Chronic immunosuppression with anti-CD20 therapy can increase the risk of serious infections including complicated COVID19.

MS and NMOSD patients treated with ocrelizumab or rituximab at University Hospitals Cleveland Medical Center were evaluated. Patients hospitalized for any infection during their anti-CD20 therapy were identified and compared to those without infection-related hospitalizations. Significant differences were evaluated in a multivariate logistic regression model to identify predictors of serious infection.

There were 184 patients treated with anti-CD20 therapy (average age 48+/-13 years, 67% females, 84% MS). Of those, 21 (11%) patients had one or more serious infection during therapy including 16 MS patients treated with ocrelizumab and 5 NMOSD patients treated with rituximab. The most common serious infections were complicated COVID19 (9), bacterial skin infections (5), bacterial pneumonia (3), urosepsis (3), ocular infection (1), and disseminated shingles (1). Compared to those without serious infections, patients with serious infections had a higher average time on anti-CD20 therapy (1087.57±5 days vs 796.28±35 t= -2.61, P=0.005) and were more likely to have total lymphopenia (80% vs 40%; p=.004). There was a trend towards higher rates of hypogammaglobulinemia in patients with serious infections (24% vs 10%; P=.07). Logistic regression identified total lymphopenia (<1.0 x109/L) as an independent predictor of serious infection in patients treated with anti-CD20 therapy.

Serious infections are rare in MS and NMOSD patients treated with anti-CD20 therapies. Those with serious infections were exposed to treatment longer and more frequently had lymphopenia and hypogammglobulinemia. Total lymphopenia during therapy is an independent risk factor for serious infections.