Cancer immunology is the study of interactions between the immune system and cancer cells. It aims to discover immunotherapies to treat cancer. The immune system can recognize cancer antigens and sometimes mounts an effective anti-tumor response. Transplantation immunology involves the immune response to transplanted tissues, known as rejection, as well as graft-versus-host disease. The major targets of transplant rejection are allogeneic MHC molecules recognized by T cells via direct and indirect pathways. Immunosuppression aims to prevent rejection by suppressing the host immune response or reducing graft immunogenicity.
Developing vaccines against infectious and epidemic diseases with the aid of Bioinformatics is now possible, by predicting epitopes on an antigen and finding possible targets for the antibody to bind. A new era of vaccine production is just ahead of us.
Watch out the ppt to know more!!!
Dr. ihsan edan abdulkareem alsaimary
PROFESSOR IN MEDICAL MICROBIOLOGY AND MOLECULAR IMMUNOLOGY
ihsanalsaimary@gmail.com
mobile : 009647801410838
university of basrah - college of medicine - basrah -IRAQ
Developing vaccines against infectious and epidemic diseases with the aid of Bioinformatics is now possible, by predicting epitopes on an antigen and finding possible targets for the antibody to bind. A new era of vaccine production is just ahead of us.
Watch out the ppt to know more!!!
Dr. ihsan edan abdulkareem alsaimary
PROFESSOR IN MEDICAL MICROBIOLOGY AND MOLECULAR IMMUNOLOGY
ihsanalsaimary@gmail.com
mobile : 009647801410838
university of basrah - college of medicine - basrah -IRAQ
This presentation talks about vaccines, currently being used in medicinal processes and therapeutics and their types. It elaborates the importance of the different types of vaccines along with their examples and their mechanism of action. The mode of production of all the types of vaccines is also discussed in the presentation including recent developments made for the production of mRNA vaccine against SARS-CoV-2
Dr. ihsan edan abdulkareem alsaimary
PROFESSOR IN MEDICAL MICROBIOLOGY AND MOLECULAR IMMUNOLOGY
ihsanalsaimary@gmail.com
mobile : 009647801410838
university of basrah - college of medicine - basrah -IRAQ
Vaccines are valuable and specialized products, of great diversity have already achieved great success in controlling many diseases of economics importance in farm and companion animals, but present they do not cover all infections, access to modern techniques are used for designing to new vaccine ,not only prolongation of immunity, but also to better practical aspects, such as product stability and less dependence on cold-storage.
The science of maternal vaccination - Slideset by prof Kathryn EdwardsWAidid
Pregnancy is a time of immunologic changes with an increased susceptibility to some infections, and maternal immunization can provide protection to the baby through the transfer of IgG induced by vaccine across the placenta. Prof. Edwards tackles in this slide set the fundamentals of maternal immunization.
Learn more on www.waidid.org
Immunology and Vaccine-Preventable Diseases
Immunology is a complicated subject, and a detailed discussion of it is beyond the scope of this text. However, an understanding of the basic function of the immune system is useful in order to understand both how vaccines work and the basis of recommendations for their use. The description that follows is simplified
vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future.
HISTORY OF VACCINES-
EDWARD JENNER conduct experiments in 1796 that lead to the creation of the first smallpox vaccine for prevention of smallpox.
A vaccine for RABIES is developed by LOUIS PASTEUR .
Vaccine for COLERA and TYPHOID were developed in 1896 and PLAGE vaccine in 1887.
The first DIPHTHERIA vaccine is developed in about 1913 by EMIL ADOLPH BEHRING,WILLIAM HALLOCK PARK.
The whole cell PERTUSIS vaccines are developed in 1914.
A TETANUS vaccine is developed in 1927.
This presentation talks about vaccines, currently being used in medicinal processes and therapeutics and their types. It elaborates the importance of the different types of vaccines along with their examples and their mechanism of action. The mode of production of all the types of vaccines is also discussed in the presentation including recent developments made for the production of mRNA vaccine against SARS-CoV-2
Dr. ihsan edan abdulkareem alsaimary
PROFESSOR IN MEDICAL MICROBIOLOGY AND MOLECULAR IMMUNOLOGY
ihsanalsaimary@gmail.com
mobile : 009647801410838
university of basrah - college of medicine - basrah -IRAQ
Vaccines are valuable and specialized products, of great diversity have already achieved great success in controlling many diseases of economics importance in farm and companion animals, but present they do not cover all infections, access to modern techniques are used for designing to new vaccine ,not only prolongation of immunity, but also to better practical aspects, such as product stability and less dependence on cold-storage.
