rejection

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Related to Immune rejection: Organ rejection

rejection

 [re-jek´shun]
the immune response of the recipient to foreign tissue cells (antigens) after homograft transplantation, with the production of antibodies and ultimate destruction of the transplanted organ. In hyperacute rejection, there is an immediate response against the graft because of the presence of preformed antibody, resulting in fibrin deposition, platelet aggregation, and neutrophilic infiltration. In acute rejection, the response occurs after the sixth day and then proceeds rapidly. It is characterized by loss of function of the transplanted organ and by pain and swelling, with leukocytosis and thrombocytopenia. In chronic rejection, there is gradual progressive loss of function of the transplanted organ with less severe symptoms than in the acute form.

re·jec·tion

(rē-jek'shŭn),
1. The immunologic response to incompatibility in a transplanted organ.
2. A refusal to accept, recognize, or grant; a denial.
3. Elimination of small ultrasonic echoes from display.
[L. rejectio, a throwing back]

rejection

/re·jec·tion/ (re-jek´shun) an immune reaction against grafted tissue that results in failure of the graft to survive.

rejection

[rijek′shən]
Etymology: L, re + jacere, to throw
1 an immunological attack against organisms or substances that the immune system recognizes as foreign, including grafts and transplants. See also acute rejection, chronic rejection.
2 the act of excluding or denying affection to another person.

rejection

Immunology An immune reaction evoked by allografted organs; the prototypic rejection occurs in renal transplantation, which is subdivided into three clinicopathologic stages. See Cyclosporin A, Graft rejection, Graft-versus-host disease, Second set rejection, Tacrolimus, Transplant rejection.
Rejection types  
Hyperacute rejection Onset within minutes of anastomosis of blood supply, which is caused by circulating immune complexes; the kidneys are soft, cyanotic with stasis of blood in the glomerular capillaries, segmental thrombosis, necrosis, fibrin thrombi in glomerular tufts, interstitial hemorrhage, leukocytosis and sludging of PMNs and platelets, erythrocyte stasis, mesangial cell swelling, deposition of IgG, IgM, C3 in arterial walls
Acute rejection Onset 2-60 days after transplantation, with interstitial vascular endothelial cell swelling, interstitial accumulation of lymphocytes, plasma cells, immunoblasts, macrophages, neutrophils; tubular separation with edema/necrosis of tubular epithelium; swelling and vacuolization of the endothelial cells, vascular edema, bleeding and inflammation, renal tubular necrosis, sclerosed glomeruli, tubular 'thyroidization' Clinical ↓ Creatinine clearance, malaise, fever, HTN, oliguria
Chronic rejection Onset is late–often more than 60 days after transplantation, and frequently accompanied by acute changes superimposed, increased mesangial cells with myointimal proliferation and crescent formation; mesangioproliferative glomerulonephritis, and interstitial fibrosis; there is in general a poor response to corticosteroids

re·jec·tion

(rĕ-jek'shŭn)
1. The immunologic response to incompatibility of a transplanted organ.
2. A refusal to accept, recognize, or grant; a denial.
3. Elimination of small ultrasonic echoes from display.
[L. rejectio, a throwing back]

Rejection

Rejection occurs when the body recognizes a new transplanted organ as "foreign" and turns on the immune system of the body.

rejection

immunological response induced by donor tissue incompatibility; i.e. recognition of non-self tissue, provoking an acute inflammatory response and ultimate death of donor tissue

rejection

the immune reaction of a recipient to a graft, usually an allograph, after transplantation. The recipient recognizes antigens, particularly major histocompatibility complex antigens that are different from self antigens. The rapidity and severity of the graft rejection parallels the degree of antigenic difference between donor and recipient. The primary rejection of a graft, called first set reaction, typically begins 6 to 10 days after engraftment and in the case of skin is characterized by an erythematous zone around the graft which subsequently shrinks and is rejected. Rejection is predominantly a cell-mediated immune response, particularly Th1 lymphocytes and activated macrophages. If the same recipient receives a second graft from the same donor the graft is rejected more rapidly and the response is more severe, called a second set reaction which is also a cell-mediated response. Lymphocytes from the recipient can be adoptively transferred to a naive recipient which if also given a graft from the same donor responds with a second set reaction.

rejection factors
antibodies, particularly IgM but also IgG, directed against antigenic determinants on the Fc region of other immunoglobulins. When the immunoglobulin binds to antigen, changes occur in the folding of the protein of the Fc region such that new, nonself antigenic determinants are exposed and it is to these that rheumatoid factors, i.e. other antibodies, are directed.
References in periodicals archive ?
If he had instead issued a strong call for therapeutic cloning from donor eggs, coupled with an equally strong sanction against the intentional creation of new fertilized eggs for research purposes and the implantation of any experimentally modified human embryos into a woman's body, he would have opened up a most promising second line of basic research for a ll, instead of restricting federal support to a set of cell lines tainted by the crushed intentions of their donors that they become people, the certainty of immune rejection down the road, and the commercial implications of a premature monopoly.
For now, however, the problem of immune rejection is a real obstacle to clinical success.
Scientists working towards pancreatic cell transplants as a cure for diabetes have taken the first step to getting around the problem of immune rejection, the British Broadcasting Corp.
Researchers at Cytograft Tissue Engineering in Novato, Califi, have created vessels from a patient's own cells, an approach that avoids inflammation, clot formation, and immune rejection.
In every one of these cases, the transplants failed because of immune rejection of the foreign tissue.
The advantages include less ethical controversy, abundant cell availability from discarded tissues from elective surgeries like breast reductions and tummy tucks, and a much reduced possibility for immune rejection when re-implanting cells extracted from a person's own fat," explained Dr.
These organs could then be implanted in the body, where they would continue developing, avoiding immune rejection.
This approach would avoid immune rejection (SN: 4/2/05, p.
There are no immune rejection issues or communicable diseases that can be obtained by using your own cells.
One means of circumventing this immune rejection problem would be to generate hematopoietic stem cells, or HSCs, using the patient's own precursor cells.
Being transparent, the cornea lacks blood cells and so doesn't prompt immune rejection.
In conjunction with research on stem cell biology and the development of potential stem cell therapies, research on approaches that prevent immune rejection of stem cells and stem cell-derived tissues should be actively pursued.