Serum uric acid and anti-N-methyl-d-aspartate receptor encephalitis.

BACKGROUND

Uric acid (UA) levels are associated with autoimmune and neurodegenerative disorders, but their relationship with anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is unknown.

METHODS

UA levels were evaluated in 58 patients with anti-NMDAR encephalitis, and 58 age- and sex-matched healthy controls (CTLs). Follow-up evaluations of 30 out of the 58 patients with anti-NMDAR encephalitis were conducted 3 months after admission. Modified Rankin scale (mRS) scores and clinical and cerebrospinal fluid parameters were evaluated in all anti-NMDAR encephalitis patients.

RESULTS

Serum UA levels were significantly lower in patients with anti-NMDAR encephalitis than those in CTLs (p < 0.001), and this was especially evident in patients with severe impairments (mRS ≥ 4 vs. <4, p = 0.004) or with limited response to treatment (vs. favourable outcome, p = 0.002). Follow-up evaluations revealed that serum UA levels normalized after treatment, with significantly increased serum UA levels (p < 0.001), and that mRS scores were significantly lower (p < 0.001) than those before treatment. In addition, serum UA levels were significantly associated with mRS scores (r = -0.463, p < 0.001).

CONCLUSION

Our results showed that serum UA levels in patients with anti-NMDAR encephalitis are reduced during attacks compared with those in CTLs, are normalized after treatment, and are associated with disease severity.