Monoclonal Light Chain and Heavy Chain Deposition Diseases
Supplemental Studies
Microscopy
- Congo Red negative
- Electron microscopy shows granular, non-fibrillar deposits
- Immnohistochemistry, in situ hybridization or flow cytometry of bone marrow often demonstrates clonal plasma cells
- Not demonstrable at site of tissue deposition
- Immunostaining of renal biopsy may demonstrate kappa light chains
Useful Laboratory Tests
- Serum or urine protein electrophoresis, immunofixation, light chain quantification
- Quantitation and typing of monoclonal immunoglobulin / light chain
- Serum free light chain analysis may be required to demonstrate clonal light chains
- These studies may be used to
- Establish presence of a monoclonal plasma cell population
- Quantitation helps subtype the plasma cell dyscrasia (i.e. >3g/dL serum monoclonal protein is a major criterion for myeloma)
- Track disease burden over time
