Mild Manifestations Research Articles

A case of SARS-CoV-2 Omicron reinfection resulting in a significant immunity boost in a paediatric patient affected by B-cell acute lymphoblastic leukemia

BackgroundSince its emergence in November 2021, SARS-CoV-2 Omicron clade has quickly become dominant, due to its increased transmissibility and immune evasion. Different sublineages are currently circulating, which differ in mutations and deletions in regions of the SARS-CoV-2 genome implicated in the immune response. In May 2022, BA.1 and BA.2 were the most prevalent sublineages in Europe, both characterized by ability of evading natural acquired and vaccine-induced immunity and of escaping monoclonal antibodies neutralization.Case presentationA 5-years old male affected by B-cell acute lymphoblastic leukemia in reinduction was tested positive for SARS-CoV-2 by RT-PCR at the Bambino Gesù Children Hospital in Rome in December 2021. He experienced a mild COVID-19 manifestation, and a peak of nasopharyngeal viral load corresponding to 15.5 Ct. Whole genome sequencing identified the clade 21 K (Omicron), sublineage BA.1.1. The patient was monitored over time and tested negative for SARS-CoV-2 after 30 days. Anti-S antibodies were detected positive with modest titre (3.86 BAU/mL), while anti-N antibodies were negative. 74 days after the onset of the first infection and 23 days after the last negative test, the patient was readmitted to hospital with fever, and tested positive for SARS-CoV-2 by RT-PCR (peak of viral load corresponding to 23.3 Ct). Again, he experienced a mild COVID-19. Whole genome sequencing revealed an infection with the Omicron lineage BA.2 (21L clade). Sotrovimab administration was started at the fifth day of positivity, and RT-PCR negativity occurred 10 days later. Surveillance SARS-CoV-2 RT-PCR were persistently negative, and in May 2022, anti-N antibodies were found positive and anti-S antibodies reached titres > 5000 BAU/mL.ConclusionsBy this clinical case, we showed that SARS-CoV-2 reinfection within the Omicron clade can occur and can be correlated to inadequate immune responses to primary infection. We also showed that the infection’s length was shorter in the second respect to first episode, suggesting that pre-existing T cell-mediated immunity, though not preventing re-infection, might have limited the SARS-CoV-2 replication capacity. Lastly, Sotrovimab treatment retained activity against BA.2, probably accelerating the viral clearance in the second infectious episode, after which seroconversion and increase of anti-S antibodies titres were observed.

The effect of ACE2 receptor, IFN-γ, and TNF-α polymorphisms on the severity and prognosis of the disease in SARS-CoV-2 infection.

To investigate the effect of genetic variations in the angiotensin converting enzyme (ACE), interferon (IFNG) and tumor necrosis factor (TNF-α) genes on the severity of coronavirus disease (COVID-19). Between September and December 2021, 33 patients with COVID-19 were included in this prospective study. The patients were classified and compared according to disease severity: mild&moderate (n = 26) vs severe&critical (n = 7). These groups were evaluated to assess possible relationships with ACE, TNF-α and IFNG gene variations using univariate and multivariable analyses. The median age of the mild&moderate group was 45.5 (22-73), and that of the severe&critical group was 58 (49-80) years (p = 0.014). Seventeen (65.4%) of the mild&moderate patients and 3 (42.9%) of severe&critical patients were female (p = 0.393). According to results of univariate analysis, the percentage of patients with the c.418-70C>G variant of the ACE gene was significantly higher in the mild&moderate group (p = 0.027). The ACE gene polymorphisms, c.2312C>T, c.3490G>A, c.3801C>T, and c.731A>G, were each only seen in separate patients with critical disease. The following variants were observed more frequently in the mild&moderate group: c.582C>T, c.3836G>A, c.511+66A>G, c.1488-58T>C, c.3281+25C>T, c.1710-90G>C, c.2193A> G, c.3387T>C for ACE; c.115-3delT for IFNG; and c.27C>T for TNF. It can be expected that patients carrying the ACE gene c.418-70C>G variant may present with a mild clinical manifestation of COVID-19. Several genetic polymorphisms may be associated with pathophysiology, as they appear to help predict COVID-19 severity and enable early identification of the patients requiring aggressive treatment.

