Finite-temperature relativistic Landau problem and the relativistic quantum Hall effect

This paper presents a study of the free energy and particle density of the relativistic Landau problem, and their relevance to the quantum Hall effect. We study first the zero temperature Casimir energy and fermion number for Dirac fields in a 2+1-dimensional Minkowski space-time, in the presence of a uniform magnetic field perpendicular to the spatial manifold. Then, we go to the finite-temperature problem, with a chemical potential, introduced as a uniform zero component of the gauge potential. By performing a Lorentz boost, we obtain Hall's conductivity in the case of crossed electric and magnetic fields.Comment: Final version, to appear in Journal of Physics A: Mathematical and Genera

Miscarriage following dengue virus 3 infection in the first six weeks of pregnancy of a dengue virus-naive traveller returning from Bali to Italy, April 2016

We report miscarriage following dengue virus (DENV)-3 infection in a pregnant woman returning from Bali to Italy in April 2016. On her arrival, the woman had fever, rash, asthenia and headache. DENV RNA was detected in plasma and urine samples collected the following day. Six days after symptom onset, she had a miscarriage. DENV RNA was detected in fetal material, but in utero fetal infection cannot be demonstrated due to possible contamination by maternal blood

Early co-circulation of different clades of influenza A/H1N1v pandemic virus in Northern Italy

Introduction. The spatial diffusion over time of pandemic influenza A/H1N1 virus (A/H1N1v) was surveyed in Northern Italy (nearly 10 million inhabitants) from April to December 2009, and the molecular characteristics of circulating viruses were analyzed to identify the appearance of drift variants. About 45% of analyzed samples were laboratory-confirmed cases of A/H1N1v. Sporadic cases occurred until the middle of June 2009, then, case numbers began to increase delineating distinct epidemiological phases of viral circulation. Methods. RNA was extracted using RNeasy Mini kit (QIAGEN GmbH, Germany). Virological diagnosis of A/H1N1v infection was carried out by real-time RT-PCR assay. Sequence analysis of hemagglutinin (HA) gene was performed through a RT-PCR assay specific for a 995 bp fragment (nt. 64-1,058) in the HA1 domain. The nucleotide sequences were obtained by automated DNA sequencing. The HA1 sequences were aligned with other sequences collected from GenBank database by ClustalX software. The multiple sequence alignment was used to perform a basic phylogenetic analysis and a phylogenetic tree from HA sequences was constructed. Results. The HA gene sequences of A/H1N1v analyzed segregated into three genetically distinct clades and were characterized by the appearance of amino acid variations that were progressively fixed in the field viral population under scrutiny. Conclusions. These data suggest an early co-circulation of genetically distinct A/H1N1v variants and emphasize the importance of a close molecular surveillance to detect rapidly the spread of new viral variants and to define their epidemiological impact

Immunogenicity and safety after the third dose of BNT162b2 anti-SARS-CoV-2 vaccine in patients with solid tumors on active treatment: a prospective cohort study

Background: Although a full course of coronavirus disease 2019 (COVID-19) vaccine is effective in cancer patients, the duration of the protection and the efficacy of a booster dose against the new variants remain unknown. We prospectively evaluated the immunogenicity of the third dose of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) BNT162b2 messenger RNA vaccine in cancer patients undergoing active treatment. Patients and methods: Patients with solid cancer, vaccinated with a booster dose during active treatment, were enrolled in this study. Patients were classified into SARS-CoV-2 naïve (without previous COVID-19 infection) and SARS-CoV-2 experienced (with previous COVID-19 infection). Neutralizing antibody (NT Ab) titer and total anti-Spike immunoglobulin G (IgG) concentration were quantified in serum. Heparinized whole blood samples were used for SARS-CoV-2 Interferon Gamma Release Assay (IGRA). The primary endpoint was to assess the increase of IgG antibody level between baseline and 3 weeks after the booster. Results: One hundred and forty-two consecutive patients were recruited. In SARS-CoV-2-naïve subjects, the median level of IgG was 157 BAU/ml [interquartile range (IQR) 62-423 BAU/ml] at T0 and reached a median of 2080 BAU/ml (IQR 2080-2080 BAU/ml) at 3 weeks after booster administration (T1; P < 0.0001). A median 16-fold increase of SARS-CoV-2 NT Ab titer (IQR 4-32) was observed in naïve subjects (from median 20, IQR 10-40, to median 640, IQR 160-640; P < 0.0001). Median interferon-γ level at T1 was significantly higher than that measured at T0 in SARS-CoV-2-naïve subjects (P = 0.0049) but not in SARS-CoV-2-experienced patients. The median level of SARS-CoV-2 NT Abs was 32-fold lower against Omicron compared to the wild-type strain (P = 0.0004) and 12-fold lower compared to the Delta strain (P = 0.0110). Conclusions: The third dose is able to trigger both the humoral and the cell-mediated immune response in cancer patients on active treatment. Our preliminary data about the neutralization of the SARS-CoV-2 vaccine against variants of concern seem to confirm the lower vaccine activity

Shedding light on the elusive role of endothelial cells in cytomegalovirus dissemination.

