Background: Early management of lupus nephritis (LN) depends on accurate and early diagnosis. Laboratory biomarkers such as Anti dsDNA antibody and complement are not sensitive or specific enough for prediction of lupus nephritis flare. This study aimed to evaluate the value of the serum level of Dickkopf-1 in the diagnosis of systemic lupus erythematosus (SLE) and LN.

Subjects and methods: This case-control study was carried out on forty-two SLE patients, 21 of them were complicated with nephritis (proved by renal biopsy), and 21 healthy age and sex matched individuals as a control group. Serum DKK-1 concentration was measured, for all participants, by enzyme linked immunosorbent assay (ELISA).

Results: SLE patients (nephritis and non-nephritis) had significantly higher serum DKK-1 levels (median was 56.3 ng/ml in nephritis group and 112 ng/ml in non-nephritis group ) than healthy controls (median was 44.4 ng/ml) P-value 0.003, also Serum DKK-1 level was significantly higher in non-nephritis group as compared to nephritis group P-value = 0.001. Serum DKK-1 level was negatively correlated with 24-hour urine proteins (p-value <0.001).

Conclusion: Serum Dkk1 may be a highly sensitive and specific SLE diagnostic marker that is dependable, promising, and non-invasive. It has a good sensitivity for LN diagnosis. Further studies are still needed to ensure these findings.