The Host Response to Grafts and Transplantation Immunology
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
Most of the grafts that are transplanted are allografts, or grafts between individuals of the same species. Such individuals are not genetically identical unless they are identical twins. Allografts can come from twins, parents, relatives, or unrelated individuals. Transplantation of grafts between identical siblings, or between mice of the same strain, are termed syngeneic. Not many humans needing grafts are lucky enough to have an identical twin to supply grafts. Such grafts, when available, are not recognized as foreign by the host because they are the same as self, i.e, not foreign. The term autograft means that the grafted tissue is from the same individual, such as skin transplanted from one part of the body to cover a part that has been damaged by a burn. Finally, the term xenograft refers to grafts between individuals of different species. Successful xenografting is a desirable goal since there are not enough human organs to be transplanted into all of the individuals that need an organ graft. Miniature pigs, because they are of a similar size with a similar circulation to that of humans, have been farmed to use as organ donors for humans. Recently, ethical review boards have blocked transplantation of organs between animals and humans because of the possibility of transmission of animal retro viruses to humans. An example of such a transfer is the human immunodeficiency virus that causes AIDS. AIDS is believed to have been transferred from chimpanzees, in whom it does not cause disease, to humans, in whom it does.
The Major Histocompatibility Complex
Constantin A. Bona, Francisco A. Bonilla in Textbook of Immunology, 2019
The vocabulary of transplantation is quite redundant, but follows simple patterns. The prefixes auto-, homo-, iso-, and syn-mean self, or same, or with. Thus, the adjectives autogenous, autologous, homologous, isogeneic, isologous and syngeneic all describe grafts from one site to another in one individual, or between two genetically identical individuals. The related nouns are autograft, homograft, and isograft. The prefix alio- means other, thus, allogeneic and allograft describe transplantation between two genetically different individuals of the same species. The prefix hetero- also means other, while xeno- means foreign. Consequently, heterologous, heterospecific and xenogeneic, together with heterograft and xenograft describe the transfer of tissue across species lines. More synonyms for these words exist, however, the general pattern of nomenclature is sufficiently evident in the above selection.
Haemopoietic Stem Cell Transplantation for Rheumatoid Arthritis—World Experience and Future Trials
Richard K. Burt, Alberto M. Marmont in Stem Cell Therapy for Autoimmune Disease, 2019
In Rotterdam, van Bekkum’s group used Buffalo rats, which develop polyarthritis one month after immunization with Mycobacterium tuberculosis and Freund’s adjuvant. Irradiation and allogeneic transplantation from a non-susceptible strain resulted in regression of the arthritis. Syngeneic transplantation was equally effective. The treatment was most effective when performed shortly after the induction of arthritis.13 A similar degree of success was achieved with true and pseudo-autologous BMT, and also with the highest tolerated doses of irradiation (8 Gy) without haematological rescue,14 but not with lower doses of TBI nor with equivalent local radiotherapy given only to the limbs. Addition of spleen cells to the graft did not influence the outcome. They hypothesized that remissions were achieved by ablation of the autoreactive immune and haemopoietic systems and regeneration of new non-autoreactive lymphocytes.
Mesenchymal stromal cells for acute respiratory distress syndrome (ARDS), sepsis, and COVID-19 infection: optimizing the therapeutic potential
Published in Expert Review of Respiratory Medicine, 2021
Ellen Gorman, Jonathan Millar, Danny McAuley, Cecilia O’Kane
Small animal models provide evidence that MSCs are efficacious in ARDS and sepsis. McIntyre et al, 2016, conducted a systematic review of preclinical models of ARDS and reported a meta-analysis of mortality outcomes following MSC administration compared with diseased control groups [92]. The majority of studies were conducted in rodent models and injury was induced by a variety of methods including direct and indirect infection, inflammation, trauma, and ventilation. MSC origin was described as syngenic (54%), xenogenic (37%), allogenic (9%), and autologous (3%). In total, 70 studies were reviewed; however, only 17 studies reported mortality outcomes and were included in the meta-analysis (n = 612 in MSC group, n = 1361 in the control group). MSCs were reported to reduce the overall risk of death (Odds Ratio (OR) 0.24, 95% confidence interval (CI) 0.18 to 0.34) [92]. A subgroup analysis reported similar protective effects of MSC administration regardless of injury model, MSC source, route of administration, or MSC preparation.
Applications of mesenchymal stem cells in ocular surface diseases: sources and routes of delivery
Published in Expert Opinion on Biological Therapy, 2023
Mohammad Soleimani, Ahmad Masoumi, Bita Momenaei, Kasra Cheraqpour, Raghuram Koganti, Arthur Y Chang, Mahmoud Ghassemi, Ali R Djalilian
Hypothetically, MSCs can be isolated from several tissues in the human body. However, there are practical limitations regarding the invasiveness and risk to the patient from obtaining the cells. The two main sources of MSCs are currently bone marrow and adipose tissue [50]. However, MSCs can also be procured from dental pulps, amniotic membrane, and the umbilical cord [51]. Nevertheless, the difficulty and potential adverse effects of the harvesting procedure should be considered before choosing where to obtain the cells. Treacy et al. found that the systemic administration of allogeneic and third party-derived BM-MSCs prolong the survival of corneal allografts in a rat model. This outcome was not observed with systemic injection of syngeneic cells. The authors hypothesized that treatment with allogeneic and third party MSCs suppresses the peripheral immune response and modulates the host’s immune reaction. This event may result in an immunoregulatory micro-environment in the corneal allograft [52].
Innate immunity: Trained immunity and innate allorecognition against the allograft
Published in International Reviews of Immunology, 2022
Mohammad Mirzakhani, Mehdi Shahbazi, Sara Shamdani, Sina Naserian, Mousa Mohammadnia-Afrouzi
Innate allorecognition and the role of innate immunity in allograft rejection were further demonstrated by Oberbarnscheidt and colleagues (2014). They used donors and recipients immunodeficient (RAG−/−γc−/−) mice, which lack T, B, and innate lymphoid cells.29 To clarify the role of allogeneic-mediated innate immunity activation, they transplanted the allogeneic or syngeneic graft to the same type of recipients. Allogeneic graft provided allogeneic signals and syngeneic graft provided danger signals. The analysis of graft infiltrated cells resulted in interesting outcomes. Monocyte-derived DCs (mono-DCs) and total DCs infiltrated the allogeneic graft were significantly more than those infiltrated the syngeneic graft. Interestingly, mono-DCs infiltrated the allogeneic graft displayed a fully mature phenotype, which highly expressed costimulatory and MHC class II molecules. In contrast, mono-DCs infiltrated the syngeneic graft displayed a less mature phenotype.