Effect of ABO blood group on asymptomatic, uncomplicated and placental Plasmodium falciparum infection: systematic review and meta-analysis

Abstract

Background: Malaria clinical outcomes vary by erythrocyte characteristics, including ABO blood group, but the effect of ABO blood group on asymptomatic, uncomplicated and placental Plasmodium falciparum (P. falciparum) infection remains unclear. We explored effects of ABO blood group on asymptomatic, uncomplicated and placental falciparum infection in the published literature.

Methods: A systematic review and meta-analysis was performed using the preferred reporting items for systematic reviews and meta-analyses guidelines. Articles in Pubmed, Embase, Web of Science, CINAHL and Cochrane Library published before February 04, 2017 were searched without restriction. Studies were included if they reported P. falciparum infection incidence or prevalence, stratified by ABO blood group.

Results: Of 1923 articles obtained from the five databases (Embase = 728, PubMed = 620, Web of Science = 549, CINAHL = 14, Cochrane Library = 12), 42 met criteria for systematic review and 37 for meta-analysis. Most studies (n = 30) were cross-sectional, seven were prospective cohort, and five were case-control studies. Meta-analysis showed similar odds of uncomplicated P. falciparum infection among individuals with blood group A (summary odds ratio [OR] 0.96, 15 studies), B (OR 0.89, 15 studies), AB (OR 0.85, 10 studies) and non-O (OR 0.95, 17 studies) as compared to those with blood group O. Meta-analysis of four cohort studies also showed similar risk of uncomplicated P. falciparum infection among individuals with blood group non-O and those with blood group O (summary relative risk [RR] 1.03). Meta-analysis of six studies showed similar odds of asymptomatic P. falciparum infection among individuals with blood group A (OR 1.05), B (OR 1.03), AB (OR 1.23), and non-O (OR 1.07) when compared to those with blood group O. However, odds of active placental P. falciparum infection was significantly lower in primiparous women with non-O blood groups (OR 0.46, 95% confidence interval [CI] 0.23 - 0.69, I² 0.0%, three studies), particularly in those with blood group A (OR 0.41, 95% CI 0.003 - 0.82, I² 1.4%, four studies) than those with blood group O.

Conclusions: This study suggests that ABO blood group may not affect susceptibility to asymptomatic and/or uncomplicated P. falciparum infection. However, blood group O primiparous women appear to be more susceptible to active placental P. falciparum infection.

Keywords: ABO blood type; Asymptomatic malaria; Placental malaria; Uncomplicated malaria.

Fig. 1

PRISMA flow diagram showing the number of articles retrieved, screened, excluded and included at each stage of the search

Fig. 2

Forest plot showing the odds of uncomplicated P. falciparum infection in individuals with blood group A, B, AB or non-O vs those with blood group O

Fig. 3

Forest plot showing the odds of asymptomatic P. falciparum infection in individuals with blood group A, B, AB or non-O vs those with blood group O

Fig. 4

Forest plot showing the odds of asymptomatic/uncomplicated P. falciparum infection in individuals with blood group A, B, AB or non-O vs those with blood group O