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Pathology of the immune system. Reactions and mechanisms of hypersensitivity. Autoimmune disease. Immunodeficiency states. in accordance with Ya.Ya . Bodnar. assistant-professor Volodymyr Voloshyn.
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Pathology of the immune system. Reactions and mechanisms of hypersensitivity. Autoimmune disease. Immunodeficiency states inaccordancewith Ya.Ya. Bodnar assistant-professor VolodymyrVoloshyn
The immune system protects the body against infectious agents and biological substances with antigenic properties.It involves peripheral organs: lymph nodes, tonsils of pharynges, lymph follicles in the intestinal wall, lymphocytes in the peripheral blood, spleen and central organs - thymus, bone marrow. Structural and functional organization of the immune system
Innate and adaptive immunity. The principal mechanisms of innate immunity and adaptive immunity are shown.
Immune defense are implemented by lymphocytes (immunocytes) and are formed from lymphoid germ in the bone marrow. There are two types of immune response: cellular and humoral. Types of immune response
Cellular immunityarebasedonT-lymphocytes (T-killer cells, T-suppressor, T helper).T-helper cells (CD4) and T suppressor (CD8) take place an important role in this process. • B-lymphocytesconduct the Humoral immunity. They transform into plasmocytes, which synthesize immunoglobulins (antibodies).Immunoglobulins have antigenic specificity and differ by amino acid composition.There are several classes of antibodies: IgA, IgG, IgM, IgD, IgE. Types of immune response
Histology of a lymph node. A, The organization of the lymph node, with an outer cortex containing follicles and an inner medulla. B, The location of B cells (stained green, using the immunofluorescence technique) and T cells (stained red) in a lymph node. C, A germinal center.
Diseases of thymus most often manifested by his congenital disorders: aplasia, hypo- and dysplasia, atrophy, thymomegaly. Accidental involution, hyperplasia of lymphoid cells and neoplastic processes are between acquired diseases. Thymus Diseases
Thymoma. A, Benign thymoma (medullary type). The neoplastic epithelial cells are arranged in a swirling pattern and have bland, oval to elongated nuclei with inconspicuous nucleoli. Only a few small, reactive lymphoid cells are interspersed. B, Malignant thymoma, type I. The neoplastic epithelial cells are polygonal and have round to oval, bland nuclei with inconspicuous nucleoli. Numerous small, reactive lymphoid cells are interspersed. The morphologic appearance of this tumor is identical to that of benign thymomas of the cortical type. In this case, however, the tumor was locally aggressive, invading adjacent lung and pericardium.
Immune response to the action of antigen areformedbylymphoid system of the body. It characterizes by: • a) specificity (valid for specific antigen); • b) potentiation (strengthening at the second introduction of antigen); • c) immunological memory (recognizes antigen through a long period of time between introductions). • The phases of the immune response: • presentation by macrophages through absorb (phagocytosis); • antigen recognition by lymphocytes; • transformation; • T-and B-lymphocytes proliferation. • Types of immune responses: • - Primary; • - Secondary.
Immune response to the action of antigen areformedbylymphoid system of the body. It characterizes by: • a) specificity (valid for specific antigen); • b) potentiation (strengthening at the second introduction of antigen); • c) immunological memory (recognizes antigen through a long period of time between introductions). The phases of the immune response: • presentation by macrophages through absorb (phagocytosis); • antigen recognition by lymphocytes; • transformation; • T-and B-lymphocytes proliferation. Types of immune responses: • - Primary; • - Secondary. Immune response to the antigen action
The primary immune response occurs at the first meeting with a specific antigen. IgM are produced by plasmacells. (IgG are appear later). • Secondary immune response occurs with repeated introduction of antigen in the body and is accompanied by accumulation of IgG. Types of immune response
Immunological hypersensitivity - peculiarities of reaction humoral or cellular immunity in sensibilisedparts of the body. • There are two types of hypersensitivity reactions: immediate and delayed types. Morphologically they display by acute or chronic immune inflammation. Hypersensitivity reactions can be realized by four ways. Immunological hypersensitivity
Hypersensitivity of first (immediate) type develop with the participation of mast cells and blood basophils. They produce IgE when antigen (allergen) introduce into organism. Hypersensitivity of first (immediate) type
Immediate hypersensitivity. A, Kinetics of the immediate and late-phase reactions. The immediate vascular and smooth muscle reaction to allergen develops within minutes after challenge (allergen exposure in a previously sensitized individual), and the late-phase reaction develops 2 to 24 hours later. B, C, Morphology: The immediate reaction (B) is characterized by vasodilation, congestion, and edema, and the late phase reaction (C) is characterized by an inflammatory infiltrate rich in eosinophils, neutrophils, and T cells. (Courtesy of Dr. Daniel Friend, Department of Pathology, Brigham and Women's Hospital, Boston, MA.)
