Phagocytosed haemozoin pigment in tissular macrophages and circulating monocytes. (A) Sections of glomeruli observed at day 13 in the kidneys of mice infected with P. yoelii (P. y) or co-infected with P. yoelii and L. sigmodontis (P. y + L. s), showing macrophages containing phagocytosed plasmodial haemozoin pigment (arrows). (B) Zoom magnification of a macrophage with haemozoin pigment. (C) Monocytes with haemozoin pigment in the blood of mice infected with P. y or P. y + L. s, at day 13. (D) Kinetics of the circulating monocytes in the blood of infected mice; n = 10; the differences between the mono-infected and co-infected mice, and the modifications during the time course of the infection were analysed by a two-way analysis of variance. For each analysis the factor group and time effects were significant. Comparison between the groups for each time point was further assessed by Bonferroni’s multiple comparison test. Significant differences between the mice infected by P. y and by P. y + L. s are reported (*p < 0.05; ***p < 0.001). (E) Enumeration of the monocytes at the peak of the kinetics, containing haemozoin or not. Results are expressed as mean ± SEM; n = 10; the differences between the mono-infected and co-infected mice, and between the monocytes containing haemozoin and the monocytes containing no haemozoin were analysed by a two-way analysis of variance. No statistical significance was observed. Comparison between the groups was further assessed by Bonferroni’s multiple comparison test (p > 0.05). (F) Splenomegaly in mice infected with P. c and P. y. Results are the mean of spleen weight ± SEM at 13 and 30 days post-inoculation (D.p.i.), (n = 3–4).