CCL21 and multiple sclerosis: Most notably CXCL13, which has been the subject of numerous studies in the past and is related to disease activity.21,40 CXCL8, CXCL12, CXCL13, CCL5, CCL21, CCL22 and IL-15 have also been reported to be differentially expressed in multiple sclerosis,8,41 but were not included in the inflammation panel.