Characterization of serotonin as a candidate biomarker of severity and prognosis of COVID-19 using LC/MS analysis.

The coronavirus disease 2019 (COVID-19) pandemic has been associated with high mortality worldwide. Owing to its complicated pathophysiology, diagnostic and prognostic biomarkers for effective patient management remain scarce. We analyzed kynurenine, tryptophan, and serotonin levels in the serum of patients with COVID-19 via liquid chromatography/mass spectrometry analysis. Serum serotonin levels were decreased in patients with more severe COVID-19, along with increased kynurenine and decreased tryptophan concentrations. Patients with moderate disease who subsequently worsened showed significantly lower serotonin concentrations compared with those who did not experience severe disease. Serum serotonin levels may represent a valuable biomarker for COVID-19 severity and prognosis.

[Hemophagocytic lymphohistiocytosis following mRNA-1273 COVID-19 vaccination].

A 34-year-old man with no medical history presented with fever 4 days after receiving the first dose of mRNA-1273 coronavirus disease 2019 (COVID-19) vaccine. He had no prior clinical evidence of severe acute respiratory syndrome coronavirus 2 infection and was negative for serial polymerase chain reaction testing. Ten days after vaccination, he was referred to our hospital because of no response to antibiotics and the emergence of neutropenia, thrombocytopenia, and liver dysfunction. Blood tests also showed elevated serum ferritin and plasma soluble interleukin-2 receptors. Serological and PCR testing excluded active infections of cytomegalovirus, Epstein-Barr virus, and hepatitis viruses. Blood culture yielded no growth. Computed tomography revealed mild hepatosplenomegaly and porta hepatis lymphadenopathy but no focus on infection. Bone marrow aspiration demonstrated hemophagocytosis but no infiltrating lymphoma cells. Immediately, 2-mg/kg intravenous methylprednisolone was commenced based on the presumptive diagnosis of hemophagocytic lymphohistiocytosis (HLH), leading to the rapid and durable improvement of his symptoms and laboratory data. Later, without other causes triggering hemophagocytosis, and with the close link between vaccination and disease onset, the final diagnosis of vaccination-induced secondary HLH was made. HLH after COVID-19 vaccination, though extremely rare, can occur regardless of the vaccine type. Therefore, clinicians should recognize and deal with this occasionally fatal adverse event.

A phase I, randomized, placebo-controlled study of molnupiravir in healthy Japanese to support special approval in Japan to treat COVID-19.

Molnupiravir (MK-4482) is an oral prodrug of the antiviral ribonucleoside analog, N-hydroxycytidine (NHC), which has activity against RNA viruses, including severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). We conducted a phase I safety and pharmacokinetic study of molnupiravir in healthy Japanese adult participants. A sample size larger than typically used in pharmacokinetic studies was implemented to collect additional safety data in the Japanese population to support special approval for emergency use in Japan. Single doses of molnupiravir up to 1600 mg and multiple doses of 400 and 800 mg administered every 12 h (q12h) for 5.5 days were generally well-tolerated. NHC appeared rapidly in plasma and reached maximum concentration (Cmax ), with a median time to Cmax (Tmax ) between 1.00 and 2.00 h. Area under the concentration versus time curve from zero to infinity (AUC0-inf ), area under the concentration versus time curve from zero to 12 h (AUC0-12 ), and Cmax of plasma NHC increased approximately dose proportionally. With q12h dosing, the geometric mean (GM) accumulation ratios for NHC AUC0-12 and Cmax were ~1 for 400 and 800 mg. Pharmacokinetics of NHC triphosphate (NHC-TP), the active metabolite of NHC was assessed in peripheral blood mononuclear cells and also demonstrated roughly dose proportional pharmacokinetics. The GM accumulation ratios for NHC-TP AUC0-12 and Cmax were ~2.5 for 400 and 800 mg. Following administration with food, only a modest reduction (24%) in plasma NHC Cmax with comparable AUC0-inf was seen, supporting administration without regard to food.

Serum stratifin and presepsin as candidate biomarkers for early detection of COVID-19 disease progression.

The prognosis of patients with severe cases of COVID-19 is poor; thus, biomarkers for earlier prediction of COVID-19 progression are vital. We measured levels of five lung injury-related biomarkers, SP-D, KL-6, presepsin, kallistatin and stratifin, in serum samples collected serially during hospitalization from 31 patients with mild/moderate or severe/critical COVID-19 pneumonia, and their predictive performances were compared. Like the previously reported presepsin, a new biomarker candidate, stratifin, was significantly elevated with the onset of severe or critical symptoms in COVID-19 patients and decreased with symptom improvement. Notably, changes in stratifin and presepsin levels were distinctly earlier than those in SP-D, KL-6 and even SpO2/FiO2 values. Furthermore, serum levels of these biomarkers were significantly higher at the pre-severe stage (before the start of oxygen support) of patients who eventually advanced to severe/critical stages than in the patients who remained at the mild/moderate stage. These results were confirmed in an independent cohort, including 71 mild/moderate and 14 severe/critical patients, for whom the performance of stratifin and presepsin in discriminating between mild/moderate and pre-severe conditions of COVID-19 patients was superior to that of the SpO2/FiO2 ratio. Therefore, we concluded that stratifin and presepsin could be used as prognostic biomarkers for severe COVID-19 progression.

Differential Diagnosis of COVID-19: Importance of Measuring Blood Lymphocytes, Serum Electrolytes, and Olfactory and Taste Functions.

Coronavirus disease 2019 (COVID-19) is associated with various symptoms and changes in hematological and biochemical variables. However, clinical features, which can differentiate COVID-19 from non-COVID-19, are not clear. We therefore examined the key clinical features of COVID-19 and non-COVID-19 patients. This study included 60 COVID-19 patients and 100 non-COVID-19 patients, diagnosed by PCR, and no significant differences in the age and sex were seen between the two groups. The frequencies of fatigue, loose stool, diarrhea, nasal obstruction, olfactory dysfunction, taste dysfunction, underlying hyperlipidemia, and the prescription of angiotensin II receptor blocker (ARB) were significantly higher in COVID-19 patients than those in non-COVID-19 patients. The counts of leucocytes, neutrophils, lymphocytes, eosinophils, monocytes, and basophils and the levels of chloride and calcium in blood of COVID-19 patients were significantly lower than those of non-COVID-19 patients. The frequencies of atypical lymphocytes and the levels of lactate dehydrogenase (LDH) and potassium were significantly higher in COVID-19 than those in non-COVID-19. The C-reactive protein (CRP) level in COVID-19 patients was significantly lower than that in non-COVID-19 patients, when we compared CRP levels among patients with elevated CRP. This study is the first to indicate that electrolyte levels and the frequency of atypical lymphocytes in COVID-19 are significantly different from those in non-COVID-19. Fatigue, loose stool, diarrhea, nasal obstruction, olfactory dysfunction, and taste dysfunction were the key symptoms of COVID-19. Furthermore, hyperlipidemia and ARB may be risk factors of COVID-19. In conclusion, leucocytes, leucocyte fractions, CRP, LDH, and electrolytes are useful indicators for COVID-19 diagnosis.