Ondracek AS, Hofbauer TM, Wurm R, et al. - In view of the observation that double-stranded (ds)DNA is released into circulation during systemic inflammatory responses and concomitant cell death, exerting pro-inflammatory effects and deoxyribonuclease (DNase) degrade dsDNA, researchers here investigated the role of DNase activity in out-of-hospital cardiac arrest (OHCA) survivors and its impact on clinical outcome. They determined dsDNA and DNase activity in 64 OHCA survivors at hospital admission (acute phase) and 24 hours (subacute phase) after return of spontaneous circulation in this prospective, single-center study. Of these patients, 26.6% (n = 17) died within 30 days. Observations revealed a strong predictive value of disproportionally increased dsDNA levels, that are uncompensated by DNase activity, for mortality in OHCA survivors. This work thereby suggests that DNase activity is potentially protective in patients undergoing cardiac arrest.