Effect of thymectomy on cellular immune function

Abstract

The present study was conducted to evaluate the effect of thymectomy during open heart surgery on immunological function of T lymphocytes in the treatment of children with congenital heart disease (CHD). No significant difference was found in the sjTREC level between pre-thymectomy and post- thymectomy in the non-thymectomy group and the small partial resection group (P>0.05) However, the sjTREC level decreased from the pre-surgical level at 1 month (P<0.01) and 12 months (P<0.01) in the sub-total resection group. No differences were found in proportions of CD3, CD4 and CD8 lymphocytes, proliferative ability of lymphocytes and expression of IL-2, IL-4 and IFN-γ after surgery between controls and three groups of patients (P>0.05). In the sub-total resection group, respiratory infection frequency (4.7±1.7 times) did not differ significantly from control group one year after surgery (P>0.05); however, mean days of anti-infection were significantly increased (P less than 0.01). In conclusion, sub-total thymectomy leads to a decrease in the sjTREC level in CHD children, whereas the function of peripheral mature T lymphocytes is normal.

The significance of neonatal thymectomy for shaping the immune system in children with congenital heart defects

“…Results obtained by Cao et al showed that the number of naive, TREC-containing T cells may be associated with the size of the preserved thymus fragment. In the group of patients after partial thymectomy (< 50%), the number of TRECs increased after 3 months from the surgery, and preoperative levels were restored after a year; among the remaining patients (in whom more than half of the thymus was removed) the number of TRECs remained significantly lower than the preoperative values, and this effect persisted in the long term [ 30 ]. Thymectomy was also shown to be associated with a decrease in the TCR repertoire and the number of regulatory nTreg cells as well as an increase in the expression of cytokines such as IL-2, IFN-γ, and IL-4 [ 30 ].…”

“…The changes in the pool of immune system cells and the disturbances in cytokine expression indicate that thymectomy has a significant influence on the immune function of peripheral T cells, B cells, and cells responsible for congenital immune response [ 28 , 30 ]. Further clinical consequences of these changes are yet to be established.…”

“…Recent studies have shown that thymectomy leads to the production of antibodies with decreased antigen affinity. The results of these studies indicate that the thymus indirectly controls the process of the maturation and selection of B cells producing high-affinity antibodies [ 28 , 30 ].…”

“…Different results were obtained by Mancebo et al ; their data indicate that children thymectomized as neonates are not more predisposed to immune system diseases. Although such children are not more likely to contract infections, the duration of their treatment and hospitalization due to typical infectious diseases (e.g., bronchitis) is significantly longer [ 22 ], as is the time required for their immune system to recover from infections [ 27 , 30 ]. Detailed histopathological assessment and immunological diagnostics after thymus removal may lead to the early diagnosis of non-neoplastic hyperplastic diseases, such as histiocytosis [ 2 ] ( Tab.…”

Outcome after Robotic-Assisted Thymectomy in Children and Adolescents with Acetylcholine Receptor Antibody-Positive Juvenile Myasthenia Gravis

“…3,5 Up to now, there has been no evidence of a negative effect of thymectomy on T-cell function and acquired immune function. 6,7 On the other hand, cumulative steroid therapy has a potentially negative effect on growth and bone mineralization in children with JMG. 8 Thoracoscopic thymectomy seems to be as effective as an open sternal approach (median transsternal approach) in adults.…”