Three microarray data sets for each immune cell, including CD19+ B cells (GSE4588, GSE100648 and GSE87095) in RA and (GSE4588, GSE10325 and GSE59250) in SLE, CD4+ T cells (GSE4588, GSE56649, and GSE71841) in RA and (GSE4588, GSE103760, and GSE59250) in SLE and CD14+ monocytes (GSE71370, GSE38351, and GSE131989) in RA and (GSE4588, GSE103760, and GSE59250) in SLE were obtained from GEO database and used in this study. The gene discussed is CD19; the disease is systemic lupus erythematosus.