And this discussion takes us into what ANCA means?
So what is ANCA?
It stands for Anti-neutrophil cytoplasmic antibody.
Stop. There are two types of ANCAs.
Aren’t there? c-ANCA, p- ANCA.
At some point during your medical education you've definitely been exposed to c-ANCA,
now I have to take you a little bit further.
I’ll tell you what does c and p stands for.
Well, we said that c was the third letter of the alphabet: A, B, C.
Therefore, anti-proteinase 3 ANCA.
The p in p-ANCA is anti-myeloperoxidase ANCA process. Clear?
Are we done? No. A wish.
Here’s the p. The p in p-ANCA,
apart from you should knowing that it’s myeloperoxidase means perinuclear.
What the heck!
Why do I have to know this, Doc Raj!
Are you just actually vomiting information at us? No!
I'm giving you information so that you can clinically differentiate;
you get every single question right. And you're not thrown off.
That p in p-ANCA is perinuclear.
You will be responsible for identifying an ANCA, okay?
You will be responsible for literally identifying on immunofluorescence,
an anti-neutrophil cytoplasmic antibody.
And when you do so, you have to be able to distinguish between
a p, perinuclear versus c, cytoplasmic.
What’s p mean? The perinuclear, around the nuclear.
With vasculitis the two relevant target antigens detected are proteinase 3 or PR3 in my face or in MPO
MPO-Anca mpo PR3-Anca associated with substantially specificities
and positive predictive values than the immunofluorescence patterns they correspond with P-ANCA and c-ANCA)
MPO-ANCA corresponding to p-ANCA is associated with:
Eosinophilic granulomatosis with polyangiitis also called EGPA or Churg-Strauss disease.
Which presents clinically with asthma and eosinophilia.
It is also associated Microscopic Polyangiitis, which clinically affects the kidneys, lungs, nerves, skin, and joints
Finally it is associated with Anti-glomerular basement membrane disease also known as Goodpasture syndrome,
which clinically presents with rapidly progressive nephritis manifesting with hematuria and decreased kidney function
PR3-ANCA corresponding to c-ANCA and is associated with:
Granulomatosis with Polyangiitis
and presents clinically with focal necrotizing vasculitis and necrotizing granulomas in the nose and sinuses, lungs, and kidney