When you are infected by a germ, you have two kinds of immune defences: innate immunity and acquired immunity.

Innate immunity is critical for babies as their main protection against bacteria and other germs, because acquired immunity has not fully developed. This makes monocytes – white blood cells from the innate immune system – critical. Monocytes not only provide immunity but they also form the basis for the development of acquired immunity through special communication molecules.

Shanie Saghafian Hedengren has studied monocytes. Hedengren says that if monocytes are not stimulated by microbes and viruses, the resulting imbalance in monocyte function may play a role in developing allergies.

Hedengren’s doctoral dissertation details a study of a group of children and the Epstein-Barr virus (EBV). The children were followed from birth to age five. Contracting EBV before 2 was correlated to lower risk of antibodies against allergens (which is a marker for allergic sensitization). However, contracting EBV after age 2 was related to a greater risk of allergic sensitization.

EBV is a very common virus. Most of us carry some of this virus throughout our lifetimes. EBV is considered a successful virus because it is easily spread by saliva and usually infects humans very early in life.

Most of us hardly notice this infection. While later in life, a person may develop a glandular fever, children often have a very mild disease with this virus.

Hedengren’s dissertation shows how innate immunity is mitigated by EBV-infection. This also may explain the mild effect the virus has on infants and toddlers. However, newborns may have a weaker monocyte reaction to microbes if they have an allergic mother. Hedegren’s advises even more adequate immune stimulation for these children, to help avoid allergies later, in the form of lots of loving kisses – all for the sake of the little immune systems, of course.

Source: Science News