Other Diseases with Monoclonal Free Light Chains

Solitary Plasmacytoma of bone

These bone tumours represent 3-5% of plasma cell neoplasms and are twice as common in women than men. Approximately 50% progress to multiple myeloma over 3-4 years while 30-50% are alive at 10 years.

A retrospective study of 116 patients with solitary bone plasmocytoma showed "an abnormal serum immunoglobulin free light chain (FLC) ratio at diagnosis may identify risk of progression to myeloma..."1

A smaller study reported "SFLC measurements can be used to detect and monitor patients with SBP. It may provide a more accurate marker of response after RT (radiotherapy)2" *.

* In the USA diagnostic use of this product is restricted to those stated in the product insert

Waldenström's macroglobulinaemia

Waldenström's macroglobulinaemia is a low-grade, lymphoproliferative disorder that is associated with the production of monoclonal IgM. It is 5-10% as frequent as myeloma with approximately 1,500 new cases per year in the USA and 300 in the UK.

Since light chain proteinuria occurs in many patients it is likely concentrations of serum free light chains are frequently abnormal. In a study of 37 patients all but one had abnormal FLC concentrations and/or abnormal κ/λ ratios3.

Since serum free light chains are elevated in nearly all patients this may be clinically useful. Their short half-life and the large clinical range should provide a sensitive marker for treatment responses. Also, free light chains do not cryoprecipitate and are not affected by other factors that can make IgM measurements difficult. Further studies are required.

B-cell, non-Hodgkin lymphomas

Non-Hodgkin lymphomas represent about 2.6% of all cancer deaths in the UK (approximately twice that of Multiple Myeloma) and the incidence is rising by 3-4% per year in all age groups and both sexes.

In order to determine the frequency of abnormal serum free light chain concentrations in B-cell non-Hodgkin lymphomas, frozen sera were studied from the Lymphoma SPORE serum bank at The Mayo Clinic by Martin et al.4 For comparison, samples were also tested for monoclonal immunoglobulins by serum protein and immunofixation electrophoresis.

26 of 202 patients had abnormal serum free light chain concentrations and in 13 patients monoclonal proteins were detected only by serum free light chain immunoassays.

B-cell chronic lymphocytic leukaemia

Raised serum free light chains have been found in many patients with B-cell chronic lymphocytic leukaemia3. Of 20 sera studied, 7 patients (35%) had abnormal serum free light chains. Using protein/immunofixation electrophoresis, only 2 (10%) had a monoclonal protein.

References

  1. David Dingli, Robert A. Kyle, S. Vincent Rajkumar, Grzegorz S. Nowakowski, Dirk R. Larson, John P. Bida, Morie A. Gertz, Terry M. Therneau, L. Joseph Melton III, Angela Dispenzieri, and Jerry A. Katzmann
    Immunoglobulin free light chains and solitary plasmacytoma of bone.
    Blood 2006;108:6 pp.1979-1983

  2. X Leleu, AS Moreau, B Hennache, S Dupire, JL Faucompret, T Facon, A Bradwell, S Reid, G Mead
    Serum free light chain immunoassays for monitoring solitary bone plasmacytoma
    hematologica / the hematology journal 2005;90(s1):110(PO.410)
  3. Bradwell AR, Mead GP, Drayson MT, Carr-Smith HD.
    Serum immunoglobulin free light chain measurement in intact immunoglobulin multiple myeloma
    Blood 2002; 100: 11 No 5054.

  4. Martin M, Clark RJ, Shanafelt T, Katzmann JA, Bradwell AR, Abraham R, Kay NE, Witzig TE.
    Detection of Serum Free Light Chains in Patients with B-Cell Non-Hodgkin Lymphoma (NHL) and Chronic Lymphocytic Leukemia (CLL)
    Blood 2003; 102:11: No 4827.