The researchers have investigated the role of the small organ thymus, or the bristle, for the regulation of immune during pregnancy. Tymus has a central role for developing an important group of immune cells, T cells (T stand for thymus). T cells act as a leader type that determines how the immune system responds. Body cells should be tolerated while overseas substances such as bacteria and viruses are assaulted.
Despite the central role of the thymus in the immune system, it is not known if the thymus function changes during pregnancy. The information we have about thymus today is mainly from studies in mice. The general perception, based on animal studies, is that the tymus reduces the size during pregnancy and the outflow decreases, so fewer T cells are discharged from the thumbs.
Immune system has weakened in animals but not in humans
In animals, fewer T cells cause the immune system to weaken, resulting in fetal tolerance. But does it work the same among people? To answer that question, researchers investigated the outflow of different types of T cells in the blood of 56 pregnant and non-pregnant women. A special type of T cells, known as regulatory T cells, are particularly interesting because they can prevent other immune cells and prevent them from attacking the body's own tissues.
– We show that women have a steady outflow of T cells of tumor during pregnancy. It was also noted that the outflow of regulatory T cells that can prevent immune response appears to increase during pregnancy. The findings can explain why fetal tolerance and infection continuity, "said Sandra Hellberg, a PhD student in the Department of Clinical and Experimental Medicine, and one of the researchers behind his / her study.
It can be important for autonomous diseases
The discovery can also be important for some automatic illnesses, where the immune system begins to attack the body's own cells. Many autoimmune diseases are associated with a thymus function, for example multiple sclerosis (MS), where the brain and the spinal cord are damaged by the immune system.
"In MS, previous research has shown the role of reduced Tumus and T cell outflow, which could explain why the symptoms of women with MS often improve during pregnancy," said Professor Jan Ernerudh, Head of Study .
The research team now intends to investigate the tumor function in women with MS who followed, during and after pregnancy, to see if changes in the balance between different types of T cells could be a factor contributing to why women with MS often improve during pregnancy.
The study was carried out in conjunction with the University Hospital in Linköping, Mödrahälsovården in Vrinnevisjukhuset in Norrköping and Karolinska Institutet in Stockholm. The research was funded with support, among others, the Swedish Research Council and the Research Council in south-east Sweden, FORSS.
"Conservative output of conventional and regulatory T cells during human pregnancy", Sandra Hellberg, Ratnesh B. Mehta, Anna Forsberg, Göran Berg, Jan Brynhildsen, Ola Winqvist, Maria C. Jenmalm and Jan Ernerudh, (2018), Journal of Alergy and Clinical Immunology, published online October 9, 2018, link: 10.1016 / j.jaci.2018.09.023