Researchers trace antibodies behind severe viral infections

by Sara Lidman, Karolinska Institutet

edited by Lisa Lock, reviewed by Andrew Zinin

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Some people carry antibodies that block the body's early defenses against viruses, increasing their risk of developing severe illnesses such as severe COVID-19. Researchers at Karolinska Institutet have now identified the immune cells that produce these antibodies. Their findings are published in the Journal of Experimental Medicine.

When viruses infect the body, an important defense system is activated that relies on signaling proteins called interferons. In some individuals, however, antibodies are produced that block these signals, making it more difficult for the body to fight off infection. Such antibodies have previously been linked to severe COVID-19 and other serious viral infections.

In the new study, the researchers analyzed blood samples from patients with severe COVID-19 and from individuals with the rare disease APS-1. They were able to identify the B cells that produce the harmful antibodies and track how these cells develop.

"We have gained a clearer picture of where these antibodies come from. This may help us understand why some people are particularly vulnerable to severe viral infections. Our hope is that this knowledge will eventually contribute to improved diagnostics and new treatments," says Qiang Pan-Hammarström, professor at the Department of Medical Biochemistry and Biophysics at Karolinska Institutet.

The researchers also found differences between the disease groups. In patients with severe COVID-19, the neutralizing antibodies primarily originated from memory B cells. In APS-1 patients, they were mainly found in so-called atypical B cells, which are often associated with long-term immune activation.

Publication details

Rui Sun et al., Cellular origin and characterization of autoantibodies against type I IFNs in COVID-19 and APS-1, Journal of Experimental Medicine (2026). DOI: 10.1084/jem.20260268

Journal information: Journal of Experimental Medicine

Key medical concepts

neutralizing antibodiesMemory B Cells

Clinical categories

Allergy and immunologyInfectious diseases Provided by Karolinska Institutet Who's behind this story?

Lisa Lock

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Citation: Researchers trace antibodies behind severe viral infections (2026, November 3) retrieved 3 November 2026 from https://medicalxpress.com/news/2026-11-antibodies-severe-viral-infections.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.