The sera of patients with Klebsiella infections contain a common anti-DNA idiotype (16/6) Id and anti-polynucleotide activity.

In view of recent reports linking Klebsiella pneumoniae with autoimmunity, we have examined the sera of 52 patients with urinary tract infection or septicaemia from this Gram-negative pathogen, for the presence of antibodies to DNA, polynucleotides, cardiolipin and a common anti-DNA idiotype 16/6. Up to 27% of these patients had anti-polynucleotide antibodies detectable, and in 37% the 16/6 idiotype was found. Absorption of the sera of two patients, with no DNA binding, against the Klebsiella polysaccharide K-30 induced a significant fall in both their anti-K30 antibody and 16/6 idiotype levels. Among 52 patients with other Gram negative infections a maximum of 17% and 19% respectively, had anti-DNA antibodies and the 16/6 idiotype present in their serum. In 37 normal controls, the rate of antibody and idiotype detection was 5% or less. The presence of autoantibodies in the serum of patients with Klebsiella infections may be the result of non-specific stimulation due to bacterial polyclonal activation. However, there might also be a specific stimulus triggered by idiotypic cross-reaction between autoantibodies and anti-Klebsiella antibodies.

Profile of autoantibodies in the serum of patients with tuberculosis, klebsiella and other gram-negative infections.

Autoantibody profiles were examined in the sera of untreated patients with tuberculosis, and those with klebsiella septicaemia, and klebsiella and E. coli urinary tract infections. Rheumatoid factors of the IgM, IgA and IgG isotypes, antinuclear antibodies and antibodies to poly(ADP-ribose) were all frequently detected (generally 15-40%). In contrast, antibodies to the extractable nuclear antigens and to the organ specific antigens were unusual (generally less than 10%). In comparison, in a group of lupus patients IgM rheumatoid factor, anti-nuclear antibodies, antibodies to poly(ADP-ribose) and antibodies to the extractable nuclear antigens were more frequently found, but IgA and IgG rheumatoid factors and antibodies to the organ-specific antigens were present in much the same frequency.

Preferential secretion of a common anti-DNA idiotype (16/6 Id) and anti-polynucleotide antibodies by normal mononuclear cells following stimulation with Klebsiella pneumoniae.

Peripheral blood mononuclear cells derived from 6 normal subjects were incubated with 5 polyclonal activators (pokeweed mitogen, Epstein-Barr virus, group-A Streptococcus, Staphylococcus aureus and Klebsiella pneumoniae. After 7 days of incubation, the supernatants were examined for immunoglobulin (IgG and IgM) production, the level of a common anti-DNA idiotype (16/6 Id) and autoantibody activity against ssDNA, dsDNA, poly(I), poly(dT) and cardiolipin. Significantly increased levels of the 16/6 Id were recorded only with the Klebsiella stimulated MNC. Increased immunoglobulin levels and autoantibody reactivity were noted with all 5 polyclonal activators. The Klebsiella cell membrane preparation induced the highest values. No correlation was found between the 16/6 levels, autoantibody activity and the absolute concentrations of IgG or IgM. This study, together with previous reports, suggests a role for Klebsiella in the etiology of autoimmune diseases. We suggest that Klebsiella can induce anti-DNA-like autoantibodies not only by polyclonal activation, but also by a more specific stimulus.