High incidence of intact or fragmented immunoglobulin in urine of patients with multiple myeloma

Abstract

In this prospective study we determined the incidence of intact/fragmented immunoglobulin and Bence Jones protein in urine immunofixation using Sebia reagents and Hydrasys^TM 2 apparatus and compared the results to concentrations of serum free light chains (FLC) assessed using Siemens BN^TM II nephelometer and the immunoassay Freelite (Binding Site) in 289 patients with multiple myeloma at diagnosis. It was found that in one third of IgG, IgA and IgD myeloma patients, intact/fragmented immunoglobulin can be detected in urine and is connected with impaired renal function and reduced survival. Urine immunofixation detects monoclonal protein (FLC and intact/fragmented immunoglobulin) in 66–79% of IgG and IgA myeloma patients while serum FLC immunoassay detect it in 82–94% of IgG and IgA myeloma patients. However, the latter method is inadequate for detection of intact/fragmented immunoglobulin in urine. Serum FLC immunoassay and urine immunofixation are complementary methods in diagnosing and monitoring monoclonal protein in patients with myeloma.

Keywords::

• Free light chains
• intact immunoglobulin
• multiple myeloma
• urine immunoglobulin

Potential conflict of interest:

Disclosure forms provided by the authors are available with the full text of this article at www.informahealthcare.com/lal.