Conclusion
This study shows that HbAS children develop a larger memory CD8+ T cell compartment than HbAA children, and associates this compartment with better control of subsequent onset of infection and parasite density. Our data suggest that central memory CD8+ T cells may play an important role in the relative protection against malaria experienced by HbAS individuals, and further work to investigate this is warranted.
Methods
Subsets of memory T cells and NK cells were analysed by flow cytometry in paired samples collected from HbAS and HbAA children, at baseline and during the first malaria episode of the ensuing transmission season. Correlations between cell frequencies and features of HbAS-mediated protection from malaria were determined.
Results
HbAS children displayed significantly higher frequency of memory CD8+ T cells at baseline than HbAA children. Baseline frequency of memory CD8+ T cells correlated with features of HbAS-mediated protection from malaria. Exploration of memory CD8+ T cell subsets revealed that central memory CD8+ T cell frequency was higher in HbAS children than in HbAA children.