Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:We have shown previously that the kidneys of NZB/W mice express a number of inflammatory mediators at the onset of proteinuria and that some of these decrease to prenephritic levels after remission induction, suggesting that they are biomarkers for active renal inflammation (19).
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