Long Term Effects of Early Childhood Thymectomy: A Population-Based Cohort Study of Association with Autoimmune Disease, Cancer, Infectious and Atopic Diseases

Judith Gudmundsdottir^1,2, Jonas Söderling³, Håkan Berggren⁴, Sólveig Óskarsdóttir⁵, Martin Neovius⁶, Olof Stephansson³ and Olov Ekwall^7,8, ¹Dept of Rheumatology and Inflammation Research, The Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, ²Children's Medical Center, Landspítali University Hospital, Reykjavík, Iceland, ³Clinical Epidemiology Unit, Dept of Medicine, Karolinska Institute, Stockholm, Sweden, ⁴Dept of Molecular and Clinical Medicine, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, ⁵Dept of Pediatrics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, ⁶Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden, ⁷Dept. of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy University of Gothenburg, Göteborg, Sweden, ⁸Dept of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden

Meeting: 2017 ACR/ARHP Annual Meeting

Date of first publication: September 18, 2017

Keywords: Autoimmunity and tolerance

Session Information

Date: Sunday, November 5, 2017

Title: Epidemiology and Public Health II: Non-Genetic Risk Factors for Incident Disease

Session Type: ACR Concurrent Abstract Session

Session Time: 4:30PM-6:00PM

Background/Purpose:

The thymus is the site of T cell maturation and selection and thus of vital importance for the development of immunological tolerance. Early thymectomy is routinely performed in infants undergoing surgical correction of congenital heart defects. Various immunological changes have been described after early thymectomy but the long-term clinical consequences are unknown. The aim of this study was to investigate the association between early thymectomy and risks of autoimmune disease, cancer, infectious and atopic diseases.

Methods:

The study is a nationwide population-based cohort study using the Medical Birth, Cause of Death and National Patient Registers in Sweden. We identified 5664 individuals born in 1973-2009 thymectomized before five years of age. For each individual, ten age and sex matched general population controls as well as 2276 surgery controls who had undergone early cardiac surgery, not involving thymectomy, were included. The main outcomes were incidence rates and hazard ratios for selected autoimmune diseases, cancer, infectious and atopic diseases.

Results:

Compared to the surgery controls, thymectomized individuals were at increased risk for hypothyroidism (HR 3.03; 95%CI 1.17-7.83), type 1 diabetes (HR 3.16; 95%CI 1.08-9.21) and both viral (HR 1.40; 95%CI 1.30-1.50) and bacterial (HR 1.26; 95%CI 1.11-1.43) infections. The HR for asthma was reduced (HR 0.69; 95%CI 0.58-0.83). Compared to the general population, increased risks were detected for hypothyroidism (HR 4.94; 95%CI 3.27-7.46), juvenile idiopathic arthritis (HR 1.85; 95%CI 1.11-3.09), rheumatic diseases (HR 1.89; 95%CI 1.00-3.57), celiac disease (HR 1.96; 95%CI 1.42-2.72), cancer (HR 1.61; 95%CI 1.07-2.43), infections (HR 3.18; 95%CI 3.07-3.30) and asthma (HR 1.84; 95%CI 1.64-2.07) in thymectomized individuals.

Conclusion:

In conclusion, early thymectomy is associated with increased risks of autoimmune disease, cancer as well as infectious disease. The study implicates important roles for the post-natal human thymus for the preservation of immunological tolerance as well as for immune effector functions. The results also indicate that avoidance of total thymectomy during early cardiac surgery may be advisable.

Disclosure: J. Gudmundsdottir, None; J. Söderling, None; H. Berggren, None; S. Óskarsdóttir, None; M. Neovius, Pfizer Inc, 2,AstraZeneca, 2,Pfizer Inc, 5; O. Stephansson, None; O. Ekwall, None.

To cite this abstract in AMA style:

Gudmundsdottir J, Söderling J, Berggren H, Óskarsdóttir S, Neovius M, Stephansson O, Ekwall O. Long Term Effects of Early Childhood Thymectomy: A Population-Based Cohort Study of Association with Autoimmune Disease, Cancer, Infectious and Atopic Diseases [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/long-term-effects-of-early-childhood-thymectomy-a-population-based-cohort-study-of-association-with-autoimmune-disease-cancer-infectious-and-atopic-diseases/. Accessed .

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