Detecting Peripheral Immune Cell Changes in Parkinson's Disease: A Cross-Sectional Analysis in an Ethnically Diverse Population from East London.

Abstract

Background/ObjectivesPatients with Parkinson's disease (PD) display changes in the levels of peripheral immune cells. A declining lymphocyte count and a raised neutrophil-to-lymphocyte ratio (NLR) may result from an impaired adaptive response and increased levels of inflammation. This study sought to identify peripheral immune cell changes in PD among a diverse population from East London.MethodsPD and healthy controls (HC) were recruited from the East London Parkinson's Disease (ELPD) project. Numbers of peripheral immune cells from PD blood samples were cross-sectionally analysed across three (pre-, within 6 months of PD diagnosis, and post-PD diagnosis) or two (pre- and post-PD diagnosis) time points and compared with HC.ResultsThe study included 145 (85 male (M), 60 female (F)) PD and 73 (47 M, 26 F) HC. All participants were included in the two-time point analysis, whereas the three-time point analysis included 41 (25M, 16F) PD and 55 (36M, 19F) HC. There was no significant difference in lymphocyte count or NLR between PD and HC. A non-significant trend towards lower lymphocyte count in PD compared with HC was observed in an unadjusted, but not partially- or fully-adjusted, model in both the three-time point (OR = 0.90; CI = 0.81-1.0, p = 0.058) and two-time point (OR = 0.94; CI = 0.88-1.0, p = 0.064) analyses.ConclusionOur study revealed no significant difference in lymphocyte count or NLR between PD and HC. A non-significant trend towards lower lymphocyte count in PD was observed post-diagnosis and may represent the onset of lymphocyte decline. Copyright © 2025, The Authors. All rights reserved.