CFTR Inhibitors Display In Vitro Antiviral Activity against SARS-CoV-2

Several reports have indicated that SARS-CoV-2 infection displays unexpected mild clinical manifestations in people with cystic fibrosis (pwCF), suggesting that CFTR expression and function may be involved in the SARS-CoV-2 life cycle. To evaluate the possible association of CFTR activity with SARS-CoV-2 replication, we tested the antiviral activity of two well-known CFTR inhibitors (IOWH-032 and PPQ-102) in wild type (WT)-CFTR bronchial cells. SARS-CoV-2 replication was inhibited by IOWH-032 treatment, with an IC50 of 4.52 μM, and by PPQ-102, with an IC50 of 15.92 μM. We confirmed this antiviral effect on primary cells (MucilAirTM wt-CFTR) using 10 μM IOWH-032. According to our results, CFTR inhibition can effectively tackle SARS-CoV-2 infection, suggesting that CFTR expression and function might play an important role in SARS-CoV-2 replication, revealing new perspectives on the mechanisms governing SARS-CoV-2 infection in both normal and CF individuals, as well as leading to potential novel treatments.

Integrated Metabolic and Inflammatory Signatures Associated with Severity of, Fatality of, and Recovery from COVID-19.

Severe manifestations of coronavirus disease 2019 (COVID-19) and mortality have been associated with physiological alterations that provide insights into the pathogenesis of the disease. Moreover, factors that drive recovery from COVID-19 can be explored to identify correlates of protection. The cellular metabolism represents a potential target to improve survival upon severe disease, but the associations between the metabolism and the inflammatory response during COVID-19 are not well defined. We analyzed blood laboratorial parameters, cytokines, and metabolomes of 150 individuals with mild to severe disease, of which 33 progressed to a fatal outcome. A subset of 20 individuals was followed up after hospital discharge and recovery from acute disease. We used hierarchical community networks to integrate metabolomics profiles with cytokines and markers of inflammation, coagulation, and tissue damage. Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) promotes significant alterations in the plasma metabolome, whose activity varies according to disease severity and correlates with oxygen saturation. Differential metabolism underlying death was marked by amino acids and related metabolites, such as glutamate, glutamyl-glutamate, and oxoproline, and lipids, including progesterone, phosphocholine, and lysophosphatidylcholines (lysoPCs). Individuals who recovered from severe disease displayed persistent alterations enriched for metabolism of purines and phosphatidylinositol phosphate and glycolysis. Recovery of mild disease was associated with vitamin E metabolism. Data integration shows that the metabolic response is a hub connecting other biological features during disease and recovery. Infection by SARS-CoV-2 induces concerted activity of metabolic and inflammatory responses that depend on disease severity and collectively predict clinical outcomes of COVID-19. IMPORTANCE COVID-19 is characterized by diverse clinical outcomes that include asymptomatic to mild manifestations or severe disease and death. Infection by SARS-CoV-2 activates inflammatory and metabolic responses that drive protection or pathology. How inflammation and metabolism communicate during COVID-19 is not well defined. We used high-resolution mass spectrometry to investigate small biochemical compounds (<1,500 Da) in plasma of individuals with COVID-19 and controls. Age, sex, and comorbidities have a profound effect on the plasma metabolites of individuals with COVID-19, but we identified significant activity of pathways and metabolites related to amino acids, lipids, nucleotides, and vitamins determined by disease severity, survival outcome, and recovery. Furthermore, we identified metabolites associated with acute-phase proteins and coagulation factors, which collectively identify individuals with severe disease or individuals who died of severe COVID-19. Our study suggests that manipulating specific metabolic pathways can be explored to prevent hyperinflammation, organ dysfunction, and death.

Transcriptionally active nasopharyngeal commensals and opportunistic microbial dynamics define mild symptoms in the COVID 19 vaccination breakthroughs.

