Angiotensin-converting enzyme insertion/deletion polymorphism and susceptibility to Kawasaki disease: a meta-analysis

A protective erythropoietin evolutionary landscape, NLRP3 inflammasome regulation, and multisystem inflammatory syndrome in children

The low incidence of pediatric severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and the associated multisystem inflammatory syndrome (MIS-C) lack a unifying pathophysiological explanation, impeding effective prevention and therapy. Activation of the NACHT, LRR, and PYD domains-containing protein (NLRP) 3 inflammasome in SARS-CoV-2 with perturbed regulation in MIS-C, has been reported. We posit that, early age physiological states and genetic determinants, such as certain polymorphisms of renin-angiotensin aldosterone system (RAAS) molecules, promote a controlled RAAS hyperactive state, and form an evolutionary landscape involving an age-dependent erythropoietin (EPO) elevation, mediating ancestral innate immune defenses that, through appropriate NLRP3 regulation, mitigate tissue injury and pathogen invasion. SARS-CoV-2-induced downregulation of angiotensin-converting enzyme (ACE)2 expression in endothelial cells (EC), impairment of endothelial nitric oxide (NO) synthase (eNOS) activity and downstream NO bioavailability, may promote a hyperactive RAAS with elevated angiotensin II and aldosterone that, can trigger, and accelerate NLRP3 inflammasome activation, while EPO-eNOS/NO abrogate it. Young age and a protective EPO evolutionary landscape may successfully inhibit SARS-CoV-2 and contain NLRP3 inflammasome activation. By contrast, increasing age and falling EPO levels, in genetically susceptible children with adverse genetic variants and co-morbidities, may lead to unopposed RAAS hyperactivity, NLRP3 inflammasome dysregulation, severe endotheliitis with pyroptotic cytokine storm, and development of autoantibodies, as already described in MIS-C. Our haplotype estimates, predicted from allele frequencies in population databases, are in concordance with MIS-C incidence reports in Europeans but indicate lower risks for Asians and African Americans. Targeted Mendelian approaches dissecting the influence of relevant genetic variants are needed.

Non-SARS, non-MERS human coronavirus infections and risk of Kawasaki disease: a meta-analysis

Aim: To study the association between non-SARS, non-MERS human coronavirus (HCoV) infections and Kawasaki disease (KD). Methods: Meta-analysis of observational studies published until 1 May 2021. Results: Out of 571 papers retrieved through database search, 10 provided data of 17,732 children. Age ranged from 2 months-14.9 years with 66% being male and 71% being complete KD. Compared with controls, there was an increased risk of developing KD in those detected to have HCoV infection (OR: 2.3 [95% CI: 1.06-4.99]; p = 0.03). The GRADE evidence for all outcomes was of 'low-certainty'. Conclusion: A 'low certainty' of evidence suggests an increased risk of KD in children infected with HCoV. We need multi-center, prospective studies to support or refute this finding. PROSPERO protocol registration: CRD42021251582.

Unleashing the mysterious link between COVID-19 and a famous childhood vasculitis: Kawasaki disease

Background

Coronavirus disease 2019 (COVID-19) emerged as a small outbreak in Wuhan rapidly progressing into the deadliest pandemic since the Spanish flu of 1918. The disease was deemed trivial in children, until the reporting, few days ago, of an emerging pediatric multi-inflammatory syndrome mimicking Kawasaki disease (KD).

Main body

This report reveals that coronaviridae were implicated in induction of several post-infectious vasculitides, namely, KD, AHEI, and HSP. This occurs in genetically susceptible individuals to vascular inflammation. Shared genetic susceptibilities between KD and CoV include genes encoding for CD 40, HLAB-15:03, and ACE. This leads to augmented inflammation with hypersecretion of cytokines especially IL-6.

Conclusion

The revealed relationships between KD and CoV can help to predict the risk of KD in COVID-19 patients through screening levels of upregulated cytokines. It might also signify that classic treatment of KD with IVIG might need to be replaced with anti-cytokine therapy in COVID-19 patients.

Angiotensin-converting enzyme insertion/deletion polymorphism and susceptibility to Henoch-Schönlein purpura: a meta-analysis

Objective:

Meta-analysis was performed in the current study to evaluate the relationship of the angiotensin-converting enzyme insertion/deletion polymorphism with the risk of the incidence of Henoch–Schönlein purpura.

Methods:

The electronic databases, including Embase, PubMed and Google scholar, were systemically retrieved to search for related articles. Meanwhile, statistical analysis was performed using the odds ratio and the corresponding 95% confidence interval.

Results:

A total of six articles enrolling 504 patients and 706 healthy controls was enrolled into the current meta-analysis. Results of the meta-analysis suggested that the angiotensin-converting enzyme D allele was markedly correlated with the risk of the incidence of Henoch–Schönlein purpura among the general population (deletion (D) vs. insertion (I): odds ratio (OR) 1.42, 95% confidence interval (CI) 1.05–1.93; DD vs. II: OR 2.23, 95% CI 1.06–4.70; DI vs. II: OR 1.36, 95% CI 1.00–1.85; dominant model: OR 1.56, 95% CI 1.00–2.42; recessive model: OR 1.83, 95% CI 1.06–3.16). Moreover, such a polymorphism was found to correlate with the susceptibility to Henoch–Schönlein purpura when studies were stratified according to the sample size of over 200. In addition, such a polymorphism was recognised to be remarkably associated with the susceptibility to Henoch–Schönlein purpura in the Caucasian population, which was not found in the Asian population.

Conclusions:

The results of the current meta-analysis indicate that the angiotensin-converting enzyme D allele might be a risk factor against the risk of Henoch–Schönlein purpura, especially in Caucasians.