The haematology of indigenous Australians

The prevalence of alloantibodies and ABO RhD blood groups in a cohort of Aboriginal and non-Aboriginal cardiac surgery patients from Australia

INTRODUCTION

Limited evidence exists on the distribution of ABO RhD blood groups and prevalence and specificity of red blood cell (RBC) alloantibodies in Aboriginal and Torres Strait Islander peoples of Australia. We investigated RBC alloantibody prevalence and ABO RhD groups in Aboriginal patients undergoing cardiac surgery at a South Australian (SA) tertiary hospital, a major cardiac surgical referral centre for Northern Territory (NT) patients METHODS: Retrospective analysis of all consecutive patients undergoing cardiac surgery at Flinders Medical Centre (FMC) between January 2014 and June 2019. ABO and RhD blood groups, and RBC alloantibody prevalence, specificity, and clinical significance in Aboriginal and non-Aboriginal cardiac patients were determined at time of surgery and on follow up to 2021.

RESULTS

2327 patients were included, 588 (25.3 %) were from NT, and 420 (18.0 %) were Aboriginal. Aboriginal patients had a higher prevalence of ABO group O (59.8 % vs 43.9 %) and RhD positive (99.0 % vs 83.8 %). One-hundred-and-eleven patients had 154 RBC alloantibodies, 57/420 (13.6 %) Aboriginal versus 54/1907 (2.8 %) non-Aboriginal (p < 0.0001). There were higher numbers of IgM alloantibodies in Aboriginal patients (59/77, 76.6 %), with Lewis, P1 and M more common. Sixty patients had antibodies detected at time of surgery, 14 NT patients with previously detected alloantibodies, prior to surgery, presented with a negative antibody screen and 37 had new antibodies detected after cardiac surgery.

CONCLUSION

A high prevalence of IgM alloantibodies was found in Aboriginal compared to non-Aboriginal cardiac surgery patients. The clinical significance of these IgM alloantibodies in Aboriginal peoples requires further investigation.

A Retrospective Cohort Study of Red Cell Alloimmunisation in Rural, Remote, and Aboriginal and Torres Strait Islander Peoples Admitted to Intensive Care in the Northern Territory, Australia

Red cell (RC) alloantibodies occur on exposure to non-self RC antigens in transfusion and pregnancy (typically IgG and clinically significant) or in association with non-RC immune environmental factors (typically IgM and not clinically significant). In Australia, the risk of RC alloimmunisation in First Nations peoples is unknown. We assessed the epidemiology, specificity, and antecedents of RC alloimmunisation via a data linkage retrospective cohort study of Northern Territory (NT) intensive care unit (ICU) patients (2015-2019). Of 4183 total patients, 50.9% were First Nations. In First Nations versus non-First Nations patients, the period prevalence of alloimmunisation was 10.9% versus 2.3%, with 390 versus 72 prevalent alloantibodies detected in 232 versus 48 alloimmunised patients, of which 135 (34.6%) versus 52 (72.2%) were clinically significant specificities. Baseline and follow-up alloantibody testing were available for 1367 patients, in whom new incident clinically significant alloantibodies developed in 4.5% First Nations versus 1.1% non-First Nations patients. On Cox proportional hazards modelling, adjusted hazard ratios (HR) showed First Nations status (HR 2.67 (95% CI 1.05-6.80), p = 0.04) and cumulative RC unit transfusion exposure (HR 1.03 (95% CI 1.01-1.05), p = 0.01) were independent predictors of clinically significant alloimmunisation. First Nations Australian patients are at increased risk of alloimmunisation due to RC transfusion, underscoring the importance of very judicious use of RC transfusions and shared decision-making with patients. Further studies are recommended to explore the role of other (non-RC) immune host factors, given the relative high prevalence of non-clinically significant IgM alloantibodies within alloimmunised First Nations patients.

The genomic landscape of blood groups in Indigenous Australians in remote communities

Background

Methods and materials

Results

Conclusion

The iron content of healthy diets for one day for breastfed babies and young children

AIMS

Early childhood anaemia due to iron deficiency is widespread in remote communities across northern Australia. Current recommendations for healthy food to complement breastfeeding at age 6 to 23 months include iron-rich and iron-enriched foods. An electronic nutrient analysis was undertaken to assess the iron content of hypothetical healthy diets for breastfed babies and young children aged 6 to 23 months in Australia, in comparison with their estimated requirements.

METHODS

Hypothetical diets for 1 day were developed that were consistent with the Foundation Diets for breastfed infants 6 to 12 months and for toddlers 13 to 23 months. Nutrient content was derived using the Australian Food Composition database in FoodWorks 10. The iron content of these two diets were compared with Estimated Average Requirements (EARs) and Recommended Dietary Intakes (RDIs) for iron for infants aged 7 to 12 months and children aged 1 to 3 years.

RESULTS

The iron content of the hypothetical diet for breastfed infants aged 6 to 12 months (5.8 mg) was less than the EAR (7 mg, 83%) and the RDI (11 mg, 53%). For young breastfed children aged 13 to 23 months, the iron content of the hypothetical diet was 4.4 mg; above the EAR (4 mg, 110%) but less than RDI (9 mg, 49%).

