PDCD1 and malaria: The T follicular helper (Tfh) cells broadly express the chemokine receptor CXCR5, the transcriptional repressor BCL-6, and the inhibitory receptor programmed cell death protein 1 (PD-1) (Vinuesa and Cyster, 2011). Multiple reports have suggested that Tfh cells, locating at germinal center (GC), can promote protective antibody responses against malaria via providing selection, survival and maturation signal to differentiate GC B cells (Obeng-Adjei et al., 2015; Ryg-Cornejo et al., 2016; Figueiredo et al., 2017; Perez-Mazliah et al., 2017).