The neutralizing response to SARS-CoV-2 Omicron variants BA.1 and BA.2 in COVID-19 patients and homologous and heterologous vaccinees.

The rapid replacement of Omicron BA.1 by BA.2 sublineage is very alarming, raising the question of whether BA.2 can escape the immunity acquired after BA.1 infection. We compared the neutralizing activity toward the Omicron BA.1 and BA.2 sub-lineages in five groups: COVID-19 patients; subjects who had received two doses of mRNA vaccine; subjects naturally infected with SARS-CoV-2 who had received two doses of mRNA; and subjects who had received three doses of homologous or heterologous vaccine. The results obtained highlight the importance of vaccine boosters in eliciting neutralizing antibody responses against Omicron sub-lineages, and suggest that the adenovirus vectored vaccine elicits a lower response against BA.1 than against BA.2 sub-lineage.

Antibody Avidity and Neutralizing Response against SARS-CoV-2 Omicron Variant after Infection or Vaccination.

Background: The recently emerged SARS-CoV-2 Omicron variant exhibits several mutations on the spike protein, enabling it to escape the immunity elicited by natural infection or vaccines. Avidity is the strength of binding between an antibody and its specific epitope. The SARS-CoV-2 spike protein binds to its cellular receptor with high affinity and is the primary target of neutralizing antibodies. Therefore, protective antibodies should show high avidity. This study aimed at investigating the avidity of receptor-binding domain (RBD) binding antibodies and their neutralizing activity against the Omicron variant in SARS-CoV-2 infected patients and vaccinees. Methods: Samples were collected from 42 SARS-CoV-2 infected patients during the first pandemic wave, 50 subjects who received 2 doses of mRNA vaccine before the Omicron wave, 44 subjects who received 3 doses of mRNA vaccine, and 35 subjects who received heterologous vaccination (2 doses of adenovirus-based vaccine plus mRNA vaccine) during the Omicron wave. Samples were tested for the avidity of RBD-binding IgG and neutralizing antibodies against the wild-type SARS-CoV-2 virus and the Omicron variant. Results: In patients, RBD-binding IgG titers against the wild-type virus increased with time, but remained low. High neutralizing titers against the wild-type virus were not matched by high avidity or neutralizing activity against the Omicron variant. Vaccinees showed higher avidity than patients. Two vaccine doses elicited the production of neutralizing antibodies, but low avidity for the wild-type virus; antibody levels against the Omicron variant were even lower. Conversely, 3 doses of vaccine elicited high avidity and high neutralizing antibodies against both the wild-type virus and the Omicron variant. Conclusions: Repeated vaccination increases antibody avidity against the spike protein of the Omicron variant, suggesting that antibodies with high avidity and high neutralizing potential increase cross-protection against variants that carry several mutations on the RBD.

Two-point-NGS analysis of cancer genes in cell-free DNA of metastatic cancer patients.

BACKGROUND: Although the efficacy of molecularly target agents in vitro, their use in routine setting is limited mainly to the use of anti-HER2 and antiEGFR agents in vivo. Moreover, core biopsy of a single cancer site may not be representative of the whole expanding clones and cancer molecular profile at relapse may differ with respect to the primary tumor. METHODS: We assessed the status of a large panel of cancer driver genes by cell-free DNA (cfDNA) analysis in a cohort of 68 patients with 13 different solid tumors at disease progression. Whenever possible, a second cfDNA analysis was performed after a mean of 2.5 months, in order to confirm the identified clone(s) and to check the correlation with clinical evolution. RESULTS: The approach was able to identify clones plausibly involved in the disease progression mechanism in about 65% of cases. A mean of 1.4 mutated genes (range 1-3) for each tumor was found. Point mutations in TP53, PIK3CA, and KRAS and copy number variations in FGFR3 were the gene alterations more commonly observed, with a rate of 48%, 20%, 16%, and 20%, respectively. Two-points-Next-Generation Sequencing (NGS) analysis demonstrated statistically significant correlation between allele frequency variation and clinical outcome (P = .026). CONCLUSIONS: Irrespective of the primary tumor mutational burden, few mutated genes are present at disease progression. Clinical outcome is consistent with variation of allele frequency of specific clones indicating that cfDNA two-point-NGS analysis of cancer driver genes could be an efficacy tool for precision oncology.

