immuno post midterm Flashcards
SLE
Systemic and multiorgan. IC are formed in serum and trapped in BM of glomeruli, skin/endothelium, synovia of joints, kidney. Unknown etiology
Immune-complex-mediated.
Ag/Ab - anti-ds-DNA, anti-phospholipids (can lead to spont abortion d/t increased coagulation), anti-leukocytes.
F/M - 10:1
RA
Excessive Type 1 cytokines. Rheumatoid factors IgM (or IgG/IgA) to the Fc of IgG. These are not essential for dz, may enhance IC. Both IL-! and TNFa are elevated in RA -> targets for therapy. Use anti-IL-1 and anti-TNFa (monoclonal Abs - eg adalimumab and fusion protein Enbrel/Enteracept). HLA DR1/DR4
Immune-complex and cell-mediated.
Ag/Ab - Fc of IgG/Ab is called rheumatoid factor
F/M - 3:1
Hashimoto’s thyroiditis
Thyroid. Goiter and/or hypothyroidism. (Hyperthyroidism first d/t dmg causing release of thyroid contents, then hypothyroidism) Peaks in ages 30s or 40s
Cell-mediated.
Ag/Ab - Ab released after gland destruction. Anti-thyroglobulin, anti-microsomal (proteins). Use Abs for dx.
F/M - 50:1
MS
Brain and spinal cord. Abs to MBP after cell death. Oligoclonal Ig bands in CSF (dx feature)
Cell-mediated. Delayed-type hypersensitivity (T cell mediated)
Ag/Ab - myelin basic protein (released after death)/anti-MBP and CNS oligoclonal Abs
F/M - 2:1
Goodpasture’s syndrome
Lungs and kidneys. Shared Ags between lung (alveolar) and GBM. Linear deposition of IgG and complement aids dx. HLA allele associated with HLA DR2
Abs to cell surface Ags
Ag/Ab - GBM/anti-GBM
F/M - 1:4, peaks in young and elderly
Pernicious anemia
Cell-specific - defective RBCs d/t malabsorption of vit B12. Abs bind cell surface Ags and destroy parietal gastric cells that secrete IF or Abs bind to IF and prevent binding of vit B12. Leads to megaloblastic anemia
Blocking Ab. Abs bind and destroy parietal cells
Ag/Ab - IF or surface antigens on parietal cells/anti-IF, anti-parietal cell
Graves’ dz
Thyroid. Stimulatory Abs mimic actions of ligand (thyroxin-stimulating hormone). Get unregulated secretion of thyroxin leading to hyperthyroidism
Stimulating Ab
Ag/Ab - TSHR/anti-TSHR
F/M - 8:1
MG
Neuromuscular transmission d/o. Abs are inhibitory and block ACh binding
Blocking Ab
Ag/Ab - ACH-R/anti-ACHR
F/M - 4:1
Cold agglutinin dz
Only manifests at temps below 37C. Occurs only at extremities (nose, fingers, toes) when pt is exposed to cold temps. Tx - keep patient warm and extremities well protected
Abs to cell surface Ags
Ag/Ab - glycophorin (Ii)/anti-Ii
Ankylosing spondylitis
Tissue specific w/systemic SE’s. HLA allele -> HLA B27. Joints - loss of lateral flexion of lumbar spine d/t stiffening if SI and spinal facet joints. Some evidence for prior infxn w/Klebsiella pneumoniae. NO rheumatoid factor!
F/M - 1:9, younger males more often affected
Wegener’s granulomatosis and Churg Strauss vasculitis
Similarities: anti-cANCA (against serum protease) and anti-PANCA Abs.
IgG and IgM Abs (IC formation, complement activation, phagocytosis)
Reticular dysgenesis
Defect: hematopoietic stem cells, autosomal recessive
Deficiencies/dysfxn: T cells, B cells, phagocytes. Anemic. Increased susceptibility to all infectious agents.
