‘Missing self’ contributes to organ rejection after transplantation – California News Times

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Immune cells, called natural killer cells, miss the “self” proteins of donor cells and contribute to organ rejection after transplantation. JASN.. A better understanding of this process may help clinicians prevent and treat organ rejection.

The transplanted organ is recognized as foreign or non-self by the recipient’s immune system, leading to organ rejection.Rejection is prevented or treated with drugs that suppress the immune system and primarily targets T Immune cellsHowever, not only may T cells not be completely suppressed by treatment, but also because of antibodies and “natural killer cells” that target donor tissue, rejection still occurs despite such treatment. There is likely to be.

Natural killer cells play an important role for humans Immune system, Because it is involved in the recognition and killing of harmful cells such as tumor cells. These harmful cells attempt to avoid immune detection by reducing the MHC protein, a protein expressed on cells that allows T cells to bind, recognize, and tolerate themselves. there is. By this mechanism, harmful cells are invisible to T cells, but not to natural killer cells. Natural killer cells can detect the deficiency of these MHC proteins and kill harmful cells via the KIR receptor. This constitutes a very important defense mechanism.

In transplantation, donor cells in the transplanted organ do not escape immune detection by reducing MHC expression, but these donor cells express different MHC proteins than their recipients.Therefore, the recipient’s natural killer cells miss these “self” MHCs. Donor cells And it becomes active.

“This is what we found in a study of 924 kidney transplants. The” lost self “predicted by genetic analysis of donor and recipient MHC molecules, and genetically determined of the recipient. The KIR repertoire predicts rejection in the kidney. Transplant biopsy “. Maarten Naesens, MD, Ph.D., Senior Author of KU Leuven, Belgium. Said. “Therefore, our study assesses the presence or absence of” self-loss “by identifying donor and recipient genotypes not only for MHC (as is done in routine clinical practice) but also for KIR. And shows that the risk can be improved. Assessment of kidney transplant rejection.

“In addition, our findings show the importance of these. Natural killer cells After transplantation, we propose new ways to prevent or treat kidney transplant rejection, “added Jasper Callemeyn, MD, also the lead author of KU Leuven.

Researchers identify immune cells that contribute to transplant rejection

For more information:
“Lack of self-induced microvascular rejection in kidney allografts: population-based study” JASN, DOI: 10.1681 / ASN.2020111558

Provided by
American Society of Nephrology

Quote: “Missing self” contributes to organ rejection after transplantation (July 22, 2021) Obtained from July 22, 2021

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