An effective immune-monitoring protocol based on gene expression profiles in the peripheral T-cell fraction reactive to graft antigens.

Background: The ability to induce tolerance, or at least minimize the need for immunosuppressive therapy, is a high priority in organ transplantation. Accomplishing this goal requires a novel method for determining when a patient has become tolerant to or is rejecting their graft. Here, we sought to develop an efficient monitoring protocol based on gene expression profiles of recipient T cells in murine skin and islet allograft models.

Methods: Unlike previous studies, here, gene expression analysis was focused on donor antigen-reactive T cells, which were prepared by collecting CD69(+) T cells from cocultures of recipient peripheral T cells and donor antigen-presenting cells. Candidate tolerance and rejection biomarker genes were selected from a CD69(+) T-cell microarray analysis, and their expression levels were measured in the recipient CD69(+) T-cell fraction using quantitative reverse transcription polymerase chain reaction.

Results: Our new monitoring protocol was capable of precisely detecting the immune status of recipients relative to their graft regardless of the organ received, whether they were taking immunosuppressive drugs, or different strains of origin.

Conclusions: Gene expression analysis focusing on recipient CD69(+) T cells as the donor antigen-reactive T-cell population could be used as an effective and sensitive method for monitoring transplant patients.