Serum cystatin C and anti‐N‐methyl‐D‐aspartate receptor encephalitis
Therefore, CysC may exert multiple functions in the pathogenesis and progression of immunological and neurological diseases. Indeed, a significant association of CysC with autoimmune diseases, such as systemic lupus erythematosus (SLE)9 and chronic arthritis,10 has been reported. Furthermore, CysC is associated with a variety of neurological diseases, including inflammatory neurological diseases, such as Guillain‐Barre syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP) and multiple sclerosis (MS)11 and neurodegenerative disorders, such as Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD).7
Anti‐N‐methyl‐D‐aspartate receptor (NMDAR) encephalitis is a rapid‐onset, immune‐mediated disorder that is often associated with psychosis, seizures, various movement disorders and autonomic system disturbances.17 It develops through the action of immunoglobulin G (NMDAR antibodies) against the GluN1 subunit of the NMDAR.18 Anti‐NMDAR encephalitis is a severe and rare disorder that can affect patients of all ages with or without tumours in various regions, such as ovarian teratomas19 Multiple studies have shown that immune cells, including B cells and T cells, are involved in the pathogenesis of anti‐NMDAR encephalitis.21
However, the importance of CysC in anti‐NMDAR encephalitis is unknown. Here, we analysed serum CysC levels in anti‐NMDAR encephalitis patients and investigated the associations between the serum CysC levels and clinical parameters in these patients.