Immunoglobulin G and immunoglobulin M antibody responses of patients with malignancies to the O antigens of bacteria causing bacteremia.

Malignancy may be associated with impairment of the immune system. In children with acute leukemia, an impaired immunoglobulin M (IgM) antibody response to poliovirus was documented previously. It was of interest, therefore, to determine the immunoclass of antibodies produced against the O antigens of bacteria causing bacteremia in patients with leukemia and other malignancies. For control purposes, parallel studies were carried out in patients without maligancies but with infections caused by gram-negative bacteria. The patients with malignancies were adults, and those without malignancies were children. The serum specimens were selected from patients mounting an antibody response. IgG and IgM antibodies were identified by mercaptoethanol reduction and chromatography. Antibody titers against the O antigens of enteric bacteria were determined by the hemagglutination procedure. Antibodies of both IgM and IgG immunoclasses were produced by all but 1 of 16 patients with leukemia and by all but 1 of 12 subjects with other malignancies. Thus, a specific IgM immune deficiency in adult patients with leukemia or other malignancies complicated by bacteremia was not present; however, the magnitude of the antibody response of the patient with leukemia was less than that of the subjets with other maligancies, with the median antibody titers of the former being 320 and those of the latter being 2,560.