Indeed, we recently showed that BLIMP1 was required for Tr1 cell development in experimental malaria and VL (28), and results from the current study showed increased frequencies of splenic Th1 and Tr1 cells in P. chabaudi-infected B6.Bach2ΔT mice, despite reductions in overall CD4+ T cells numbers, relative to littermate controls. The gene discussed is CD4; the disease is malaria.