The present study tested the association between CCL3L1/CCL3L3 CNs and SLE susceptibility using an mrcPCR assay21, which was designed for the determination of CNs specific for CCL3L1 and CCL3L3, and was not confounded by each other or the other CCL3L-related genes that may have confounded the estimation of CNs for CCL3L1 or CCL3L3 as indicated previously23. Here, CCL3L3 is linked to systemic lupus erythematosus.