Tumor necrosis factor gene polymorphism and septic shock in surgical infection

Introduction: During surgical infection, excessive tumor necrosis factor (TNF) production may induce uncontrolled inflammatory response and higher mortality. Genetic polymorphism. TNF2 allele was associated with higher baseline and induced TNF mRNA expression than TANF1 allele. The study was to evaluate the genotype distribution of TNF2 allele with regard to the development of septic shock, mortality and plasma TNF concentration in patients with surgical infection. Methods: We prospectively enrolled 104 postoperative critically ill patients who had a definite focus of infection that was verified during surgical intervention and positive a blood culture. Blood sample was obtained at 24 hr after ICU admission and within 2 hr after the onset of septic shock to determine plasma TNF level and genotype analysis of biallelic polymorphism of the TNF by Ncol RELP. Patients were followed up for the development of septic shock and outcome. Results: Thirty-six patients (34%) fulfill the criteria of septic shock during their ICU stay. The frequency of the TNF2 polymorphism was 18 % in our critically infected patients. The TNF2 allele patients did not have higher incidence of septic shock than TNF1(41% vs. 37%). The mortality rate was similar between TNF2 and TNF1 patients (57 vs.49%). In the subgroup of patients who developed septic shock, the TNF2 allele patients had a significantly higher mortality rate than TNF1 allele patients (87 vs.66%). In regard to plasma TNF level, the baseline TNF level was not different between TNF1 and TNF2 allele patients. Only in those patients who developed septic shock, the TNF2 allele had significantly higher peak TNF level than TNF1 allele (987.4 ± 102.5. vs. 658 ± 89.4 pg/ml). Conclusions: Our study found that the patients with surgical infection and need ICU admission have a higher TNF2 allele frequency than general population (18% vs. 5.1). The TNF2 allele ICU patients are not more prone to the development of septic shock nor had higher baseline TNF level after a severe infection. Only in patients who developed septic shock, those with TNF2 allele had significantly higher plasma TNF level and mortality rate than TNF1 allele patients.