Immunoblotting and Goldmann-Witmer Coefficient for Ocular Toxoplasmosis

Comparison of Immunoblotting (IgA and IgG) and the Goldmann-Witmer Coefficient for Diagnosis of Ocular Toxoplasmosis in Immunocompetent Patients

Ocular toxoplasmosis (OT) is a common cause of posterior uveitis worldwide. The diagnosis of OT is based on clinical findings, but in most cases, laboratory tests are required to confirm the etiology, especially when other diseases are suspected. The aim of this study was to evaluate which methods, between the Goldmann-Witmer coefficient (GWC) and immunoblotting (IB) with both IgG and IgA, in aqueous humour (AH) samples, can be the most sensitive to diagnose OT, in current practice, especially in the first three weeks.

Goldmann-Witmer coefficient (GWC): compares the levels of intraocular antibody (igG) production to that serum, as measured by ELISA.

GWC = (Level of specific IgG in aqueous humour/level of specific IgG in serum)/(Total IgG in aqueous humour/Total IgG in serum)

0.5 to 2: No intraocular antibody production, 2 to 4: Suggestive of intraocular antibody production, > 4: Diagnostic of intraocular antibody production to a specific microbial pathogen

Inclusion Criteria:

• Patients who had underwent aqueous humor and serum sample for ocular toxoplasmosis diagnosis

Exclusion Criteria:

• Immunocompromised patients