Cytomegalovirus (CMV) is frequently transmitted by solid organ transplantation and is associated with graft failure. By forming the boundary between circulation and organ parenchyma, endothelial cells (EC) are suited for bidirectional virus spread from and to the transplant. We applied Cre/loxP-mediated green-fluorescence-tagging of EC-derived murine CMV (MCMV) to quantify the role of infected EC in transplantation-associated CMV dissemination in the mouse model. Both EC- and non-EC-derived virus originating from infected Tie2-cre(+) heart and kidney transplants were readily transmitted to MCMV-naïve recipients by primary viremia. In contrast, when a Tie2-cre(+) transplant was infected by primary viremia in an infected recipient, the recombined EC-derived virus poorly spread to recipient tissues. Similarly, in reverse direction, EC-derived virus from infected Tie2-cre(+) recipient tissues poorly spread to the transplant. These data contradict any privileged role of EC in CMV dissemination and challenge an indiscriminate applicability of the primary and secondary viremia concept of virus dissemination

Analysis of the humoral and cellular immune response after a full course of BNT162b2 anti-SARS-CoV-2 vaccine in cancer patients treated with PD-1/PD-L1 inhibitors with or without chemotherapy: an update after 6 months of follow-up

Background: The durability of immunogenicity of SARS-CoV-2 vaccination in cancer patients remains to be elucidated. We prospectively evaluated the immunogenicity of the vaccine in triggering both the humoral and the cell-mediated immune response in cancer patients treated with anti-programmed cell death protein 1/programmed death-ligand 1 with or without chemotherapy 6 months after BNT162b2 vaccine. Patients and methods: In the previous study, 88 patients were enrolled, whereas the analyses below refer to the 60 patients still on immunotherapy at the time of the follow-up. According to previous SARS-CoV-2 exposure, patients were classified as SARS-CoV-2-naive (without previous SARS-CoV-2 exposure) and SARS-CoV-2-experienced (with previous SARS-CoV-2 infection). Neutralizing antibody (NT Ab) titer against the B.1.1 strain and total anti-spike immunoglobulin G concentration were quantified in serum samples. The enzyme-linked immunosorbent spot assay was used for quantification of anti-spike interferon-γ (IFN-γ)-producing cells/106 peripheral blood mononuclear cells. Fifty patients (83.0%) were on immunotherapy alone, whereas 10 patients (7%) were on chemo-immunotherapy. We analyzed separately patients on immunotherapy and patients on chemo-immunotherapy. Results: The median T-cell response at 6 months was significantly lower than that measured at 3 weeks after vaccination [50 interquartile range (IQR) 20-118.8 versus 175 IQR 67.5-371.3 IFN-γ-producing cells/106 peripheral blood mononuclear cells; P < 0.0001]. The median reduction of immunoglobulin G concentration was 88% in SARS-CoV-2-naive subjects and 2.1% in SARS-CoV-2-experienced subjects. SARS-CoV-2 NT Ab titer was maintained in SARS-CoV-2-experienced subjects, whereas a significant decrease was observed in SARS-CoV-2-naive subjects (from median 1 : 160, IQR 1 : 40-1 : 640 to median 1 : 20, IQR 1 : 10-1 : 40; P < 0.0001). A weak correlation was observed between SARS-CoV-2 NT Ab titer and spike-specific IFN-γ-producing cells at both 6 months and 3 weeks after vaccination (r = 0.467; P = 0.0002 and r = 0.428; P = 0.0006, respectively). Conclusions: Our work highlights a reduction in the immune response in cancer patients, particularly in SARS-CoV-2-naive subjects. Our data support administering a third dose of COVID-19 vaccine to cancer patients treated with programmed cell death protein 1/programmed death-ligand 1 inhibitors

Sequential mutations associated with adaptation of human cytomegalovirus to growth in cell culture

