MPO and acute kidney injury: To get further insight to the role of neutrophil activation in the pathogenesis of PUUV-HFRS by we correlated the acute plasma levels of MPO, HNE, histone H3, and IL-8 to variables reflecting severity of AKI (maximum plasma creatinine level measured during the hospital stay), and to hematological variables (minimum blood platelet count, maximum blood leukocyte count, and plasma tissue plasminogen activator (tPA) level) (Table 1).