CTLA4 and malaria: Within CD4 and B cell subsets, tolerogenic responses appeared dominated by a major upregulation of IL10. Within CD4 T cells, the Tr1 cell subset was the most highly activated during malaria, and these cells had significantly increased transcription of both canonical cytokines IL10 and IFNγ, and multiple co-inhibitory receptors (including LAG3, OX40, TNFR2, GITR, TIM3 and CTLA4).