescence technique in combination with immunoenzymatic and immunochromatographic tests for viral marker screening of hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency virus (HIV) in donated blood in a country of sub-Saharan Africa.

METHOD

This study was conducted in a population of 113,406 blood donors at the National Centre of Blood Transfusion in Senegal. The data were obtained from the 'INLOG' software and donor registers. Statistical analyses used Excel 2010 and Epi Info v6. Screening for HBsAg viral markers, anti-HCV Ab, HIV p24 Ag, anti-HIV1 and anti-HIV2 antibodies were first carried out using the chemiluminescence technique. Blood donations screened positive for HBV or HCV were retested in a second chemiluminescence equipment. HIV-positive donations and their controls were subjected to solid phase immunochromatographic and indirect enzyme immunoassay techniques.

RESULTS

The prevalence among donors of HBV was 8.39 %, 0.56 % for HCV and 0.18 % for HIV. Of the donors tested positive for HIV in screenings and in doubled-controls, only 61.54 % were confirmed by the alternative tests; 34.02 % were negative and 4.44 % discordant between the three techniques.

CONCLUSION

This study shows the importance of introducing the chemiluminescence technique in association with serological screening of transfusion-transmitted viruses to improve blood supply safety in low-income countries.

Investigation of Delayed Transfusion Reactions in Sickle Cell Disease Patients Polytransfused in the Brazilian Amazon

BACKGROUND

Sickle cell disease (SCD) affects approximately 100,000 people in the United States and millions worldwide, with the highest prevalence of 70% of SCD being found in individuals of African ethnicity. Delayed hemolytic, alloimmunization, and anamnestic transfusion reactions in multiple transfusion patients need to be investigated and managed to avoid a worsening of the patient's clinical status.

OBJECTIVE

This paper aims to investigate delayed transfusion reactions in SCD patients who were polytransfused in the Brazilian Amazon.

MATERIAL AND METHODS

The clinical and laboratory indicators of SCD patients with more than four transfusions were investigated. The patients were treated at the Fundação Hospitalar de Hematologia e Hemoterapia do Estado do Amazonas, Brazil.

RESULTS

A total of 44 polytransfused patients with SCD were followed. Regarding Rh phenotype, it was possible to observe a frequency of 26.6% (12) patients with the RZRZ (DCE/DCE) phenotype, in addition to 4.5% (two) patients with RH and RHCE variants. It was also possible to observe 20.5% (nine) patients with an alloimmunization reaction, who presented the following alloantibodies: anti-RhD, anti-E, anti-K, anti-Jkb, anti-N, anti-S, and anti-Dia, two of which are unidentified. Of these, four (44.4%) patients also presented autoantibodies, anti-e, and three unidentified antibodies, and four (44.4%) patients presented an anamnestic reaction, with anti-RhD, K, and Jkb antibodies. Of the 44 patients monitored, 54.4% (24) had clinical and laboratory indicators of a delayed hemolytic reaction.

CONCLUSION

Delayed transfusion reactions, often neglected, occur frequently. Therefore, transfusions need to be monitored for at least 28 days, with medical investigation of clinical and laboratory indicators to make greater use of this therapeutic resource.

Seroprevalence of Transfusion-Transmissible Infections among Family Replacement Donors and Voluntary Non-Remunerated Blood Donors During the COVID-19 Pandemic in Sub Saharan Africa

Introduction : According to WHO,  regular, voluntary, unpaid blood donors are the safest group of donors, as they have the lowest prevalence of blood transmitted infections. However, family/replacement blood donors is widely used in sub Saharan Africa and this practice was exacerbated during the COVID 19 pandemic. This study aimed to compare the seroprevalence of infectious markers in family replacement blood donors and voluntary non-remunerated  blood donors during the COVID 19 pandemic in a country of sub Saharan Africa.   Materials and Methods Blood donors received at the National Centre of Blood Transfusion (NBTC) of Dakar from August 1st to October 31th 2021, were included in this study. All donors completed a pre-donation questionnaire. Donors identity, epidemiological parameters, reasons for donation and laboratory results were collected in the Inlog® software of the NBTC. The serological tests for HBV, HIV and HCV were performed with chemiluminescence technology. The Rapid Plasma Reagent test was used to find out treponemal antibodies. The determination of ABO and Rh blood groups was performed using monoclonal antisera following classical hemagglutination test on a plate. Results A total of 5002 donors were collected during this COVID-19 pandemic period. Blood family/replacement donors represented 54.0% and new voluntary donors represented 52.6%. Comparison of HIV, HCV and syphilis markers seroprevalence showed no statistically significant difference between new voluntary donors and new family replacement donors (p>0.05). However, for HBV the seroprevalence was significantly higher in new family replacement donors (p=0,002). Conclusion The proper supply of blood was impacted by the COVID-19 pandemic meanwhile replacement donations had contributed to limiting the damage observed with blood shortages. However, the significant differences noted on the seroprevalences of transfusion-transmissible infections between voluntary non-paid donors and family/replacement donors strengthens WHO recommendations for the selection of volunteer non-paid donors to lower transfusion-transmissible HBV in sub Saharan Africa.