What happens with we find renal pathology findings and they confirm a monoclonal strain of B cell clone. A bone marrow is done and there is MGUS revealed. Is that now MGUS really undetermined or insignificant. A new term now referred to MGUS disorders with renal biopsy findings as MGRS( monoclonal gammopathy of renal significance). These patients are hard to treat as they are never classified as having a hematologic disease. They are usually classified as MGUS with MIDD or MGUS with MPGN. Other diseases that have been identified to be consistent with monoclonality are fibrillary, immunotactoid and certain cryoglobulinemias.
A lot of the MGUS patients with renal disease have been receiving no treatment or undertreated given the confusion. No one receives standard therapy for MM at the time of diagnosis.
How do we treat these disorders? A recent article by Leunget al in Blood summarizes some suggestions: Treating the underlying clone, myeloma-based treatments have shown more response rates although lymphoma based treatments have been used as well. The authors think that these disorders don’t require treatment from a “tumoral” standpoint but from a renal deterioration standpoint it’s needed. Hence the term MGRS fits better for this entity.
Diseases that are now associated with MGRS( or could have been classified)
2. AL amyloidosis
3. Fibrillary GN
4. Type I and II Cryoglobulinemic GN
5. Immunotactoid GN
7. Proliferative GN with monoclonal deposits