Cryoglobulinaemia is defined as the presence of circulating immunoglobulins that reversibly precipitate on cooling. These immunoglobulins can precipitate around the circulation, typically causing a peripheral cutaneous purpuric rash, mononeuritis multiplex, mild hepatitis, mesangiocapillary GN (type I) and occasionally, alveolar capillaritis. As in SLE, immunoglobulins deposited within the GBM excite an inflammatory response with mesangial cell proliferation and capillary wall thickening.