The science of maternal vaccination - Slideset by prof Kathryn EdwardsWAidid
Pregnancy is a time of immunologic changes with an increased susceptibility to some infections, and maternal immunization can provide protection to the baby through the transfer of IgG induced by vaccine across the placenta. Prof. Edwards tackles in this slide set the fundamentals of maternal immunization.
Learn more on www.waidid.org
Immunology and Vaccine-Preventable Diseases
Immunology is a complicated subject, and a detailed discussion of it is beyond the scope of this text. However, an understanding of the basic function of the immune system is useful in order to understand both how vaccines work and the basis of recommendations for their use. The description that follows is simplified
vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future.
HISTORY OF VACCINES-
EDWARD JENNER conduct experiments in 1796 that lead to the creation of the first smallpox vaccine for prevention of smallpox.
A vaccine for RABIES is developed by LOUIS PASTEUR .
Vaccine for COLERA and TYPHOID were developed in 1896 and PLAGE vaccine in 1887.
The first DIPHTHERIA vaccine is developed in about 1913 by EMIL ADOLPH BEHRING,WILLIAM HALLOCK PARK.
The whole cell PERTUSIS vaccines are developed in 1914.
A TETANUS vaccine is developed in 1927.
Immunotherapy is based in reactivating the patient immune system specifically against the neoplasia, tumors have immunosuppression mechanisms that allow them to control and evade the immune response.
There are different immunotherapy approaches like tumor-targeting monoclonal antibodies, adoptive T cell transfer, anticancer vaccines, checkpoint inhibitors, most of these in important clinical trials in which the effects and toxicities are still evaluated. They are also beginning tested on a combination of immunotherapies and other non-immunological therapies in order to increase the survival of patients. Immunotherapy is still a young area and it needs to reach its peak, but it will surely be a great tool to treat and cure cancer.
This intro is geared towards interested novices who wish to find a resource that can serve as a starting point for further self-study. This is not meant to replace a doctor's advice. Please approach a medical professional for any health condition.
Limitations of Immunotherapeutic Approaches for Cancer Treatment_Crimson Publ...CrimsonpublishersCancer
Of the multiple approaches to cancer therapy, few are as complex as those regimens that encompass immune-based agents. Immunotherapeutic approaches have been the central focus of medical investigators for the past several years. This advance in oncologic care is highlighted by the recognition of the Nobel commission in awarding the 2018 Nobel prize to Allison and Honjo [1]. Their seminal work concentrated on an immunotherapeutic approach to combatting cancers via immune checkpoint receptors’ enhancement of the adaptive immune system. A previous review emphasized the potential role of checkpoint inhibitors in the treatment and cure of HIV also through enhancement of adaptive immune function to counter this virus [2].
Conquering Difficulties of Immunotherapy in Forceful Blood Disease--.pdfsyedanusrat1234
In tending to the intricacies of serious blood disease cure, the blending of corresponding pharmacotherapy has arisen as a vital procedure. This far-reaching technique offers a promising answer for overcoming the difficulties connected with immunotherapy in most malignant blood growth.
A multidisciplinary strategy is necessary to overcome the obstacles associated with immunotherapy in aggressive blood disorders. It is crucial to emphasize in presentations the complexity of the immune system's interactions with cancer cells, including evasion strategies and immune suppression occurring inside the tumor micro-environment. It can give hope to highlight the continuous research being done to clarify these pathways and create novel immunotherapy approaches specific to blood malignancies.
The possibility for overcoming resistance and improving treatment results might be emphasized by talking about the significance of combination medicines, biomarker identification, and patient stratification based on molecular profiling. Furthermore, highlighting the improvements in survival rates and quality of life that immunotherapy has brought about for patients with severe blood illnesses can inspire additional funding and cooperation in this vital field of cancer research and care.
Figuring out the Scene of Forceful Blood Malignant growth
Forceful blood malignant growths, which incorporate intense myeloid leukemia (AML) and high-risk myelodysplastic disorders (MDS), present strong constraints in ideal therapy models. These malignancies are described via expedient turn of events and protection from ordinary cures, requiring inventive techniques for strong administration.
Determining the site of a potent blood danger necessitates a complex analysis of various factors, such as genetic alterations, environmental effects, and adaptive system responses. Researchers study how these elements work together to drive the development of aggressive blood cancers such as lymphoma and leukemia. Through deciphering the fundamental mechanisms underlying these illnesses, scientists hope to develop targeted therapies that disrupt carcinogenic cycles while confining damage to healthy cells.
