Diseases Of The Immune System Flashcards
What Is immunity
Immunity refers to protection against infections.
Give 2 types of immunity
Innate and Adaptive immunity
Describe innate immunity
Innate immunity is mediated by cells and proteins
that are always present and poised to fight against
microbes and are called into action immediately in
response to infection.
4 components of innate immunity
- Epithelial barriers of skin, GIT and respiratory
tract. - Phagocytic leukocytes(Neutrophils,
macrophages) - Natural killer cell
- Several plasma proteins
What is adaptive immunity
Adaptive immunity( acquired or specific immunity)
is silent and responds to the presence of infectious
microbes by becoming active, expanding, and
generating potent mechanism for neutralizing and
eliminating microbes.
What are the components of adaptive immune system
Components of adaptive immune system are
lymphocytes and their products.
Types of adaptive immune responses
- Humoral immunity, mediated by soluble antibody
proteins that are produced by B lymphocytes - Cell mediated immunity, mediated by T
lymphocytes
Describe lymphocytes
Lymphocytes: are the mediators of adaptive
immunity and the only cells that produce specific
and diverse receptors for antigens
Describe t lymphocytes
T lymphocytes: express antigen receptors called T
cell receptors that recognize peptide fragments of
protein antigens that are displayed by MHC
molecules on the surface of the antigen presenting
cells.
Describe (Major histocompitibilty complex) molecules:
MHC(Major histocompitibilty complex) molecules:
the peptide display system of adaptive immunity
Describe B lymphocytes( Bone marrow-derived):
B lymphocytes( Bone marrow-derived): express
membrane bound antibodies that recognize a wide
variety of antigens. B cells are activated to become
plasma cells, which secrete antibodies.
Describe Natural killer cells
Natural killer cells: kills cells that are infected by some
microbes, or are stressed and damage beyond repair.
NK cells express inhibitory receptors that recognize
MHC molecules that are normally expressed on healthy
cells, and are thus prevented from killing normal cells.
Antigens presenting cells
Antigen- presenting cells: capture microbes and
other antigens, transport them to lymphoid organs,
and display them for recognition by lymphocytes.
The most efficient APCs are dendritic cells, which
live in epithelia and most tissue.
Describe the overview of normal immune responses
The physiologic function of immune system is
defense against infectious microbes.
The early reaction to microbes is mediated by the
mechanism of innate immunity, which are ready to
respond to microbes. These mechanism include
epithelial barriers, phagocytes, NK cells, and
plasma proteins, e.g. of the complement system.
The reaction of innate immunity is often manifested
as inflammation
The defense reactions of adaptive immunity develop
slowly, but are more potent and specialized.
Microbes and other foreign antigens are captured by
dendritic cells and transported to lymph nodes, where
the antigens are recognize by naïve lymphocytes. The
lymphocytes are activated to proliferate and
differentiate into effector and memory cells.
Cell-mediated immunity is the reaction of Tlymphocytes,
Design to combat cell- associated microbes( e.g.
phagocytosed microbes and microbes in the
cytoplasm of infected cells)
Humoral immunity is mediated by antibodies and is
effective against extracellular microbes( in the
circulation and mucosal lumens)
CD4+ helper T cells help B cells to make
antibodies, activates macrophages to destroy
Microbes and block their infectivity, and promote
the phagocytosis and destruction of pathogens.
Antibodies also confer passive immunity to
neonates.
Describe the 4 hypersensitive reactions
- I (Immediate Hypersensitivity)
- II (Antibody Mediated Hypersensitivity)
- III (Immune-Complex Mediated Hypersensitivity)
- IV (Cell-Mediated Hypersensitivity)
Describe type 1 hypersensitivity
Immediate” means seconds to minutes
“Immediate Allergic Reactions”, which may lead to
anaphylaxis, shock, edema, dyspnea death
1) Allergen exposure
2) IMMEDIATE phase: MAST cell
DEgranulation, vasodilatation, vascular
leakage, smooth muscle (broncho)-
spasm
3) LATE phase (hours, days):
Eosinophil’s, PMNs, T-Cells
Describe type 2 hypersensitivity
ABs attach to cell surfaces
OPSONIZATION (basting the turkey)
PHAGOCYTOSIS
COMPLEMENT FIXATION (cascade of
C1q, C1r, C1s, C2, C3, C4, C5….. )
LYSIS (destruction of cells by rupturing
or breaking of the cell membrane)
Name type 2 diseases
Autoimmune Hemolytic Anemia, AHA
Idiopathic Thrombocytopenic Purpura, ITP
Goodpasture Syndrome (Nephritis and Lung
hemorrhage)
Rheumatic Fever
Myasthenia Gravis
Graves Disease
Pernicious Anemia, PA
Describe type 3 hypersensitivity
Antigen/Antibody “Complexes”
Where do they go?
