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Here again, with an immunology video, stuffed with an in-depth explanation with amazing visuals. The topic under discussion is Chronic Inflammation and Granulomatous Diseases. So, bring your pen and paper to note down all the details. Acute vs Chronic Inflammation Inflammation is part of the body's defense mechanism, by which the immune system recognizes and removes harmful or foreign stimuli, and begins the healing process. Now, inflammation can be either: Acute Inflammation Chronic Inflammation I know you always end up mixing these types, so we have a complete comparison of both in the video! Chronic Inflammation A prolonged inflammation, characterized by mononuclear infiltration, which leads to simultaneous tissue destruction and repair. It may be preceded by acute inflammation. Tissues affected by chronic inflammation commonly show evidence of these pathologic processes: Immune response Phagocytosis Necrosis Tissue repair Chronic inflammation can develop in response to both antigenic and non-antigenic injurious agents. On the basis of morphology, it is classified into two types: Granulomatous Chronic Inflammation Non-granulomatous Chronic Inflammation Granulomatous Chronic Inflammation This is a special type of chronic inflammation, characterized by the formation of granuloma. Granuloma is a focal collection of inflammatory cells at sites of tissue infection, and includes activated macrophages, epithelioid cells, Langhans’ giant cells, and lymphocytes. Granulomas “wall off” a resistant stimulus without completely eradicating or degrading it. This leads to persistent inflammation, fibrosis or scarring, and may damage the organ. Granulomas are typically classified into two types: Epithelioid cell granuloma – Represents an immune response, in which macrophages are activated by lymphokines from specifically stimulated T cells. Example: tuberculosis and leprosy. Foreign body granuloma – Represents non-immune phagocytosis of foreign non-antigenic material by macrophages. Example: silicosis. On the basis of histology, granulomas have two types: Caseating – Associated with central necrosis, typically seen in infectious etiologies such as tuberculosis and fungal infections. Non-caseating – Shows no central necrosis, typically seen in autoimmune diseases like sarcoidosis and Crohn's disease. (A detailed discussion of all types of granulomas is provided in the video.) Non-Granulomatous Chronic Inflammation Non-granulomatous chronic inflammation is characterized by the accumulation of sensitized lymphocytes, plasma cells, and macrophages in the injured area. These cells are scattered diffusely throughout the tissue and do not form granulomas. Examples include: Chronic viral infections Autoimmune diseases Chronic toxic diseases Infections like lepromatous leprosy and leishmaniasis Granulomatous Diseases Granulomas are found in several diseases. Some examples include: Tuberculosis Sarcoidosis Crohn’s disease Primary biliary cirrhosis Temporal arteritis Eosinophilic granuloma Chronic granulomatous disease I cannot pen down all their details here, but we have made all the effort for you in the video. So, grab their details there.

Here again, with an exciting immunology video stuffed with in-depth knowledge, easy to grab with life-saver mnemonics. The topic under discussion is Type III Hypersensitivity reactions or otherwise, immune complex diseases. So, bring your pens and paper to note down all the details on conditions like Systemic Lupus erythematosus (SLE), Glomerulonephritis, Rheumatoid Arthritis, and many more. Hypersensitivity Well, hypersensitivity is an exaggerated or inappropriate immunologic response occurring in response to an antigen or allergen. Now, these hypersensitivity reactions are classified into 4 types, according to Gell and Coomb’s classification: Type 1 Hypersensitivity: Anaphylactic or Immediate hypersensitivity reactions. Type 2 Hypersensitivity: Cytotoxic or Antibody-mediated hypersensitivity reactions. Type 3 Hypersensitivity: Immune-complex Mediated hypersensitivity reactions. Type 4 Hypersensitivity: Delayed or T-cell Mediated hypersensitivity reactions. I know you always end up mixing these types. So, I have an easy mnemonic for you! You can memorize these types by the word “ACID.” Our topic of concern here is Type 3 Hypersensitivity, the immune-complex mediated hypersensitivity reactions. Type III Hypersensitivity is quite easy to remember because three things are stuck together here: Antigen Antibody Complement Type 3 Hypersensitivity Pathophysiology In type 3 hypersensitivity reactions: IgG antibodies bind to circulating antigens to form an antigen-antibody complex. This complex then deposits in particular tissues, mostly blood vessels, the basement membrane of the lungs, kidneys, and the joints. This deposition activates the complement cascade and attracts neutrophils. Neutrophils release lysosomal enzymes, causing cell death and inflammation. Immune Complex Immune complexes, also