['To assess the prevalence and predictive value of natural autoantibodies to high-mobility group box 1 (HMGB1) during sepsis.', 'Anti-HMGB1 and anti-human serum albumin (HSA) autoantibodies were detected by ELISA in 178 plasma samples longitudinally collected from 40 critically ill patients with septic shock. One hundred thirty-two plasma samples from healthy donors were used as control.', 'IgGs to HMGB1 were detected in 15/40 patients (37.5%). The prevalence of anti-HMGB1 antibodies was significantly higher in the patients who survived (55%) compared to the patients who did not (20%) (p<0.0001). The detection of anti-HMGB1 antibodies during the course of the disease was significantly associated with patient survival (p=0.038). Moreover, there is a progressive and significant emergence of anti-HMGB1 antibodies during the course of the disease, mostly in patients who survived.'] Is emergence of autoantibodies to HMGB1 associated with survival in patients with septic shock?