Novel treatment approach for autoimmune diseases with interleukin-2

A study conducted by the Department of Immunology at the University Hospital Zurich and the University of Zurich on patients with systemic lupus erythematosus shows the potential of interleukin-2 for the targeted treatment of autoimmune diseases.

In many cases, drugs that suppress the activity of the immune system are used to treat autoimmune diseases. Although this keeps the disease in check, this weakening of the immune system also increases the risk of infections and cancer. In a study conducted by the Department of Immunology at the University Hospital Zurich and the University of Zurich, a team of researchers led by Onur Boyman and Miro E. Raeber has now tested a novel therapy concept in 12 patients with systemic lupus erythematosus (SLE) for the first time in Switzerland.

“Lupus” can lead to severe organ damage

The majority of women of childbearing age are affected by SLE. The immune system attacks the body’s own healthy cells, triggering an inflammatory reaction that can lead to organ damage. The most common symptoms are pronounced tiredness (fatigue), migratory joint pain, dryness of the mucous membranes, hair loss and recurring mouth ulcers. The kidneys are affected in a third of those affected and a third also suffer from involvement of the nervous system, known as neuropsychiatric SLE. The disease can occur in episodes or be permanently active. The disease is not curable. In Switzerland, between 2000 and 4000 patients are affected by SLE.

Significant improvement due to interleukin-2

As part of the clinical trial, the participating SLE patients were treated with low-dose interleukin-2. This therapy led to a significant improvement in their symptoms, as measured by validated clinical scores. At the same time, an increase in so-called regulatory T cells was observed in the patients. These cells are a specialized subgroup of T lymphocytes that control immune activation. The researchers were able to show that interleukin-2 not only activated the regulatory T cells, but that specific subtypes with migration properties into specific tissues also increased as a result. These included subtypes of regulatory T cells that can migrate into the skin, the intestine and acutely inflamed tissue. Using skin biopsies taken from patients before and after interleukin-2 therapy and analyzed using highly parametric microscopy, the study also demonstrated for the first time the proliferation of these regulatory T cells in tissue affected by the disease.

Targeted elimination of harmful cells without weakening the immune system

The study thus not only represents the most detailed investigation to date into immune regulation by interleukin-2 in humans, but also demonstrates the great potential of interleukin-2 immunotherapy in that low-dose interleukin-2 can be used to specifically inhibit the activity of harmful immune cells without restricting the immune defense of microorganisms.