Effect of Immunosuppression on Target Blood Immune Cells Within 1 Year After Lung Transplantation: Influence of Age on T Lymphocytes

Background: Lymphocytes are targeted by immunosuppressive therapy in solid organ transplantation and they influence allograft outcome. Material/Methods: Peripheral blood lymphocyte subsets (PBLS) determined by flow cytometry during the first year post-transplant from patients who underwent a first lung transplantation in a French University Hospital between December 2011 and July 2013 were retrospectively analyzed according to recipient characteristics and allograft outcome. Results: Fifty-seven recipients were enrolled and 890 PBLS were collected. T lymphocytes and NK cells were rapidly decreased, below normal range, from the first postoperative days. B cells decreased more gradually, remaining within normal range, with the lowest level reached after day 100. In multivariate analysis, greater T lymphopenia was found in older recipients (-414 [-709 to -119] cells/mu L, p=0.007). According to the outcome, multivariate analysis evidenced lower levels of lymphocytes when bacterial and viral infection occurred (-177 [-310 to -44] cells/mu L, p= 0.009 and (-601 [-984 to -218] cells/mu L, p=0.002, respectively), higher CD8+ T lymphocytes with BOS (+324 [+94 to + 553] cells/mu L, p=0.006), and higher leukocytes with restrictive allograft syndrome (+3770 [+418 to +7122] cells/mu L, p= 0.028). Conclusions: Aging is associated in our cohort with more severe T lymphopenia after induction therapy for lung transplantation. The analysis of leukocytes and PBLS is associated with specific profile according to the allograft outcome.