The development of COVID 19 vaccines as an effort to mitigate the outbreak, has saved millions of lives globally. However, vaccination breakthroughs have continuously challenged the vaccines' effectiveness and provided incentives to explore facets holding potential to alter vaccination-induced immunity and protection from subsequent infection, especially VOCs (Variants Of Concern). We explored the functional dynamics of nasopharyngeal transcriptionally active microbes (TAMs) between vaccination breakthroughs and unvaccinated SARS-CoV-2 infected individuals. Microbial taxonomic communities were differentially altered with skewed enrichment of bacterial class/genera of Firmicutes and Gammaproteobacteria with grossly reduced phylum Bacteroidetes in vaccination breakthrough individuals. The Bacillus genus was abundant in Firmicutes in vaccination breakthrough whereas Prevotella among Bacteroides dominated the unvaccinated. Also, Pseudomonas and Salmonella of Gammaproteobacteria were overrepresented in vaccination breakthrough, whilst unvaccinated showed presence of several genera, Achromobacter, Bordetella, Burkholderia, Neisseria, Hemophilus, Salmonella and Pseudomonas, belonging to Proteobacteria. At species level, the microbiota of vaccination breakthrough exhibited relatively higher abundance of unique commensals, in comparison to potential opportunistic microbes enrichment in unvaccinated patients' microbiota. Functional metabolic pathways like amino acid biosynthesis, sulphate assimilation, fatty acid and beta oxidation, associated with generation of SCFAs (short chain fatty acids), were enriched in vaccination breakthroughs. Majorly, metabolic pathways of LCFAs biosynthesis (long chain fatty acids; oleate, dodecenoate, palmitoleate, gondoate) were found associated with the unvaccinated. Our research highlights that vaccination decreases the microbial diversity in terms of depleting opportunistic pathogens and increasing the preponderance of commensals with respect to unvaccinated patients. Metabolic pathway analysis substantiates the shift in diversity to functionally modulate immune response generation, which may be related to mild clinical manifestations and faster recovery times during vaccination breakthroughs.

Thyroid Hormone Resistance Syndrome in an Adolescent Girl: A Case Report

Introduction: Resistance to Thyroid Hormones (RTH) is a rare, hereditary disease characterized by diminished sensitivity of target tissues to thyroid hormones. Most cases (~85%) are caused by mutations in the thyroid hormone receptor beta (THRβ) gene (RTHβ). The clinical spectrum of RTHβ is quite broad and highly heterogeneous, and the hallmark of the condition is a paucity of signs and symptoms of thyroid dysfunction despite elevated levels of T4 and T3, with a concomitant non-suppressed TSH. Case Report: Here, we describe a rare case of RTHβ in a female adolescent who was initially misdiagnosed and treated for Graves’ disease, but whose unusual evolution motivated her transference to a tertiary center. The patient exhibited mild manifestations, presenting with a goiter without compressive symptoms and some degree of cognitive impairment with learning disability. Misdiagnosis of RTHβ as Graves’ disease can lead to unnecessary treatments such as anti-thyroid medication, thyroidectomy or radioiodine, but treatment is generally not necessary for most patients with RTHβ. Discussion and Conclusion: Establishing the diagnosis of RTHβ can be challenging. It must be considered in patients who present with a goiter and increased thyroid hormone levels with an unsuppressed TSH, to potentially avoid an incorrect diagnosis of primary hyperthyroidism and the implementation of unnecessary and harmful treatments. Most patients with RTHβ are asymptomatic, and in children, particular attention must be paid to growth, bone maturation, and mental development.

Thyroid dysfunction as a long-term post-COVID-19 complication in mild-to-moderate COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), may lead to thyroid disorders, including both thyrotoxicosis and suppression of thyroid function. The aim of the present study was to assess the post-COVID-19 effects on thyroid function in patients without history of thyroid disease after complete recovery from mild-to-moderate COVID-19. Thyroid function tests [thyroid-stimulating hormone (TSH), free thyroxine (fT4), antithyroid antibodies] were performed on 113 patients (median age of 43.0 years; 31.0% male) two months after initial SARS-CoV-2 infection. TSH and fT4 were determined again one month later in this observational, prospective study. Thyroid dysfunction was registered in 61.1% of the patients (78.3% subclinical hypothyroidism, 13% subclinical hyperthyroidism and 8.7% overt hypothyroidism) two months after COVID-19. Moderate rather than mild manifestation of COVID-19 was significantly associated with a higher risk of thyroid dysfunction (OR 5.33; 95% CI: 1.70–16.69, p = 0.002), presence of thyroglobulin antibodies and need for levothyroxine therapy. At the follow-up, the subclinical hypothyroidism persisted in 28.3% of the subjects. Moreover, the TSH level was significantly reduced in comparison to the second month after the initial COVID-19 infection in all the patients (p < 0.001), but not in those with subclinical hypothyroidism and without hormone replacement therapy. Our findings indicate that COVID-19 could have long-term, negative effects on thyroid function. Therefore, thyroid function testing should be included in the follow-up algorithm of COVID-19 survivors.

