Serum and CSF alpha-synuclein levels do not change in COVID-19 patients with neurological symptoms.

SARS-CoV-2 infection can associate diverse neurological manifestations. Several studies have provided proof to support the theory of neurotropic involvement of SARS-CoV-2. Alpha-synuclein has been described as a native antiviral factor within neurons, and upregulation of this protein can be seen in animals that suffered other neuroinvasive infections. To assess if increased expression of this protein takes place in COVID-19 patients with neurological symptoms, we analyzed serum total alpha-synuclein levels in three groups: seven COVID-19 patients with myoclonus, Parkinsonism and/or encephalopathy; thirteen age- and sex-matched COVID-19 patients without neurological involvement and eight age- and sex-matched healthy controls. We did not find differences among them. In a subset of four patients, the change in serum alpha-synuclein before and after the onset of neurological symptoms was not significant either. Cerebrospinal fluid alpha-synuclein levels were also similar between neurological COVID-19 and healthy controls. Overall, these results cannot support the hypothesis of alpha-synuclein upregulation in humans with neurological symptoms in COVID-19. Further research taking into account a larger group of COVID-19 patients including the whole spectrum of neurological manifestations and disease severity is needed.

Regional reference values for some quantities measured with the ADVIA Centaur analyser. A model of co-operation between the in vitro diagnostic industry and clinical laboratories.

This work is a model of co-operation between the in vitro diagnostic industry and clinical laboratories for the production of reference values. Thirteen clinical laboratories having an ADVIA Centaur analyser and representing the majority of the geographical regions of Spain have shared the search for reference individuals and the production of reference values for thyrotropin, free thyroxine, free triiodothyronine, cobalamine and folate concentrations in serum. All the logistic work has been done in co-operation with the Spanish supplier of the ADVIA Centaur analyser. The reference limits produced in the virtual laboratory are derived from the blend of reference values obtained by each laboratory. The multicentre reference limits were estimated according to the recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC).