Immunohistochemical study of lymph nodes in patients with cat scratch disease.
OBJECTIVE
Bartonella henselaeis the causative agent of cat scratch disease (CSD), manifesting as fever and acute regional lymphadenopathy. Although serologic testing is the reference method for diagnosis, successful use of immunohistochemical (IHC) stain of regional lymph nodes for the diagnosis of CSD has been reported. To determine the characterization and diagnostic potential of IHC in lymphadenopathy of CSD, lymph nodes were excised from patients with suspected CSD for further evaluation.


METHODS
Polyclonal antibody-based IHC studies were performed for the detection of B. henselae. Between January 2001 and December 2004, the reference laboratory of the Center for Disease Control, Taiwan, received a total of 377 sera from 352 reported suspected CSD cases. Twenty-three formalin-fixed paraffin-embedded lymph nodes from 16 patients and two skin biopsies from two patients suspected of having CSD were included in this study. Nine of them were serologically confirmed to have CSD and the others were seronegative but suspected to have CSD by the attending physicians. Seven lymph node specimens were obtained from tuberculosis patients for comparison.


RESULTS
We demonstrated that the microorganisms existed in the cytoplasm of histiocytes within the granulomatous lesions in nine lymph nodes and one skin biopsy. Among the nine lymph nodes with IHC (+) stains, three were seronegative. On the other hand, three cases were IHC (+) and six cases were IHC (-) among nine seronegative patients. In addition, two seronegative patients with skin biopsy showed one IHC (+) and one IHC (-).


CONCLUSIONS
IHC can contribute to the etiologic diagnosis of B. henselaelymphadenopathy when serology and molecular techniques are not available.
Lin
Ying-You
YY
Graduate Institute of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
Hsiao
Cheng-Hsiang
CH
Hsu
Yung-Hsiang
YH
Lee
Chin-Cheng
CC
Tsai
Hsiang-Jung
HJ
Pan
Ming-Jeng
MJ
D000328:Adult; D002372:Cat-Scratch Disease / Q000382:microbiology*; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000382:microbiology*; D008206:Lymphatic Diseases / Q000382:microbiology*; D008297:Male