Bidirectional alloreactivity: A proposed microchimerism-based solution to the NIMA paradox

Chimerism. Apr-Jun 2012;3(2):29-36. doi: 10.4161/chim.21668. Epub 2012 Apr 1.


The NIMA paradox is the observation that in transplants of allogeneic kidneys or hematopoietic stem cells, siblings benefit from re-exposure to non-inherited maternal antigens (NIMA), whereas re-exposure to a transplant from mother herself, theoretically the ideal "NIMA" donor, does not yield clinical results superior to a father-donated allograft. Recent observations of bidirectional alloreactivity in kidney and cord blood transplantation offer a possible solution to this paradox. If correct, the proposed solution points the way to clinical applications of microchimerism in solid organ and hematopoetic transplants.

Publication types

  • Review

MeSH terms

  • Animals
  • Chimerism*
  • Cord Blood Stem Cell Transplantation
  • Graft vs Host Disease / immunology
  • Humans
  • Immune Tolerance / immunology
  • Isoantigens / immunology
  • Kidney Transplantation
  • Transplantation Tolerance / immunology
  • Transplantation, Homologous


  • Isoantigens