Differential recognition of ABO blood groups by IgG and IgM from Plasmodium vivax patients

Background - The destruction of uninfected RBCs has been associated with anaemia in malaria but the mechanisms involved in their clearance remain unknown, particularly in regard to Plasmodium vivax. One of the factors that could contribute to this destruction is self-antibodies produced during the infection. However, few studies have concerned the relationship between autoimmunity and anaemia in P. vivax infections. The aim of this study was to evaluate the possible associations between IgG or IgM antibody responses against erythrocytes from different blood groups (A, B and O) and anaemia in patients infected with P. vivax. Materials and methods: Cell-ELISA assays were performed using erythrocytes from healthy donors never exposed to malaria whose blood groups were A, B or O. Patients with uncomplicated vivax malaria residing in low endemic areas in the Brazilian Amazon basin (n = 75) were evaluated. Results and conclusions: The IgG recognition against blood group A erythrocytes molecules was lower than that observed for both B and O blood groups. On the other hand, the IgM response to the red blood cells of group B were less recognized in comparison to erythrocytes from the other two blood groups. Moreover, no significant association was found between exposure or parasitaemia and antibody response against membrane molecules of the three different blood groups tested. However, negative associations between haemoglobin and IgG or IgM antibodies were observed. Interestingly, regardless the blood group tested, IgG and IgM antibody responses were higher for the anaemic patients compared to the non-anaemic ones. These represents one important step aiming to understanding the relationship between ABO blood group and anaemia in during P. vivax infection.