Abstract
BackgroundHost susceptibility to P.falciparum is critical for understanding malaria in pregnancy, its consequences for the mother and baby, and for improving malaria control in pregnant women. Yet host genetic factors which could influence placental malaria risk are little studied and there are no reports of the role of blood group polymorphisms on pregnancy outcomes in malaria endemic areas.This study analyses the association between ABO blood group phenotypes in relation to placental malaria pathology.MethodsA total of 198 mother/child pairs delivering in Banjul and the Kombo-St Mary District (The Gambia) were analysed. ABO blood group was measured by agglutination. Placental malaria parasites wee enumerated and the presence of malaria pigment noted. Birth anthropometry was recorded and placental weight. Maternal and infant haemoglobin was measured.Results89 (45%) subjects were primiparae and 110 (55%)multiparae. The ABO phenotype distribution was 38(A), 52(B), 6(AB) and 102(O). Placental histo-pathology showed active placental malaria in 74 (37%), past infection in 42 (21%) and no infection in 82 cases (41%). In primiparae blood group O was associated with a higher risk of active infection (OR = 2.99; 95% CI = 1.24–7.25), and a lower risk of past infection (OR = 0.31, 0.10–1.01, p < 0.05). In multiparae the O phenotype was associated with reduced prevalence of active or past placental infection (OR = 0.45; 95% CI 0.21–0.98). The mean feto-placental weight ratio was significantly higher in multiparae with group O women compared to non-O phenotypes (5.74 vs 5.36; p = 0.04). Among primiparae with active placental infection, mean birth weight was higher in children of mothers with the O phenotype (p = 0.04).ConclusionThese results indicate that blood group O was significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae. This parity related susceptibility was not present with other ABO phenotypes. Cell surface glycans, such as ABO and related antigens have special relevance in reproductive biology and could modulate specific cell interactions as those associated with the pathogenesis of placental malaria.
Highlights
Host susceptibility to P.falciparum is critical for understanding malaria in pregnancy, its consequences for the mother and baby, and for improving malaria control in pregnant women
These results indicate that blood group O was significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae
This parity related susceptibility was not present with other ABO phenotypes. Cell surface glycans, such as ABO and related antigens have special relevance in reproductive biology and could modulate specific cell interactions as those associated with the pathogenesis of placental malaria
Summary
Host susceptibility to P.falciparum is critical for understanding malaria in pregnancy, its consequences for the mother and baby, and for improving malaria control in pregnant women. Available preventive and therapeutic tools can only achieve a partial reduction in the health hazards caused by placental malaria [5,6] In this context, a better knowledge of host susceptibility to placental P.falciparum infection is central for improving understanding of malaria in pregnancy, as a basis for improved control. The protective role of several erythrocytic variants, some of them related to blood groups, is one of the best examples of this genetic modulation [8] These include haemoglobins S, C and E, α and β thalassaemias, Glucose-6phosphate dehydrogenase deficiency, Southern Asian Ovalocytosis, and Glycophorins A, B and C variants, all of which influence malaria pathogenesis [9]
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