Immune system of newborn babies is stronger than previously thought

A new study led by King's College London has found that newborn babies have a strong immune defense system. The study was published in Nature Medicine and revealed that newborn immune T-cells may have the ability to trigger an inflammatory response to bacteria.

The human immune system is made up of several different types of immune cells, including T-cells, which target cells infected with viruses and microbes.

Before now, it was believed that babies had an immature immune system. The general belief was that newborn immune systems did not trigger the same inflammatory response to foreign bacteria as in adults.

It was thought that babies' T-cells were suppressed to prevent inflammatory damage to the developing child.

The King's College team were not convinced of this notion and set out to investigate the properties of T-cells. The study examined very small samples of blood in twenty-eight highly premature babies, as they developed over the first few weeks of life.

Analysis of these blood samples let to the discovery that T-cells in newborn babies are signficantly different to the T-cells in adults. Further analysis revealed that this difference is not because newborns are immunosuppressed. In fact, newborns produce a potent anti-bacterial molecule known as IL8 that activates the immune response to attack foreign invaders.

Dr Deena Gibbons, lead author of the study explained: "We found that babies have an in-built anti-bacterial defense mechanism that works differently to adults, but nevertheless may be effective in protecting them. This may also be a mechanism by which the baby protects itself in the womb from infections of the mother. The next stage of our work will be to better understand the pathways that result in the immune cells of newborns being so different to those in adults."

This revelation in T-cell activity could become beneficial for boosting the immune systems of neonatal babies being cared for in intensive care units (ICU). These ICU environments have a major infection risk, which impacts on the survival of patients.

This research is also a great advancement for the health of premature babies who can develop inflammatory diseases such as Necrotising Enterocolitis (NEC), which destroys tissues in the gut. NEC currently has a mortality rate of 20-40% in Australian premature babies.