Fetal fat and "red spots" in newborn babies a defense against bacterial attacks

It is common that babies are born with fetal fat and develop red spots on their skin. Pediatricians have always explained this as a passing and normal skin reaction in newborn children. Now Giovanna Marchini at the Karolinska Hospital, Sweden, together with her research team, has discovered that this is a sign of a powerful immune defense system.

Fully 2000 years ago in Mesopotamia, an area roughly corresponding to today’s Iraq, doctors described spots on the skin of newborn babies as benign and passing. But not until now have doctors been able to explain what these spots result from.

It is now known that the spots are in all probability a sign of an immunological defense that develops as early as the fetal stage and is activated at delivery. This inborn defense consists of white blood corpuscles and functions at lightning speed, in the course of a few minutes. Even as a fetus the baby prepares itself to encounter the immediate and massive exposure to alien microbes that is part of its adjustment to life outside the womb.

Giovanna Marchini’s research team collaborates with scientists at the Karolinska Institute and the University of Aarhus, Denmark. They have found antibiotic-like substances in fetal fat, the white layer of fat that covers the skin of newborns. These body’s own antibiotic-like substances are also found in the skin and indicate an inborn capacity in newborns to ward off infections.

“Our studies show what enormous capacity newborn babies have to protect themselves from bacterial attacks. The reaction is so powerful that we can see it with the naked eye. The red spots are an immunological response that is activated when microbes come into direct contact with the cells of the skin. This reinforces the ability of the skin to resist attacks from bacteria. The inborn immune system also helps to maintain a microbial balance between the baby and the naturally occurring microbes on the skin and mucous linings,” says Giovanna Marchini.