Related Experiment Videos
Accelerated arteriosclerosis in heart transplant recipients is associated with a T-lymphocyte-mediated
R H Hruban1, W E Beschorner, W A Baumgartner
1Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland.
Insights
Accelerated arteriosclerosis in heart transplant recipients is linked to immune rejection. Studies show cytotoxic T-lymphocytes may drive this dangerous complication by attacking blood vessel linings.
Area of Science:
- Cardiovascular Pathology
- Transplantation Immunology
- Oncology
Background:
- Accelerated arteriosclerosis is a critical complication for heart transplant survivors.
- It is hypothesized to be an immune-mediated process related to transplant rejection.
Observation:
- Endothelialitis was observed in coronary arteries of explanted hearts from patients with severe transplant-related accelerated arteriosclerosis.
- A review of 23 heart transplant autopsy cases revealed significant pathological changes in coronary arteries.
Findings:
- Lymphocytic endothelialitis was more prevalent in recipients with accelerated arteriosclerosis (10/11) compared to those without (3/14).
- Immunohistochemistry identified T lymphocytes and macrophages in the subendothelial space, associated with smooth muscle cell proliferation.
- Detailed analysis of one explanted heart indicated cytotoxic T lymphocytes (CD8+, CD2+) were the predominant T cell type.
Implications:
- Cytotoxic T-lymphocyte-directed endothelialitis may be a key mechanism in accelerated arteriosclerosis post-heart transplantation.
- Understanding this immune response could lead to targeted therapies to prevent graft vasculopathy.
- Further research is needed to confirm the role of cytotoxic T cells in transplant arteriosclerosis.
Abstract:
Accelerated arteriosclerosis has emerged as a major life-threatening complication in long-term survivors of heart transplantation. It has been proposed that accelerated arteriosclerosis is an immune-mediated complication of rejection. We observed a striking endothelialitis in the coronary arteries of two explanted hearts obtained from patients with severe transplant-related accelerated arteriosclerosis. This finding prompted us to review the pathologic changes in the coronary arteries of 23 autopsied patients who had received heart transplants. The infiltrate in these vessels was characterized using immunohistochemical stains for lymphocytes (CD45), macrophages (MAC-387), T lymphocytes (CD45RO), B lymphocytes (L-26), and smooth muscle cells (actin). In addition, a full panel of monoclonal antibodies was used on the fresh-frozen tissue available from one of the two explanted hearts. Ten of the eleven recipients with accelerated arteriosclerosis had a moderate to marked lymphocytic endothelialitis compared to 3 of 14 without transplant-related arteriosclerosis (P less than 0.005). Immunohistochemical staining of the paraffin-embedded material demonstrated that most of the lymphocytes in the subendothelial space of these vessels were T lymphocytes and that this infiltrate was associated with an accumulation of macrophages and a proliferation of smooth muscle cells in the intima. In the explanted heart from which fresh-frozen tissue was available for more detailed cell typing, the T cells marked predominantly as cytotoxic T lymphocytes (CD8+, CD2+). These results suggest that accelerated arteriosclerosis may be mediated, in part, by a cytotoxic T-lymphocyte-directed endothelialitis.