Serum anti-lipid A antibodies in multiple myeloma and Waldenström's macroglobulinaemia.

Anti-lipid A antibodies were determined in sera from 38 patients with IgG multiple myeloma, 33 patients with IgA multiple myeloma and 38 patients with Waldenström's macroglobulinaemia using an enzyme-linked immunosorbent assay (ELISA). Compared to 34 healthy adults, significantly (p less than 0.025, p less than 0.005, p less than 0.0025) lower serum anti-lipid A antibody levels were measured for the respective patient groups. Low anti-lipid A antibody levels correlated with a higher infection rate with gram-negative bacteria in patients with monoclonal B-cell malignancies. The highest infection rate was seen in patients with simultaneous low anti-lipid A levels and secondary antibody deficiency.