[Longitudinal study of serological response to Bartonella henselae by indirect fluorescence assay in cat scratch disease].

Sequential serologic testing for IgG and IgM titers to Bartonella henselae were evaluated by an indirect fluorescence assay (IFA) in patients with CSD. The IFA test for the detection of IgG and IgM antibodies to B. henselae in 52 CSD patients showed that 40 (76.9%) were positive for IgG antibody and 9 (17.3%) were positive for IgM antibody. Two or more consecutive serum samples from 30 patients with CSD were assessed. In regard to the detection of IgG antibody, 5 patients had rapidly elevated titers in the acute phase, 12 patients had high titers from the acute phase, and 5 patients had a positive titer 24 weeks after the onset. B. henselae IgM antibody kinetics varied widely between patients with CSD. The seropositive rate for the antibody to B. henselae was analyzed at overtime after the onset and we found that the IgG-seropositive rate was high from 2 weeks after the onset and low after 25 weeks. The sensitivity of the IgM IFA was low, and IgM antibody to B. henslelae was not detected from 9 weeks. The detection from consecutive serum samples of antibodies to B. henselae by IFA is very useful for diagnosis in the case of clinically suspected CSD.