Frequency of immunoreactivity for Epo, EpoR and CD131 on neurons and glia. A-F. The degree of staining per tissue section with the various markers was semi-quantitated using the following grading scale: 0, no staining; 1, <1% cells staining; 2, 1%-10% of cells staining; 3, >10% cells staining. G-H. The relative abundance (r.a.) of CD131 to EpoR was determined for each brainstem section: 0, no staining for either CD131 or EpoR; 1, grade of immunolabelling for CD131 < EpoR; 2, grade of immunolabelling for CD131 = EpoR; 3, grade of immunolabelling for CD131 > EpoR. Each dot represents the results from a brainstem section of an individual patient. Results are divided into patient groups: NNC, non-neurological UK control; non-CM, non- cerebral malaria; CM, cerebral malaria; NC, neurological UK control (see Tables 1 & 2 for detailed patient descriptions).