Evaluation of intrathecal synthesis of specific IgG antibodies against Toxoplasma gondii in the diagnosis assessment of presumptive toxoplasma encephalitis in aids patients

Abstract

The diagnosis of neurotoxoplasmosis in patients with acquired immunodeficiency syndrome is mainly based on tomographic or magnetic resonance findings and on the response to specific treatment. We studied 55 patients with AIDS and neurotoxoplasmosis according to these diagnostic criteria (group 1), 37 patients with AIDS and neurological involvement of other etiology (group 2), and 16 anti-HIV-negative individuals with neurological manifestations (group 3). Serum and cerebrospinal fluid were examined for the presence of anti-T. gondii IgG, by indirect immunofluorescence. In 72 of them, the total amounts of these antibodies were determined in order to assess local production of anti-T. gondii antibodies in the central nervous system and to correlate their titers with infection activity in patients with AIDS and neurotoxoplasmosis. IgG titers > 1/64 in cerebrospinal fluid reached 100% specificity for the diagnosis of neurotoxoplasmosis in AIDS. Evidence of local synthesis of these antibodies was detected in 42.8% of patients of group 1, in 29.1% of patients of group 2 and in no patient of group 3. The test showed 70.8% specificity and therefore was not useful in our study for the differential diagnosis of neurotoxoplasmosis in patients with AIDS.

Compartmentalized intrathecal immunoglobulin synthesis during HIV infection — A model of chronic CNS inflammation?

“…It could be of major theoretical importance to study the MRZ pattern in this context since HIV offers a unique opportunity to investigate chronic intrathecal inflammation lasting for years or even decades. During toxoplasmic encephalitis in AIDS, intrathecal synthesis against T. gondii (ASI) was observed in 43-78% of patients, 78% had local oligoclonal synthesis, and a high antibody index persisted after recovery (Contini et al, 2000;Borges and Figueiredo, 2004). Free light chains showed local oligoclonal banding of Kappa type in 8/9 patients and of Lambda type in 4/9 patients, and these bands demonstrated specificity toward T. gondii antigens (Contini et al, 2000).…”

Infections of the Central Nervous System in Patients Infected With Human Immunodeficiency Virus

“…The presence of antiToxoplasma IgG in CSF does not help establish a diagnosis of Toxoplasma encephalitis. However, in one study, a titer greater than or equal to 1:64 by immunofluorescence was 100% specific for a diagnosis of Toxoplasma encephalitis (Borges and Figueiredo, 2004).…”