called antigen-antibody complexes, are the lattices of antigen and antibody. Antigens can be derived from various sources (infection, environment, or autoantigen). Immune complexes will form only when the ratio between antigen and antibody is exactly right. What happens when either antigen or antibody is in excess? I’m not gonna reveal it here — you need to watch the video to know this. Also, the clearance mechanism for immune complexes, and the failure of this clearance, all the information is just under your click. Immune Complex Diseases Lack of clearance of immune complexes leads to immune complex diseases, or what you call type 3 hypersensitivity. A few typical examples of immune complex diseases can be kept safe in your mind by the mnemonic “SPAR.” S → Serum Sickness and Systemic Lupus Erythematosus (SLE) P → Polyarteritis Nodosa and Poststreptococcal Glomerulonephritis A → Arthus Reaction R → Rheumatoid Arthritis (RA) I cannot pen down all their details here, but obviously, I have made all the effort for you in the video. So, grab their details there. Treatment of Immune Complex Disease Antigen avoidance is possible in some cases of Type III hypersensitivity, like in a farmer’s lung, or with some drugs and vaccines. However, in the case of autoantigens (like DNA), avoidance is clearly not possible. Here, drug therapy plays the role. It includes: Corticosteroids, which block some of the damage caused by effector cells, such as neutrophils. Cyclophosphamide, an alkylating agent that impairs DNA synthesis and prevents rapid proliferation of cells such as lymphocytes. Although cyclophosphamide has some effects on T cells, its main benefit is in reducing B-cell proliferation and hence autoantibody levels.

This video lecture is going to be a detailed and full of knowledge video, about Cancer Immunology. How does cancer develop in Immune cells? And Then How do Immune cells work against cancer? You will get answers to all these questions in this video. Cancer Immunology Cancer is a disease characterized by uncontrolled cell division. Immunology is the branch of science that deals with the study of the Immune system. So, in Cancer immunology, we will get to know the relationship between cancer and the Host Immune system. Over the past many years, scientists have found ways that help eradicate cancer. Although the Immune system does not seem to play an astonishing role, still immunologists are hopeful that increasing knowledge about the relationship of cancer with immune cells, will one day help in cancer eradication. If you want to know about this relationship, this video will surely help you with that. Lymphoid Tumors The uncontrolled division of malignant lymphocytes leads to the development of Lymphoid tumors. The cellular basis of these tumors can be, B cells (in any developmental stage), or T cells. The main causes of these lymphoid malignancies or tumors are: Chromosomal Translocations Pathogens Chromosomal Translocations: A molecular process in which a gene segment from one chromosome is translocated on another chromosome of a heterologous pair. Or a part of a gene sequence from one position to another of the same chromosome. That gives rise to a novel chromosome with abnormal gene linkage. Pathogens: So many pathogens like Herpes Virus, Retrovirus, EBV, H. pylori, and some other viruses can also cause cancer. Such cancers are called virus-associated cancer. Tumor Antigens Tumor antigens are the molecular sequences or proteins that appear on the surface of tumor cells and show some immunogenicity. But unlike infection, tumor antigens are usually normal cellular proteins that can’t be detected by the Immune system. But sometimes mutated or truncated proteins appear on tumor cells that can be recognized as dangerous by the host Immune system. These tumor antigens can be: Viral proteins Developmental proteins or Oncofetal proteins Lineage-specific proteins Proteins produced through translocations or mutated proteins Tumor Escape Mechanisms The immune system is unable to efficiently recognize and eradicate tumor cells. It is so because tumor cells adopt some escape mechanisms to avoid Immune responses. Some important escape mechanisms of tumor cells are: Avoidance of recognition by the host Immune system Immunoregulatory effects of tumor cells on leukocyte functions Activation of myeloid-derived suppressor cells (MDSCs) by tumor cells Elevated number of Treg cells by tumor cells Apoptosis of incompetent cells Utilization of Immune checkpoints Immunotherapy Immunotherapy is a type of cancer treatment. It uses substances made by the body or in a laboratory to boost the Immune system and help the body find and destroy cancer cells. With the increasing knowledge of the relationship between cancer and the Immune system, scientists are developing much more efficient ways of immunotherapy. The main approaches used by scientists for immunotherapy are: Monoclonal Antibodies Tumor vaccines Peptide and DNA-based vaccines Tumor cell vaccines Transfected tumor cell vaccines