Abstract： Objective To evaluate the influence of serum estradiol,prolactin and testosterone levels on human leukocyte antigen-DR ( HLA-DR ),soluble myeloid cell receptor-1 (sTREM-1) and prognosis in patients with severe abdominal infection,in order to evaluate the clinical value of the above-mentioned sex hormones.Methods From July 10,2009 to February 9,2010,73 cases with severe intra-abdominal infections hospitalized in surgical intensive care unit ( ICU ) of Tianjin Nankai Hospital were enrolled.Within 72 hours after enrollment,serum estradiol,prolactin and testosterone levels were detected by radioimmunoassay.Based on their levels,all the cases were divided into increased estradiol group ( n=38 ) and non-increased estradiol group ( n=35 ),increased prolactin group ( n=28 )and non-increased prolactin group ( n=45 ),decreased testosterone group (n=33) and non-decreased testosterone group (n=40) respectively.In addition,H LA-DR (flow cytometry),as well as of sTREM-1 (enzyme linked immunosorbent assay ),acute physiology and chronic health evaluation Ⅱ ( APACHE Ⅱ ) score,hospital days,the ICU length,hospital costs and 28 day mortality were reco4rded.Results Compared with non-increased estradiol group,HLA-DR in increased estradiol group decreased significantly [(61.22 ± 22.39)％ vs. (75.09 ± 14.85)％],while sTREM-1 (ng/L) increased obviously (291.59 ± 148.13 vs.216.48 ± 124.82 ),APACHE Ⅱ score lowered dramatically ( 11.47 ± 6.88 vs.15.36 ± 8.79),hospital costs (ten thousands) raised significantly ( 10.98 ± 8.15 vs 6.25 ± 3.51 ),ICU length (days) was much shorter ( 8.56 ± 4.05 vs.12.17 ± 7.99 ),and 28 days mortality was significantly lowered ( 10.00％ vs.32.75％,P＜0.05 or P＜0.01 ).Compared with non-increased prolactin group,increased prolactin group had much lower HLA-DR levels [(61.19 ± 21.50)％ vs. (72.02 ± 18.49)％],higher sTREM-1 levels (307.92 ±173.93 vs.223.01 ± 106.93),at the same time,their cost of hospitalization (7.75 ± 3.52 vs.11.36 ± 8.24) and ICU stay length (9.14 ± 3.15 vs.13.24 ± 2.16) were significantly lower (all P＜0.05 ).Compared with non-decreased testosterone group,HLA-DR in decreased testosterone group increased significantly [(74.69 ± 14.72 )％ vs.(62.24 ±22.54)％ ],while sTREM-1 decreased obviously (208.77 ± 77.80 vs.294.20 ± 169.36),APACHE Ⅱ score lowered dramatically ( 10.57 ± 6.97 vs.15.39 ± 9.46),hospital costs decreased significantly (7.67 ± 3.81 vs.11.19 ± 8.05 ),and 28 days mortality lowered significantly (0 vs.30.14％,P＜0.05 or P＜0.01 ).Conclusion In the early stage of severe intra-abdominal infection,estrogen,prolactin and testosterone levels had powerful influences on immune,inflammation,and orognosis,which may indicated a widespread clinical application.