Relationships Between the Corpus Callosum Index and Current Blood Parameters and Temporal Changes in these Parameters in Patients with Multiple Sclerosis

Objectives: This study aimed to investigate changes in blood parameters and examine the relationships among the corpus callosum index (CCI), plaque characteristics, and blood parameters in multiple sclerosis (MS) patients. In MS, the CCI is associated with brain atrophy and disease progression. Methods: In this retrospective, cross-sectional study, demographic data from 103 MS patients (38 males), along with blood parameters obtained five years earlier and current values, were analyzed in relation to magnetic resonance imaging (MRI) findings. The CCI calculated from MRI scans was assessed in relation to plaque distribution and number. Statistical analyses included paired sample t tests, Wilcoxon tests, and Spearman correlation analysis. Results: Current lymphocyte, platelet, and monocyte levels were significantly lower than those measured five years earlier (p<0.001; p=0.026; p<0.001), whereas the systemic immune-inflammation index (SII) significantly increased (p=0.035). The CCI was positively correlated with the monocyte/neutrophil ratio (MNR) (p=0.011, r = 0.251) and negatively correlated with the SII (p=0.048, r=–0.196). Additionally, the CCI was significantly negatively correlated with periventricular and juxtacortical plaque number, the Expanded Disability Status Scale (EDSS), and MS attack frequency. Conclusion: In MS patients, the CCI is negatively associated with the SII, plaque distribution, and plaque number and positively associated with the MNR. A decreased MNR and increased SII are linked to corpus callosum atrophy.