Obesity leaves a "trace" in immune cells, scientists have discovered

Scientists have discovered that obesity can leave a long-lasting "imprint" on the human immune system that persists even after weight loss and increases the risk of diabetes and certain forms of cancer. This is according to a study published in the journal EMBO Reports.

A research team from the University of Birmingham found that T-helper cells of the immune system retain a kind of "memory" of obesity. This memory is formed through epigenetic changes — DNA methylation, in which chemical tags are attached to the genetic material of cells.

According to the scientists, such changes can persist for five to ten years after weight loss. As a result, immune cells continue to function as if the body were still in a state of obesity. This can disrupt tissue clearance processes, inflammation regulation, and accelerate age-related changes in the immune system.

The study is based on the analysis of blood and tissue samples from several groups of people: patients with obesity, volunteers after weight loss, participants in physical training programs, and patients with rare genetic forms of obesity. Additionally, the scientists studied data from experiments on mice and cell models.

The results showed that even after body weight normalization, the immune system can retain an "imprint" of the previous metabolic state. This means that the risk of developing obesity-related diseases — including type 2 diabetes and certain forms of cancer — may remain elevated for a long time after weight loss.

The researchers note that disruptions in autophagy — the cellular clearance mechanism — and accelerated aging of immune cells play a key role in this process. These changes form a lasting restructuring of immune system function.

The authors emphasize that the findings do not mean that disease is inevitable, but point to the need for long-term maintenance of a healthy weight. Looking ahead, the scientists are exploring the possibility of developing therapies that could "overwrite" the immune memory of obesity and restore normal cell function.