Utility of Bartonella henselae IgM Western Blot Bands for Serodiagnosis of Cat Scratch Disease

Abstract

We evaluated the utility of Western blot (WB) bands of Bartonella henselae in detecting anti-B. henselae immunoglobulin M (IgM) for serodiagnosis of cat scratch disease (CSD). IgM band patterns were examined using sera from 92 patients clinically suspected of having CSD and from 130 healthy individuals. Positive WB bands were observed in 49 (53.5%) of the 92 patient sera. Three bands at 8 to 10, 31 to 35, and 70 kDa were regarded as relevant for B. henselae because all of the positive sera yielded at least one of the three bands, and none of the healthy control sera showed reactivity to any of them. In contrast, the positive rate of the patient sera by conventional indirect fluorescence antibody assay (IFA) for B. henselae IgM was 28.3% (26/92) among the patients. These finding suggest that the IgM-WB assay, although cumbersome to perform, can be used for confirmatory diagnosis of CSD with no false positivity in the control sera. Purification of proteins in the specific bands may contribute to the development of an IgM enzyme-linked immunosorbent assay (IgM-ELISA) with improved specificity and sensitivity.

Keywords: Bartonella henselae; IgM Western blot; cat scratch disease; serodiagnosis.

FIG 1

Typical patterns of IgM Western blot analysis using Bartonella henselae whole-cell antigens. Western blot analysis was performed by use of B. henselae whole-cell antigens to examine the reactivities of anti-B. henselae IgM from the sera of 7 representative patients suspected of having cat scratch disease (P1 to P7) and 3 healthy control individuals (C1 to C3). Molecular size markers (kDa) are indicated in the left margin.