Progressive multifocal leukoencephalopathy associated with systemic lupus erythematosus: longitudinal observation of lymphocytes, JC virus in cerebrospinal fluid, and brain magnetic resonance imaging

Abstract

Abstract Progressive multifocal leukoencephalopathy (PML) rarely occurs in patients with systemic lupus erythematosus (SLE). This report presents a patient who developed PML due to SLE-associated lymphocytopenia. A 60-year-old woman diagnosed with SLE undergoing multiple immunosuppressive therapies, including azathioprine, presented with cerebral cortical symptoms, lymphocytopenia, and vitamin B12 deficiency and was subsequently diagnosed with SLE-associated PML. We evaluated the cause and disease activity of PML, focusing on the longitudinal assessment of lymphocytopenia, JC virus (JCV) DNA copy number in the cerebrospinal fluid, and magnetic resonance imaging (MRI) findings. Immunosuppressive therapy contributes to lymphocytopenia and PML; discontinuing azathioprine and initiating alternative immunosuppressive treatments (with intramuscular vitamin B12 injections) affected lymphocytopenia and disease management. The large hyperintense and punctate lesions observed on the fluid-attenuated inversion recovery images exhibited varying behaviors, indicating fluctuating PML disease activity. In addition, prominent hypointense signal rims were evident on susceptibility-weighted imaging during the late stages, particularly when JCV DNA copies were low. Clinicians should be meticulous when assessing the underlying pathology of lymphocytopenia owing to the multifactorial causes of PML due to SLE. This case’s time-dependent changes in lymphocytopenia, JCV DNA copy number, and MRI findings could provide clinicians with valuable assessment support.