Persistence of Human Immunodeficiency Virus-Associated Cerebral Toxoplasmosis Lesions in Successfully Treated Patients Receiving Combination Antiretroviral Therapy

Background: Toxoplasmic encephalitis (TE) is a life-threatening complication of people with human immunodeficiency virus (PWH) with severe immunodeficiency, especially those with a CD4⁺ T-cell count <100 cells/µL. Following a clinical response to anti-Toxoplasma therapy, and immune reconstitution after initiation of combination antiretroviral therapy (ART), anti-Toxoplasma therapy can be discontinued with a low risk of relapse.

Methods: To better understand the evolution of magnetic resonance imaging (MRI)-defined TE lesions in PWH receiving ART, we undertook a retrospective study of PWH initially seen at the National Institutes of Health between 2001 and 2012, who had at least 2 serial MRI scans. Lesion size and change over time were calculated and correlated with clinical parameters.

Results: Among 24 PWH with TE and serial MRI scans, only 4 had complete clearance of lesions at the last MRI (follow-up, 0.09-5.8 years). Of 10 PWH off all anti-Toxoplasma therapy (median, 3.2 years after TE diagnosis), 6 had persistent MRI enhancement. In contrast, all 5 PWH seen in a pre-ART era study who were followed for >6 months had complete clearance of lesions. TE lesion area at diagnosis was associated with the absolute change in area (P < .0001).

Conclusions: Contrast enhancement can persist even when TE has been successfully treated and anti-Toxoplasma therapy has been stopped, highlighting the need to consider diagnostic alternatives in successfully treated patients with immune reconstitution presenting with new neurologic symptoms.