Interferon-ε as potential inhibitor of Chlamydia trachomatis infection.

Chlamydia trachomatis, the main cause of bacterial sexually transmitted diseases, is responsible for severe reproductive sequelae. Amongst all the cytokines involved in host immunity towards this pathogen, IFN-ε has recently acquired importance for its potential contribution to the female reproductive tract innate defenses. Herein, our study aimed to explore, for the first time, the activity of IFN-ε toward C. trachomatis in an in vitro infection model, by testing its effects on the different phases of chlamydial developmental cycle, as well as on the ultrastructural characteristics of chlamydial inclusions, via transmission electron microscopy. Main result is the capability of IFN-ε to alter C. trachomatis growth, as suggested by reduced infectious progenies, as well as a patchy distribution of bacteria and altered morphology of reticulate bodies within inclusions. In conclusion, our results suggest that IFN-ε could play a role in the innate and adaptive immune defenses against C. trachomatis; in the future, it will be needed to investigate its activity on an infection model more closely resembling the physiological environment of the female genital tract.

Alterations in the Expression of IFN Lambda, IFN Gamma and Toll-like Receptors in Severe COVID-19 Patients.

Contradictory results have been reported regarding interferon (IFN) lambda (λ1-3) and IFN gamma (γ) production in COVID-19 patients. To gain insight into the roles played by these IFNs in SARS-CoV-2 infection, IFNλ1-3 and IFNγ mRNA expression was evaluated in peripheral blood mononuclear cells (PBMCs) (n = 32) and in cells of paired bronchoalveolar lavages (BALs) (n = 12). Lower IFNλ1-3 values (p < 0.001 for IFNλ1 and 3 and p = 0.013 for IFNλ2) in the PBMCs of severely ill patients were found compared to healthy donors (n = 15). Reduced levels of IFNγ were also detected in patients' PBMCs (p < 0.01) and BALs (p = 0.041) compared to healthy donors. The presence of secondary bacterial infections was associated with decreased IFNλ amounts in PBMCs (p = 0.001, p = 0.015 and p = 0.003, respectively) but increased concentrations of IFNλ3 (p = 0.022) in BALs. Patients with alterations in C-reactive protein, lactate dehydrogenase and D-dimer levels had decreased IFNλ1 and 3 (p = 0.003 and p < 0.001) and increased IFNγ (p = 0.08) in PBMCs. Analyzing Toll-like receptors (TLRs) involved in IFN production, we found that TLR3 was highly expressed (p = 0.033) in patients with bacterial superinfections, while TLR7 and 8 (p = 0.029 and p = 0.049) were reduced in BALs of deceased patients. Overall, severe COVID-19 might be characterized by dysregulation in IFNγ, IFNλ and TLR3, 7 and 8 production.

High prevalence of Merkel cell polyomavirus is associated with dysregulation in transcript levels of TLR9 and type I IFNs in a large cohort of CF patients from the Italian (Lazio) reference center for cystic fibrosis.

