Immunodiagnosis of ocular toxocariasis using Western-blot for the detection of specific anti-Toxocara IgG and CAP™ for the measurement of specific anti-Toxocara IgE

A prospective multicentric study was carried out to assess both the performance of Western-blot (WB) detecting specific anti-Toxocara IgG and that of CAP measuring specific IgE titre for the immunodiagnosis of ocular toxocariasis. For 14 outpatients presenting ophthalmic symptoms (choroiditis, chorioretinitis, papillar oedema, hyalitis, retinal detachment and/or uveitis), samples of serum and aqueous fluid (AF) were sent to the Department of Parasitology, University Hospitals, Toulouse, France. All patients but two tested positive with WB on the serum; 13 WB tests were performed on the AF, 12 of which were positive. The two patients who had a negative WB serum result tested positive for the AF. Specific IgE detection was considered as a complementary test of WB. Two patients showed a greater specific IgE titre in the AF than in the serum, and one had a positive result in the AF, but not in the serum. These six patients were considered as clear cases of ocular toxocariasis. Western-blot coupled with specific anti-Toxocara IgE detection appeared therefore to be an accurate procedure for the immunodiagnosis of ocular toxocariasis, provided the testing was simultaneously performed on the serum and AF.