The Lymphatic/Immune System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
Thymic lymphocytes (also called thvmus-dependent lymphocytes or T-cells) are so named because they are formed in the thymus, pass through it, or are influenced by it on their way to the tissue. T-lymphocytes are components of cellular or cell-mediated immunity. T-lymphocytes fall into two categories: T-suppressor cells inhibit the stimulation of antibody production and serve a regulatory function in immunity; T-helper cells (also called CD4+ cells because of the CD4" receptor site on their surface) assist such stimulation. T-lymphocytes also can attach to and kill large antigenic cells such as cancer cells and transplant cells, so they are involved in the process of transplant rejection.
History-taking model
Kaji Sritharan, Vivian A Elwell, Sachi Sivananthan in Essential OSCE Topics for Medical and Surgical Finals, 2007
ExplainYou have two kidneys, which are located in the right and left flank/ loin.Renal biopsy is a method of obtaining a sample of tissue from the kidney by introducing a biopsy needle (possibly several times) through the skin overlying the affected kidney.Ultrasound will be used to guide the needle into the kidney.The tissue sample obtained will be tested to try to identify a cause (e.g. scarring, infection, abnormal deposits) for the symptoms experienced (e.g. renal failure, haematuria, proteinuria, transplant rejection) and to determine the best course of management.
Miscellaneous Drugs during Pregnancy
“Bert” Bertis Britt Little in Drugs and Pregnancy, 2022
Among 38 pregnancies to 29 women with liver transplants, 13 percent of mothers had signs of organ rejection (Radomski et al., 1995). There were 31 live births (eight abortions) and 32 percent had low birth weight, with 39 percent premature. Infection complicated >25 percent of the liver transplant pregnancies. Immunosuppression is a mainstay of treatment to prevent transplant rejection. Two of 15 infants born to liver transplant patients had birth defects (Kallen et al., 2005). A review of 450 pregnancies in 306 liver transplant recipients (systematic review, 8 studies) indicated that miscarriage was 17.1 percent, pregnancy induced hypertension 21.9 percent and C-section 44.6 percent (Deshpande et al., 2012). Compared to renal transplant obstetric patients, liver transplant pregnancies lasted longer (36.5 vs. 35.6 weeks) had greater birth weight (2866 g vs. 2420 g).
Lessons from transmissible cancers for immunotherapy and transplant
Published in Immunological Medicine, 2022
Rafael Cardoso Maciel Costa Silva, Carolina Panis, Bruno Ricardo Barreto Pires
Transplant rejection is mediated mostly by the adaptive immune system [3]. There are three main mechanisms by which adaptive immunity is triggered to mediate allogeneic tissue rejection: direct, indirect, and semi-direct [4]. The direct pathway is based on the ability of dendritic cells (DCs) from the donor tissue (or transmissible cancer) to present allopeptides and activate host T cells through a non-self MHC. Around 1–10% of T cells can recognize the complex non-self MHC-peptide and mount a specific immune response [5]. The direct pathway is believed to be the dominant immune response during acute rejection. The ability of non-self MHC to present more than one allopeptide, referred as the multiple binary complex model, seems to contribute to the amplification of immune responses and graft rejection [6,7]. The indirect pathway is related to the presentation, by host DCs, of peptides from polymorphic antigens (or neoantigens, in the case of tumors) of the donor [2]. This pathway is associated with late chronic rejection of the transplanted tissues, and it is believed that the T cells clones reactive to this polymorphic alloantigens are distinct from those activated by the direct pathway [2]. The semi-direct pathway is related to the shedding by exosomes, from donor cells, of peptide-loaded MHC into the membrane of recipient DCs, which will present donor MHC-allopeptides to T cells. Several murine studies demonstrated the acquisition of intact alloantigens to recipient DCs after vascularized allograft challenge [8–10]. The semi-direct anddirect pathway would lead to activation of the same T cell clones [2].
Cemiplimab-rwlc as first and only treatment for advanced cutaneous squamous cell carcinoma
Published in Expert Review of Clinical Pharmacology, 2019
Saqib R. Ahmed, Erik Petersen, Ravi Patel, Michael R. Migden
As previously mentioned, organ transplant patients have an increased risk of advanced CSCC due to their immunosuppression. Currently, having an organ transplant is a relative contraindication in receiving immunotherapy given concerns of transplant rejection (organ transplantation is not a contraindication in FDA approved labeling). In an article by Kittai et al, the authors discuss 12 cases of patients that were treated with immunotherapy in the setting of organ transplant [28]. Of the 12 patients, 4 patients experienced transplant rejection. The 4 patients that experienced transplant rejection received PD-1 blockade and not CTLA-4 blockade [28]. The authors conclude that PD-1 blockade is more detrimental than CTLA-4 blockade for transplant recipients.28 This population will likely need more treatment options in the future. Potential solutions include more targeted immunotherapy versus more focused immunosuppression.
Renal allograft surveillance with allospecific T-cytotoxic memory cells
Published in Renal Failure, 2020
Vinayak S. Rohan, Karim M. Soliman, Ahmad Alqassieh, Duaa Alkhader, Neha Patel, Satish N. Nadig
Determining the risk of renal transplant rejection can lead to early diagnosis and intervention and enhance graft survival. Previous studies have shown that enhanced donor-specific alloreactivity measured with allospecific CD154-expressing T-cytotoxic memory cells (CD154 + TcM) predicts ACR after liver or intestine transplantation in children [1–3]. This FDA-approved test has a sensitivity and specificity approaching or exceeding 80% [3]. In an exploratory cohort of patients with metabolic liver disease who were treated with hepatocyte transplantation, loss of graft function was preceded by an increase in donor-specific CD154 + TcM [4]. In another cohort of liver transplant recipients, infusion of T-regulatory cells resulted in reduced the frequencies of circulating donor-specific CD154 + TcM [5]. Finally, intestine allografts with ACR, which is usually accompanied by circulating DSA were associated with enhanced donor-specific alloreactivity measured with CD154 expression in both, the TcM and the B-cell compartments [6]. Among RTR undergoing ‘for cause’ biopsies for elevated serum creatinine (SCr), allospecific CD154 + TcM demonstrated sensitivity and specificity exceeding 80% for association with T-cell-mediated rejection (TCMR) [7]. It is not known whether allospecific TcM can also predict outcomes in a mixed cohort of RTR with stable graft function, or graft dysfunction due to various causes, as is typically seen in a clinical practice.
Related Knowledge Centers
- Abo Blood Group System
- Antibody
- Immunosuppressive Drug
- Major Histocompatibility Complex
- Immune System
- Lymphocyte
- T Cell
- Antigen
- Complement System
- Organ Transplantation