Mutations that occurred during adaptation of human cytomegalovirus to cell culture were monitored by isolating four strains from clinical samples, passaging them in various cell types and sequencing ten complete virus genomes from the final passages. Mutational dynamics were assessed by targeted sequencing of intermediate passages and the original clinical samples. Gene RL13 and the UL128 locus (UL128L, consisting of genes UL128, UL130 and UL131A) mutated in all strains. Mutations in RL13 occurred in fibroblast, epithelial and endothelial cells, whereas those in UL128L were limited to fibroblasts and detected later than those in RL13. In addition, a region containing genes UL145, UL144, UL142, UL141 and UL140 mutated in three strains. All strains exhibited numerous mutations in other regions of the genome, with a preponderance in parts of the inverted repeats. An investigation was carried out on the kinetic growth yields of viruses derived from selected passages that were predominantly non-mutated in RL13 and UL128L (RL13+UL128L+), or that were largely mutated in RL13 (RL13−UL128L+) or both RL13 and UL128L (RL13−UL128L−). RL13−UL128L− viruses produced greater yields of infectious progeny than RL13−UL128L+ viruses, and RL13−UL128L+ viruses produced greater yields than RL13+UL128L+ viruses. These results suggest strongly that RL13 and UL128L exert at least partially independent suppressive effects on growth in fibroblasts. As all isolates proved genetically unstable in all cell types tested, caution is advised in choosing and monitoring strains for experimental studies of vulnerable functions, particularly those involved in cell tropism, immune evasion or growth temperance

Segregation of Virulent Influenza A(H1N1) Variants in the Lower Respiratory Tract of Critically Ill Patients during the 2010–2011 Seasonal Epidemic

BACKGROUND: Since its appearance in 2009, the pandemic influenza A(H1N1) virus circulated worldwide causing several severe infections. METHODS: Respiratory samples from patients with 2009 influenza A(H1N1) and acute respiratory distress attending 24 intensive care units (ICUs) as well as from patients with lower respiratory tract infections not requiring ICU admission and community upper respiratory tract infections in the Lombardy region (10 million inhabitants) of Italy during the 2010-2011 winter-spring season, were analyzed. RESULTS: In patients with severe ILI, the viral load was higher in bronchoalveolar lavage (BAL) with respect to nasal swab (NS), (p<0.001) suggesting a higher virus replication in the lower respiratory tract. Four distinct virus clusters (referred to as cluster A to D) circulated simultaneously. Most (72.7%, n = 48) of the 66 patients infected with viruses belonging to cluster A had a severe (n = 26) or moderate ILI (n = 22). Amino acid mutations (V26I, I116M, A186T, D187Y, D222G/N, M257I, S263F, I286L/M, and N473D) were observed only in patients with severe ILI. D222G/N variants were detected exclusively in BAL samples. CONCLUSIONS: Multiple virus clusters co-circulated during the 2010-2011 winter-spring season. Severe or moderate ILI were associated with specific 2009 influenza A(H1N1) variants, which replicated preferentially in the lower respiratory tract

CMV Infection Attenuates the Disease Course in a Murine Model of Multiple Sclerosis

Recent evidence in multiple sclerosis (MS) suggests that active CMV infection may result in more benign clinical disease. The goal of this pilot study was to determine whether underlying murine CMV (MCMV) infection affects the course of the Theiler's murine encephalitis virus (TMEV) induced murine model of MS. A group of eight TMEV-infected mice were co-infected with MCMV at 2 weeks prior to TMEV infection while a second group of TMEV-infected mice received MCMV two weeks post TMEV. We also used 2 control groups, where at the above time points MCMV was replaced with PBS. Outcome measures included (1) monthly monitoring of disability via rotarod for 8 months; (2) in vivo MRI for brain atrophy studies and (3) FACS analysis of brain infiltrating lymphocytes at 8 months post TMEV infection. Co-infection with MCMV influenced the disease course in mice infected prior to TMEV infection. In this group, rotarod detectable motor performance was significantly improved starting 3 months post-infection and beyond (p≤0.024). In addition, their brain atrophy was close to 30% reduced at 8 months, but this was only present as a trend due to low power (p = 0.19). A significant reduction in the proportion of brain infiltrating CD3+ cells was detected in this group (p = 0.026), while the proportion of CD45+ Mac1+ cells significantly increased (p = 0.003). There was also a strong trend for a reduced proportion of CD4+ cells (p = 0.17) while CD8 and B220+ cell proportion did not change. These findings support an immunomodulatory effect of MCMV infection in this MS model. Future studies in this co-infection model will provide insight into mechanisms which modulate the development of demyelination and may be utilized for the development of novel therapeutic strategies