Peripheral Inflammation Links with the Severity of Clinical Phenotype in Spinocerebellar Ataxia 2

ABSTRACT Background The role of peripheral inflammation in spinocerebellar ataxia type 2 (SCA2) is unknown. Objective The objective of this study was to identify peripheral inflammation biomarkers and their relationship with the clinical and molecular features. Methods Blood cell count–derived inflammatory indices were measured in 39 SCA2 subjects and their matched controls. Clinical scores of ataxia, nonataxia, and cognitive dysfunction were assessed. Results The neutrophil‐to‐lymphocyte ratio (NLR), the platelet‐to‐lymphocyte ratio (PLR), the Systemic Inflammation Index (SII), and the Aggregate Index of Systemic Inflammation (AISI) were significantly increased in SCA2 subjects compared with controls. The increases in PLR, SII, and AISI were even observed in preclinical carriers. NLR, PLR, and SII were correlated with the Scale for the Assessment and Rating of Ataxia speech item score rather than with the total score. The NLR and SII were correlated with the nonataxia and the cognitive scores. Conclusions Peripheral inflammatory indices are biomarkers in SCA2, which may help to design future immunomodulatory trials and advance our understanding of the disease. © 2023 International Parkinson and Movement Disorder Society.