Cytophilic antibodies to Plasmodium falciparum Glutamate Rich Protein are associated with malaria protection in an area of holoendemic transmission -: art. no. 48

Background: Several studies conducted in areas of medium or low malaria transmission intensity have found associations between malaria immunity and plasma antibody levels to glutamate rich protein ( GLURP). This study was conducted to analyse if a similar relationship could be documented in an area of intense malaria transmission. Methods: A six month longitudinal study was conducted in an area of holoendemic malaria transmission in north-eastern Tanzania, where the incidence of febrile malaria decreased sharply by the age of three years, and anaemia constituted a significant part of the malaria disease burden. Plasma antibodies to glutamate rich protein ( GLURP) were analysed and related with protection against malaria morbidity in models correcting for the effect of age. Results: The risk of febrile malaria episodes was reduced significantly in children with measurable anti-GLURP IgG1 antibodies at enrolment [ adjusted odds ratio: 0.39 (95% CI: 0.15, 0.99); P = 0.047]. Interestingly, there was an inverse relationship between the plasma anti- GLURP IgG1 and IgG3 levels and the levels of parasitaemia at enrolment. However, anti- GLURP IgG2 and IgG4 levels were not associated with reduction in parasite density. Similarly, antibody levels were not associated with haemoglobin levels or anaemia risk. Conclusion: Cytophilic IgG1 and IgG3 antibodies against R0-GLURP may contribute to the control of parasite multiplication and reduction in febrile malaria incidence in children living in an area of intense malaria transmission.