Abstract： Objective To explore the mRNA expressions of NLRP1 (NOD-like receptor 1 ) and NLRP3 inflammasomescomponents and related pro-inflammation cytokines in peripheral blood mononuclear cells (PBMCs).Methods A total of 21 septic patients,20 non-infectious SIRS patients and 20 health subjects were enrolled in this study.The mRNA expressions of inflammasomes components and related proinflammation cytokines were measured by using RT-PCR,and serum levels of IL-1β and IL-18 were measured using ELISA.One-way ANOVA was usedd to compare the data of all three groups,and SNK-q was employed to compare thedata among different groups.Spearman correlation analysis was used to analyze the correlation between these biomarkers and the severity of septic patients.Results ①The mRNA expression of NLRP1 in PBMCs of septic patients in early stage and non-infectious SIRS patients was down-regulated in comparison with healthy subjects (P ＜0.01 ).The expression of NLRP3 in septic patients was not differentfrom that in healthy subjects ( P ＞ 0.05 ),but NLRP3 mRNA expression in non-infectious SIRS patients was significantly higher than that in septic patients and in healthy subjects ( P ＜ 0.01 ).ASC ( apoptosis associated speck like protein containing a CARD) and caspase-1 mRNA expressions in septic patients and non-infectious SIRS patients were higher than those in healthy subjects ( P ＜ 0.01 ).There was no difference in level of IL-1β found among all groups.IL-18 mRNA expression in septic patients and non-infectious SIRS patients was higher than that in healthy subjects ( P ＜ 0.01 ),and that in non-infectious SIRS patients was highest.②)Serum protein level of IL-1β in septic patients was lower than that in healthy subjects (P ＜0.05 ),and serum level of IL-18 in septic patients was significantly higher than that in non-infectious SIRS patients and in healthy subjects ( P ＜ 0.01 ).③NLRP1 was negatively related to SOFA ( sepsis-related organ failure assessment) score (r =-0.44,P ＜ 0.05 ) and negatively related to APACHE Ⅱ score as well ( r =- 0.52,P ＜ 0.05 ).Conclusions NLRP1 mRNA expression was down regulated in patients with early sepsis and its expression was negatively correlated to the severity of septic patients,indicating the lower NLRP1 mRNA expression the severer illness.