Tx: bone marrow transplant
Severe combined immunodeficiency disorder (SCID)
Defect: ADA deaminase (purine metabolism) deficiency, JAK-3 deficiency, CD132 defect, T-B SCID (Rag1, Rag2 defects)
Deficiencies/dysfxn: lymphocytes primarily. ADA - highest activity in lymphocytes, increased metabolites (deoxyATP and deoxyadenosine). These metabolites inhib RN reductase. CD132 is signaling molecule for cytokine recs (IL-2R, IL-4R, IL-7R, IL-9R, IL-15R)
Tx: ADA - polyethylene glycol-ADA (PEG-ADA), gene therapy for pts for whom PEG-ADA is ineffective and no bone marrow transplant is available
DiGeorge’s syndrome
Defect: Thymus. Most improve with age (may have activation of extrathymic maturation site)
Deficiencies/dysfxn: T cells (all phenotypes)
Tx: transplantation of fxn’l component of fetal thymus (in renal capsule), abx for milder cases
X-linked (Bruton’s) agammaglobulinemia (hypogammaglobulinemia)
Defect: developmental block in B cell differentiation from pro-B cell to pre-B cell due to signaling defect in btk. Manifests at 5-6 months (most of maternally-derived Abs degraded). Live vaccines contraindicated in pts w/this immunodeficiency. PE can reveal absent or hypoplastic tonsils in toddlers. More susceptible to autoimmune dz’s: inflammatory bowel disease, juvenile RA
Deficiencies/dysfxn: marked decrease in B cells and ALL antibody isotypes -> recurrent bacterial infxns, esp encapsulated pyogenic bacteria (Haemophilus influenzae, S. pneumoniae), and certain viral infxns (enterovirus, coxsackie virus)
Dx: serum protein electrophoresis, quantitative Igs, PHA stimulation test/candida hypersensitivity test
Tx: Igs (regular txt’s), abx, nutritional supplementation for pts w/recurrent abdominal infxns and subsequent malabsorption
Chronic mucocutaneous candidiasis
Defect: Hole in the T cell repertoire to Candida albicans. Nml B cell immunity to C. albicans
Deficiencies/dysfxn: CD4+ cells (especially)
Chediak Higashi syndrome
Defect: Abnormal fusion of cytoplasmic granules w/lysosomes (phagocytes and NK cells), LYST gene mutation
Deficiencies/dysfxn: phagocytes, CTL, NK cells
Tx: short-term: anti-fungal and anti-bacterial agents. Long-term: bone marrow transplant
Chronic granulomatous disease
Defect: NADPH oxidase
Deficiencies/dysfxn: phagocytosis -> recurrent and uncontrolled bacterial and fungal infections
Tx: short-term - anti-fungal and anti-bacterial agents; IFNy enhances production of ROIs. Long-term: bone marrow transplant
Paroxysmal nocturnal hemoglobinuria (PNH)
Defect: glycosylphosphatidylinositol (GPI) linkage for DAF (CD55) w/decreased protectin (CD59) in RBCs -> causes stabilized C3 convertase and activation of terminal pathway and formation of MAC -> lysis
Deficiencies/dysfxn: RBCs lysed by complement
Hereditary angio(neurotic)edema (HANE or HAE)
Defect: C1 esterase inhibitor protein
Deficiencies/dysfxn: uncontrolled activation of C1 -> proteolysis of C2/C4, enhanced production of C2b (vasoactive kinin), increased C4 (anaphylatoxin -> increased vascular permeability). CI inhibitor protein also inactivates kallikrein (that cleaves kininogen -> bradykinin, which increases vascular permeability). Life-threatening acute, intermittent attacks of skin and mucosal edema
Tx: infusion of C1 esterase inhibitor
Leukocyte adhesion deficiency
Defect: CD18 adhesion molecule (B2 integrin) - LAD 1. Defect in counter molecule for E selection - LAD2
Deficiencies/dysfxn: impaired trafficking of leukocytes to sites of infection, defective adhesion and margination. Increased susceptibility to fungal and bacteria infxns
Tx: bone marrow transplantation