Pathology of immune reconstitution inflammatory syndrome in multiple sclerosis with natalizumab-associated progressive multifocal leukoencephalopathy

摘要: Natalizumab is an approved medication for highly active multiple sclerosis (MS). Progressive multifocal leukoencephalopathy (PML) may occur as a severe side effect of this drug. Here, we describe pathological and radiological characteristics immune reconstitution inflammatory syndrome (IRIS), which occurs in natalizumab-associated PML after the cessation therapy, differentiate it from ongoing PML. Brain biopsy tissue MRI scans five MS patients with were analyzed their histology compared non-MS Histology showed extensive CD8-dominated T cell infiltrate numerous macrophages within lesions, nondemyelinated white grey matter, four out cases. Few or no virally infected cells found. This was indicative IRIS known HIV Outstandingly high numbers plasma present to typical lesions. compatible IRIS, revealing enlarging lesions band-like speckled contrast enhancement either at lesion edge Only fifth patient pathology, low inflammation cells. similar interval between drug withdrawal (3.5 months) rest cohort (range 2.5–4 months). could not PML-associated We detail histopathology PML–IRIS, infection, exacerbation be impossible discern clinically alone. provide some clues distinguishing different pathologies that can differentiated histologically. In our individual cases, helped clarify diagnoses