According to the results of a new American study, removing the thymus from patients undergoing chest surgery would be harmful to their health. Explanations from Dr Ivan Pourmir, oncologist at the Georges-Pompidou European Hospital (Paris).
The thymus is a gland located under the sternum, in the upper part of the thorax, near the lungs. The role of this organ is to produce certain white blood cells, T lymphocytes (T for thymus, precisely), which help our body to defend itself. American scientists have conducted a study which allows us to better understand its role
An organ removed during surgical operations
For this work, scientists studied the health data of 1,420 volunteers who had their thymus removed during an operation, compared to those of 6,021 volunteers who still had this organ and were therefore considered patient controls. They then compared the number of deaths of the participants, the occurrence of cancers and autoimmune diseases in the two groups.
Results 5 years after removal of the thymus (thymectomy), researchers noted:
- An increased risk of mortality for these patients with 8% deaths compared to 2.8% in the control group;
- An increased risk of cancer with 7.4% of patients in the group having undergone thymectomy compared to 3.7% in the control group;
- An increased risk of autoimmune diseases;
- A decrease in the production of T lymphocytes;
- A higher level of pro-inflammatory cytokines in the blood.
A link with the immune system?
In a statement, one of the authors, Dr. Kameron Kooshesh, an internist at Massachusetts General Hospital, states that “The magnitude of mortality and cancer in thymectomy patients was the biggest surprise to me. The results suggested to us that the absence of the thymus appears to disrupt fundamental aspects of immune function.The authors therefore conclude that thymectomy disrupts immune homeostasis and can lead to adverse health consequences. They recommend prioritizing preservation of the thymus as much as possible.
In a commentary accompanying the study, a specialist in autoimmune myasthenia gravis criticizes the lack of data in the study and believes that thymectomy remains useful in this indication.
Questioned, Dr. Ivan Pourmir, oncologist at the Georges-Pompidou European Hospital in Paris, finds the conclusions of this study interesting. However, he notes a factor of confusion “regarding the choice of patients, because very often, those who have undergone a thymectomy have had it because of cancer surgery, particularly lung cancer. They are therefore also naturally more at risk of relapse of their disease and in this type of study, with a large number of volunteers, it is often difficult to make adjustments..
Beyond this remark, the doctor finds it “useful” to highlight this link between the thymus, an active organ from birth to the end of adolescence, and immunity. “The thymus plays an important role in the maturation of T lymphocytes, particularly from birth to late adolescence. After its role declines, it becomes smaller and less active, but this study seems to show that its role remains important even after this period of life.”.