A poor and delayed anti-SARS-CoV2 IgG response is associated to severe COVID-19 in children.

BACKGROUND: Most children and youth develop mild or asymptomatic disease during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, a very small number of patients suffer severe Coronavirus induced disease 2019 (COVID-19). The reasons underlying these different outcomes remain unknown. METHODS: We analyzed three different cohorts: children with acute infection (n=550), convalescent children (n=138), and MIS-C (multisystem inflammatory syndrome in children, n=42). IgG and IgM antibodies to the spike protein of SARS-CoV-2, serum-neutralizing activity, plasma cytokine levels, and the frequency of circulating Follicular T helper cells (cTfh) and plasmablasts were analyzed by conventional methods. FINDINGS: Fifty-eight percent of the children in the acute phase of infection had no detectable antibodies at the time of sampling while a seronegative status was found in 25% and 12% of convalescent and MIS-C children, respectively. When children in the acute phase of the infection were stratified according disease severity, we found that contrasting with the response of children with asymptomatic, mild and moderate disease, children with severe COVID-19 did not develop any detectable response. A defective antibody response was also observed in the convalescent cohort for children with severe disease at the time of admission. This poor antibody response was associated to both, a low frequency of cTfh and a high plasma concentration of inflammatory cytokines. INTERPRETATION: A weak and delayed kinetic of antibody response to SARS-CoV-2 together with a systemic pro-inflammatory profile characterize pediatric severe COVID-19. Because comorbidities are highly prevalent in children with severe COVID-19, further studies are needed to clarify their contribution in the weak antibody response observed in severe disease. FUNDING: National Agency for Scientific and Technological Promotion from Argentina (IP-COVID-19-0277 and PMO-BID-PICT2018-2548).

Blood neutrophils from children with COVID-19 exhibit both inflammatory and anti-inflammatory markers.

BACKGROUND: Perhaps reflecting that children with COVID-19 rarely exhibit severe respiratory symptoms and often remain asymptomatic, little attention has been paid to explore the immune response in pediatric COVID-19. Here, we analyzed the phenotype and function of circulating neutrophils from children with COVID-19. METHODS: An observational study including 182 children with COVID-19, 21 children with multisystem inflammatory syndrome (MIS-C), and 40 healthy children was performed in Buenos Aires, Argentina. Neutrophil phenotype was analyzed by flow cytometry in blood samples. Cytokine production, plasma levels of IgG antibodies directed to the spike protein of SARS-CoV-2 and citrullinated histone H3 were measured by ELISA. Cell-free DNA was quantified by fluorometry. FINDINGS: Compared with healthy controls, neutrophils from children with COVID-19 showed a lower expression of CD11b, CD66b, and L-selectin but a higher expression of the activation markers HLA-DR, CD64 and PECAM-1 and the inhibitory receptors LAIR-1 and PD-L1. No differences in the production of cytokines and NETs were observed. Interestingly, the expression of CD64 in neutrophils and the serum concentration of IgG antibodies directed to the spike protein of SARS-CoV-2 distinguished asymptomatic from mild and moderate COVID-19. INTERPRETATION: Acute lung injury is a prominent feature of severe COVID-19 in adults. A low expression of adhesion molecules together with a high expression of inhibitory receptors in neutrophils from children with COVID-19 might prevent tissue infiltration by neutrophils preserving lung function. FUNDING: This study was supported by the Ministry of Science and Technology (National Agency for Scientific and Technological Promotion, IP-COVID-19-0277 and PMO BID PICT 2018-2548), and University of Buenos Aires from Argentina (20020170100573BA).

Does Lepidium meyenii (Maca) improve seminal quality?

Maca (Lepidium meyenii) is a herbaceous plant grown at over 4,000 m in Peru. It has been studied worldwide for its properties on fertility. Previous studies have assessed maca effects on semen quality, but there is need of randomised, double-blind trials in order to make clinical decisions. The objective of this study was to assess the effect of maca on seminal parameters in infertile adult men. This is a double-blind, randomised, placebo-controlled pilot trial in which sixty-nine patients diagnosed with mild asthenozoospermia and/or mild oligozoospermia were supplied by maca (n = 35) or placebo (n = 34) (2 g/day) for a period of 12 weeks. When compared patients treated with maca and patients treated with placebo, there were no significant differences in semen volume (2.95 ± 0.52 vs. 2.90 ± 0.52; p = .392), sperm motility (22.34 ± 2.22 vs. 23.05 ± 2.22; p = .462) and normal sperm morphology (7.89 ± 1.89 vs. 7.04 ± 2.28; p = .801), but there was a significant difference in sperm concentration (15.04 ± 5.61 vs. 10.16 ± 3.59, respectively; p = .011). In conclusion, patients treated with 2 g of maca for a period of 12 weeks showed a significant improvement in seminal concentration compared with patients treated with placebo. There were no significant differences in semen volume, sperm mobility and morphology when compared both groups.