Aqueous humor analysis as a diagnostic tool in toxoplasma uveitis

Abstract

Analysis of local toxoplasma antibody production to confirm a suspected clinical diagnosis of toxoplasma chorioretinitis is a valuable diagnostic tool. Determination of toxoplasma antibodies in the blood of the patient is of limited use. When blood toxoplasma tests are negative this indicates that toxoplasma as a causative organisms in the pathogenesis of uveitis is unlikely. A positive blood test is a sensitive test (100% patients positive) but not a specific test since so many healthy individuals already have undergone subclinical infection and have acquired humoral immunity against the parasite. We analysed 93 paired aqueous and serum samples for toxoplasma antibodies and total IgG and determined the Goldmann-Wittmer coefficient. In patients retrospectively diagnosed as having toxoplasma chorioretinitis 16 out of 22 had a positive coefficient, indicating local parasite antibody production. In one patient with AIDS we also found a positive toxoplasma coefficient. Three out of 15 patients with posterior uveitis of unknown origin also had a positive coefficient. None of the cataract patients tested (n = 32) had a positive coefficient. Major drawbacks of aqueous humor analysis are that a false negative antibody coefficient can occur when a massive blood aqueous barrier breakdown has occurred.

Infectious Uveitis in Immunocompromised Patients and the Diagnostic Value of Polymerase Chain Reaction and Goldmann-Witmer Coefficient in Aqueous Analysis

“…[7][8][9][10] Consequently, the analysis of intraocular fluids constitutes an important tool for a correct and quick diagnosis. 3,11,12 Polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) analysis of aqueous humor play a prominent role in the diagnosis of viral and Toxoplasma infections in immunocompetent patients. 11,[13][14][15][16][17] In immunocompromised patients, PCR analysis is preferred because the production of antibodies is unpredictable.…”

“…3,11,12 Polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) analysis of aqueous humor play a prominent role in the diagnosis of viral and Toxoplasma infections in immunocompetent patients. 11,[13][14][15][16][17] In immunocompromised patients, PCR analysis is preferred because the production of antibodies is unpredictable. 3,7 However, immunodeficient patients with a positive GWC were reported previously.…”

“…3,7 However, immunodeficient patients with a positive GWC were reported previously. 11,12 The diagnostic value of both techniques in immunocompromised patients is not known. In this report, the specific diagnoses of 56 immunocompromised patients with intraocular inflammation were assessed and the diagnostic value of PCR and GWC analysis performed on aqueous humor was determined.…”

“…3,17 The GWC was considered positive when its value exceeded 3. 11,18 None of the samples was inhibited during PCR analysis or were unable to be analyzed for the presence of antibody. Of the 56 samples, 27 were analyzed at the NORI and 29 at the UMCU.…”

Virus Diagnostics and Antiviral Therapy in Acute Retinal Necrosis (ARN)

“…Moreover, there are serological crossreactivites between HSV and VZV (Pepose et al, 1992). Finally, the intraocular antibody generation can be variable in immunosuppressed or HIV-infected patients (de Boer et al, 1996;Doornenbal et al, 1996;Kijlstra et al, 1989Kijlstra et al, , 1990). …”