Fig. 2

Possible mechanisms of WS occurrence in patients with CTDs

In cases of abnormal coagulation functions, such as the presence of anticardiolipin antibody (ACA) and lupus anticoagulants (LACs) and the use of anticoagulant medications, a hypercoagulable state results in a marked increase in renal vascular pressure. Immune complexes are deposited within renal tubules and microvessels, potentially leading to vascular embolism or necrosis. The activation of the complement system in patients with CTDs induces a complement-dependent cytotoxic (CDC) effect to attack vascular endothelial cells. Similarly, the existence of autoantibodies mediates an antibody-dependent cell-mediated cytotoxic (ADCC) effect, contributing to renal vascular damage. The ANCA binds to the target antigen of neutrophils, triggering degranulation and the release of granular substances, which, along with reactive oxygen species (ROS) generation, jointly cause local vascular damage. Additionally, the catabolic effect of glucocorticoid treatment on tissues can exacerbate potential renal parenchymal or vascular rupture. Moreover, the dysregulated immune status of CTDs is prone to concurrent multiple infections, releasing inflammatory factors that reach the kidneys through the bloodstream, and providing facilitating conditions for the occurrence of WS