Impact of ACE and Endoplasmic Reticulum Aminopeptidases Polymorphisms on COVID-19 Outcome.

COVID-19 outcomes display multiple unexpected varieties, ranging from unnoticed symptomless infection to death, without any previous alarm or known aggravating factors. To appraise the impact of ACErs4291(A/T) and ERAP1rs26618(T/C) human polymorphisms on the outcome of COVID-19. In total, 240 individuals were enrolled in the study (80 with severe manifestations, 80 with mild manifestations, and 80 healthy persons). ACErs4291(A/T) and ERAP1rs26618(T/C) genotyping was performed using RT-PCR. The frequency of the ACErs4291AA genotype was higher among the severe COVID-19 group than others (p &lt; 0.001). The ERAP1rs26618TT genotype frequency was higher among the severe COVID-19 group in comparison with the mild group (p &lt; 0.001) and non-infected controls (p = 0.0006). The frequency of the ACErs4291A allele was higher among severe COVID-19 than mild and non-infected groups (64.4% vs. 37.5%, and 34.4%, respectively), and the ERAP1rs26618T allele was also higher in the severe group (67.5% vs. 39.4%, and 49.4%). There was a statistically significant association between severe COVID-19 and ACErs4291A or ERAP1rs26618T alleles. The coexistence of ACErs4291A and ERAP1rs26618T alleles in the same individual increase the severity of the COVID-19 risk by seven times [OR (95%CI) (LL-UL) = 7.058 (3.752-13.277), p &lt; 0.001). A logistic regression analysis revealed that age, male gender, non-vaccination, ACErs4291A, and ERAP1rs26618T alleles are independent risk factors for severe COVID-19. Persons carrying ACErs4291A and/or ERAP1rs26618T alleles are at higher risk of developing severe COVID-19.

Impasses and Nuances of Vaccination for COVID-19 in Children Aged 5-11 Years

Background: In relation to COVID-19, pediatric patients are usually asymptomatic or with mild manifestations of lesser severity. On the other hand, the literature demonstrates the reduced existence of cases that progressed to serious complications. Therefore, the release of a vaccine for this age group is extremely important for children's health and for reducing the spread of the virus. Furthermore, the immunization of children against SARS-CoV-2 was implemented in some countries and, as a result, the panorama regarding this subject has changed completely, being saturated with opinions and divergences related to the topic. In view of this, the present article aims to clarify the nuances of SARS-Cov-2 immunization in children between the ages of 5-11 years old.&#x0D; Methodology: For this study, we have conducted a review on the literature regarding vaccination against COVID-19 on the 5-11 years pediatric age group, using the MeSh terms "COVID-19", "vaccination", "children", and "pandemic", in the following databases: "Google Scholar", "PubMed" and "BVS".&#x0D; Results: Overall, the research has shown that the most common side effects in the pediatric age group, when present, were local pain (48,7%), headache (20,4%), fatigue (27,7%), myalgia (11,4%), and local erythema (11,4%), whilst severe symptoms, such as myocarditis, occurred with a low incidence (0,16%).&#x0D; Conclusion: Due to the absence or, if present, mild /local side effects on children, the recommendations of the main health agencies are in favor of the immunization of this age group, although, further work on the social opinion is needed in order to increase public acceptance concerning the importance and safety of vaccination against COVID-19 in children between the ages of 5-11.

Factor XII deficiency: a clinical and molecular genetic study.

