OBJECTIVE: To evaluate the combined blood expression of neuromuscular and 
inflammatory biomarkers as predictors of disease progression and prognosis in 
amyotrophic lateral sclerosis (ALS).
METHODS: Logistic regression adjusted for markers of the systemic inflammatory 
state and principal component analysis were carried out on plasma levels of 
creatine kinase (CK), ferritin, and 11 cytokines measured in 95 patients with 
ALS and 88 healthy controls. Levels of circulating biomarkers were used to study 
survival by Cox regression analysis and correlated with disease progression and 
neurofilament light chain (NfL) levels available from a previous study. 
Cytokines expression was also tested in blood samples longitudinally collected 
for up to 4 years from 59 patients with ALS.
RESULTS: Significantly higher levels of CK, ferritin, tumor necrosis factor 
(TNF)-α, and interleukin (IL)-1β, IL-2, IL-8, IL-12p70, IL-4, IL-5, IL-10, and 
IL-13 and lower levels of interferon (IFN)-γ were found in plasma samples from 
patients with ALS compared to controls. IL-6, TNF-α, and IFN-γ were the most 
highly regulated markers when all explanatory variables were jointly analyzed. 
High ferritin and IL-2 levels were predictors of poor survival. IL-5 levels were 
positively correlated with CK, as was TNF-α with NfL. IL-6 was strongly 
associated with CRP levels and was the only marker showing increasing expression 
towards end-stage disease in the longitudinal analysis.
CONCLUSIONS: Neuromuscular pathology in ALS involves the systemic regulation of 
inflammatory markers mostly active on T-cell immune responses. Disease 
stratification based on the prognostic value of circulating inflammatory markers 
could improve clinical trials design in ALS.