Consult Rounds: Cryoglobulins and the Kidney

Cryoglobulins and the Kidney

Cryoglobulins are Igs that reversibilly precipitate at temperatures <37C.  This results in symptoms that can lead to rashes, vasculitis, ulcers, ischemia, joint pains, and eventually in 25% cases – renal injury.

Two mechanisms: immune complex GN vs high viscosity related.  All have nephritic/nephrotic syndrome with various levels of kidney function.

1/3 with purpura and arthralgia
¾ with low C4 and ½ with low C3

All 3 types of cryoglobulins reported with renal disease

Most commonly it occurs in settings of type II (“mixed”) cryo secondary to hepatitis C virus.  Most patients with type II or III cryoglobulins have a positive rheumatoid factor.  The pathology pattern of injury is either membranoproliferative or diffuse proliferative GN.

•          Type 1 Cryo( monoclonal IgM or IgG) – MM, MGUS, WM, lymphomas and CLL

•          Type 2 Cryo(monoclonal IgM + polyclonal IgG)- CLL, lymphoma, SLE, Hep C

•          Type 3 Cryo(polyclonal)- lymphoproliferative diseases, SLE

Treatment

Treatment of underlying cause- Hep, SLE, Myeloma

Steroids

Alkylating Agents

Anti CD-20 agents( good response in some cases)

Plasmapheresis ( adjunct) if skin involved and early renal
involvement