Factor XII deficiency is a rare inherited disorder caused by clotting factor XII (FXII, F12) deficiency. It is often asymptomatic but can have both thrombotic and haemorrhagic symptoms. The aim of this study was to describe the spectrum of F12 gene mutations in a Russian population and learn more about the relationship between F12 variants and clinical phenotypes. We obtained and analysed genetic and clinical data from 33 apparently unrelated patients with FXII plasma levels below 60% and genetic data from 26 healthy controls with no history of FXII deficiency. Forty mutant alleles and six different deleterious substitutions were identified. Of these substitutions, three were major in the Russian population (c.-62C > T, c.-57G > C and c.1532-1G > A, total frequency 92.5%) and the three others (p.615 del C, c.1180_1181delCA, and CD218 TAT- > CAT p.Tyr218His) were rare and novel in the world population. Eight patients with mild FXII deficiency were found to be homozygous for a hypomorphic variant of functional polymorphism C46T and have no other deleterious substitutions in the F12 gene. Contrary to data in the literature, our study showed that mild haemorrhagic manifestations are common among patients with FXII deficiency.

Carriers of the m.3243A&gt;G variant require comprehensive work-up for subclinical or mild clinical phenotypic manifestations

Carriers of the m.3243A&gt;G variant require comprehensive work-up for subclinical or mild clinical phenotypic manifestations

Inflammatory and coagulation marker profiles in severe pediatric COVID-19 patients: a systematic review

Background Children are susceptible to SARS-CoV-2 infection and often present mild manifestations. However, severe and critical cases have also been reported. The inflammation and coagulation marker profile pattern in these patients along with the white blood cell differential count in critical PICU cases with non-COVID-19 etiology is not entirely clear.&#x0D; Objective To evaluate the inflammation and coagulation profiles in children presenting with severe/critical SARS-CoV-2 infection.&#x0D; Methods A systematic search and review of scientific literature was conducted following the PRISMA guidelines using ProQuest, SCOPUS, EBSCOHost, ScienceDirect, Cochrane, EMBASE, and Pubmed databases. All relevant original studies until March 11, 2021, were included. The risk of bias was appraised using the Modified Newcastle Ottawa Scale and JBI Critical Appraisal Checklist tools.&#x0D; Results We identified 14 studies across 6 countries, including a total sample of 159 severe and critically ill pediatric COVID-19 patients. Most of the subjects showed normal leukocytes, but increased CRP, procalcitonin, ferritin, and IL-6. Studies on coagulation profiles showed normal thrombocytes, PT, aPTT, and inconsistent D-dimer results. &#x0D; Conclusion Inflammation and coagulation parameters in severe/critically ill children with COVID-19 are atypical. Several inflammatory markers were elevated, including CRP, ferritin, procalcitonin, and IL-6. However, the elevated marker values are still lower compared to non-COVID infection patients. Further investigation of the parameters need to be done in serial examination multicenter studies, which include control subjects.

Lung Involvement in Systemic Juvenile Idiopathic Arthritis: A Narrative Review.

Systemic juvenile idiopathic arthritis associated with lung disorders (sJIA-LD) is a subtype of sJIA characterized by the presence of chronic life-threatening pulmonary disorders, such as pulmonary hypertension, interstitial lung disease, pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia, which were exceptionally rare before 2013. Clinically, these children show a striking dissociation between the relatively mild clinical manifestations (tachypnoea, clubbing and chronic cough) and the severity of the pulmonary inflammatory process. Our review describes sJIA-LD as having a reported prevalence of approximately 6.8%, with a mortality rate of between 37% and 68%. It is often associated with an early onset (&lt;2 years of age), macrophage activation syndrome and high interleukin (IL)-18 circulating levels. Other risk factors may be trisomy 21 and a predisposition to adverse reactions to biological drugs. The most popular hypothesis is that the increase in the number of sJIA-LD cases can be attributed to the increased use of IL-1 and IL-6 blockers. Two possible explanations have been proposed, named the "DRESS hypothesis" and the "cytokine plasticity hypothesis". Lung ultrasounds and the intercellular-adhesion-molecule-5 assay seem to be promising tools for the early diagnosis of sJIA-LD, although high resolution computed tomography remains the gold standard. In this review, we also summarize the treatment options for sJIA-LD, focusing on JAK inhibitors.

