Role of serum complement, immunoglobulins, and cell-mediated immune system in the pathogenesis of spontaneous bacterial peritonitis (SBP).

Spontaneous bacterial peritonitis (SBP) is a common complication of advanced liver disease, which has a reported prevalence of between 4 and 27%. Frequent bacteremias due to inadequate host defense mechanisms, particularly the reticuloendothelial system (RES), with seeding of an ascitic fluid that lacks a normal opsonic activity, is believed to be the principal cause of SBP. Little data exist as to the role of serum levels of complement and immunoglobulins as well as the cell-mediated immune system in the pathogenesis of SBP. The aim of this study was to determine the serum levels of the third and fourth components of complement (C3, C4), total hemolytic complement activity (CH100), and properdin factor B (PFB) and immunoglobulins G, A, and M and various T-cell parameters in individuals admitted to hospital with ascites and advanced liver disease and to determine whether one or more of these factors could be used to predict the development of SBP in patients with advanced liver disease. Fourteen consecutive patients (nine male and five female; age 47.5 +/- 3.1 years, mean +/- SEM) with end-stage liver disease and ascites, who were evaluated for possible liver transplant at the University of Pittsburgh and who developed SBP, comprised the study group. The diagnosis of SBP was determined by positive ascitic fluid culture (three patients) and/or ascitic fluid neutrophil count of greater than 250 cells/mm3 (all patients). The control group consisted of 14 patients, matched for type of liver disease, age, and sex, who did not develop SBP.(ABSTRACT TRUNCATED AT 250 WORDS)