Merkel cell polyomavirus (MCPyV) has been detected in respiratory specimens including those from Cystic Fibrosis (CF) patients, raising questions about its immunological and clinical relevance in the respiratory tract. MCPyV might promote an inappropriate antiviral response contributing to a chronic inflammatory response and resulting in detrimental effects in CF. Respiratory samples (n = 1138) were randomly collected from respiratory tract of CF patients (n = 539) during July 2018-October 2019. MCPyV-DNA detection was performed by real time PCR and positive samples were characterized by sequencing of the NCCR genomic region. The transcript levels of Toll-like receptor 9 (TLR9) and type I interferon (IFN-I) genes (IFNα, IFNß and IFNε) were examined by real-time RT-PCR assays. MCPyV-DNA was detected in 268 out of 1138 respiratory specimens (23.5%) without any difference in the prevalence of MCPyV-DNA according to age, gender or bacteriological status of CF individuals. Thirteen out of 137 CF patients remained positive for MCPyV-DNA over the time (a median follow-up period of 8.8 months). Detection of MCPyV-DNA in respiratory specimens was not associated with the occurrence of exacerbation events. Both MCPyV positive adolescents (11-24 years) and adults (≥25 years) had lower mRNA levels of TLR9, IFNß, IFNε and IFNα than the negative patients of the same age group, while MCPyV positive children produced increased levels of TLR9 and IFN-I genes (p < 0.05 for TLR9, IFNß, IFNε) with respect to the negative ones. There were significant differences in TLR9 levels (p < 0.01), but not in those of IFNs, between MCPyV-DNA positive and negative patients with S. aureus, P. aeruginosa or both. Overall, these results indicate that MCPyV-DNA is frequently detected in the respiratory samples of CF patients and might influence the expression levels of IFN-related genes in an age dependent manner. The concomitant detection of MCPyV together with S. aureus and/or P. aeruginosa correlated with alterations in TLR9 levels suggesting that virus-bacteria coinfections might contribute to affect antiviral immunity in CF patients.

Analysis of serum microRNAs and rs2910164 GC single-nucleotide polymorphism of miRNA-146a in COVID-19 patients.

Alteration of micro-RNAs (miRNAs) expression, including miRNA-122a, -146a and -205 family members, can have profound effects on inflammatory and IFN pathways (miRNA-146a), known as hallmarks of COVID-19. SARS-CoV-2-infected patients were recruited at Policlinico Umberto I Hospital of Sapienza University of Rome (Italy). MiRNA-122a, -146a, -205 and IFI27 (Interferon Alpha Inducible Protein 27) levels were screened in SARS-CoV-2 patients (n = 14) and healthy controls (n = 10) by real-time RT-PCR assays. Then, miRNA-146a rs2910164 GC single-nucleotide polymorphism (SNP) was genotyped in a larger group of COVID-19 patients (n = 129), and its relationship with severe disease [Intensive Care Unit (ICU) support or survival/death] was assessed. SARS-CoV-2-positive patients had increased PCR, D-Dimer and Fibrinogen levels compared to healthy controls (p < .05 for all measurements). MiRNA-122a and -146a serum levels were upregulated in COVID-19 patients (miRNA-122a: p = .002; miRNA-146a: p < .001). Decreased IFI27 levels were observed in COVID-19 patients with higher miRNA-146a levels (p = .047). Moreover, miRNA-146a rs2910164 C/G genotypes distributions were similar in COVID-19 patients and in validated European healthy subjects (n = 37,214). MiRNA-146a SNP was not associated with severe COVID-19 outcome (ICU or death). MiRNA-122a and -146a levels were elevated in SARS-CoV-2 infected patients, with miRNA-146a upregulation possibly contributing to IFN pathways dysregulation (e.g., reduced IFI27 levels) observed in severe COVID-19, although there is no evidence for the involvement of rs2910164 SNP.

Distribution of Interferon Lambda 4 Single Nucleotide Polymorphism rs11322783 Genotypes in Patients with COVID-19.

Type III interferons (IFN-III), also known as IFN-Lambda, have a pivotal role during SARS-CoV-2 infection. IFN-Lambda response among individuals is heterogeneous and its association with COVID-19 symptoms severity needs to be further clarified. We analyzed the genotype frequencies of IFNL4 single nucleotide polymorphism (SNP) rs11322783 in patients with COVID-19 (n = 128), in comparison with a validated data set of European healthy controls (n = 14152). The IFNL4 SNP was also analyzed according to the haematological and clinical parameters of patients with COVID-19. The distributions of IFNL4 genotypes among SARS-CoV-2 positive patients [TT/TT 41.4% (n = 53), TT/ΔG 47.7% (n = 61) and ΔG/ΔG 10.9% (n = 14)] and healthy controls were comparable. Different levels of white blood cells (p = 0.036) and neutrophils (p = 0.042) were found in the IFNL4 different genotypes in patients with COVID-19; the ΔG/ΔG genotype was more represented in the groups with low white blood cells and neutrophils. There were no differences in major inflammation parameters (C-reactive protein, D-dimer, Albumin, and Lactate-dehydrogenase (LDH)] and survival rate according to the IFNL4 genotypes. In conclusion, although patients with COVID-19 did not exhibit a different distribution of the IFNL4 SNP, the ΔG/ΔG genotype was associated with a lower count of immune cell populations. These findings need to be confirmed in larger groups of patients with COVID-19 and the role of IFNL4 SNP needs to be also investigated in other respiratory viral infections.

