Despite having an overactive immune system, people with lupus may still struggle to fight bacterial infections. My team and I found that this paradox may be because chronic inflammation pushes their immune cells toward the wrong kind of response.

To understand why an overactive immune system can still fail to control bacterial infection, we focused on neutrophils, which are white blood cells that are among the first to respond when bacteria enter the body. Neutrophils can release webs of DNA and antimicrobial proteins called neutrophil extracellular traps, or NETs, that can trap bacteria, limiting their spread and killing them.

Scientists often discuss these traps as if they are all the same, but the body can produce NETs through different pathways, and they do not all work equally well.

For example, healthy neutrophils responding to infection from Staphylococcus aureus can sense lactate, a chemical byproduct made by the bacteria. That signal helps trigger neutrophils to release a type of NET that........

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