Tofacitinib-induced Progressive Multifocal Leukoencephalopathy with Immune Reconstitution Inflammatory Syndrome.

Background: Progressive multifocal leukoencephalopathy (PML) with subsequent immune reconstitution inflammatory syndrome (IRIS) is a rare disease associated with compromised immune systems. It has never been described in a patient taking tofacitinib.

Case Presentation: A 49-year-old woman with history of systemic lupus erythematous treated with tofacitinib presented with several weeks of intermittent fevers and altered mental status. MRI revealed multifocal T2-weighted FLAIR hyperintensities in the subcortical white matter, including the subcortical U-fibers, without mass effect or contrast enhancement, compatible with PML. Tofacitinib was stopped and the patient's symptoms initially improved. However, the patient presented again less than a week after discharge with three days of left arm weakness, left facial droop, dysarthria, and one day of confusion. Repeat MRI demonstrated interval progression in T2/FLAIR hyperintensities with development of patchy gadolinium enhancement on T1-post contrasted sequences, consistent with development of IRIS in the setting of tofacitinib cessation.

Discussion: This is the first case describing PML-IRIS in the setting of administration and subsequent cessation of tofacitinib.