Kidney (Glomerular Basement Membrane)
Blood Vessels
Skin
Joints (synovium)
Common Type III Diseases- SLE (Lupus),
Poly(Peri)arteritis Nodosa, Poststreptococcal
Glomerulonephritis, Arthus reaction (hrs), Serum
sickness (days)
Type 4 hypersensitivity
Tuberculin Skin Reaction
DIRECT ANTIGENCELL CONTACT
GRANULOMA FORMATION
CONTACT DERMATITIS
Describe autoimmune diseases
Failure of SELF RECOGNITION
Failure of SELF TOLERANCE
TOLERANCE
CENTRAL (Death of self reactive lymphocytes)
PERIPHERAL (anergy, suppression by T-cells,
deletion by apoptosis, sequestration (Ag masking))
STRONG GENETIC PREDISPOSITION
OFTEN RELATED TO OTHER AUTOIMMUNE
DISEASES
OFTEN TRIGGERED BY INFECTIONS
Name the classic autoimmune diseases
LUPUS (SLE) Systemic Lupus
Erythematosus
RHEUMATOID ARTHRITIS
SJÖGREN SYNDROME
SYSTEMIC SCLEROSIS (scleroderma)
MCD (Mixed Connective Tissue Dis.)
Poly (Peri-) arteritis nodosa
Give classic autoimmune diseases(local)
HASHIMOTO THYROIDITIS
AUTOIMMUNE HEMOLYTIC ANEMIA
MULTIPLE SCLEROSIS
AUTOIMMUNE ORCHITIS
GOODPASTURE SYNDROME
AUTOIMMUNE THROMBOCYTOPENIA (ITP)
“PERNICIOUS” ANEMIA
INSULIN DEPENDENT DIABETES MELLITUS
MYASTHENIA GRAVIS
GRAVES DISEASE
Lupus
Etiology: Antibodies (ABs) directed against the patient’s
own DNA, HISTONES, NON-histone RNA, and
NUCLEOLUS
Pathogenesis: Progressive DEPOSITION and
INFLAMMATION to immune deposits, in skin, joints,
kidneys, vessels, heart, CNS
Morphology: “Butterfly” rash (NOT discoid)
, skin deposits, glomerolunephritis
Clinical expression: Progressive renal and vascular
disease, POSITIVE A.N.A.
SJÖGREN
SYNDROME
Hematologic
Arthritis
Skin
Fever
Fatigue
Weight loss
Renal
Central nervous system
Pleuritis
Myalgia
Pericarditis
Gastrointestinal
Raynaud phenomenon
Ocular
Peripheral neuropathy
ImmunoDefiency S
yndromes (-IDS)
PRIMARY (GENETIC)
SECONDARY (A
CQUIRED) (A-IDS)
Primary
CHILDREN with repeated, often severe infections, cellular
AND/OR humoral immunity problems, autoimmune defects
BRUTON (X-linked agammaglobulinemia)
COMMON VARIABLE
IgA deficiency
Hyper -IgM
DI GEORGE (THYMIC HYPOPLASIA)
SCID (Severe Combined Immuno Deficiency)
COMPLEMENT DEFICIENCIES
(A)IDS(SECONDARY IDS)
Etiology: HIV
Pathogenesis: Infection, Latency,
Progressive T-Cell loss
Morphology: MANY
Clinical Expressions: Infections,
Neoplasms, Progressive Immune Failure,
Death, HIV+, HIV-RNA (Viral Load)
NATURAL HISTORY OF HIV
INFECTION
1) PRIMARY INFECTION
2) LYMPHOID INFECTION
3) ACUTE SYNDROME
4) IMMUNE RESPONSE
5) LATENCY
6) AIDS
GENERAL IMMUNE
ABNORMALITIES
LYMPHOPENIA
DECREASED T-CELL FUNCTION
B-CELL ACTIVATION,
POLYCLONAL
ALTERED
MONOCYTE/MACROPHAGE
FUNCTION
Opportunistic Infection
Protozoal/Helminthic:
Cryptosporidium, PCP (Pneumocystis
Carinii (really Jiroveci) Pneumonia),
Toxoplasmosis
Fungal: Candida, and the usual 3
Bacterial: TB, Nocardia, Salmonella
Viral: CMV, HSV, VZ (Herpes Family)
CANCERS of AIDS
KAPOSI SARCOMA
B-CELL LYMPHOMAS
CNS LYMPHOMAS
CERVIX CANCER,
SQUAMOUS CELL
AMYLOIDOSIS
BUILDUP OF AMYLOID “PROTEIN”
AL (Amyloid Light Chain)
AA (NON-immunoglobulin protein)
Aß (Alzheimer’s)
WHERE? BLOOD VESSEL WALLS, at first
KIDNEY
SPLEEN
LIVER
HEART
AMYLOID ASSOCIATIONS
PLASMA CELL “DYSCRASIAS”, i.e.,
MULTIPLE MYELOMA
CHRONIC GRANULOMATOUS DISEASE,
e.g., TB
HEMODIALYSIS
HEREDOFAMILIAL
LOCALIZED
ENDOCRINE MEAs (Multiple Endocrine
Adenomas)
AGING
