A group from Medical University of South Carolina, Charleston, USA, etc. has reported that reduced sphingosine levels provide a sensitive and selective serologic biomarker for the early identification of asymptomatic versus symptomatic COVID-19 patients.
https://www.nature.com/articles/s41598-021-93857-7
There was a slight but significant increase in the levels of sphingosine (p < 0.05) in individuals who are antibody positive (n = 134) compared to negative (n = 130), with sphingosine levels 28.96 versus 23.25 pmol/5 × 10−5 L serum, respectively. And further, COVID-19 patients’ serum sphingosine levels were around 15-fold decreased compared to that of asymptomatic donors from 28.96 to 1.88 pmol/5 × 10−5 L serum, respectively (Sphingosine (Sph), dihydro-sphingosine (dhSph), sphingosine 1-phosphate (Sph-1p)).
From the ROC analysis, a sphingosine threshold (or cut-off) value of 8.2 pmol/5 × 10−5 L resulted in 98.47% (95% CI 94.60–99.73%) sensitivity and 98.51% (95% CI 94.72–99.73%) specificity, suggesting that serum sphingosine level provides a selective and sensitive biomarker to identify symptomatic patients versus asymptomatic donors who are positive for SARS-CoV-2 antibody. It was also found that Sphingosine and dihydro-sphingosine do not appear to monitor the disease’s severity.
It was know that one of the biochemical biomarkers, lactate dehydrogenase (LDH), was highly elevated in symptomatic patients with an increased mortality rate. Interestingly, reduced sphingosine levels observed here were not associated with disease severity in COVID-19 patients. These data might suggest that increased or sustained serum sphingosine levels might prevent COVID-19 disease, while reduced sphingosine could result in enhanced inflammation and symptomatic response in some individuals.