Peripheral CD56^dimCD16⁺ NK cells correlate with serum NfL and ALS progression: An exploratory immunophenotyping...

Peripheral immune dysregulation may contribute to the pathogenesis of amyotrophic lateral sclerosis (ALS), yet, specific immunophenotypes correlated with disease progression remain unclear. We conducted an exploratory analysis to identify peripheral immune cell subsets correlated with ALS progression and serum biomarkers.

Multicolor flow cytometry was used to evaluate 55 immune cell subsets in peripheral blood from 16 ALS patients. We assessed correlation with clinical progression (defined by monthly decline in the ALS Functional Rating Scale-Revised) and serum biomarkers: neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and estimated glomerular filtration rate (eGFR).

CD56^dimCD16⁺ natural killer (NK) cells were inversely correlated with both ΔALSFRS-R and serum NfL, and also showed a significant correlation with GFAP. Naive B cells positively correlated with ΔALSFRS-R. Monocyte subsets were differentially correlated with eGFR. Among all cells examined, CD56^dimCD16⁺ NK cells were the only subset significantly correlated with three clinical and biological measures.

CD56^dimCD16⁺ NK cells showed consistent correlations with ALS progression markers, although this exploratory study has small sample size and lacks healthy and disease controls, limiting conclusions in terms of statistical power and ALS-specificity about the observed immune alterations. These preliminary findings support the utility of immunophenotyping in ALS biomarker research and warrant validation in larger cohorts.