CCR2 and systemic lupus erythematosus: Cluster 1 contained transcripts that were largely up-regulated in HC and down-regulated or not changed in the active SLE group including the membrane-associated protein tyrosine kinase activity (EPHA1) and the chemokine receptor, CCR2. Cluster 2 grouped up-regulated transcripts which were strongly expressed in active SLE T cells (Figure 2, right panel).