Hypersensitivity of first (immediate) type • These reactions are manifested with eczema, dermatitis, allergic rhinitis and gastroenteritis, atonic asthma - local manifestations. • Anaphylactic reactions and shock - systemic manifestations.
Hypersensitivity of second type (antibody-mediated hypersensitivity) develops when interacting antibodies (IgG or IgM) with the antigen on the surface of cell with subsequent (наступним) damage due to lysis, phagocytosis by macrophages, cell cytotoxicity by T-cell lymphocytes, change cell function (neutralization or hyperaction) Hypersensitivity of second type (type II)
Hypersensitivity of type II • Examples of such reactions may be the reactions of the destruction of red blood cells after blood transfusion, hemolytic disease of newborn, reactions with the destruction of neutrophils, platelets (thrombocells) and others.
occurs when blood incompatibility of mother and fetus mainly through Rh factor (the mother "Rh-" fetus "Rh+"), which leads to hemolysis of fetal red blood cells by mother’s antibody. Haemolytic disease
Mother’s anamnesis: ІІІ pregnancy, ІІ deliveryІ pregnancy (1999) – healthy baby,ІІ pregnancy (2002) – dieddown.Mother has ІІІ Rh (-), titre of аntibodies1:64; Caesareansection; 37-38 weeks,valuation byApgar scale 7/8 balls, Mass 2550; Child АВ (ІV) Rh (+);Bilirubin from umbilical cord – 62,1; through 7 hours - 101,3 mkmoll/l;through 13 hours- 133,6 mkmoll/l 1stday of life - with signs of intestinal obstruction, Haemolytic disease of new-born shift into department of Intensive therapy of neonates; perforation and peritonitis developed through intestinal impassability of ІV degrees; After 22 days - the child died.
Hypersensitivity of Type III (immunocomplex hypersensitivity) develops due to the formation of immune complexes after interaction of antibody and antigen, which leads to complement activation and acute inflammation and necrosis development. Hypersensitivity of Third Type (Type III)
Hypersensitivity of Type III • Immunocomplex hypersensitivity may be systematic - serum sickness, systemic lupus erythematosus; or local - Arthus phenomenon after repeated administration of antigen with the vaccine.
Hypersensitivity of type IV (delayed hypersensitivity) is implemented with the participation of cells. There are sensitized lymphocytes and macrophages, which can exposure directly cytotoxicity (T-killer cells) or lymphokines producting. Hypersensitivity of Fourth Type(Type IV)
Hypersensitivity of type IV • This reaction develops within 24-72 hours after antigen introduction into sensibilised organism. It is characterized by the development of granulomatous inflammation with caseous necrosis
Autoimmune disease - a manifestation of the damage of natural tolerance of the immune system to its own antigens. This tolerance is formed in the embryonic period yet. Autoimmune diseases
Autoimmune diseases Autoimmune diseases can be: • - Organospecific(Hashimoto thyroiditis, insulinresistant diabetes mellitus, multiple sclerosis, encephalomyelitis, polyneuritis, aspermatogeny and others); • - Organononspecificor systemic disease (systemic lupus erythematosus, rheumatoid arthritis, dermatomyositis, and others).
