The immune response (IR) is shaped by the MHC antigens inherited from mother and father and by maternal microchimerism−derived noninherited maternal antigens (NIMA).22−26 In postpartum women, and younger siblings, paternal HLA due to persistent fetal microchimerism can also have consequences for autoimmunity later in life.22−24 The present study demonstrates that MHC class II antigens arising from lung or heart transplant donor organs can also impose new self−recognition patterns upon graft recipients. This evidence concerns the gene HLA-C and Autoimmunity.