Figure 6

Single molecular array (Simoa) and Mesoscale discovery (MDS) immunodetection of plasma protein candidates selected from the PBMCs and brain/plasma proteomic studies. In a re-test cohort of B-ALS and L-ALS patients with a fast (PRL > 0.7) and slow (PRL < 0.7) progressing disease immunodetection results are in line with the findings of the proteomic experiments. (a) Neurofilament light polypeptide (NfL) is overexpressed in plasma from limb onset ALS patients with a relatively fast progressing disease compared to bulbar onset ALS patients with a similar rate of disease progression (p = 0.0438), whilst plasma NfL expression in both bulbar and limb onset fast progressing ALS patients is significantly up-regulated compared to healthy controls (p = 0.0005 and p < 0.0001, respectively). (b) Receiver operating characteristic (ROC) shows NfL good performance in separating fast B-ALS from fast L-ALS (area under the curve (AUC): 0.8754 p = 0.0002). (c) Plasma NfL in fast and slow progressing ALS patients is significantly different from healthy controls as previously reported⁴, whilst (d) plasma NfL ROC is highly performant in fast vs slow-progressing ALS patients separation (AUC: 0.9254 p < 0.0001). (e) Plasma neurofilament heavy polypeptide (NfH) in fast B-ALS patients has higher but not significantly different expression than fast L-ALS patients, while plasma NfH expression in both subgroups is significantly upregulated compared to healthy controls (p < 0.0001 and p = 0.0003, respectively). (f) Plasma NfH in fast progressing ALS (but not in ALS slow) is significantly higher compared to healthy controls. (g) ROC indicates that NfH separates well fast progressing bulbar vs limb onset disease (AUC: 0.7863 p < 0.0001). (h) Plasma ApoE expression is higher in fast B-ALS compared to fast L-ALS but not statistically significant, whilst plasma ApoE is moderately over-expressed in fast progressing ALS compared to slow progressing ALS (p = 0.0350) as previously reported¹⁸. (j) ROC analysis of ApoE expression in ALS-fast and ALS-slow shows a modest performance in the separation of the two sub-groups (AUC:0.6759 p = 0.024).