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1.3.2. Polyclonal FLC studies

Chapter 1

The previous edition summarised data from many observational studies reporting elevated polyclonal sFLCs in association with various diseases. Subsequently, in 2012, Dispenzieri et al. [33] published data from follow-up of over 15000 people seen at the Mayo Clinic in Rochester, Minnesota, USA. After removal of all subjects with an abnormal sFLC ratio or other evidence of a monoclonal process, there was a significant association between elevated polyclonal sFLC concentrations and early mortality (Section 35.10). These findings have been corroborated in two further, independent, populations by Eisele et al. [34] and Anandram et al. [35]. The risk associated with elevated sFLC was found to be independent of other markers of renal function, inflammation or acute-phase response but the early mortality was attributable to multiple causes, indicating no obvious path for clinical intervention. This remains an area of active research.