Lung transplantation for interstitial lung disease in idiopathic inflammatory myositis: A cohort study

In patients with interstitial lung disease (ILD) complicating classical or amyopathic idiopathic inflammatory myopathy (IIM), lung transplantation outcomes might be affected by the disease and treatments. Here, our objective was to assess survival and prognostic factors in lung transplant recipients with IIM-ILD. We retrospectively reviewed data for 64 patients who underwent lung transplantation between 2009 and 2021 at 19 European centers. Patient survival was the primary outcome. At transplantation, the median age was 53 [46-59] years, 35 (55%) patients were male, 31 (48%) had classical IIM, 25 (39%) had rapidly progressive ILD, and 21 (33%) were in a high-priority transplant allocation program. Survival rates after 1, 3, and 5 years were 78%, 73%, and 70%, respectively. During follow-up (median, 33 [7-63] months), 23% of patients developed chronic lung allograft dysfunction. Compared to amyopathic IIM, classical IIM was characterized by longer disease duration, higher-intensity immunosuppression before transplantation, and significantly worse posttransplantation survival. Five (8%) patients had a clinical IIM relapse, with mild manifestations. No patient experienced ILD recurrence in the allograft. Posttransplantation survival in IIM-ILD was similar to that in international all-cause-transplantation registries. The main factor associated with worse survival was a history of muscle involvement (classical IIM). In lung transplant recipients with idiopathic inflammatory myopathy, survival was similar to that in all-cause transplantation and was worse in patients with muscle involvement compared to those with the amyopathic disease.

Hepatic manifestations of coronavirus disease 2019 infection: Clinical and laboratory perspective.

The novel coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2, has become a global challenge of unprecedented nature since December 2019. Although most patients with COVID-19 exhibit mild clinical manifestations and upper respiratory tract involvement, in approximately 5%-10% of patients, the disease is severe and involves multiple organs, leading to multi-organ dysfunction and failure. The liver and gastrointestinal tract are also frequently involved in COVID-19. In the context of liver involvement in patients with COVID-19, many key aspects need to be addressed in both native and transplanted organs. This review focuses on the clinical presentations and laboratory abnormalities of liver function tests in patients with COVID-19 with no prior liver disease, patients with pre-existing liver diseases and liver transplant recipients. A brief overview of the history of COVID-19 and etiopathogenesis of the liver injury will also be described as a prelude to better understanding the above aspects.

Germline Variants in MDM4 Cause a Disorder of p53 Dysregulation and Insufficient Telomere Maintenance

Introduction: Telomere biology disorders (TBD) comprise a group of hereditary disorders characterized by a genetically determined insufficiency of telomere maintenance leading to fibrosis and malfunction, especially of bone marrow (BM), liver, and lungs. TBD can present with highly variable phenotype as so-called "cryptic" forms with only mild clinical manifestations. Known genetic causes include defects in genes encoding mainly for proteins directly involved in telomere biology. However, today, still a relevant subgroup of patients with the clinical picture of TBD remain without a molecular diagnosis. Recently, members of yet a single family carrying a dominantly inherited missense variant in MDM4 (NM_002393.5:c.1361C>T, p.(Thr454Met)) with premature telomere length (TL) shortening were reported (Toufektchan et al., 2020) presenting with a phenotype similar to the classical TBD, Dyskeratosis congenita. The MDM4-gene encodes a 490-amino acid protein that interacts with and negatively regulates p53. In vitro and murine studies suggested a loss of p53 regulation by the defective MDM4 protein leading to augmented p53 activity and insufficient telomere maintenance. In line with this finding, mice with an overactive TRP53 developed BM failure and lung fibrosis resembling the phenotype of TBD. Here, we report three patients from different families carrying germline variants in MDM4 presenting with a TBD phenotype of varying severity. Methods: All patients were included in the Aachen Telomere Registry (ATR). Informed consent for genetic analyses was obtained from all participants. All patients received analysis of TL via flow-FISH and genetic work-up using whole exome sequencing (WES). Results: Patient 1 is a newborn boy with uncomplicated delivery. At 4 weeks of age, the patient presented jaundice and a routine blood sample was taken. Clinical examination showed no abnormalities. Blood counts showed neutropenia with 500/µl and normal hemoglobin and platelet counts. WES revealed the identification of the same heterozygous MDM4-variant ( NM_002393.5:c.1361C>T, p.(Thr454Met)) previously reported by Toufektchan et al.. Subsequent analyses of the parents showed maternal inheritance. Additional TL measurement showed no significant shortening of TL for all family members. Physical examination and medical history of the mother revealed no relevant abnormalities. Patient 2 is a male patient who, at the age of six years, first showed thrombocytopenia and leukopenia. During follow-up, he developed liver dysfunction with persisting elevated transaminases at the age of eleven years and portal hypertension and esophageal varicosis at the age of 13. During follow-up, the patient developed progressive cytopenia at the age of 16 and BM hypocellularity with reduced and partially dysplastic megakaryopoiesis and granulopoiesis. Flow-FISH analyses revealed a TL below the 1% percentile in lymphocytes. Genetic work-up using trio-based WES of the parents and the patient showed a de-novo stopgain variant in MDM4 (NM_002393.5:c.1333C>T, p.(Arg445*)). Patient 3 is an adult 53-year-old male patient presenting with BM failure. Initial diagnostic work-up including BM biopsy showed hypocellular BM. FISH analysis of the BM sample revealed a deletion of 7q and the diagnosis of hypocellular myelodysplastic syndrome was established. TL measurement showed TL below the 1% percentile in lymphocytes. Clinical examination showed no TBD typical stigmata or abnormalities. However, hepatic steatosis was reported. Additional WES revealed a rare missense variant in MDM4 (NM_002393.5:c.1334G>A, p.(Arg445Gln)). Conclusions: Here, we provide strong evidence from three unrelated patients that genomic germline variants in MDM4 cause a disorder of insufficient telomere maintenance resulting in a phenotype resembling features of TBD. Similar to TBD, the age at disease onset of our reported patients varied from early infant age to adulthood. So far, a single family with a proposed pathogenic MDM4 variant had been reported, which left a degree of uncertainty concerning the pathogenicity of MDM4 variants in general. In summary, our data confirm that there is an MDM4-associated TBD disorder with a broad phenotypic clinical spectrum.