Developments in personalized medicine and genomic profiling present intriguing avenues for tailoring drugs to specific patients, improving outcomes, and raising overall endurance rates. Furthermore, ongoing efforts to unravel the complexities of growth micro-environments provide important insights into potential therapeutic targets and systems to effectively combat aggressive blood cancers.
Immunotherapeutic drugs can be broadly classified into four types: checkpoint inhibitors, cytokines, monoclonal antibodies, and vaccines. However, immunotherapeutic drugs still have some problems, such as off-target side effects and poor pharmacokinetics.
Presentation of the Philippine Goat Industry to the Meat and Milk Hygiene Class of Prof. Tadasu Urashima of Obihiro University of Agriculture and Veterinary Medicine
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Hemodialysis: Chapter 3, Dialysis Water Unit - Dr.Gawad
Lary nel abao cancer immunology report
1. アバオラリーネルビルバオ February 4, 2010
Infection Immunology おがわ先生
Cancer Immunology & Transplantation Immunology
According to Wikipedia, cancer immunology is the study of interactions between the
immune system and cancer cells (also called tumors or malignancies). It is also a
growing field of research that aims to discover innovative cancer immunotherapies to
treat and retard progression of this disease. The immune response, including the
recognition of cancer-specific antigens, is of particular interest in this field.
Knowledge accumulated in the field drove (and is still driving) the development of
new vaccines and antibody therapies.
For instance in 2007, Ohtani published a paper finding a tumor infiltrating
lymphocytes to be quite significant in human colorectal cancer.1 The host was given
a better chance of surviving if the cancer tissue showed infiltration of inflammatory
cells (in particular lymphocytic reactions). The results yielded suggested some
extent of anti-tumor immunity that is present in colorectal cancers in humans.
Over the past ten (10) years, there has been a notable progress and an accumulation
of scientific evidence for the concept of cancer immune surveillance and immune
editing based on: (1) protection against development of spontaneous and chemically-
induced tumors in animal systems; and (2) identification of targets for immune
recognition of human cancer. In 1999, a rat with immunity to cancer was discovered
by Dr. Zheng Cui.
Through the lecture conducted and reading materials in cancer immunology, I have
learned a lot of things. First, tumors express antigens that are recognized by the
immune system, but most tumors are weakly immunogenic and immune responses
often fail to prevent the growth of tumors. The immune system can be stimulated to
effectively kill tumors.2
Secondly, tumor antigens recognized by CTLs are the principal inducers of and
targets for antitumor immunity. These antigens include mutants of oncogenes and
other cellular proteins, normal proteins (whose expression is dysregulated or
increased in tumors), and products of oncogenic viruses.
Thirdly, antibodies specific for tumor cells recognize antigens that are used for
diagnosis and are potential targets for antibody therapy. These antigens include
oncofetal antigens, which are expressed normally during fetal life and whose
expression is dysregulated in some tumors; altered surface glycoproteins and
glycolipids; and molecules that are normally expressed on the cells from which the
tumors arise and are thus differentiation antigens for particular cell types.
Fourthly, immune responses that are capable of killing tumor cells consist of CTLs,
NK cells, and activated macrophages. The role of these immune effector
mechanisms in protecting individuals from tumors is not well-defined.
1
H. Ohtani, (2007). Focus on TILs: Prognostic significance of tumor infiltrating lymphocytes in human colorectal
cancer. Cancer Immunity 7: 4.
2 th
Abul K. Abbas, Cellular and Molecular Immunology (6 Edition), pp. 397-416.
1
2. Fifthly, tumors evade immune responses by several mechanisms, including down-
regulating the expression of MHC molecules, selecting cells that do not express
tumor antigens, producing immunosuppressive substances, and inducing tolerance
to tumor antigens.
And lastly, immunotherapy for tumors is designed to augment active immune
responses against these tumors or to administer tumor-specific immune effectors to
patients. Immune responses may be actively enhanced by vaccination with tumor
cells or antigens, administration of tumors modified to express high levels of co-
stimulators or cytokines that stimulate T cell proliferation and differentiation, and
systemic administration of cytokines. Anti-tumor immunity may also be enhanced by
blocking inhibitory pathways of immuno-regulation. Approaches for passive
immunotherapy include the administration of anti-tumor antibodies, antibodies
conjugated with toxic drugs (immunotoxins), and tumor-reactive T cells and NK cells
isolated from patients and expanded by culture with growth factors.
Meanwhile, transplantation immunology is defined as a general term for the complex
phenomena involved in allo- and xenograft rejection by a host and graft vs. host
reaction.3 Although the reactions involved in transplantation immunology are
primarily thymus-dependent phenomena of cellular immunity, humoral factors also
play a part in late rejection.
