New research demonstrates that patients with multiple sclerosis (MS) who were asymptomatic for COVID-19 had lower antibody levels against SARS-CoV-2, its causative virus, due to having fewer B cells.
Previous research has shown that certain disease-modifying treatments (DMTs) can affect the immune system’s response to SARS-CoV-2, the virus that causes COVID-19, among patients with multiple sclerosis (MS), but also that additional factors can influence patient outcomes, such as greater disability.
Now research has been released that elucidates the immune system’s response among patients with MS who had asymptomatic COVID-19 infection, with B-cell depletion being a possible indicate of a less robust antibody response against SARS-CoV-2. These findings appear in a recent issue of JAMA Neurology.
“Limited information is available regarding SARS-CoV-2 antibodies in patients with MS,” the authors explained. “The objective of this study was to test for SARS-CoV-2 antibodies in a large MS cohort to evaluate asymptomatic infections and immunological responses to COVID-19.”
Overall, 23.6% of the 148 patients tested for COVID-19 via polymerase chain reaction (PCR) had positive results, and of this group, 82.6% were positive for antibodies. In addition, among the 76.4% testing negative via PCR, 18.4% had positive antibody results, and of this group, 14% had asymptomatic infection.
The most common symptom among those with positive antibody results was loss of taste and/or smell (47%).
In addition, antibody levels were less prevalent among the 74.2% of individuals who were on some sort of DMT. This part of the investigation compared injectable drugs (interferon β and glatiramer acetate) and other treatments, at 4% vs 13.1%, respectively (P = .04).
The findings from this prospective cohort study cover 546 patients (mean [SD] age, 46.9 [12.1] years; median 12 years since MS diagnosis; 71.1% women) from the MS Center Amsterdam in Amsterdam, the Netherlands, who were invited to participate on July 31, 2020. Data were collected through December 18, blood samples were drawn to confirm SARS-CoV-2 antibody levels, and questionnaires were distributed to gauge demographics, current MS complaints, and COVID-19 symptoms.
In particular, analysis also shows a lowered median (interquartile [IQR]) antibody response among patients on ocrelizumab vs other patients: 0.2 (IQR, 0.1-0.4) vs 2.5 (IQR, 0.6-2.5; P < .001) normalized optical density (nOD) units—a finding that echoes data presented earlier this year on ocrelizumab at the American Academy of Neurology annual meeting.
In the present study, an antibody measure was considered low if it ranged from 0.1 to 1.0 nOD and high if it came in above 1.0 nOD.
Limitations on findings include possible underrepresentation of patients with MS who had asymptomatic cases of COVID-19, “because patients may have been more willing to participate in this study after experiencing symptoms fitting COVID-19,” the authors noted, and the overall small percentage who were SARS-CoV-2 positive.
Still, the authors believe their findings hold merit, especially that B-cell depletion may be a risk factor for reduced SARS-CoV-2 antibody production.
“This holds important consequences for humoral immunity after COVID-19 infection and possibly vaccination,” they concluded.
van Kempen ZLE, Strijbis EMM, Al MMCT, et al. SARS-CoV-2 Antibodies in adult patients with multiple aclerosis in the Amsterdam MS cohort. JAMA Neurol. Published online April 30, 2021. doi:10.1001/jamaneurol.2021.1364