Heavy Chain Disease Can Be Detected by Capillary Zone Electrophoresis

Capillary electrophoresis (CE) is an analytical technique for the separation of molecules on the basis of molecular size, electric charge, and hydrophobicity. Since automated clinical instruments have become available, the major clinical application of this technique has been the rapid and effective separation of serum proteins. The detection of monoclonal protein components (MCs) is the main purpose of serum protein separation assays. Several reports have dealt with the feasibility of CE for the detection of MCs, and some pitfalls of this technique have also been described (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Immunosubtraction is used in conjunction with CE for typing any detected MC, for confirming the diagnosis of monoclonal gammopathies, and for identifying the heavy and light chains constituting the monoclonal immunoglobulin molecule. Different types of MCs (IgG, IgA, or IgM, with associated κ or λ light chains) and free light chains (either κ or λ) have been reported to be detectable by CE, but there have been no observations concerning the behavior of free heavy chains in CE. We report a case of γ-heavy chain disease (γ-HCD) detected in the course of routine serum assay by CE, characterized by immunosubtraction, and confirmed by further techniques. The patient was a 91-year-old man who …