A case of chyluria with nephrotic-range proteinuria caused by lymphatic malformation, leading to a diagnosis of Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a rare syndrome, which is clinically diagnosed by the presence of unilateral limb hypertrophy with vascular malformation including cutaneous capillaries, veins and lymphatic vessels. Most cases typically exhibit cutaneous manifestations such as port-wine stains and limb hypertrophy from infancy, but cases with mild manifestations may remain undiagnosed. We here report a case of KTS who was diagnosed by chance chyluria. A 15-year-old girl who exhibited hematochyluria with nephrotic-range proteinuria was referred to our hospital. She had been diagnosed as idiopathic scoliosis accompanied by left lower limb hypertrophy in the past. She noticed her milky urine for the first time two months before. Immediately thereafter, she noticed edema of her left leg. Hematochyluria with nephrotic-range proteinuria was found by our initial urine examination. Magnetic resonance imaging suggested venous or lymphatic malformation along the left common iliac vein at the retroperitoneal side. Lymphoscintigraphy showed congestion of radioisotope around backside of the pancreas to the left renal hilus, suggesting an existence of lymphostasis. Based on the findings, we diagnosed the patient as KTS. After admission, hematochyluria and proteinuria were decreased and became insignificant by three days with bed rest. Her left leg edema was reduced. After taking a guidance to avoid intensive exercise, she was discharged in two weeks. Because the present case exhibited mild manifestations, diagnosis was made by urine abnormalities for the first time. The case suggests that we should be aware of the presence of undiagnosed patients of KTS due to relatively mild manifestations.

Diagnostic Approach to Patients with Low Serum Alkaline Phosphatase.

Increased serum levels of alkaline phosphatase (ALP) are widely recognized as a biochemical marker of many disorders affecting the liver or bone. However, the approach for patients with low ALP phosphatase is not well-established. Low serum ALP is an epiphenomenon of many severe acute injuries and diseases. Persistently low serum ALP may be secondary to drug therapy (including antiresorptives) or a variety of acquired disorders, such as malnutrition, vitamin and mineral deficiencies, endocrine disorders, etc. Hypophosphatasia, due to pathogenic variants of the ALPL gene, which encodes tissue non-specific ALP, is the most common genetic cause of low serum ALP. Marked bone hypomineralization is frequent in severe pediatric-onset cases. However, adult forms of hypophosphatasia usually present with milder manifestations, such as skeletal pain, chondrocalcinosis, calcific periarthritis, dental problems, and stress fractures. The diagnostic approach to these patients is discussed. Measuring several ALP substrates, such as pyrophosphate, pyridoxal phosphate, or phosphoethanolamine, may help to establish enzyme deficiency. Gene analysis showing a pathogenic variant in ALPL may confirm the diagnosis. However, a substantial proportion of patients show normal results after sequencing ALPL exons. It is still unknown if those patients carry unidentified mutations in regulatory regions of ALPL, epigenetic changes, or abnormalities in other genes.

