BACKGROUND: Endemic Burkitt's lymphoma (eBL) has been associated with Epstein-Barr virus (EBV) and holoendemic Plasmodium falciparum malaria. But recent evidence suggests that other risk factors are involved. METHODS: We hypothesised that selenoprotein glutathione peroxidase (GPx), a surrogate of nutritional status, is an important biomarker for eBL risk. We measured plasma GPx, anthropometric markers of malnutrition, EBV viral loads and malaria parasitaemia in children aged 1-9 years (n=258) from two locations in Nyanza Province, Kenya, with higher-than-expected and lower-than-expected incidence of eBL. The study participants were malaria asymptomatic children from the community. RESULTS: Children from eBL high-incidence areas had significantly lower GPx levels, high EBV viral load and more evidence of chronic malnutrition than children from eBL low-incidence areas (all P<0.001). Additionally, GPx levels were significantly lower in children with the highest EBV viral load and for those with P. falciparum infections (P=0.035 and P=0.004, respectively). CONCLUSIONS: These results suggest that selenium deficiency may be a risk factor for eBL.

Cross-sectional seroepidemiological studies of populations naturally exposed to Plasmodium falciparum suggest an association between protection from malaria and circulating antibodies to the carboxyl terminus of merozoite surface protein 1 (MSP1). Questions remain regarding the significance of cell-mediated immunity to MSP1 in conferring protection and inducing immunologic memory. Vaccine constructs have been based on the 42-kDa recombinant MSP1 protein (MSP1(42)), which includes the 19-kDa (MSP1(19)) and 33-kDa (MSP1(33)) fragments containing the major B- and T-cell epitopes, respectively. To evaluate T-cell responses to the MSP1(33) fragment, two libraries of overlapping 18-mer peptides from the 3D7 and FVO MSP1(33) regions were used to screen a cohort of asymptomatic Kenyan adults. Gamma interferon (IFN-gamma) measured by enzyme-linked immunospot assay (ELISPOT) at multiple time points assessed the magnitude and stability of these responses. The percentage of individuals with IFN-gamma responses to single MSP1(33) peptides ranged from nil to 24%, were clustered among a subset of peptides, and were not consistently recalled over time. In comparison to peptide responses, IFN-gamma ELISPOT responses to recombinant MSP1(42) were more prevalent, more frequently elicited by the 3D7 as opposed to the FVO allele, and more stable over time. The prevailing MSP1(33) genotype infection was 3D7, with few mixed infections and no sole FVO infections. This study demonstrates that immunity against MSP1(33) after cumulative natural infections consists of low-magnitude and difficult-to-detect IFN-gamma responses. Although immunity against MSP1 alone will not confer protection against malaria, demonstrating a relative and sustained increase in T-cell immunity to MSP1 after vaccination would be a reasonable measurement of vaccine responsiveness.