Increased soluble CD72 in systemic lupus erythematosus is in association with disease activity and lupus nephritis

•CD72 is a B cell regulatory molecule.•Soluble CD72 is elevated in SLE.•High levels of soluble CD72 are correlated with SLEDAI.•High levels of soluble CD72 are correlated with kidney involvement in SLE.•High levels of soluble CD72 are correlated with aCL and ds-DNA antibodies.

IntroductionB cell receptor (BCR) -mediated signals are enhanced when CD72 expression is deficient on B cells in autoimmune diseases. The significance of soluble CD72 (sCD72) has not been elucidated.MethodsSoluble CD72 was analyzed in the serum of 159 SLE patients, 40 rheumatoid arthritis (RA) patients, and 100 healthy individuals. Correlations between sCD72 and SLE disease activity (SLEDAI) were assessed.ResultsSoluble CD72 was found increased in SLE patients, when compared to both RA patients and healthy individuals (20.2 ± 1.2 ng/ml; 10.6 ± 4.6 ng/ml and 7.2 ± 3.3 ng/ml; p < 0.001). Soluble CD72 level was significantly higher in SLE patients with renal involvement than in patients without (31.8 ± 2.3 ng/ml vs 13.9 ± 0.9 ng/ml; p < 0.001) and also with the presence of auto-antibodies.ConclusionSoluble CD72 is significantly increased in SLE patients mainly in those with renal involvement. Increased sCD72 may become a potential biomarker for renal involvement in SLE.