Impact of anti-HLA antibodies on the immunological status of patients with cardiac allograft vasculopathy (CAV) after heart transplantation.

Purpose: Heart transplantation (HTx) is an established method of treating patients with end-stage heart failure. Properly selected immunosuppression effectively reduces the risk of acute transplant rejection; however, it may also lead to various side effects including cardiac allograft vasculopathy (CAV), which is one of the most common causes of death in patients during the first year after HTx. There is an urgent need to develop new strategies for monitoring a patient's immune system to modify the immunosuppressive therapy, if needed. The purpose of this study is to compare the immune status of patients with diagnosed CAV+ to that of patients without CAV-.

Material and methods: We collected blood samples from patients long-term after transplantation: 19 clinically stable patients CAV+ and 19 CAV-. Immunological parameters were assessed by analyzing lymphocyte subpopulations with flow cytometry and detecting the presence of alloantibodies with the use of Luminex technology.

Results: Statistical analysis demonstrated significant differences between CAV+ and CAV- patients only within the group of patients with detected alloantibodies (AlloAb+). The most notable observation is that a significantly higher proportion of CAV+AlloAb+ patients demonstrated the CD4+ T lymphocyte population expressing IL2 compared to CAV-AlloAb+ patients. Similarly, in these groups, we observed a prevalence of CD8+ lymphocytes expressing IFNγ+ and IL2+TNFα+IFNγ+.

Conclusion: Our study provides new evidence that the presence of alloantibodies in the bloodstream of patients after HTx impacts T cells activation and subsequent cytokine production. These data may facilitate establishing parameters that could help identify patients with a higher risk of CAV progression.