[Determination of anti-Bartonella henselae antibody by indirect fluorescence antibody test--comparison of two types of antigen: non-cocultivated B. henselae and cocultivated B. henselae with Vero cells].

Serum anti-Bartonella henselae IgG and IgM antibody titers for the diagnosis of cat scratch disease (CSD) were determined by indirect fluorescence antibody (IFA) tests. B. henselae as antigen were harvested either by cocultivating with Vero cells (cocultivated B. henselae) or by cultivating without them (non-cocultivated B. henselae). Based on the results on 110 healthy adults, cut off values were set at 1:32 for IgG, and < 1:20 for IgM antibodies. According to these criteria, IgG antibody was positive in 2.7% of the 110 adults, while nobody was positive for IgM antibody. The titers did not change depending on the types of antigen used. On the other hand, IgG antibody titers against cocultivated B. henselae tended to be higher than those against non-cocultivated B. henselae in 33 CSD suspected patients; 75.8% of the patients were anti-B. henselae IgG positive when tested with cocultivated B. henselae as antigen, while only 48.5% of the same patients gave positive results with non-cocultivated B. henselae. Anti-B. henselae IgM antibody was positive in 24.2% of the 33 CSD suspected patients against both types antigen. Vero cells themselves seemed to nonspecifically bind some IgM (but not IgG). We recommended cocultivated B. henselae as antigen for IgG IFA, and non-cocultivated B. henselae for IgM IFA in the serological tests of CSD.