Post transplant MPGN

A nice recent paper in Kidney International April 2010 edition talks about the examination of MPGN post transplant at a single center.  Few interesting observations they noted:- They found that the risk of recurrence was increased most with patients who had pre transplant low complement levels and elevated monoclonal proteins.  The 29 patients they studied, 5 lost their graft and 2 patients remained on plasmapheresis.  The recurrence rate was low but was important to note few clinical key points.

What does this mean? MPGN is a tough diagnosis to make in my opinion. They ruled out all DDD and fibrillary patients from their study. They did include rare causes like Rheumatoid Arthritis but "clinically" all secondary causes were ruled out. That's my concern as MPGN is one disease that has found to have so many secondary causes.  From infectious to autoimmune diseases, you name it and it can cause MPGN.  Now recently, there has been some suggestion that paraproteins can be related to cause of primary MPGN.  Again, we cannot call it primary if we have found a secondary cause. MPGN like pattern of injury can be seen in TMA, Autoimmune diseases and paraproteinemias. If those are all negative, and there are deposits, perhaps its primary. Also, in post transplant- its even tougher, as immune mediated changes can lead to an MPGN like pattern on the biopsy, CNI induced chronic TMA can look like MPGN as well and transplant glomerulopathy is basically an MPGN pattern of injury. First we need to differential pattern of injury from primary MPGN.
Regardless, the two great points that come up are:
Should we screen everyone with MGPN regularly with complements and if they are low, then their risk post transplant recurrence is high?
Should we screen everyone prior to transplant with serum free light chain assays and if they are present:- not transplant them or consider a bone marrow prior to transplant?
No clear answers but this study raises these important questions!!