The Antimicrobial Peptide Esc(1-21) Synergizes with Colistin in Inhibiting the Growth and in Killing Multidrug Resistant Acinetobacter baumannii Strains.

Multidrug-resistant microbial infections and the scarce availability of new antibiotics capable of eradicating them are posing a serious problem to global health security. Among the microorganisms that easily acquire resistance to antibiotics and that are the etiological cause of severe infections, there is Acinetobacter baumannii. Carbapenems are the principal agents used to treat A. baumannii infections. However, when strains develop resistance to this class of antibiotics, colistin is considered one of the last-resort drugs. However, the appearance of resistance to colistin also makes treatment of the Acinetobacter infections very difficult. Antimicrobial peptides (AMP) from the innate immunity hold promise as new alternative antibiotics due to their multiple biological properties. In this study, we characterized the activity and the membrane-perturbing mechanism of bactericidal action of a derivative of a frog-skin AMP, namely Esc(1-21), when used alone or in combination with colistin against multidrug-resistant A. baumannii clinical isolates. We found that the mixture of the two compounds had a synergistic effect in inhibiting the growth and killing of all of the tested strains. When combined at dosages below the minimal inhibitory concentration, the two drugs were also able to slow down the microbial growth and to potentiate the membrane-perturbing effect. To the best of our knowledge, this is the first report showing a synergistic effect between AMPs, i.e., Esc(1-21), and colistin against colistin-resistant A. baumannii clinical isolates, highlighting the potential clinical application of such combinational therapy.

Alteration of type I interferon response is associated with subclinical atherosclerosis in virologically suppressed HIV-1-infected male patients.

Given human immunodeficiency virus-1 (HIV-1)-infected patients have alterations in the type I interferon (IFN-I) pathway and are also at elevated risk of atherosclerosis, we evaluated IFN-I response and subclinical cardiovascular disease (CVD) association in HIV-1-infected patients. Transcript levels of IFN-α/ß and IFN-stimulated gene 56 (ISG56) were evaluated by RT/real-time PCR in peripheral blood mononuclear cells collected from asymptomatic HIV-1-positive male patients at high risk of developing CVD (n = 34) and healthy subjects (n = 21). Stenosis degree (≥ or <50%), calcium volume score, calcium Agatston score, and myocardial extracellular volume were examined by coronary computerized tomography scan. Carotid intima-media thickness (cIMT), Framingham risk score, atherosclerotic cardiovascular disease (ASCVD) score, and risk score developed by data collection on adverse effects of anti-HIV drugs (D:A:D) were also measured. Increased IFN-α, IFN-ß, and ISG56 levels were observed in all HIV-1-infected males compared to healthy controls (p < .001 for all genes analyzed). HIV-1-infected patients with a stenosis degree ≥50% showed a higher Framingham risk score (p = .019), which was correlated with IFN-ß and ISG56 levels. HIV-1-infected males with enhanced IFN-I levels and stenosis displayed a higher ASCVD calculated risk (p = .011) and D:A:D score (p = .004). Also, there was a trend toward higher IFN-α and ISG56 mRNA levels in HIV-1-positive patients with an increased cIMT (p > .05). Dysregulation of IFN-I response might participate in the pathogenesis of HIV-1-associated CVD.

