Many infants that undergo cardiac surgery develop an aged immune system

Infants that undergo cardiac surgery often have their thymus gland removed. The thymus performs important functions during the development of the immune system and a new study at Sahlgrenska Academy shows that infants, whose thymus was surgically removed, have an immune system at 18 years of age comparable to one normally seen in 65-70 year-olds.

Approximately 1 percent of all children are born with heart defects and, since the 1980s, the number of children undergoing corrective heart surgery during the newborn period has increased. 

During major cardiac surgery where the heart is accessed from the front the thymus gland, which is in the way and prevents access to the heart, is often removed. Today, approximately 250-300 children per year have their thymus glands removed in connection with cardiac surgery in Sweden. 

A new study at Sahlgrenska Academy, University of Gothenburg, has followed up children who have undergone cardiac surgery, where their thymus was removed. The children were examined before the operation, 18 months after the operation and at 18 years of age, to examine the immunological and clinical effects of having had their thymus removed. 

“Overall, the study shows that children who have had their thymus gland removed as infants have a greatly altered immune system at 18 years of age. This can be compared to how it normally appears at 65-70 years of age,” says Judith Gudmundsdottir, Pediatrician and PhD student at Sahlgrenska Academy. 

The results show that at 18 years of age, children had a clear immunological deviation, with an absence of newly generated T-cells, low numbers of T-cells with shortened telomeres and a deviant receptor repertoire. 

11 children born between 1993-1995 that had been operated on before the age of six months, at Queen Silvia’s Children’s Hospital that is part of Sahlgrenska University Hospital, were included in the follow-up study. 

“It is difficult to draw any definite conclusions as to the clinical implications of having the thymus removed, as the study contained a relatively small number of people. It is, however, clear that further studies are needed to eventually be able to recommend changed surgical methods where the thymus is not removed during cardiac surgery,” says Olov Ekwall, Professor and Consulting Physician at Sahlgrenska Academy. 

The study, Early thymectomy leads to premature immunological ageing; an 18-year follow-up is published in the Journal of Allergy and Clinical Immunology, one of the leading journals in clinical immunology, on 7 July. 

Contact:
Judith Gudmundsdottir, Pediatrician and Researcher, Sahlgrenska Academy, University of Gothenburg
+354 825 9362
judith.gudmundsdottir@gu.se 

Olov Ekwall, Consulting Physician and Professor, Sahlgrenska Academy, University of Gothenburg
+46 31 3438085, +46 709-554594
olov.ekwall@gu.se 

Johanna Hillgren
Press officer
Sahlgrenska academy, University of Gothenburg
+46 31-786 4029
+46 766-18 4029
johanna.hillgren@gu.se

The Sahlgrenska Academy is the faculty of health sciences at the University of Gothenburg. Education and research are conducted within the fields of pharmacy, medicine, odontology and health care sciences. About 4,000 undergraduate students and 1,200 postgraduate students are enrolled at Sahlgrenska Academy. Around 1,400 people work at the Sahlgrenska Academy, 850 of them are researchers and/or teachers. 2013 Sahlgrenska Academy had a turnover of 2,4 billion SEK.

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