Preventing The Harmful Immune Response To Newly Transplanted Organs

January 6, 2006

University Hospital Zurich researchers have determined a way to prevent the harmful immune response to newly transplanted organs, which can lead to organ rejection. The study appears in the January 4, 2006 issue of the Journal of Clinical Investigation.

Transplantation medicine is potentially useful in treating a variety of diseases, but the need for life-long suppression of the immune response limits the usefulness of this therapeutic approach. Strategies have been previously designed to try and eliminate the recipient's immune response to the transplanted material, however this apparent tolerance seldom persists for long periods of time.

Rare cases of acceptance of transplanted material after patients have discontinued use of immunosuppressive drugs have been observed and this is often the result of what is known as macro- or microchimerism - where greater than or less than 1% of donor cells are found in the recipients blood, respectively. For stable graft acceptance to occur, the recipient's T cells must remain unresponsive to the transplanted material over the long term.

In this new study, Weldy Bonilla and colleagues investigated whether persistence of donor cells is the cause or consequence of long-lasting T cell unresponsiveness.

They show that when less than 1% of donor cells were found in the blood of graft recipients, graft-specific T cells were not present and donor cell-specific T cell unresponsiveness was long-lasting. The results suggest that inducing donor cell microchimerism at the time of solid organ transplantation may be beneficial for transplant recipients.

TITLE: Microchimerism maintains deletion of the donor cell-specific CD8+ T cell repertoire. View the PDF of this article at: the-jci.org/article.php?id=26565

Brooke Grindlinger

press_releases@the-jci.org

Journal of Clinical Investigation

Copyright © 2006 Medical News Today.

This article posted February 4, 2006.