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The Host Response to Grafts and Transplantation Immunology
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Early attempts at tissue transplantation revealed the existence of strong, immunologic responses that destroy transplanted tissues. These responses effectively eliminate the possibility of tissue transplantation into immunologically competent recipients in the absence of tissue matching or immunosuppression. Since the practice of tissue transplantation is a product of twentieth century medicine, it is difficult to explain the evolutionary significance of an immunologic process designed to prevent tissue exchange, and thus frustrate transplant surgeons. In fact, graft rejection is caused by immunologic mechanisms that are regularly employed to assure survival of the individual by controlling infection. The rejection of foreign tissues is therefore the result of strongly selected and highly conserved immunologic mechanisms, the functions of which are the identification and elimination of “nonself” or foreign, be that infectious agents or transplanta ted foreign tissue.
Polymer Materials for Oral and Craniofacial Tissue Engineering
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Iriczalli Cruz Maya, Vincenzo Guarino
The oral and maxillofacial regions are complex areas since they are composed of different tissues. These regions can be affected by abroad range of pathologies, congenital defects, oncologic resection, trauma and infections (Susarla et al. 2011). The current strategies involve the use of allogenic, xenogeneic and autogenic grafts (Wang et al. 2005). However, there are drawbacks regarding the graft rejection, transmission of diseases and infection causing regeneration failure. Moreover, the complexity of cranio-maxillofacial tissues is a challenge due to the interactions between different types of tissues, including epithelium, mineralized and non-mineralized connective tissues (Bartold et al. 2000; Aurrekoetxea et al. 2015). Researchers focused on the study of new strategies based on the basic principle of tissue engineering—which means the use of cells, scaffolds and bioactive molecules to regenerate damaged tissues.
Tissue Grafting Techniques
Published in Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan, Comprehensive Textbook on Vitiligo, 2020
Various factors that can cause graft rejection include seroma, hematoma, or accumulation of air bubbles between the graft and dermabraded surface; improper immobilization; technical error, where the graft is placed with dermal surface facing upward; and traumatized grafts.
Emerging treatment strategies in hepatobiliary cancer
Published in Expert Review of Anticancer Therapy, 2023
Deniz Can Guven, Hasan Cagri Yildirim, Elvin Chalabiyev, Fatih Kus, Feride Yilmaz, Serkan Yasar, Arif Akyildiz, Burak Yasin Aktas, Suayib Yalcin, Omer Dizdar
Immune checkpoint inhibitors have a more favorable toxicity profile compared with TKIs. However, close follow up and timely initiation of corticosteroids and other immunosuppressive agents are needed if autoimmune toxicities including skin rash, colitis, hepatitis, pneumonitis, endocrinopathies, and other toxicities develop [135]. Treatment with ICIS in patients with autoimmune diseases and organ transplant recipients requires consideration of risks and benefits as well as shared decision making with a multidisciplinary team (MDT) and the patient [136,137] . Experience with ICI treatment in patients with recurrent HCC after liver transplantation is limited with case reports. In a pooled analysis of the cases, graft rejection was reported in 6 out of 27 patients (22%) [137]. Preliminary data suggests a role for the pre-transplant use of ICIs, but further studies are needed before implementing this strategy in routine practice [138].
Novel Proposed Algorithm in Congenital Hereditary Endothelial Dystrophy
Published in Seminars in Ophthalmology, 2023
Neet Mehta, Muralidhar Ramappa
The correct time for surgical intervention is still unclear. While the surgical timing lacks uniform consensus, there is a trend toward early intervention to circumvent irreversible stromal changes, particularly when it comes to endothelial grafting. Pediatric PK poses several unique challenges that are not encountered in adults. Intraoperative challenges17 in PK for CHED in younger age groups include managing the low scleral rigidity and tendency for anterior rotation of the lens-iris diaphragm that predispose to shallowing of the anterior chamber, peripheral anterior synechiae (PAS) formation, iris incarceration in the wound, endothelial trauma, glaucoma, and expulsion of intraocular contents due to an “open to sky’ procedure. Also, there is a high demand for postoperative care. Pediatric patients tend to a rapid and severe inflammatory response, predisposing them to graft rejection, PAS formation, glaucoma, and cataract. Robust wound healing may result in corneal neovascularization, uneven contraction of tissue, early loosening of sutures, irregular astigmatism, overriding of graft tissue with poor epithelialization, and ulceration. Frequent, often monthly, examinations under anesthesia and vigilant parental or caregiver observation for signs of rejection are important for early detection of graft rejection and suture-related complications. Along with these, a corneal wound that is of full-thickness is at a higher risk of traumatic rupture especially in children. Considering these, corneal surgeries have often been delayed for as long as possible, if not avoided in this age group.
Prior Contralateral Penetrating Keratoplasty Is a Risk Factor for Second Eye Graft Rejection
Published in Ocular Immunology and Inflammation, 2023
Eric J. Shiuey, Qiang Zhang, Christopher J. Rapuano, Brandon D. Ayres, Kristin M. Hammersmith, Parveen K. Nagra, Zeba A. Syed
Aside from its retrospective design, limitations of this study include lack of data pertaining to race/ethnicity, graft donor characteristics, visual outcomes, and disease severity of comorbidities (e.g. autoimmune disease, glaucoma). Our study may not have been adequately powered to determine the effect of certain risk factors on graft rejection, and therefore our statistical analyses were limited. We could not assess patient compliance with postoperative steroid regimens, which could affect the rate of rejection and subsequent graft failure. Additionally, only 53.3% of cases had ≥ 3.0 years of follow-up, possibly due to a relatively high rate of follow-up with a local ophthalmologist; many of the surgical referrals in our practice return to their local ophthalmologist after the post-operative period. Nonetheless, it is our experience that patients typically return to our practice if complications arise post-transplant, thus potentially allowing for sporadic but longer-term follow-up. Individual chart review by the same two authors to ensure standardized data collection, consistency in clinical management at a single center, and a sizable cohort all lend to our study’s accuracy.