This is important to consider when we get a diagnosis of MPGN back from the pathologist and checking serum free light chains and possibly have analysis of anti light chain antibodies to detect a possible MGUS in the biopsy specimen and a complete workup in serum and urine immunofixation before embarking to treatment.
We also recently published a case report of MPGN diagnosis and few months later the patient developed Celiac Sprue and treatment of sprue led to disappearance of the MPGN as well.
Secondary causes of MPGN are increasing and pattern recognition is important: four most important being:-
Immune complex diseases, viral diseases, paraproteins and thrombotic microangiopathies can mimic a MPGN pattern of injury on the kidney biopsy!!
When the cause of a disease is identified then the numbers of so called 'idiopathic' drop. An important example is Essential Mixed Cryo - after HCV was identified as a major cause there is probably no more EMC.
ReplyDeleteBut the increased association of MGUS with MPGN has nothing to do with reduction of idiopathic MPGN. Both are different diseases. Idiopathic MPGN is a disease of teens with specific manifestations and is probably due to an unknown virus- the incidence is TRULY falling for unclear reasons.
Whereas secondary MPGN is not a disease but a pattern on biopsy and is due to (a) immune complex (b) TMA and (3) paraproteinemia. In other words it is a response to subacute endothelial injury. The same thing happens in Transplant Glomerulopathy.
When studying MPGN it is wrong to combine primary MPGN and MPGN patterns on biopsy into one group.