TOPIC DISCUSSION: Crystalglobulinemia and prarproteins and the kidney

Crystalglobulin induced nephropathy is a known complication of paraproteinemias.  A recent review In JASN focuses on this presentation of kidney damage from paraproteins. Monoclonal proteins can also deposit in the kidney as crystals and cause tissue damage. This happens in cases of  light chain proximal tubulopathy, crystal-storing histiocytosis, and crystalglobulinemia. Crystalglobulinemia is a rare complication of multiple myeloma that results from crystallization of monoclonal proteins in the systemic vasculature, leading to vascular injury, thrombosis, and occlusion. One can observe diffuse rectangular, rhomboid and sharp needle shaped hyaline-like  crystals depositing in multiple organ systems, including the kidneys, myocardium, coronary arteries, tricuspid and  pulmonary valves, lungs, bone marrow and other organs. Usually, this is a quick and drastic leading to AKI, and ESRD. The reason why this happens is unclear.  It is possible that it related to the abnormal glycosylation of light chains and their interactions with albumin.  IgG k and IgG lambda chains both have been reported to be involved. Heavy chains have also been reported.  Both cases of MM and MGRS have been reported to be present with crystalglobulinemia.

Fig 1: Crystals in urinary space

Fig 2: Intracardiac crystalline deposits