Immunologic Aging in Adults with Congenital Heart Disease: Does Infant Sternotomy Matter?

Thymectomy is performed routinely in infants undergoing cardiothoracic surgery. Children post-sternotomy have decreased numbers of T lymphocytes, although the mechanisms involved and long-term consequences of this have not been defined. We hypothesized that lymphopenia in patients with adult congenital heart disease (ACHD) would be reflective of premature T cell maturation and exhaustion. Adults with ACHD who had sternotomy to repair congenital heart disease as infants (<1 year) and age-matched ACHD patients without prior sternotomy were studied using polychromatic flow cytometry interrogating markers of lymphocyte maturation, exhaustion and senescence. Group differences were analyzed using Mann-Whitney U and Fisher's exact tests. Eighteen ACHD patients aged 21-40 years participated: 10 cases and 8 controls. Median age at sternotomy for cases was 52 days. Cases and controls were matched for age (28.9 vs. 29.1 years; p = 0.83), gender (p = 0.15) and race (p = 0.62) and had similar case complexity. Cases had a lower mean percentage of cytotoxic CD8 lymphocytes compared to controls (26.8 vs. 33.9 %; p = 0.016), with fewer naive, undifferentiated CD8 T cells (31.0 vs. 53.6 %; p = 0.027). CD8 cells expressing PD1, a marker of immune exhaustion, trended higher in cases versus controls (25.6 vs. 19.0 %; p = 0.083). Mean percentage of CD4 cells was higher in cases versus controls (65.6 vs. 59.6 %; p = 0.027), without differences in CD4 T cell maturation subtype. In summary, ACHD patients who undergo sternotomy as infants exhibit differences in T lymphocyte composition compared to ACHD controls, suggesting accelerated immunologic exhaustion. Investigation is warranted to assess the progressive nature and clinical impact of this immune phenotypic change.

Duke Scholars

Author Allan Douglas Kirk Surgery, Abdominal Transplant Surgery