TNFRSF1B and progressive multifocal leukoencephalopathy: Baseline soluble TNFR2 in serum and TNFR2 expression on Tregs was higher in sarcoidosis patients of infliximab responders than in non-responders.27 Hence, it could be useful to analyse these markers in sarcoidosis patients that develop PML and compare the treatment responses.