Immunohistochemical Detection of Toxocaral Antigens in Human Liver Biopsies

The distribution of Toxocara species larval antigens in tissue was studied by immunohis tochemical techniques in five human cases of toxocariasis. Patients had a clinical his tory suggestive of the infection, a positive enzyme-linked immunosorbent assay test for toxocaral antibodies, and histopathologic patterns of toxocariasis. Liver biopsies were taken from all five patients, usually under suspicion of liver abscess or of meta static or primary liver neoplasia. In one case a segment of the right colon adjacent to the liver lesions was also examined. Immunohistochemical techniques using polyclonal antiserum raised in rabbits against excretory secretory (TES) antigens of Toxocara canis larvae detected antigen deposits phagocyte ed by macrophages at the periphery of eosinophil-rich granulomas, in the portal inflammatory infiltrate, between epithelioid cells close to the areas of necrosis, and sequestered in the collagen of the periportal region. Both nonabsorbed and Strongyloides venezuelensis and Ascaris suum absorbed sera essentially detected similar antigenic sites, but these sites were more frequently observed and more evident when the former was used. The importance of antigen detection for the etiologic diagnosis of eosinophilic granulomatous inflammation and eosinophil-rich inflammatory infiltrates is stressed. Int J Surg Pathol 2(2):117-124, 1994