Immune reconstitution is not a prognostic factor in progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is typically associated with minimal inflammation; however, patients may develop an inflammatory response due to immune reconstitution (IRIS). The authors aimed to determine if characteristics and outcomes of PML are altered in those with IRIS. A retrospective records review was performed on 87 patients diagnosed with PML at Johns Hopkins, 27 of which had a syndrome consistent with IRIS. Gadolinium enhancement on MRI occurred in 44.4% of cases of PML-IRIS versus 5.1% in PML (p < 0.05), and thus had low diagnostic sensitivity and specificity. In HIV+ cases, CD4 counts were lower in those who later developed IRIS (mean 34.8 vs. 71.7, p < 0.05) and was predictive of the development of IRIS (p < 0.05). Improved prognosis was seen with higher cerebrospinal fluid (CSF) white blood cell counts and protein levels, but not for gadolinium enhancement and there were no differences in survival for PML versus PML-IRIS.