Early aqueous humor analysis in patients with human ocular toxoplasmosis.
To evaluate the diagnostic sensitivity of a panel of laboratory tests for ocular toxoplasmosis performed at the time of presentation, paired samples of aqueous humor and serum were collected from 49 consecutive episodes of ocular toxoplasmosis with a clinical course of less than 3 weeks. Total immunoglobulin G (IgG) and Toxoplasma gondii-specific IgG, IgM, and IgA were quantified by enzyme-linked immunosorbent assay. The avidity of T. gondii-specific IgG was determined, and DNA extracted from aqueous humor was amplified for detection of a glycoprotein B gene sequence of T. gondii. The diagnosis was confirmed for 73% (36 of 49) of the patients; this rate rose to 79.5% if data from a later analysis of aqueous humor derived from five of the negative patients were included. The analysis of serum (detection of T. gondii-specific IgM and analysis of consecutive serum samples) alone did not contribute to the diagnosis. Calculation of local antibody production lacked diagnostic sensitivity when it was determined less than 3 weeks after the manifestation of clinical symptoms (28 of 49 patients [57%]), but this rose to 70% after an analysis of a second aqueous humor sample. The antibody avidity index attained diagnostic significance in only 8 of 43 instances (19%), and T. gondii DNA was amplified from no more than 6 of 39 (16%) aqueous humor samples. However, T. gondii-specific IgA was found within the aqueous humors of 11 of 43 patients (26%); measurement of the T. gondii-specific IgA level thus contributed substantially to the diagnostic sensitivity of the laboratory tests.
Garweg
J G
JG
Department of Ophthalmology, University of Bern, Inselspital, CH-3010 Bern, Switzerland. justus.garweg@insel.ch
Jacquier
P
P
Boehnke
M
M
D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis*; D000917:Antibody Formation; D000918:Antibody Specificity; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D001082:Aqueous Humor / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D002955:Leucovorin / Q000627:therapeutic use; D011739:Pyrimethamine / Q000627:therapeutic use; D012680:Sensitivity and Specificity; D013411:Sulfadiazine / Q000627:therapeutic use; D014122:Toxoplasma / Q000276:immunology*; D014126:Toxoplasmosis, Ocular / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology*
D000913:Antibodies, Protozoan; D000981:Antiprotozoal Agents; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D013411:Sulfadiazine; D002955:Leucovorin; D011739:Pyrimethamine