Platelet-to-lymphocyte ratio and neutrophil-tolymphocyte ratio may reflect differences in PD and MSA-P neuroinflammation patterns.

Aim Of The Study: To assess the usefulness of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in evaluating the inflammatory process in alpha-synucleinopathies.

Clinical Rationale For The Study: The role of neuroinflammation in PD and MSA pathogenesis is indisputable. However, there is no method available in everyday use that would enable its evaluation. We suggest that NLR and PLR, as non-specific parameters of inflammation, due to its approachability could be helpful in the assessment of inflammatory activity in alpha-synucleinopathies in everyday clinical practice.

Material And Methods: 98 patients with a clinical diagnosis of PD, 28 with MSA-P, and 99 healthy age-matched controls, were included in the study. Blood samples were analysed in order to count neutrophil and lymphocyte rates and, subsequently, NLR and PLR. The obtained parameters were compared between the groups. Results were statistically analysed.

Results: Our results indicate that patients with PD have higher values of NLR and PLR compared to controls. For MSA-P, only NLR was significantly higher in relation to the control group. There were no statistically significant differences between patients with PD and MSA-P in relation to NLR and PLR values. There was a positive average correlation between NLR and disease duration for MSA-P patients.

Conclusions: NLR and PLR values are significantly higher in alpha-synucleinopathies (MSA-P and PD) in relation to a control group. In PD patients, both NLR and PLR values are significantly higher in relation to a control group, whereas in patients with MSA-P, only NLR is significantly increased. The observed differences may reflect distinct neuroinflammatory patterns present in these entities.

Clinical Implications: NLR and PLR are features of peripheral inflammation. Their specificity is relatively low, although increased values suggest possible inflammatory pathogenesis of clinical entities. NLR is based on the observations that in chronic and acute diseases the neutrophil rate has a tendency to rise, while the lymphocyte rate tends to decline. This aspect of inflammatory processes has been primarily evaluated in Intensive Care Units. PLR is a marker presenting changes in platelet and lymphocyte counts caused by acute inflammatory or prothrombotic states. Different values of NLR and PLR in PD and MSA-P compared to healthy controls suggest that in these two alpha-synucleinopathies, different patterns of neuroinflammation might be present. The role of inflammation in the differential diagnosis of parkinsonian syndromes remains unexplored.