In transplantation immunology, I came to know some general principles through the
lecture conducted and by reading related materials (in the Internet and some books).4
First, transplantation of tissues from one individual to a genetically non-identical
recipient leads to a specific immune response called rejection that can destroy the
graft. The major molecular targets in transplant rejection are allogeneic class I and
class II MHC molecules.
Secondly, many different, normally present T cell clones specific for different foreign
peptides plus self-MHC molecules may cross-react with an individual allogeneic MHC
molecule. This high frequency of T cells capable of directly recognizing allogeneic
MHC molecules explains why the response to alloantigens is much stronger than the
response to conventional foreign antigens.
Thirdly, allogeneic MHC molecules may be represented on donor APCs to recipient T
cells (the direct pathway), or the alloantigens may be picked-up by lymphoid organs
and be processed and presented to T cells as peptides associated with self MHC
molecules (the indirect pathway). Graft rejection is mediated by T cells, including
CTLs that kill graft cells and helper T cells that cause DTH reactions, and by
antibodies.
Fourthly, several effector mechanisms cause rejection of solid organ grafts, and each
mechanism may lead to a histologically characteristic reaction. Pre-existing
antibodies cause hyper acute rejection characterized by thrombosis of graft vessels.
Alloreactive T cells and antibodies produced in response to the graft cause blood
vessel wall damage and parenchymal cell death, called acute rejection. Chronic
rejection is characterized by fibrosis and vascular abnormalities (accelerated
arteriosclerosis), which may represent a chronic DTH reaction in the walls of arteries.
3
http://www.mondofacto.com/facts/dictionary?transplantation+immunology
4 th
Abul K. Abbas, Cellular and Molecular Immunology (6 Edition), pp. 375-395.
2
3. Fifthly, rejection may be prevented or treated by immuno-suppression of the host and
by minimizing the immunogenicity of the graft (by limiting MHC allelic differences).
Most immunosuppresion is directed at T cell responses and entails the use of
cytotoxic drugs, specific immunosuppressive agents, or anti-T cell antibodies. The
most widely used immunosuppressive agent is cyclosporine, which blocks T cell
cytokine synthesis. Immuno-suppression is often combined with anti-inflammatory
drugs such as corticosteroids that inhibit cytokine synthesis by macrophages.
Sixthly, patients receiving solid organ transplants may become immunodeficient
because of their therapy and are susceptible to viral infections and virus-related
malignant tumors.
Seventhly, xenogeneic transplantation of solid organs is limited by the presence of
natural antibodies to carbohydrate antigens on the cells of discordant species that
cause hyper acute rejection, antibody-mediated acute vascular rejection, and a
strong T cell-mediated immune response to xenogeneic MHC molecules.
And lastly, bone marrow transplants are susceptible to rejection, and recipients
require intense preparatory immuno-suppression. In addition, T lymphocytes in the
bone marrow graft may respond to alloantigens of the host and cause GVHD. Acute
GVHD is characterized by epithelial cell death in the skin, intestinal tract, and liver; it
may be fatal. Chronic GVHD is characterized by fibrosis and atrophy of one or more
of these same target organs as well as the lungs and may also be fatal. Bone
marrow transplant recipients also often develop severe immunodeficiency, rendering
them susceptible to infections.
In conclusion, future advances in tolerance induction will come from approaches that
exploit the normal mechanisms that establish and maintain self-tolerance.5 These
approaches may take the form of pharmacologic agents, biological agents, gene
therapy, or some combination. Recent studies suggesting that expression of the
Fas-ligand gene can make tissue sites immunologically privileged are an exciting
example of how this knowledge and technology can be put to practical use.
One of the foremost difficulties will be clinical trial design. To the extent that current
therapy provides excellent short-term outcomes, large studies with long observation
periods will be required to demonstrate that new strategies are superior.
Alternatively, trials might focus on high-risk patients (such as those undergoing re-
transplantation or experiencing rejection); however, the likelihood of seeing success
is concomitantly reduced. The problem of how to individualize treatment because no
treatment is uniformly successful should also be considered. With the present
medications, some patients are at low risk for rejection (and steroid therapy can
perhaps be withdrawn), whereas others have a higher risk.
The, there is also the issue of shortage of donors for patients willing to have
transplants. Because of this, there is a race for the successful development of
artificial organs. Thus, the sub-fields of regenerative medicine and
xenotransplantation will be up for some challenges and excitement.
5
Laurence A. Turka, What's New in Transplant Immunology: Problems and Prospects, Annals of Internal Medicine.
3