Serum complement levels in anti-N-methyl-d-aspartate receptor encephalitis

Area of Science:

• Neuroimmunology
• Clinical Immunology

Background:

• Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a severe autoimmune neurological disorder.
• The role of serum complement system activation in NMDAR encephalitis pathogenesis requires further elucidation.

Purpose of the Study:

• To investigate the relationship between serum complement levels and anti-NMDAR encephalitis.
• To explore correlations between complement factors, disease severity, and treatment response.

Main Methods:

• Serum levels of complement components (C3, C4, CH50), immunoglobulins, and C-reactive protein were measured in 40 anti-NMDAR encephalitis patients and 40 controls.
• Clinical data, including Modified Rankin Scale (mRS) scores, and cerebrospinal fluid parameters were assessed.
• Follow-up evaluations were performed on 11 patients after 6 months.

Main Results:

• Serum C4 levels were significantly elevated in anti-NMDAR encephalitis patients compared to controls, particularly in females and those with severe impairment (mRS ≥ 4).
• Elevated serum CH50 levels were associated with severe impairment and limited treatment response.
• Serum C4 positively correlated with C3, CH50, and mRS scores, while C3 correlated with CH50 and CSF white blood cells. CH50 correlated with age, mRS, and CRP.
• Follow-up showed improved mRS scores, with a negative correlation between changes in C3 and mRS.

Conclusions:

• Serum C4 is elevated in anti-NMDAR encephalitis and is associated with disease severity and other complement factors.
• These findings suggest a potential role for complement system dysregulation in the pathophysiology of anti-NMDAR encephalitis.