The polyethylene glycol precipitation technique and the particle-counting immunoassay for detection of circulating immune complex-like material in liver cirrhosis and septicemia.

Both the PEG-N technique and the PACIA were applied to determine ICLM in sera from patients with liver cirrhosis and gram-negative septicemia, that have been shown to yield positive reactions for endotoxemia with the LAL test. The precision of the PEG precipitation technique, with a stabilized fraction of human HAG of known molecular size used as a calibrator, was satisfactory. In liver cirrhosis, the detectable ICLM was mainly composed of IgG and C3, whereas in gram-negative septicemia IgM, IgG, and C3 were found. PACIA also measured significantly elevated levels of ICLM with rheumatoid factor-binding activity in both patient groups, although the two assay systems did not correlate. PEG precipitates from both patient groups analyzed by gel-chromatography and passive hemolysis test contained large immune aggregates and various amounts of immunoglobulins with specificity directed toward lipid A, the least variable portion of endotoxin. These compositional differences of detected substances may imply the presence of different types of ICLM in patients with liver cirrhosis and gram-negative septicemia.