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:Aside from the effects on Th1 cells, IL-27 has recently reported that played a regulatory role in limiting excessive inflammation during infection with Toxoplasma gondii by modulating the development of Th17 cells (20, 21).
Category: