Application of specific IgG detection in intraocular fluid for the laboratory diagnosis of ocular toxocariasis

Abstract

Objective To evaluate the clinical value of detecting specific IgG against Toxocara canis in intraocular fluid for the diagnosis of ocular toxocariasis(OT). Methods Fifty patients diagnosed as having OT(OT group), 152 otolaryngology patients (serum control group) and 70 other oculopathy patients (intraocular fluid control group) were enrolled in the study. Intraocular fluids(28 aqueous humor and 22 vitreous humor) and serum samples of OT group were analyzed for specific IgG against Toxocara canis by enzymelinked immunosorbent assay, so were the intraocular fluids(46 aqueous humor and 24 vitreous humor) and 152 serum samples of two control group. Specific IgG level was compared between paired serum and intraocular fluids of OT group. Results 68.00% serum samples of OT group were positive for specific IgG against Toxocara canis and the U value was 20.42±17.01. The positive rate was 88.00% and U value 25.72±23.04 in intraocular fluids. In serum control group, it was 2.63% and 2.37±2.71 respectively. The intraocular fluids were negative and U value 0.69±0.34 in intraocular fluid control group. The difference of specific IgG level was proved significant between OT group and control group in both serum and intraocular fluid (Z=8.962, 8.120; P=0.000, 0.000). Twenty-eight patients (56.00%) were positive for specific IgG in both serum and intraocular fluid. Six patients (12.00%) were positive only in serum, and 16 patients (32.00%) only in intraocular fluid. The positive rate was significantly higher in intraocular fluid than in serum (χ2=4.720, P=0.028). Moreover, 64.00% intraocular fluid showed higher specific IgG level than pared serum. Conclusion The complementary detection of intraocular specific IgG have referential value in diagnosing ocular toxocariasis. Key words: Toxocariasis/diagnosis; Larva migrans; Toxascariasis; Immunoglobulin G/diagnostic use