There seem to be no differences in T lymphocyte populations between hospitalized and nonhospitalized patients with COVID-19 during anti-CD20 treatment, according to a case series published in CNS Neuroscience and Therapeutics. However, previous research has shown increased COVID-19 severity and a higher risk of death due to COVID-19 in patients treated with anti-CD20 medications.

The effect of the reduction of T-cell count due to anti-CD20 treatment on the risk of increased COVID-19 severity is still not well understood, which is what these researchers aimed to investigate.

The team led by Andrew Chan, MD, PhD, from the Department of Neurology at Bern University Hospital in Switzerland investigated whether T cell counts are different in patients treated with anti-CD20 medications with severe or mild COVID-19 courses. 

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The researchers analyzed 14 patients with multiple sclerosis or neuromyelitis optica spectrum disorder (NMOSD), aged 28 to 53 years receiving anti-CD20 treatments and who had COVID-19 while receiving the treatment.

The median expanded disability status scale score of the patients was 2. None of the patients apart from 1 were vaccinated against COVID-19. The median time between the last anti-CD20 infusion and COVID-19 infection was 4.4 months.

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The researchers found that there were no differences in the median number of T cell counts between patients who were hospitalized for COVID-19 and those who were not.

“One reason for negative results of our case series might be that the overall severity of COVID-19 was still relatively moderate without any death related to COVID-19,” the researchers wrote. They invite other researchers to share their data to overcome this limitation afflicted by the small sample size of this study.


Hoepner R, Kamm C, Friedli C, Salmen A, Chan A. Is COVID-19 severity associated with reduction in T lymphocytes in anti-CD20-treated people with multiple sclerosis or neuromyelitis optica spectrum disorder? CNS Neurosci Ther. Published online April 12, 2022. doi:10.1111/cns.13841