CONCLUSIONS

Breastfeeding has health and neurodevelopmental benefits for infants and young children that are particularly important in remote Australia where food insecurity and poor nutrition compromise health and wellbeing. Adequate iron intake is also important for neurodevelopment in early life but healthy diets for breastfed babies and young children may have insufficient iron content to meet requirements. The upcoming revision of the Australian Dietary Guidelines provides an opportunity to consider this issue.

Narrative Review of Hyperferritinemia, Iron Deficiency, and the Challenges of Managing Anemia in Aboriginal and Torres Strait Islander Australians With CKD

Aboriginal and Torres Strait Islander Australians (Indigenous Australians) suffer some of the highest rates of chronic kidney disease (CKD) in the world. Among Indigenous Australians in remote areas of the Northern Territory, prevalence rates for renal replacement therapy (RRT) are up to 30 times higher than national prevalence. Anemia among patients with CKD is a common complication. Iron deficiency is one of the major causes. Iron deficiency is also one of the key causes of poor response to the mainstay of anemia therapy with erythropoiesis-stimulating agents (ESAs). Therefore, the effective management of anemia in people with CKD is largely dependent on effective identification and correction of iron deficiency. The current identification of iron deficiency in routine clinical practice is dependent on 2 surrogate markers of iron status: serum ferritin concentration and transferrin saturation (TSAT). However, questions exist regarding the use of serum ferritin concentration in people with CKD because it is an acute-phase reactant that can be raised in the context of acute and chronic inflammation. Serum ferritin concentration among Indigenous Australians receiving RRT is often markedly elevated and falls outside reference ranges within most national and international guidelines for iron therapy for people with CKD. This review explores published data on the challenges of managing anemia in Indigenous people with CKD and the need for future research on the efficacy and safety of treatment of anemia of CKD in patients with high ferritin and evidence iron deficiency.

Comprehensive blood group antigen profile predictions for Western Desert Indigenous Australians from whole exome sequence data

BACKGROUND

The distribution of RBC antigens, which define blood group types, differs among populations. In contrast to many world populations, blood group profiles for Indigenous Australians have not been well studied. As it is now possible to predict comprehensive blood group antigen profiles from genomic data sets, we aimed to apply this for Indigenous Australians and to provide a comparison to other major world populations.

STUDY DESIGN AND METHODS

Whole exome sequence data for 72 Western Desert Indigenous Australians was provided by the Telethon Kids Institute. Variants (against hg19) were annotated using computer software (ANNOVAR, Qiagen Bioinformatics) and filtered to include only variants in genes for 36 blood group systems, and the transcription factors KLF1 and GATA1. The RHCE*C allele and RHD zygosity were identified by copy number variant analysis of sequence alignments. The impact of missense variants was investigated in silico using a meta-predictor of disease-causing variants (Meta-SNP).

RESULTS

For 21 blood group systems the predicted blood group antigen frequencies were comparable to those for other major world populations. For 13 systems, interesting points of contrast were identified. Furthermore, we identified 12 novel variants, one novel D allele, and four rare variants with potential clinical significance.

CONCLUSION

This is the first systematic assessment of genomic data to elucidate blood group antigen profiles for Indigenous Australians who are linguistically and culturally diverse. Our study paves the way to understanding the geographic distribution of blood group variants in different Indigenous groups and the associated RBC phenotypes. This in turn is expected to guide transfusion practice for Indigenous individuals.

Anaemia in school-aged children in an Australian Indigenous community

OBJECTIVE

Indigenous Australians have poorer health outcomes compared to the non-Indigenous population. Malnutrition, and subsequently iron-deficiency anaemia, impairs childhood development. The aim of this study was to identify the prevalence of anaemia in school-aged children of an Australian Indigenous community and evaluate the effectiveness of treatment.

DESIGN

A retrospective cohort study.

SETTING

A Northern Territory Indigenous community.

PARTICIPANTS

Two hundred and one school-age students (5-15 years old) undergoing annual school screening.

MAIN OUTCOME MEASURES

Presence of anaemia. Anaemic and non-anaemic students were compared to determine any differences in age, gender, BMI and past history of anaemia. The response to treatment was analysed using initial and repeat haemoglobin results.

RESULTS

Altogether, 201 students were screened with 105 (52%) classified as anaemic. No significant association was found between anaemic students and age, gender, BMI or prior history of anaemia. After treatment, the mean rise in haemoglobin was 13% (95% CI 11-15) at the 4-week interval. Age (P = 0.17), gender (P = 0.53) and weight (P = 0.14) were not significantly associated with treatment efficacy. Only 11 students (17%) were still anaemic after treatment.

DISCUSSION

Anaemia in Indigenous Australian school-aged children is a major public health issue. The prevalence of anaemia in this population is 52% and many times higher than that of the general Australian population. As per current guidelines, the recommended treatment is effective in over 80% at the 4-week interval. Community wide interventions are required to combat this alarming issue.