We then used the intersection of biomarker determination from SLE vs. HC and SLE vs. RA and obtained seven proteins that could be used as a final biomarker combination for SLE diagnosis, including IFIT3, MX1, OAS3, STAT1, STAT2, mitochondrial import receptor subunit TOM40 homolog (TOMM40), and structural maintenance of chromosome protein 1A (SMC1A). This evidence concerns the gene STAT1 and rheumatoid arthritis.