20-OR

• Published in: Human immunology 2012-10, Vol.73, p.17-17
• Main Authors: Wozniak, Laura J, Korin, Yael D, Lopez, Giovanni, Smith, Tiffany, McDiarmid, Sue V, Reed, Elaine F
• Format: Article
• Language: English
• Subjects: Allergy and Immunology
• ISSN: 0198-8859
• DOI: 10.1016/j.humimm.2012.07.052

Aim The aim of our study was to characterize regulatory immune cells in pediatric liver transplant (pLTx) recipients via immunophenotyping. We hypothesized the analysis would identify a distinct cellular profile of pLTx tolerance. Methods PBMCs were collected during routine visits from pLTx recipients classified as tolerant (TOL, normal liver function off immunosuppression, n = 9) or non-tolerant (NON-TOL, ⩾1 late rejection episode, on double/triple immunosuppression, n = 10). Immunophenotyping was performed with multi-color monoclonal antibody panels on an LSR Fortessa™ and analyzed with FCS Express V4. Stable pLTx recipients on tacrolimus (n = 8) and healthy, young-adult controls (n = 3) were used to establish and validate flow panels. Results As shown in the table, TOL patients had more mature naïve Bcells as well as switched and nonswitched memory Bcells. TOL patients had fewer central memory Tcells, more central naïve Tcells and a trend towards higher total Tregs. TOL patients had greater %CD56+ NKcells containing more cytotoxic (CD56+CD16+) NK and CD3-CD8dim cells. TOL patients had lower %PD-1+ monocytoid and plasmacytoid dendritic cells (DC). Conclusions Our data show a distinct regulatory immune cell profile that differentiates TOL and NON-TOL patients and that may contribute to increased regulatory cytokine production and/or inhibition of allospecific cells, ultimately creating a tolerogenic environment [ Table 1 ].