Immunology Flashcards
Describe the 2 signal process of T-cell activation from an APC.
T-cell activation requires 2 signals between the T-cells and APC:
Signal 1: T-cell [TCR:peptide:MHC] APC – necessary but not sufficient
Signal 2: T-cell [CD28:B7] APC – activation of T-cell with IL-2 release and T-cell proliferation
What are CTLA-4 receptors?
CTLA-4 receptors are the doppelganger of CD28 in that they bind preferentially to B7 on APC cell and prevent the activation and proliferation of T-cells.
Normal function is to prevent autoimmunity.
Which interleukin is implicated in T-cell proliferation?
IL-2 is released upon activation of T-cell to promote T-cell proliferation
What is polyarteritis nodosa (PAN)? Which sex is it more likely to affect?
Medium vessel vasculitis that affects M > F.
Which organ systems are implicated in polyarteritis nodosa (PAN)? Which organ system that tends NOT to be implicated?
Systemic - fever, malaise, weight loss 80%
Neuropathy - mononeuritis multiplex, polyneuropathy 75%
Arthralgia/myalgia 60%
Skin - livedo reticularis, pupura, ulcers 50%
Renal disease 50%
GI - abdominal pain, rectal bleeding 40%
HTN - new onset 35%
Orchiditis - testicular pain 20%
Lungs tend NOT to be involved.
Which viral illness is polyarteritis nodosa (PAN) associated with?
Hep B
What are the investigations for polyarteritis nodosa (4)?
- Angiogram (mesenteric/renal) for vasculitis
- Hep B serology
- Complement C3/C4 - normal
- Biopsy affected tissue
True/False: complement C3/4 is elevated in polyarteritis nodosa (PAN).
False.
What is the treatment of polyarteritis nodosa (s)?
- Steroids
- Cytotoxics
- Treat Hep B is relevant.
What are 6 conditions are associated with pANCA (use mnemonic).
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(MPCIRG = pANCA)
Microscopic polyangitis (MPA)
Polyarteritis nodosa (PAN)
Churg-Strauss (EGPA/Eosinophilic GPA)
IBD (esp. UC)
RPGN - Rapidly Progressive Glomerulonephritis (necrotising/cresentic GN)
Goodpasture’s Syndrome (anti-GBM)
What is the new name for Wegener’s Granulomatosis?
GPA (Granulomatosis with PolyAngiitis)
How is GPA (granulomatosis with polyangiitis) diagnosed (biochemistry/immunofluorescence/histopathology/urine)?
Biochem: c-ANCA, PR3
Immunofluorescence: Pauci-immune
Histopathology: necrotising medium vessels + granulomas
Urine: postive urinary sediment
Which organ systems are implicated in GPA (granulomatosis with polyangiitis)?
ELK:
ENT
Lung - PE (20x risk)
Kidney - haematuria/RPGN
What type of glomerular disease is GPA (granulomatosis with polyangiitis) associated with?
Rapidly-progressive GN (RPGN)
True/False: GPA (granulomatosis with polyangiitis) is more likely to relapse than Microscopic Polyangitis?
True.
What is the treatment of GPA (3)?
- Rituximab + prednisone (Rituximab as good as cytotoxic with less SEs)
- If RPGN then IVIG
- Maintenance = AZA or MTX (only if cytotoxics used)
- Relapse = cytotoxics then AZA afterwards