Diagnosis and monitoring a case of light-chain deposition disease in the kidney using a new, sensitive immunoassay.

A 59-year-old male was diagnosed with nephrotic syndrome secondary to light-chain deposition disease. There was no other evidence of a B cell clonal disorder or amyloidosis; circulating free light chains were identified using a new immunoassay (Freelite) and used to monitor disease progression. Improvement in renal function and proteinuria following VAMP chemotherapy correlated with a reduction in circulating light-chain levels.