A Comparison of Two Analytical Approaches for the Quantification of Neurofilament Light Chain, a Biomarker of Axonal Damage in Multiple Sclerosis.

Neurofilament light chain (NfL), is a neuron-specific cytoskeletal protein detected in extracellular fluid following axonal damage. Extensive research has focused on NfL quantification in CSF, establishing it as a prognostic biomarker of disability progression in Multiple Sclerosis (MS). Our study used a new commercially available Enzyme-Linked Immunosorbent Assay (ELISA) kit and Single Molecular Array (Simoa) advanced technology to assess serum NfL levels in MS patients and Healthy Controls (HC). Verifying the most accurate, cost-effective methodology will benefit its application in clinical settings. Blood samples were collected from 54 MS patients and 30 HC. Protocols accompanying the kits were followed. The ELISA thershold was set as 3 S.D. above the mean of the HC. For Simoa, the Z-score calculation created by Jens Kuhle's group was applied (with permission). Samples exceeding the threshold or z-score ≥1.5 indicated subclinical disease activity. To our knowledge, this is the first study to find strong-positive correlation between ELISA and Simoa for the quantification of NfL in serum (r = 0.919). Despite the strong correlation, Simoa has better analytical sensitivity and can detect small changes in samples making it valuable in clinical settings. Further research is required to evaluate whether serum NfL quantification using ELISA could be utilized to predict disability progression.

SARS CoV- 2 vaccination induces antibodies against cardiolipin.

OBJECTIVE: Cases of thrombosis have been reported after administration of SARS-CoV-2 vaccines, with controversial results relating to Oxford-AstraZeneca's ChAdOx1-S. Despite such cases being rare, they still raised concerns for their involvement in coagulopathies. Anti-cardiolipin (aCL) IgG antibodies have been linked to venous and arterial thrombosis. The aim was to evaluate the concentration of aCL IgG antibodies in vaccinated and COVID-19 positive individuals using indirect ELISA and commercial sourced calibrators. RESULTS: The concentration of aCL IgG antibodies was measured in the serum of COVID-19 positive (n = 37), ChAdOx1-S vaccinated (n = 37) and BioNTech Pfizer BNT162b2 vaccinated (n = 42) individuals. Samples from COVID-19 negative, unvaccinated individuals (n = 41) served as controls. The highest percentage of positivity was in the COVID-19 positive group (18.9%). Concerning vaccination, BNT162b2 had the highest percentage of positivity (11.9%) (p = 0.0037). Additionally, aCL concentrations were evaluated at different time points in both vaccinated groups (before, 3 weeks after and 3 months after the second dose). A significant difference in the levels of aCL IgG antibodies over time (p = 0.0391) was observed only in ChAdOx1-S individuals. Our study concluded that levels of aCL, after vaccination with either of the vaccines or following SARS-CoV-2 infection, were not clinically pathogenic for the risk of thrombosis.