Progressive multifocal leukoencephalopathy and black fungus in a patient with rheumatoid arthritis without severe lymphocytopenia

Abstract

Although peripheral lymphocyte counts were never low and CD4 T-cell count was close to normal, the persistent black fungus infection was a hallmark of severely compromised cellular immunity. The unexpected extremely low absolute B-cell count might suggest a protective role for B-cells. The paradoxical, clinical PML onset months after immunosuppressive discontinuation suggests that it was only discovered in the context of an immune reconstitution inflammatory syndrome.