A 34-year-old HIV-positive man on HAART presented with 1-month history of cerebellar ataxia. His CD4 count was 30 cells/microL. A CT scan of the brain showed hypodensity in the left cerebellar hemisphere and generalised cerebral atrophy. MRI was requested, which showed multiple high-signal changes on T2-weighted imaging involving the pons and right cerebellar hemisphere with some enhancement post contrast (Figure 2). No restriction was noted on DWI. Tests for toxoplasmosis were negative, and CSF yielded no growth. The JC virus was positive in the CSF. The patient was treated with triple antibiotic therapy, as well as anti-tuberculosis medication. The possibility of a CNS IRIS was considered, and a course of steroids was added. The HAART was optimised and the patient was discharged to a rehabilitation unit.