Immunology Conditions+Treatments

DiGeorge Syndrome

PP/E: born without a thymus→t cell deficiency
congenital

P: no txt→early age death

Hypersensitivity 1

PP: immediate anaphylactic hypersensitivity
repeat exposure to allergen→allergen cross links→bind to IgE on cells→degranulation+release of mediators (ex: histamine)

E: IgE-mediated
allergen
antigen→mast cell/basophil-binding IgE antibody→sensitization

CM: hives
urticaria
pruritis

Hypersensitivity 2

PP: antibody binds to cell-membrane antigens→complement mediated lysis of cells (ex: transfusion/Rh reactions)/autoimmune hemolytic anemia

E: cytotoxic
IgG-mediated
antigens on a cell surface→Tfh+b cell activation→sensitization

P: OB clinical correlation
prevented by rhogan

Hypersensitivity 3

PP: antigen-antibody immune complexes deposited in tissues+neutrophils attracted to site→release lysosomal enzymes→tissue damage
IgM/IgG→complement also involved

E: immune complex
mediated by multiple types of antibodies
soluble antigens→Tfh+b cells activation→sensitization

Type 3 Clinical Correlates

systemic lupus erythematosus (SLE):

autoantibodies against:

• double stranded DNA

• histones

• nucleolar proteins

• other components of the cell nucleus

• deposits in kidney/skin/joints

rheumatoid arthritis (RA):

• autoantibodies (IgM called rheumatoid factors) formed against IgG

• deposits in synovial membranes

IgA nephropathy:

• IgA containing immune complexes found lining in glomeruli→cause glomerulonephritis

• delayed

• t cell mediated

• sensitization via CD4 and/or CD8 T cells sensitized by protein antigens

• memory t cells activated by immune system→relase cytokines upon 2nd exposure to same antigen→induce inflammation+activate macrophages→release inflammatory mediators

Anaphylaxis

PP: massive doses of antigen-IgE complexes on mast cells
-most severe type 1 hypersensitivity

E: peanuts
shellfish
bee venom
mx→penicillin

CM: severe bronchoconstriction
HTN
wheezing
hoarseness
laryngeal edema
pruritis
urticaria
-life threatening

TX: medical ICU intervnetion
pressors+intubation

Multiple Sclerosis

PP: autoreactive t cells+activted macrophages→demyelination of white matter in brain

E: viral infection→stimulation of autoreactive t cells
-primarily→one type of cell/organ

DX:
MRI: white matter→plaques
spinal fluid testing: oglioclonal bands of IgG

TX: immunosuppressive mx→target CD20 (b cell marker)→prevent flares

Chronic Thryoiditis

PP: antibodies→form against thyroglobulin+thryoid peroxidase→fibrosis of thyroid gland

E: thryoid
hashimoto’s thyroiditis

TX: thyroid hormone replacement

Immune Thrombocytopenic Purpura (ITP)

PP: antibodies→directed against platelets

E: primarily→one type of cell/organ

Autoimmune Hemolytic Anemia

PP: mx→lead to autoantibodies directed against RBCs→hemolysis of erythrocytes/RBCs

E: mx
primarily→one type of cell/organ

Pernicious Anemia

PP: antibodies→to intrinsic factor (released by stomach cells)→loss of vitamin B12 absorption

E: primarily→one type of cell/organ

TX: vitamin B12 supplementation

Diabetes Mellitus Type 1

PP: autoreactive t cells→destroy islet cells (produce insulin)→can’t produce insulin

E: primarily→one type of cell/organ
pancreas

Antibodies to Different Receptors in Dxs

insulin-resistant DM→insulin receptors

myasthenia gravis→acetylcholine receptors

hyperthyroidism/graves dx→thyrotropin receptors

Pemphigus Vulgaris

PP: autoantibodies→against desmoglein

E: desmoglein

TX: systemic glucocorticoids (steroids)

Celiac Disease

PP: autoantibodies form on transglutimase tissue

E: gliadin (protein)
-wheat
-barley
-rye

DX: transglutimase tissue antibody testing

TX: diet change→gluten-free diet

IBS: Crohns+Ulcerative Collitis

PP/E: normal intestinal flora→dysregulation of Th-1+Th-17 cells→immune response→chronic inflammation

TX: corticosteroids
DNA synthesis inhibitors
TNF inhibitors

IgA Nephropathy→Glomerulonephritis

PP/E: IgA→contains immune complexes→deposit into glomeruli

CM: classic sx→hematuria

P: end stage renal disease (ESRD)

Psoriasis

PP: autoimmune skin dx or arthritis

E: inflammatory infiltrate

Immunodeficiency Etiology+Components

E: m/c→immunosuppressive mx
rare→congenital

components
b cells
antibodies
t cells
complement
phagocytes

Diagnostically Detectable Proteins: Carcinoembryonic Antigen (CEA)

carcinoembryonic antigen (CEA)

circulates in:

• colon cancer

• pancreatic cancer

• breast cancer

• liver cancer

not as regionally specific as other antigens

decreases→surgical removal of tumor
increases→returning tumor

Diagnostically Detectable Proteins: Alphafetoprotein (AFP)

hepatocellular cancer→occurs in several malignancies
-ex: CA 19-9→ovarian cancer

produced by fetal liver

Transplants+Types of Transplants

recipients of grafts/transplanted organs

depends on similarity between pt+donor

types

• allograft→own tissue to another site of body

• synergenic graft→transferse tissue between genetically identical pts (twins)

• xenograft→transfer of tissues between different species

• allograft→genetically different members of same species (donor)
  -body doesn’t accept new donation→requires immunosuppressive mx
  -depends on difference between donor+recipient at MHC site

Allograft Rejection

allograft transplants→rely on immunosuppression→prevent rejection→requires HLA matching

acute allograft rejection

• 11-12 days post-vascularization of graft

• blood flow reduced→immune cells infiltrate graft→necrosis+rejection

• rejection→caused by t cell-mediated rxn
  -antibodies may play a role and contribute as well (humoral immunity)

Rhogam

only used in Rh- mothers that are having a baby that are Rh+→prevents type 2 hypersensitivity rxn

uses IgG→cross links baby’s blood cells that may interact with mom’s immune system during birth/pregnancy

protects future babies

• rhogam binds to cells→flags them to be cleared by mom’s spleen→no antibodies are made

• avoids creating antibodies to future Rh- babies