Electrophoretic analysis of microheterogeneity of paraproteins in a patient with IgD myeloma.

High-resolution two-dimensional polyacrylamide gel electrophoresis (2-DE) was used to analyze more precisely serum and urine specimens of a patient suffering from IgD myeloma associated with renal insufficiency. The application of 2-DE with immobilized pH gradient followed by immunoblotting revealed the presence of acidic monoclonal delta chains, hidden on 2-DE by albumin. This approach also enabled to detect two other forms of delta heavy chains expressing both reduced (45 kDa) and high (110 kDa) mol. weight. The analysis of urine specimen proved the presence of three acidic isoforms of monoclonal lambda light chains together with multiple monoclonal light chain fragments, which strongly suggests amyloidogenicity of these monoclonal light chains.