Analysis of saliva for antibodies to the LPS of Escherichia coli O157 in patients with serum antibodies to E. coli O157 LPS.

The salivary antibody response to the Escherichia coli O157 LPS antigen was assessed in 44 patients with serum antibodies binding to the LPS of E. coli O157. Saliva from 477 controls was also examined to assess the specificity of the immunoassay used. Twenty of the 44 patients had salivary antibodies to E. coli O157 LPS, giving the salivary antibody test a sensitivity of 0.45 and a predictive positive value for seropositivity of 1.00. The presence of these antibodies appeared not to relate to the time interval between serum sampling and saliva sampling. None of the 477 volunteers had salivary antibodies binding to the LPS of E. coli O157 alone; however, 15 had antibodies which bound non-specifically to both O157 LPS and BSA.