Pharyngitis Immune Case Study

Pharyngitis – Immune System – Case Study Name: ____hh_______________ Henry is a 5 year-year-old boy who presents with fever, sore throat, and headache. PE reveals swollen and erythematous tonsils, pharynx and uvula. His temperature is elevated. Bilateral cervical lymphadenopathy is noted. A CBC reveals leukocytosis with an elevated neutrophil count with a left shift. Henry is diagnosed with acute bacterial pharyngitis following a positive beta-hemolytic streptococci throat swab. Penicillin 250mg po TID x 10 days. Questions 1. What are the four cardinal signs of inflammation. How does each relate to changes in blood vessel activity during inflammation? 1. Redness – Results from vasodilation which increases blood flow to the area 2. Heat - Results from vasodilation which increases blood flow to the area 3. Swelling – Increases vascular permeability, which allows fluid to accumulate in tissues 4. Pain – Chemical mediators and pressure from swelling 2. What role do neutrophils play in the resolution of bacterial infection? Use the terms adhesion molecules, diapedesis, chemotaxis, opsonization, left shift, and phagocytosis in your answer. Neutrophils adhere to blood vessel walls due the adhesion molecules, they migrate through the vessel walls which is diapedesis and follows the chemical signals via chemotaxis to the infection site. They perform phagocytosis which is enhanced by opsonization by marking pathogens for destruction. The left shift occurs in the CBC which an increase in immature neutrophils which is caused by the response to an acute infection 3. Describe the structure and function of lymph nodes. What other organs and tissues comprise the lymphatic system? Lymph nodes are small, that filter lymph and house immune cells like lymphocytes. They trap and destroy pathogens. Other lymphatic organs include the spleen, thymus, tonsils, and lymphatic tissues like Peyer’s patches. 4. What is the mechanism by which fever is induced and what are its benefits in terms of combating an infection? Fever is induced by pyrogens, which trigger the hypothalamus to raise the body’s temperature. This increased temperature enhances immune function, inhibits bacterial growth, and speeds up tissue repair. Makes iron move intracellularly Immunity and abnormal response 1. The three main components of the immune system are: 1. Innate Immune System: • Cells: Neutrophils, macrophages, natural killer (NK) cells, dendritic cells. • Tissues: Epithelial barriers (skin and mucous membranes). • Organs: None specific, but tissues involved in innate immunity are distributed throughout the body. 2. Adaptive Immune System: • Cells: T cells (helper and cytotoxic), B cells (which produce antibodies). • Tissues: Lymphoid tissues such as the lymph nodes. • Organs: Thymus (where T cells mature), spleen, and lymph nodes. 3. Lymphatic System: • Cells: Lymphocytes (T cells, B cells). • Tissues: Lymphatic vessels, lymphoid tissues. • Organs: Lymph nodes, spleen, thymus, and bone marrow. 2. A cell surface antigen is a molecule or protein located on the outer surface of a cell membrane that is recognized by the immune system. These antigens can be self or foreign, helping the immune system differentiate between the body’s own cells and invading pathogens (such as bacteria, viruses, or foreign tissues). Cell surface antigens are important because they: 1. Enable Immune Recognition: They allow immune cells to identify and respond to pathogens or infected cells, crucial for initiating immune responses. 2. Aid in Communication: They help cells communicate with each other, coordinating immune responses. 3. Facilitate Self-Tolerance: They help the immune system recognize self-cells, preventing autoimmunity, where the body attacks its own tissues. 3 Examples of cell surface antigens include MHC (major histocompatibility complex) molecules and blood group antigens. The Major Histocompatibility Complex (MHC) is a group of genes that encode proteins responsible for presenting peptide antigens on the cell surface to the immune system, playing a critical role in immune recognition. In humans, MHC molecules are also known as Human Leukocyte Antigens (HLAs). There are two main classes of MHC molecules: 1. MHC Class I: Found on almost all nucleated cells, these present intracellular antigens (like viral proteins) to cytotoxic T cells (CD8+ T cells). 2. MHC Class II: Found primarily on antigen-presenting cells (like macrophages and dendritic cells), these present extracellular antigens (like bacterial proteins) to helper T cells (CD4+ T cells). The term HLA refers to the specific human version of MHC molecules. Each person has a unique set of HLA proteins, which is why these antigens are crucial in organ transplantation, as mismatched HLA types can lead to organ rejection by the immune system. HLAs help the immune system recognize self from non-self, ensuring proper immune responses against pathogens while avoiding attacks on the body’s own cells. 3.