Allotransplant (''allo-'' meaning "other" in

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

) is the transplantation of cells, tissues, or organs to a recipient from a genetically non-identical donor of the same species. The transplant is called an allograft, allogeneic transplant, or homograft. Most human tissue and

organ transplant Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or org ...

s are allografts. It is contrasted with autotransplantation (from one part of the body to another in the same person), syngenic transplantation of isografts (grafts transplanted between two genetically identical individuals) and xenotransplantation (from other species). Allografts can be referred to as "homostatic" if they are biologically inert when transplanted, such as bone and

cartilage Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...

.(W. P. Longmire, ''J. National Cancer Institute'' 14, 669: ''The term ''homostatic graft'' might be applied to inert tissues such as bone and cartilage when transferred from one individual to another of the same species; and the term ''homovital graft'' might be used in reference to grafts whose cells must continue to grow and reproduce for the graft to be effective after similar transplantation''; H. Conway, ''The Bulletin of the Hong Kong Chinese Medical Association'' 13, 43: ''These grafts persist however as homostatic grafts and are completely replaced by host tissues in time.)'' An immune response against an allograft or xenograft is termed rejection. An allogenic bone marrow transplant can result in an immune attack on the recipient, called

graft-versus-host disease Graft-versus-host disease (GvHD) is a syndrome, characterized by inflammation in different organs. GvHD is commonly associated with bone marrow transplants and stem cell transplants. White blood cells of the donor's immune system which rema ...

Procedure

Material is obtained from a donor who is a living person, or a deceased person's body receiving mechanical support or ventilation, or a deceased person's body whose heart stopped beating. Screening for pathology and risk factors for communicable diseases such as HIV and Hepatitis B and C is then conducted. In the US, donor tissue must be recovered and processed adhering to the Current Good Tissue Practices rule. In most cases, it is sent to tissue banks for processing and distribution. Each year,

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

regulated and American Association of Tissue Banks-accredited tissue banks distribute 1.5 million bone and tissue allografts.

Transplantable organs and tissues

A variety of organs and tissues can be used for allografts, including: *

Anterior cruciate ligament The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. The two ligaments are called "cruciform" ligaments, as they are arranged in a crossed formation. In ...

(ACL) repair * Joint reconstruction in the

knee In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

and

ankle The ankle, the talocrural region or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The ...

* Meniscal replacement * Reconstruction due to cancer or trauma * Ridge augmentation in dental procedures * Shoulder repair *

Spinal fusion Spinal fusion, also called spondylodesis or spondylosyndesis, is a surgery performed by Orthopedic surgery#Practice, orthopaedic surgeons or neurosurgeons that joins two or more vertebrae. This procedure can be performed at any level in the spine ...

* Urological procedures *

Skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

transplants *

Cornea The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...

l transplants * Heart transplants *

Heart valve A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. A mammalian heart usually has four valves. Together, the valves determine the direction of blood flow through the heart. Hea ...

s * Lung transplantation * Intestinal transplantation (isolated small bowel, intestine & liver, multivisceral) * Liver transplants * Kidney transplants * Pancreas transplantation * Islet cell transplantation *

Bone marrow transplant Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood, in order to replicate inside a patient and produce a ...

s *

Bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

allograft *

Ligament A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...

tendon A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tensi ...

allograft

Laws and regulations

United States

In the US, the

(FDA) has regulated human tissue intended for transplants since 1993. In order to ensure the quality of donor tissue and reduce contamination and disease transmission risks, three regulations addressing manufacturing activities associated with human cells, tissues, and cellular and tissue-based products (HCT/Ps) were promulgated in May 2005: * companies producing and distributing HCT/Ps must register with the FDA. * "Donor Eligibility" rule: prescribes criteria for donor eligibility. * "Current Good Tissue Practices" rule: oversees overall processing and distribution practices of each company.

Other transplant options

* Autograft, tissue transplanted from one site to another on the same patient. An autograft reduces the risk of rejection but requires a second surgery site, adding pain, risk and possible longer aftercare. * Xenograft, a transplant from another species * Isograft, a transplant from a genetically identical donor, such as an identical twin. * Synthetic and metal implants. Unlike allografts, such grafts do not corporate into the body.

Risks

As with many operations, allotransplantation risks some side effects. A limiting factor in tissue allotransplantation for reconstructive surgery deals with the side effects of

immunosuppression Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...

(metabolic disorders, malignancies, opportunistic infections) which is a predominant issue. The risk of transmitting infection is high.

References

External links

Tissue & Tissue Products

OrganDonor.gov
(How to register to be a donor in the USA)
Allogeneic stem cell transplantation
entry in the public domain NCI Dictionary of Cancer Terms
Allogeneic bone marrow transplantation
entry in the public domain NCI Dictionary of Cancer Terms {{Organ transplantation Transplantation medicine Immunology