TRNA abundance, modification and fragmentation in nasopharyngeal swabs as biomarkers for COVID-19 severity.

Emerging and re-emerging respiratory viruses can spread rapidly and cause pandemics as demonstrated by the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. The early human immune responses to respiratory viruses are in the nasal cavity and nasopharyngeal regions. Defining biomarkers of disease trajectory at the time of a positive diagnostic test would be an important tool to facilitate decisions such as initiation of antiviral treatment. We hypothesize that nasopharyngeal tRNA profiles could be used to predict Coronavirus Disease 19 (COVID-19) severity. We carried out multiplex small RNA sequencing (MSR-seq) on residual nasopharyngeal swabs to measure simultaneously full-length tRNA abundance, tRNA modifications, and tRNA fragmentation for the human tRNA response to SARS-CoV-2 infection. We identified distinct tRNA signatures associated with mild symptoms versus severe COVID-19 manifestations requiring hospitalization. These results highlight the utility of host tRNA properties as biomarkers for the clinical outcome of SARS-CoV-2.

COVID-19's next top model

To date, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reportedly infected over 630 million people, leading to the deaths of more than 6.5 million people. Despite expansive investigation of its pathogenesis and the development of vaccines and therapeutics, research in preclinical models must continue to ensure that we can combat the continuing COVID-19 and future pandemics. Two exemplary animal models – Syrian golden hamsters and K18-promoter-driven human ACE2-expressing (K18-hACE2) mice – recapitulate the human pathology, immune response and clinical manifestations of COVID-19, and are also accessible with low cost. However, there are vast differences in the severity of disease in these models, with mild clinical manifestations in the hamsters and high lethality in the mice.Jeong and colleagues intranasally infected Syrian golden hamsters and K18-hACE2 mice with the same dose of SARS-CoV-2, resulting in mild clinical signs in hamsters, such as minor decreases in body weight, and severe manifestations in mice, leading to death by 7 days post-infection (dpi). The authors thoroughly interrogated the infection in these animals to elucidate the mechanisms behind the differing clinical outcomes. They used in situ hybridization imaging to show that SARS-CoV-2 infection was mainly confined to microvillar club (∼88%) and ciliated (∼12%) cell subsets in the bronchus region of hamsters. These infected cells were rapidly eliminated, with high levels of cell death apparent at 2 dpi. By 5 dpi, in the hamsters, the infected area was highly infiltrated with B and CD8+ T cells, which are important for clearing infected cells. Surprisingly, lung pathology was more severe in hamsters than in mice at 5 and 7 dpi, with imaging revealing markers of bronchioalveolar adenoma and bronchopneumonia in hamsters. However, after 7 dpi, pulmonary lesions and adaptive immune cell accumulation were ameliorated, with only regenerative hyperplasia apparent in the bronchus at 14 dpi. Overall, the initial robust immune response was key in limiting and resolving SARS-CoV-2 infection in hamsters.By contrast, SARS-CoV-2 primarily infected the alveolar area of mouse lungs, with type 1 alveolar cells comprising roughly 97% of total infected cells, and very few infected cells were eliminated. The infection also spread to distal organs, such as the spleen at 2 dpi and the brain at 7 dpi, which resulted in inflammatory cell death and histopathological damage in several organs. B and T cells progressively accumulated in the mouse lungs up until death at 7 dpi, but the extent of infiltration was much lower than that in hamsters at early time points. The deficient clearance of infected cells in the mice was potentially due to the lower levels of CD8+ T cells, which are associated with COVID-19 mortality in humans. Taken together, these results indicate that the pathology of SARS-CoV-2 infection in K18-hACE2 mice mimics severe COVID-19 in humans.COVID-19 pathology is highly variable in humans, and the mechanism behind this variability needs to be thoroughly explored to optimise prognosis and treatment. Direct comparison of these two integral disease models not only informs future research using animal models of COVID-19, but also provides comprehensive insights into variation in COVID-19 pathology.