BAFF Expression is Increased in Patients with Lupus Nephritis and Associated with Antinucleosome Antibodies, C1 Inhibitor, Α-1-Acid-Glycoprotein and Endothelial Activation Markers

Abstract

Objectives: B cell activating factor (BAFF) inhibitor therapy has recently been approved for non-renal Systemic Lupus Erythematosus (SLE). While BAFF plays a role in experimental lupus nephritis (LN), its role human LN is not well studied. Methods: Case control study in 102 SLE patients, 30 with LN (+LN) and 72 without LN (-LN) and 31 healthy controls. We analysed BAFF mRNA expression in PBMCs (BAFF-RQ) and serum BAFF (s-BAFF) levels and investigated their relation with clinical, histological- and additional acute phase proteins. Results: s-BAFF and BAFF-RQ were increased in +LN patients compared to controls, but their expression did not correlate with ISN/RPS class, Activity- or Chronicity index on biopsy. s-BAFF correlated with levels of anti-nucleosome antibodies, C1 inhibitor and α-1-acid-glycoprotein (AGP), while BAFF-RQ correlated inversely with Factor VIII. Conclusions: s-BAFF and BAFF mRNA levels are increased in LN patients, but do not reflect histological disease severity. The association of increased BAFF expression with both pro- and anti-inflammatory markers and reduced endothelial activation suggest that BAFF inhibition in LN may have diverse effects.