Intact immunoglobulin heavy/light chain paired assays

AUTORI

ABSTRACT

International guidelines recommend serum protein electrophoresis (SPEP) and immunofixation as laboratory tests to improve monoclonal gammopathy patient management. In patients with multiple myeloma (MM) these measurements are required to assess patient response to therapy, which help guide treatment and may influence clinical decisions. Here we discuss the potential role of new immunoassays that quantify the intact immunoglobulin Ig’k and Ig’l serum concentrations for IgG, IgA, IgM and IgD isotypes. The Freelite assay revolutionised patient management, particularly in the case of AL amyloidosis, and, due to the polyclonal nature of the antisera used, had a broad recognition for the highly heterogeneous free light chains (FLC). Similarly, the Ig’k and Ig’l assays utilise polyclonal antisera, identifying all MM patient sera tested to date, including those not readily identifiable by SPEP. Furthermore, as with the assessment of FLC k/l ratios by Freelite, Ig’k/Ig’l ratios have prognostic value at presentation and maximum response and may represent a hitherto unidentified MM cell biology that selectively suppresses isotype matched immunoglobulin production. Finally, we propose an algorithm utilising Ig’k and Ig’l and FLC measurements that may improve the detection of clonal evolution in MM patients.

BIBLIOGRAFIA