Progressive multifocal leukoencephalopathy secondary to idiopathic CD4 lymphocytopenia treated with pembrolizumab

Abstract

Background: Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease due to a lytic infection of oligodendrocytes caused by John Cunningham polyoma virus (JCV) infection. Idiopathic CD4+ T-cell lymphocytopenia (ICL) is a very rare cause of PML.

Methods: We present an individual with PML secondary to ICL treated with 3 doses of pembrolizumab, a Programmed-Death-1 Immune Checkpoint Inhibitor following with complete resolution of symptoms and conduct a review of the literature.

Conclusion: This report illustrates the objective clinical and radiological improvement in a patient with PML due to ICL and suggests further study of immune checkpoint inhibitors as potential treatment for patients with PML.

Keywords: Idiopathic lymphocytopenia; John Cunningham Virus; Neuroinflammation; PD-1 Checkpoint Inhibitor; Pembrolizumab; Progressive multifocal leukoencephalopathy.