Antibodies that block inflammation

What they are

Monoclonal antibodies are medicines made to attach to a single target. The ones tested in schizophrenia block one inflammatory signal, such as interleukin-6, interleukin-1β or tumour necrosis factor, or stop immune cells from entering the brain. They were tested on the idea that inflammation contributes to the illness in some people, and recent trials include only people with signs of inflammation in their blood.^1,2

How well they work

Tocilizumab blocks the receptor for interleukin-6. In a US trial, 36 people with persistent symptoms received three monthly infusions or a placebo. Symptoms and thinking skills did not change, although the inflammation marker C-reactive protein (CRP) fell; the researchers suggest the medicine may not reach the brain.³ In England, the PIMS trial gave a single infusion only to people with raised interleukin-6, and measured the loss of pleasure and interest. It ended in November 2025, and its results have not been published.^1,4

Canakinumab blocks interleukin-1β. In an Australian trial, 27 people with schizophrenia and raised inflammation received one injection or a placebo. CRP fell, and hallucinations and delusions eased in the canakinumab group by eight weeks; but they also eased in the placebo group, earlier, at four weeks. People whose CRP fell more improved more.⁵

Natalizumab stops immune cells from crossing into the brain. In a London study of people with a first episode of psychosis, it did not change a brain-scan marker of the brain’s immune cells or the level of glutamate. Symptoms fell slightly in the natalizumab group.^6,7

Infliximab blocks tumour necrosis factor. A trial in the United States is recruiting people with schizophrenia who have a raised CRP and a marked loss of motivation.²

Side effects

In the tocilizumab trial, one person developed a severe drop in white blood cells (agranulocytosis), and two in each group had low neutrophil counts.³ In the canakinumab trial, 7 in 100 stopped treatment.⁵ The natalizumab study reported no serious side effects caused by the medicine.⁶

Alternatives

For psychosis caused by antibodies against nerve cells, immunotherapy (opens in a new tab) is the standard treatment. Other immune treatments tested in schizophrenia include rituximab (opens in a new tab), prednisolone (opens in a new tab) and minocycline (opens in a new tab).

What we don’t know yet

• Whether blocking a single inflammatory signal helps people with schizophrenia and raised inflammation.
• Whether these medicines reach the brain in amounts that matter.