ABO and Rhesus blood group variability and their associations with clinical malaria presentations

Plasmodium falciparum infection is associated with the human ABO blood group. However, there is a paucity of data on the role that ABO and Rhesus blood groups play in malaria clinical presentations. Therefore, the objective of this study was to assess the association of human ABO blood groups and the Rhesus blood (Rh) types with the severity of malaria.

This cross-sectional study was carried out at the Suhum Government Hospital in the Eastern region of Ghana. Conveniently, study participants with malaria, diagnosed by microscopy, were selected into the study. Subsequently, their ABO and Rh blood groups were determined (Accucare ABO/Rh monoclonal antibodies, Chennai, India). Malaria severity was assessed using the criteria for assessing severe malarial anaemia published by the World Health Organization. According to the criteria, severe malarial anaemia was classified as having haemoglobin (Hb) < 5 g/dL for children < 12 years and in patients ≥ 12 years, Hb level < 7 g/dL, with parasitaemia > 10,000/µL in both cases. Severe malarial anaemia was also classified as having plasma bilirubin > 50 µmol/L with parasitaemia ≥ 100,000/µL, for all ages. Chi square statistical analysis was used to test the association between the blood groups and the clinical or laboratory findings, while multivariate analysis was performed to identify which blood groups were more vulnerable to develop severe malarial anaemia.

Of the total number of the study participants (n = 328), most of the patients had blood group O Rh positive (35.7%) while few of them had blood group AB Rh negative (2.1%). The types of Rhesus did not associate with malaria. However, compared to blood group O, the odds of developing severe malarial anaemia, in children < 12 years and in patients ≥ 12 years, were 16 times and 17.8 times higher among patients with blood group A, respectively. Furthermore, the odds of having bilirubin level > 50 µmol/L with parasitaemia ≥ 100,000 /µL was 10 times higher among patients with blood groups A and 2.6 times higher in patients with blood group B, compared to blood group O. Finally, in patients with blood group A majority (71.6%) of them developed high temperature (> 37.5 °C) while 43.3% of them vomited and had diarrhoea. However, pallor (group B = 46.2% vs group A = 37.3%), fever (group B = 84.6% vs group A = 79.1%) and nausea (group B = 46.2% vs group A = 25.4%) were more frequent in patients with blood group B than A.

This study found that people with blood groups A and B were severely affected by malaria, with group A being the most vulnerable. It is recommended that blood group assessment be performed for all patients with malaria. Patients found to have blood group A or B must be promptly and efficiently managed to avoid the development of severe malaria anaemia.