Salivary biomarkers in SLE

Abstract

Abstract Background Lupus Nephritis (LN) affects close to half of all SLE patients and is currently diagnosed through kidney biopsy. In search for a noninvasive diagnostic method, four serum biomarkers of SLE (IGFBP2, sTNFRII, Axl, VCAM1) were valued for their diagnostic potential in the saliva of SLE patients. Methods IGFBP2, STNFRII, Axl, VCAM1 were ELISA assayed in the serum and saliva of SLE patients (16 inactive, 10 active non-renal, 10 active renal) and 14 healthy controls. Group wise analysis by Mann Whitney test and Spearman correlation analyses between serum and saliva were done. Results IGFBP2 was elevated in SLE serum compared to controls (FC=3.2 P=0.0002) while sTNFRII and VCAM1 showed elevation in active compared to inactive SLE (FC=2.2 P=0.002 and FC=2.8 P<0.0001 respectively). Salivary IGFBP2 and sTNFRII were elevated in SLE compared to controls (FC=2.4 P=0.01, FC=2.8 P=0.04 respectively), but was not associated with disease activity or renal involvement. Saliva and serum biomarkers did not correlate in this sample cohort. Conclusion Although all four biomarkers (IGFBP2, sTNFRII, Axl, VCAM1) have shown diagnostic potential in SLE serum, only IGFBP2 and sTNFRII were elevated in SLE saliva. Further exploration into other salivary biomarkers through an unbiased aptamer based protein screening platform is in progress.