Immune cells tweak the body’s metabolism to help control obesity

Obesity has reached epic proportions in the United States and is rising in other developed and developing countries as they adopt our diet and lifestyle. Autoimmune diseases, like celiac disease and multiple sclerosis, and allergies, also immune-mediated, have blossomed recently, too.

These conditions have exploded within too short of a time period to be attributable to genetic changes, so environmental factors, from synthetic pesticides to plastics to antibiotics, have been blamed for their increased prevalence. While it's probably simplistic to search for one cause to explain away both these types of modern ills, some studies are indicating that immune cells and molecules are important for regulating metabolism—and are dysregulated in obesity.

A specific type of immune cells, called Group 2 innate lymphoid cells (ILC2s), were found in white adipose tissue in mice last year. Now, they have been found in the same tissue in humans. Obese people, along with obese mice, have fewer of these cells in their fat than lean individuals do.