Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organs or organ systems. SLE and one of its most common complications, lupus nephritis (LN), are characterized by chronic inflammation due to the secretion of pro-inflammatory molecules and a tissue deposition of immune complexes formed by autoantibodies and their target antigens, such as double-stranded DNA, other nuclear antigens, and complement proteins. Increased activity of phospholipase A2 enzymes (PLA2) like calcium-independent PLA2 (iPLA2), secretory PLA2 (sPLA2), and cellular PLA2 (cPLA2) has a crucial role in the maintenance of the inflammatory process during the course of SLE. This study aimed to evaluate PLA2 activity and identify the dominant type of PLA2 enzymes in a cohort of Bulgarian patients with SLE and LN. Additionally, we investigated whether the increased PLA2 activity was correlated with the presence of autoantibodies specific to the complement proteins C3 and factor H.