Topic Discussion: Proliferative GN with Monoclonal igG Deposits

Classically the dysproteinemias have glomerular involvement as
1. Light chain or Heavy chain deposition diseaese
2. Cryoglobulenemia
3. Amyloidosis
4. Immunotactoid GN
5. Fibrillary GN

Recently, a new entity has been identified called Proliferative GN with dysproteinemias or monoclonal igG deposits ( PGNMID)
Some features
1. MPGN pattern of injury, with endocapilary proliferation.  (Now if we look back at the original papers of secondary MPGN pattern of injury one of the classic causes is dysproteinemias, so unclear why this is a new category)
2. Interestingly, only 50% ended up having a bone marrow proven lymphoma or myeloma diagnosis( so now what do we do?)
3. All had proteinuria
4. 75% or more had hematuria
5. Treatment in this one study with immunomodulators showed no benefit
6.Type 1 Cyro MPGN pattern has to be ruled out.

Ref:
http://www.ncbi.nlm.nih.gov/pubmed/14675039
NephSap July 2011