ASN 2011: MPGN revisted

MPGN classically has been associated with Type 1, II and III variant and divided based on electron microscopic(EM) findings.
This ASN, a paradigm shift of thinking was mentioned.

The thinking now is to think of it more like a pattern of injury and classify based on immunofluorescence (IF) rather than EM.

The four major categories are:

Immune complex :  chronic infection related or auto immune 

Complement dysregultion : familial and acquired, the c3 glomerulopathies

Chronic tma:  atypical hus, other TMAs, APLAS

Paraprotein.  Any variant can come here, that is monoclonal

Old classification:  Based on extent of deposits on EM and where they are

New classification: Based on pathophysiology and IF findings more

So If you have IgG and C3 on IF:- then think more immune complex based

If you have Ig G monoclonal:- think monoclonal disease 

If you have C3 only:- think C3 glomerulopathies  or Dense Deposit Disease

If you have No C3 or IgG:- then think TMA

Idiopathic MPGN in an adult is a diagnosis of exclusion, more common in children and its usually polyclonal and C3 positive. 

So think differently when thinking about MPGN from now on. Always a tough disease to battle

take a look at a prior concept map on this

http://www.nephronpower.com/2011/08/concept-map-of-mpgn-pattern-of-injury.html