Researchers have long known that obesity rewires the immune system. Now a new study suggests these effects can be so profound they could turn a drug meant to treat a common inflammatory disease into one that makes things worse.
Scientists discovered that mice with atopic dermatitis, a painful and itchy skin rash often triggered by an allergic reaction, were worse off if they were obese. A closer look at their immune responses led to a surprise finding: Different immune cell types drove the disease in obese versus lean mice. That caused a standard treatment to exacerbate symptoms in heavier animals, but adding another drug that made the immune response of the obese mice resemble those of lean animals made the treatment regimen work again.