Reference values of left atrial size and function according to age: should we redefine the normal upper limits?

Different cut-offs have been proposed for left atrial (LA) size. Furthermore, conflicting results have been reported about the influence of age on LA size and data on the impact of age on LA myocardial function are scanty. The aim of this study was to derive references values for LA size and function in healthy subjects and to evaluate the impact of age. We conducted a systematic literature search of MEDLINE database. We included only studies evaluating healthy subjects, with age ranged between 18 and 80 years. Parameters were compared among four age groups, < 30, 30-45, > 45-60, > 60 years. Three hundred twenty-six studies met the inclusion criteria and the final population consisted of 62,821 subjects. LA volume index (LAVi) did not differ among different age groups (p = 0.21). The normal upper limit of LAVi was 24 mL/m2. LA reservoir function, measured by strain, did not differ among age groups (38 ± 3%, 32-43%; p = 0.74). Left ventricular (LV) size and function were not different among groups, except LV mass index. A decrease in E/A ratio and an increase in E/e' ratio were found with advancing age (p < 0.0001 and p = 0.001, respectively). In healthy subjects the normal upper limit of LAVi was lower than that recommended and is not influenced by advancing age. Furthermore, also LA function measured by strain was not affected by age. The current reference values of LAVi should be used with caution when applied to healthy subjects.

MRI-based assessment of the pineal gland in a large population of children aged 0-5 years and comparison with pineoblastoma: part I, the solid gland.

INTRODUCTION: Differentiation between normal solid (non-cystic) pineal glands and pineal pathologies on brain MRI is difficult. The aim of this study was to assess the size of the solid pineal gland in children (0-5 years) and compare the findings with published pineoblastoma cases. METHODS: We retrospectively analyzed the size (width, height, planimetric area) of solid pineal glands in 184 non-retinoblastoma patients (73 female, 111 male) aged 0-5 years on MRI. The effect of age and gender on gland size was evaluated. Linear regression analysis was performed to analyze the relation between size and age. Ninety-nine percent prediction intervals around the mean were added to construct a normal size range per age, with the upper bound of the predictive interval as the parameter of interest as a cutoff for normalcy. RESULTS: There was no significant interaction of gender and age for all the three pineal gland parameters (width, height, and area). Linear regression analysis gave 99 % upper prediction bounds of 7.9, 4.8, and 25.4 mm(2), respectively, for width, height, and area. The slopes (size increase per month) of each parameter were 0.046, 0.023, and 0.202, respectively. Ninety-three percent (95 % CI 66-100 %) of asymptomatic solid pineoblastomas were larger in size than the 99 % upper bound. CONCLUSION: This study establishes norms for solid pineal gland size in non-retinoblastoma children aged 0-5 years. Knowledge of the size of the normal pineal gland is helpful for detection of pineal gland abnormalities, particularly pineoblastoma.

MRI helps depict clinically undetectable risk factors in advanced stage retinoblastomas.

