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 ?
For now, however, the problem of immune rejection is a real obstacle to clinical success.
This discovery resolves both the ethical issue and the immune rejection problem of ESCs and the need for donor 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.
August 20, 2015 -- Scientists here and abroad have discovered that induced pluripotent stem cells (iPSCs) derived from an individual's own cells can be differentiated into various types of functional cells with different fates of immune rejection.
To protect the implanted cells from immune rejection, the PEC-01 cells are encapsulated in a proprietary device with a selectively porous membrane called the Encaptra drug delivery system.
Once fused, the hybrid cells have DNA from both the donor and recipient, raising hopes that immune rejection of embryonic stem cell therapies can be avoided without drugs.
Because these treatments use a person's own bone marrow cells, they avoid the immune rejection that can arise from conventional marrow transplants.
The collaboration is working on therapeutic stem cells whose genetic make-up may avoid the problem of transplant immune rejection and thus could benefit many patients of different ages, sexes and racial groups,
The Encaptra device is designed to protect the implanted cells from possible immune rejection, to permanently contain the cells and prevent their distribution away from the implantation site, and to provide a plat form for product vascularization.
She believes that the use of adult stem cells would have several advantages over embryonic stem cells because they do not have the ethical controversy that surrounds embryonic stem cells, and they may avoid the immune rejection response, as the patient's own cells can be used.