Extracellular histones are associated with the degree of brain swelling demonstrated on MRI scan. (A) Serum histone levels at admission in children who went on to die (Fatal; n = 24) and in those who survived (Nonfatal; n = 146). Differences between these groups were compared using a Student t test on log-transformed data. (B) Typical example of an MRI from a Malawian child with Ret⁺CM with a severely swollen brain (top) compared with an MRI from a Malawian child with Ret⁺CM with no swelling (bottom). (C) Circulating histones in children presenting with Ret⁺CM at different levels of brain swelling: those with no evidence of brain swelling or who woke up on the day of admission before they had a scan (n = 22) compared with mild (n = 22), moderate (n = 37), or severe brain swelling (n = 40). Black lines and error bars indicate geometric mean and 95% CI. Differences between the groups were compared by an ANOVA on log-transformed data with the Dunnett’s test to compare individual differences between no swelling and other swelling groups.