Background & Aims Great interest has been raised by the possible protective role of vitamin D in coronavirus disease 2019 (COVID-19), but objective data on 25(OH)vitamin D deficiency in hospitalized COVID-19 patients are not conclusive. The aim of this study was to determine the prevalence of 25(OH)vitamin D deficiency in COVID-19 patients admitted to an Italian referral hospital and explore its association with clinical outcomes and the markers of disease severity. Methods In this single-center cohort study, 129 consecutive adult COVID-19 patients hospitalized in an Italian referral center were enrolled from March to April 2020. 25(OH)Vitamin D serum levels were assessed 48 hours since hospital admission and categorized into: normal (≥30 ng/mL), insufficient (<30 - ≥20 ng/mL), moderately deficient (<20 - ≥10 ng/mL), severely deficient (<10 ng/mL). Results The prevalence of 25(OH)vitamin D insufficiency, moderate deficiency and severe deficiency was 13.2%, 22.5% and 54.3%, respectively. 25(OH)Vitamin D deficiency (<20 ng/mL) was not associated with COVID-19 clinical features and outcomes. Unexpectedly, after adjusting for major confounders, a significant positive association between increasing 25(OH)vitamin D levels and in-hospital mortality (on a continuous logarithmic scale, odds ratio=1.73 [95% CI, 1.11 to 2.69]; P=.016) was observed. Conclusions Very low 25(OH)vitamin D levels were highly prevalent and suggestive of deficiency among our hospitalized severe COVID-19 patients, but low 25(OH)vitamin D levels were not associated with outcome variables. Whether 25(OH)vitamin D adequacy may influence clinical outcomes in COVID-19 and the unexpected correlation between higher 25(OH)vitamin D levels and mortality require further investigations by large intervention trials.

BackgroundInterstitial lung disease occurring in children is a condition characterized by high frequency of cases due to genetic aberrations of pulmonary surfactant homeostasis, that are also believed to be responsible of a fraction of familial pulmonary fibrosis. To our knowledge, ABCA3 gene was not previously reported as causative agent of fibrosis affecting both children and adults in the same kindred.MethodsWe investigated a large kindred in which two members, a girl whose interstitial lung disease was first recognized at age of 13, and an adult, showed a diffuse pulmonary fibrosis with marked differences in terms of morphology and imaging. An additional, asymptomatic family member was detected by genetic analysis. Surfactant abnormalities were investigated at biochemical, and genetic level, as well as by cell transfection experiments.ResultsBronchoalveolar lavage fluid analysis of the patients revealed absence of surfactant protein C, whereas the gene sequence was normal. By contrast, sequence of the ABCA3 gene showed a novel homozygous G > A transition at nucleotide 2891, localized within exon 21, resulting in a glycine to aspartic acid change at codon 964. Interestingly, the lung specimens from the girl displayed a morphologic usual interstitial pneumonitis-like pattern, whereas the specimens from one of the two adult patients showed rather a non specific interstitial pneumonitis-like pattern.ConclusionsWe have detected a large kindred with a novel ABCA3 mutation likely causing interstitial lung fibrosis affecting either young and adult family members. We suggest that ABCA3 gene should be considered in genetic testing in the occurrence of familial pulmonary fibrosis.

BackgroundIn the recessive aminoaciduria Lysinuric Protein Intolerance (LPI), mutations of SLC7A7/y+LAT1 impair system y+L transport activity for cationic amino acids. A severe complication of LPI is a form of Pulmonary Alveolar Proteinosis (PAP), in which alveolar spaces are filled with lipoproteinaceous material because of the impaired surfactant clearance by resident macrophages. The pathogenesis of LPI-associated PAP remains still obscure. The present study investigates for the first time the expression and function of y+LAT1 in monocytes and macrophages isolated from a patient affected by LPI-associated PAP. A comparison with mesenchymal cells from the same subject has been also performed.MethodsMonocytes from peripheral blood were isolated from a 21-year-old patient with LPI. Alveolar macrophages and fibroblastic-like mesenchymal cells were obtained from a whole lung lavage (WLL) performed on the same patient. System y+L activity was determined measuring the 1-min uptake of [3H]-arginine under discriminating conditions. Gene expression was evaluated through qRT-PCR.ResultsWe have found that: 1) system y+L activity is markedly lowered in monocytes and alveolar macrophages from the LPI patient, because of the prevailing expression of SLC7A7/y+LAT1 in these cells; 2) on the contrary, fibroblasts isolated from the same patient do not display the transport defect due to compensation by the SLC7A6/y+LAT2 isoform; 3) in both normal and LPI monocytes, GM-CSF induces the expression of SLC7A7, suggesting that the gene is a target of the cytokine; 4) GM-CSF-induced differentiation of LPI monocytes is comparable to that of normal cells, demonstrating that GM-CSF signalling is unaltered; 5) general and respiratory conditions of the patient, along with PAP-associated parameters, markedly improved after GM-CSF therapy through aerosolization.ConclusionsMonocytes and macrophages, but not fibroblasts, derived from a LPI patient clearly display the defect in system y+L-mediated arginine transport. The different transport phenotypes are referable to the relative levels of expression of SLC7A7 and SLC7A6. Moreover, the expression of SLC7A7 is regulated by GM-CSF in monocytes, pointing to a role of y+LAT1 in the pathogenesis of LPI associated PAP.

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