Background and objectives: The literature on severe West Nile virus (WNV) neuroinvasive disease (WNND) in patients treated with anti-CD20 therapies is limited to case reports. We systematically characterize cases of WNND in the tertiary academic UCHealth system. Methods: A retrospective cohort (January 2016 to January 2024) of patients with a validated diagnosis of WNND and anti-CD20 medication use was identified with electronic medical record (EMR) query followed by individual chart review. Results: We identified 25 patients, of whom multiple sclerosis was the most common indication for anti-CD20 therapy in 13 patients (52%). 21 patients (84%) presented with meningoencephalitis. Cerebrospinal fluid (CSF) WNV IgM was positive in 5/21 patients (24%) who were tested, while 13/14 tested patients (93%) had positive RT-PCR findings in the CSF. MRI demonstrated anomalies associated with WNND in 12/23 patients (52%) with available imaging. ICU admission was required in 8 patients (32%) and 12 patients (48%) were treated with intravenous immunoglobulin. Worsening of ≥1 point from pre-WNV baseline modified Rankin scale (mRS) to the 90-day post-discharge mRS was seen in 18 patients (75%). Two patients (8%) died by 90-days. Discussion: WNND leads to disability accrual in patients on B-cell depleting anti-CD20 therapies. Utilization of RT-PCR is important in optimizing diagnosis due to limited sensitivity of antibody testing.

A.M. Carlson reports grant funding by Amgen which overlapped with the period in which this study was completed.

This study did not receive any funding.

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This retrospective cohort study was reviewed by the Colorado Multiple Institutional Review Board (COMIRB) and exempted based on secondary use of deidentified data. Patient consent was not required.

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