Serum antibodies against common antigens of bacterial lipopolysaccharides in healthy adults and in patients with multiple myeloma.

The incidence of infections caused by gram-negative bacteria is increased in patients with multiple myeloma due to secondary humoral immunodeficiency. In order to diagnose patients with increased susceptibility to gram-negative infections, serum antibodies against common determinants of lipopolysaccharides (lipid A and core-polysaccharide) were determined by a rapid enzyme-linked immunosorbent assay (ELISA). It was possible to define a group of patients at high risk of contracting gram-negative infections using this test. Intravenous IgG preparations used as a substitute were shown to contain antibodies against these common antigens. However, it is suggested that the clinically recognized efficacy of these preparations could be due to their containing anti-LPS antibodies.