The platelet counts
were drastically reduced in WT, IFNAR1−/−, or IFN-γR1−/− mice on day 9 and 7 after either sporozoite or blood-stage PbA infection, respectively (Fig. 2C and D). They remained low for the next 3–4 weeks in ECM-resistant mice, confirming that thrombocytopenia RO4929097 is not an indicator of platelet sequestration in brain microvessels in this model, but may rather reflect decreased production or increased activation of platelets . WT mice showed a clear reduction in the number of circulating white blood cells (Fig. 2E and F), largely attributed to a decrease in the number of lymphocytes (Fig. 2G and H) on day 9 or 7 after either sporozoite or blood-stage LEE011 in vitro PbA infection, respectively. In contrast, in IFN-γR1−/− mice lymphocyte counts were increased on day 9 or 7 postinfection, and white blood cell and lymphocyte counts
further augmented to reach circa 100 × 103 cells/μL 3 weeks postinfection (Fig. 2E–H). IFNAR1−/− mice had white blood cell and lymphocyte counts similar to naive mice on day 9 after sporozoite PbA infection although they were as reduced as in infected WT mice on day 7 of blood-stage PbA infection (Fig. 2E–H). Thereafter, white blood cell and lymphocyte counts increased dramatically in the surviving IFNAR1−/− mice, similar to what was seen in IFN-γR1−/− mice, further augmenting to reach ca 100 × 103 cells/μL two to three weeks postinfection (Fig. 2E–H). Therefore, the partial or full resistance of IFNAR1−/− or IFN-γR1−/− mice to ECM development, respectively, was not associated with reduced thrombocytopenia, but with reduced lymphopenia Ergoloid and even leukocytosis. Since ECM sensibility and hematological alterations appeared largely independent of the PbA stage used for infection, the neuropathology of IFN pathway-deficient mice was further characterized by MRI and MRA in blood-stage PbA-infected mice. These noninvasive tools are used
in human patients for neurological disease investigation during CM [26-30]. In murine ECM, MRI/MRA allow a semiquantitative analysis of swelling/edema, focal ischemia, brain morphological changes, and microvascular pathology due to small vessel obstruction by erythrocytes and leukocytes and endothelial cell damage [30-33]. WT mice and mice deficient in type I and type II IFN pathways were examined at day 7 after blood-stage PbA infection, when sensitive mice are developing acute ECM. Typical MRI and MRA brain images are shown in Figure 3A and B, respectively. While WT mice presented distinct signs of ischemic brain damage, with brain stem swelling and cerebellum compression, and vascular blood flow perturbations after PbA infection, IFN-γR1−/− mice displayed normal MRI parameters without any sign of microvascular obstruction and IFNAR1−/− mice had an intermediate phenotype.