Immunoassays for detection of ran proteins

A method comprising, in the following order:

• (i) performing an electrochemiluminescence immunoassay on a first blood sample obtained from a mammalian subject having or suspected of having amyotrophic lateral sclerosis (ALS), wherein the electrochemiluminescence immunoassay is a meso scale detection (MSD) assay that comprises a step of contacting the blood sample with an anti-RAN protein antibody that binds to poly [Gly-Pro] RAN proteins and a detectable reagent that labels the anti-RAN protein antibody, wherein the detectable reagent comprises a Ruthenium complex, and wherein the first blood sample is obtained before administration of an agent for treatment of ALS selected from riluzole, trazodone, baclofen, diazepam, phenytoin, trihexyphenidyl, amitriptyline, and an anti-RAN protein antibody to the mammalian subject, and wherein the electrochemiluminescence assay is performed within 24 hours of the first blood sample being obtained;
• (ii) performing an electrochemiluminescence immunoassay on a second blood sample obtained from the mammalian subject, wherein the electrochemiluminescence immunoassay is an MSD assay that comprises a step of contacting the second blood sample with an anti-RAN protein antibody that binds to poly [Gly-Pro] RAN proteins and a detectable reagent that labels the anti-RAN protein antibody, wherein the detectable reagent comprises a Ruthenium complex, and wherein the second blood sample is obtained after administration of the agent for treatment of ALS to the mammalian subject, and wherein the electrochemiluminescence assay is performed within 24 hours of the second blood sample being obtained;
• (iii) detecting electrochemiluminescence levels of the Ruthenium complex in the detectable reagent labeling the anti-RAN protein antibody bound to poly [Gly-Pro] RAN proteins in the first and second blood samples, wherein the electrochemiluminescence levels detected are greater than a level of electrochemiluminescence of a control sample;
• (iv) determining the electrochemiluminescence level detected in the second blood sample is lower than the electrochemiluminescence level detected in the first blood sample, and
• (v) continuing to administer the agent for treatment of ALS to the mammalian subject after determining the electrochemiluminescence level detected in the second blood sample is lower than the electrochemiluminescence level detected in the first blood sample.