Association of serum neurofilament light chain levels and neuropsychiatric manifestations in systemic lupus erythematosus

BACKGROUND: The aim was to evaluate the diagnostic potential of serum neurofilament light chain (sNfL) measurements in patients with neuropsychiatric systemic lupus erythematosus (NPSLE). METHODS: sNfL levels were determined by single molecule array assay in a retrospective cross-sectional cohort of 144 patients with systemic lupus erythematosus (SLE). After log-transformation of sNfL levels, mean sNfL levels were compared between NPSLE patients and SLE patients without neuropsychiatric disease using Student’s t test. Furthermore, the association of different neuropsychiatric manifestations with sNfL levels was assessed using a one-way analysis of variance (ANOVA) with post hoc analysis. Associations of sNfL with clinical and laboratory parameters were assessed by correlation and multiple linear regression analysis. RESULTS: NPSLE patients (n = 69) had significantly higher sNfL levels than SLE patients without neuropsychiatric disease manifestations (n = 75; mean difference: 0.13, 95% CI: 0.04–0.22, p = 0.006). With regard to the category of NPSLE manifestation, mean sNfL levels were only increased in NPSLE patients with focal central nervous system (CNS) involvement (n = 45; mean difference: 0.16, 95% CI: 0.02–0.30, p = 0.019), whereas mean sNfL levels of NPSLE patients with diffuse CNS and peripheral nervous system involvement did not differ from those of SLE patients without neuropsychiatric manifestations. Age and serum creatinine concentrations were identified as relevant contributors to sNfL levels. CONCLUSION: sNfL is a promising, easily accessible biomarker for neuropsychiatric involvement in SLE patients and might therefore complement the diagnostic workup of SLE patients with suspected involvement of the nervous system.