CD19 and systemic lupus erythematosus: However, we observed an age-dependent correlation between CXORF21 and SLE Disease Activity Index (SLEDAI).CXORF21 protein abundance is positively correlated with SLEDAI in SLE females <35 years of age (CXORF21 ~ SLEDAI * Stratified Age) in both CD14+ monocytes and CD19+ B cells (Supplementary Fig. 13).A likelihood ratio test (LRT) rejected the model of SLEDAI as a single variable (upper panels Supplementary Fig. 13) in favour of an interaction model in monocytes (LRT P = 0.0002) and B cells (LRT P = 0.0006).