Bidirectional causal relationships between IgA nephropathy and COVID-19: genetic evidence from Mendelian randomization (preprint)

Purpose Previous studies have suggested that patients with IgA nephropathy (IgAN) was associated with an increased risk of coronavirus disease 2019 (COVID-19) infection. However, the findings were inconsistent, and whether there was a causality between IgAN and COVID-19 infection remains unknown. This study was performed to estimate the casual effect between IgAN and COVID-19 infection with the implementation of bidirectional Mendelian randomization (MR) analysis.Methods Genetic summary data of IgAN was derived from a large genome-wide association study (GWAS) that consisted of 14,361 cases and 43,923 controls. The genetic data of COVID-19 comprised of three phenotypes, including hospitalization, severity and infection, which had a population more than 20 million. The methods of inverse variance weighting (IVW), MR-Egger, weight median and weighted mode were applied for causal inference in MR analysis.Results In the forward direction, the IVW’s results proved that IgAN did not have causal relationships with hospitalization COVID-19 (OR = 1.077, 95%CI: 0.953–1.217, P = 0.236), severe COVID-19 (OR = 1.059, 95%CI: 0.878–1.278, P = 0.547) and COVID-19 infection (OR = 0.973, 95%CI: 0.929–1.109, P = 0.243). Furthermore, reverse MR analysis showed no evidence of causal associations of hospitalization COVID-19 (OR = 1.017, 95%CI: 0.968–1.069, P = 0.499), severe COVID-19 (OR = 1.005, 95%CI: 0.979–1.078, P = 0.781) and COVID-19 infection (OR = 1.030, 95%CI: 0.909–1.169, P = 0.641) with the risk of IgAN.Conclusion Our study does not support a casual association of IgAN with the risk of COVID-19 infection, nor does the causality between COVID-19 infection and IgAN risk.

Clinical and Virological Features of the First Occurrence of COVID-19 Delta Variant in Anhui Province, China (preprint)

Objectives Since the outbreak of coronavirus disease 2019 (COVID-19), it has caused serious casualties worldwide. In recent months, the virus has mutated into an increasingly infectious form (Delta variant) and spread rapidly.Methods In the current study, we analyzed the clinical, epidemiological and viral genetic characteristics of the first four imported Delta cases in Anhui Province, China.Results The four imported Delta cases developed chest inflammation, tissue damage and recovered after admission, the serum high-sensitivity C-reactive protein (hs-CRP) and CRP levels showed a first increasing and then decreasing trend. The changes of hs-CRP /CRP and serum neutralizing antibodies (Nab) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) levels were associated with the regression of chest lesions. The combination of genetic sequencing and epidemiological analysis suggested that the SARS-CoV-2 delta variant infection of these four patients may originate from Russia.Conclusions Our study found the certain correlations of serum hs-CRP/CRP and Nab levels with the occurrence, development and outcome of COVID-19 delta variant, suggesting that monitoring hs-CRP/CRP and Nab levels of COVID-19 delta variant patients at hospital admission may be useful for understanding the severity of patients’ current conditions.