Immature CD10^low blood neutrophils are enriched in people with multiple sclerosis

Neutrophils are proposed to contribute to inflammation at the onset of multiple sclerosis (MS). However, as neutrophils must be analysed rapidly following blood collection, their characterisation remains challenging, and the biology of neutrophils during episodes of MS is poorly understood. Neutrophils can comprise of several subpopulations and diverse phenotypes that are modified across health states and tissues. We hypothesised that neutrophil subpopulations would significantly differ in abundance between people with MS and controls.

Our pilot study applied flow cytometry to analyse phenotypes of neutrophils present in the peripheral blood of 10 people with recently active MS or clinically isolated syndrome (CIS) and 12 control participants.

Using both unsupervised and supervised analyses of flow cytometry data, we identified that CD10^low neutrophils were significantly enriched in the blood of people with CIS and MS compared with controls. These CD10^low neutrophils featured decreased CD16 and CD11b expression, with CD184 expression absent, suggesting they were an immature neutrophil population. In people with MS, the proportions of CD10^low neutrophils were non-significantly correlated with expanded disability status scores (p=0.06).

These findings point to immature CD10^low blood neutrophils as a population of interest to active MS disease, whose functions should be studied in greater detail in context of MS pathology and biomarkers.