α2,6-Sialylation Is Upregulated in Severe COVID-19, Implicating the Complement Cascade.

Better understanding of the molecular mechanisms underlying COVID-19 severity is desperately needed in current times. Although hyper-inflammation drives severe COVID-19, precise mechanisms triggering this cascade and what role glycosylation might play therein are unknown. Here we report the first high-throughput glycomic analysis of COVID-19 plasma samples and autopsy tissues. We find that α2,6-sialylation is upregulated in the plasma of patients with severe COVID-19 and in autopsied lung tissue. This glycan motif is enriched on members of the complement cascade (e.g., C5, C9), which show higher levels of sialylation in severe COVID-19. In the lung tissue, we observe increased complement deposition, associated with elevated α2,6-sialylation levels, corresponding to elevated markers of poor prognosis (IL-6) and fibrotic response. We also observe upregulation of the α2,6-sialylation enzyme ST6GAL1 in patients who succumbed to COVID-19. Our work identifies a heretofore undescribed relationship between sialylation and complement in severe COVID-19, potentially informing future therapeutic development.

α2,6-Sialylation is Upregulated in Severe COVID-19 Implicating the Complement Cascade.

Better understanding of the mechanisms of COVID-19 severity is desperately needed in current times. Although hyper-inflammation drives severe COVID-19, precise mechanisms triggering this cascade and what role glycosylation might play therein is unknown. Here we report the first high-throughput glycomic analysis of COVID-19 plasma samples and autopsy tissues. We find α2,6-sialylation is upregulated in plasma of patients with severe COVID-19 and in the lung. This glycan motif is enriched on members of the complement cascade, which show higher levels of sialylation in severe COVID-19. In the lung tissue, we observe increased complement deposition, associated with elevated α2,6-sialylation levels, corresponding to elevated markers of poor prognosis (IL-6) and fibrotic response. We also observe upregulation of the α2,6-sialylation enzyme ST6GAL1 in patients who succumbed to COVID-19. Our work identifies a heretofore undescribed relationship between sialylation and complement in severe COVID-19, potentially informing future therapeutic development.

All-cause mortality and causes of death in persons with haemophilia: A systematic review and meta-analysis.

INTRODUCTION: Improvements in haemophilia treatment over the last decades resulted in increased life expectancy in persons with haemophilia (PWH). AIM: We conducted a systematic review and meta-analysis to examine all-cause mortality and causes of death among PWH. METHODS: We systematically searched EMBASE, MEDLINE, Web of Science, CINAHL and Cochrane central register of controlled trials from inception through March 15, 2021. Studies that reported a mortality estimate of PWH compared with the general population and/or reported causes of death were included. Random-effects meta-analysis with inverse variance method was used to obtain pooled estimates. We stratified the analysis by the year of cohort entry (before 2000 vs after 2000). RESULT: Of the 4769 studies identified, 52 met the eligibility criteria. The pooled all-cause standardized mortality ratio (SMR) from 9 studies in PWH was 1.93 (95% CI 1.38-2.70; I2 = 97%). The pooled SMRs before and after the year 2000 were 2.40 (95% CI 1.92-3.00; I2 = 87%) and 1.20 (95% CI 1.03-1.40; I2 = 62%), respectively. Before the year 2000, 31.2% deaths occurred due to HIV followed by haemorrhage (26.0%), cardiovascular disease (18.2%), liver disease (9.0%), and cancer (8.9%). Fewer (13.9%) deaths were attributable to HIV after the year 2000 with the proportion of deaths due to haemorrhage remaining unchanged. CONCLUSION: With treatment advances, mortality in PWH has declined over the last few decades approaching that of the general population. However, haemorrhage remains a leading cause of death requiring further attention.