This study compared high-resolution MRI with histology in advanced stage retinoblastomas in which ophthalmoscopy and ultrasonography did not give an exhaustive depiction of the tumour and/or its extension. MRI of orbits and head in 28 retinoblastoma patients (28 eyes) treated with primary enucleation were evaluated. Iris neoangiogenesis, infiltrations of optic nerve, choroid, anterior segment and sclera suspected at MR and histology were compared. Abnormal anterior segment enhancement (AASE) was also correlated with histologically proven infiltrations. Brain images were also evaluated. Significant values were obtained for: prelaminar optic nerve (ON) sensitivity (0.88), positive predictive value (PPV) (0.75) and negative predictive value (NPV) (0.71); post-laminar ON sensitivity (0.50), specificity (0.83), PPV (0.50) and NPV (0.83); overall choroid sensitivity (0.82), and massive choroid NPV (0.69); scleral specificity (1), and NPV (1). AASE correlated with iris neoangiogenesis in 14 out of 19 eyes, and showed significant values for: overall ON PPV (0.65), prelaminar ON sensitivity (0.65), and PPV (0.61), post-laminar ON NPV (0.64); overall choroid sensitivity (0.77), PPV (0.59) and NPV (0.73); scleral NPV (0.83); anterior segment sensitivity (1), and NPV (1). Odds ratios (OR) and accuracy were significant in scleral and prelaminar optic nerve infiltration. Brain examination was unremarkable in all cases. High-resolution MRI may add important findings to clinical evaluation of advanced stage retinoblastomas.

Next generation sequencing in sporadic retinoblastoma patients reveals somatic mosaicism.

In about 50% of sporadic cases of retinoblastoma, no constitutive RB1 mutations are detected by conventional methods. However, recent research suggests that, at least in some of these cases, there is somatic mosaicism with respect to RB1 normal and mutant alleles. The increased availability of next generation sequencing improves our ability to detect the exact percentage of patients with mosaicism. Using this technology, we re-tested a series of 40 patients with sporadic retinoblastoma: 10 of them had been previously classified as constitutional heterozygotes, whereas in 30 no RB1 mutations had been found in lymphocytes. In 3 of these 30 patients, we have now identified low-level mosaic variants, varying in frequency between 8 and 24%. In 7 out of the 10 cases previously classified as heterozygous from testing blood cells, we were able to test additional tissues (ocular tissues, urine and/or oral mucosa): in three of them, next generation sequencing has revealed mosaicism. Present results thus confirm that a significant fraction (6/40; 15%) of sporadic retinoblastoma cases are due to postzygotic events and that deep sequencing is an efficient method to unambiguously distinguish mosaics. Re-testing of retinoblastoma patients through next generation sequencing can thus provide new information that may have important implications with respect to genetic counseling and family care.

Oligogenic germline mutations identified in early non-smokers lung adenocarcinoma patients.

OBJECTIVES: A polygenic model is commonly assumed for the predisposition to common cancers. With respect to lung cancer, Genome Wide Association Studies (GWAS) have identified three loci at 15q25, 5p15.33, and 6p21. However, the relative risks associated with alleles at these loci are low; in addition, the data are limited to smokers, and have not been quite reproducible. MATERIALS AND METHODS: In order to investigate genetic susceptibility we have adopted an entirely novel patient selection strategy. First, we have selected for adenocarcinoma (ADCA) histology only; second, we have selected non-smokers; third we have selected patients who developed ADCA of lung before the age of 60 and who had an older unaffected sib: we have identified 31 such sib-pairs. Among them, we selected two patients with very early age at disease onset (37- and 49-years old), and having a healthy sibling available for genome comparison older than at least 7 years. RESULTS: On germline DNA samples of four subjects of two such pairs we have carried out whole exome sequencing. Truncating mutations were detected in 8 'cancer genes' in one affected, and in 5 cancer genes in the other affected subject: but none in the two healthy sibs (p=0.0026). Some of these mutant genes (such as BAG6, SPEN and WISP3) are recognized as major cancer players in lung tumors; others have been previously identified in other human cancers (JAK2, TCEB3C, NELFE, TAF1B, EBLN2), in mouse models (GON4L, NOP58, and RBMX) or in genome-wide association studies (KIAA2018, ZNF311). CONCLUSIONS: This study identifies for the first time in non-smokers with lung adenocarcinoma specific sets of germline mutations that, together, may predispose to this tumor.