Heat-insoluble cryoglobulin in a patient with essential type II cryoglobulinemia and cryoglobulin-occlusive membranoproliferative glomerulonephritis: Case report and literature review

Background A type of heat-insoluble cryoglobulin has been rarely reported and poorly understood. We report the case of a 79 y-old female who was admitted to hospital due to edema and renal failure. Methods Serial biochemical, immunological, and histological investigations were conducted. Results This patient had elevated serum urea and creatinine with positive rheumatoid factor and low serum C3 and C4. Her serum was positive for cryoglobulin at 4 °C. The precipitate did not dissolve at 37 °C until it was heated to 56 °C. Electrophoresis of the cryoglobulin demonstrated a monoclonal spike in the gamma region characterized as IgG-κ and polyclonal IgM by immunofixation. Bone marrow aspiration showed presence of 5% plasma cells. Histological examination of renal biopsy revealed a diffuse increase in mesangial matrix, cellularity and endocapillary proliferation. Numerous monocyte/macrophages were present within mesangium and capillary lumina. Focal double contouring of glomerular basement membrane with subendothelial deposits and “hyaline thrombi” were noted. Accordingly, a type II heat-insoluble cryoglobulinemia associated with membranoproliferative glomerulonephritis and monoclonal gammopathy of undetermined significance was made. Conclusions The unusual heat-insoluble cryoglobulins may indicate severe clinical consequence. Proper laboratory procedure and careful examination of cryoglobulin will assure early recognition and detection of heat-insoluble cryoglobulins.