Differential induction of type I and III interferon genes in the upper respiratory tract of patients with coronavirus disease 2019 (COVID-19).

The natural course of type I and III interferon (IFN) response in the respiratory tract of COVID-19 patients needs to be better defined. We showed that type I/III IFNs, IFN-regulatory factor 7 (IRF7), and IFN stimulated genes (ISGs), are highly expressed in the oropharyngeal cells of SARS-CoV-2 positive patients compared to healthy controls. Notably, the subgroup of critically-ill patients that required invasive mechanical ventilation had a general decrease in expression of IFN/ISG genes. Heterogeneous patterns of IFN-I/III response in the respiratory tract of COVID-19 patients may be associated to COVID-19 severity.

ACE2 expression is related to the interferon response in airway epithelial cells but is that functional for SARS-CoV-2 entry?

In vitro interferon (IFN)α treatment of primary human upper airway basal cells has been shown to drive ACE2 expression, the receptor of SARS-CoV-2. The protease furin is also involved in mediating SARS-CoV-2 and other viral infections, although its association with early IFN response has not been evaluated yet. In order to assess the in vivo relationship between ACE2 and furin expression and the IFN response in nasopharyngeal cells, we first examined ACE2 and furin levels and their correlation with the well-known marker of IFNs' activation, ISG15, in children (n = 59) and adults (n = 48), during respiratory diseases not caused by SARS-CoV-2. A strong positive correlation was found between ACE2 expression, but not of furin, and ISG15 in all patients analyzed. In addition, type I and III IFN stimulation experiments were performed to examine the IFN-mediated activation of ACE2 isoforms (full-length and truncated) and furin in epithelial cell lines. Following all the IFNs treatments, only the truncated ACE2 levels, were upregulated significantly in the A549 and Calu3 cells, in particular by type I IFNs. If confirmed in vivo following IFNs' activation, the induction of the truncated ACE2 isoform only would not enhance the risk of SARS-CoV-2 infection in the respiratory tract.

SARS-CoV-2 Entry Genes Expression in Relation with Interferon Response in Cystic Fibrosis Patients.

The expression rate of SARS-CoV-2 entry genes, angiotensin-converting enzyme 2 (ACE2), the main viral receptor and the proteases, furin and transmembrane serine protease 2 (TMPRSS2) in cystic fibrosis (CF) individuals is poorly known. Hence, we examined their levels in upper respiratory samples of CF patients (n = 46) and healthy controls (n = 45). Moreover, we sought to understand the interplay of type I interferon (IFN-I) with ACE2, furin and TMPRSS2 by evaluating their gene expression with respect to ISG15, a well-known marker of IFN activation, in upper respiratory samples and after ex vivo IFNß exposure. Lower ACE2 levels and trends toward the reduction of furin and TMPRSS2 were found in CF patients compared with the healthy controls; decreased ACE2 amounts were also detected in CF individuals with pancreatic insufficiency and in those receiving inhaled antibiotics. Moreover, there was a strong positive correlation between ISG15 and ACE2 levels. However, after ex vivo IFNß stimulation of nasopharyngeal cells, the truncated isoform (dACE2), recently demonstrated as the IFN stimulated one with respect to the full-length isoform (flACE2), slightly augmented in cells from CF patients whereas in those from healthy donors, dACE2 levels showed variable levels of upregulation. An altered expression of SARS-COV-2 entry genes and a poor responsiveness of dACE2 to IFN-I stimulation might be crucial in the diffusion of SARS-CoV-2 infection in CF.

SARS-CoV-2 diagnostics in the virology laboratory of a University Hospital in Rome during the lockdown period.

Italy was one of the most affected nations by coronavirus disease 2019 outside China. The infections, initially limited to Northern Italy, spread to all other Italian regions. This study aims to provide a snapshot of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) epidemiology based on a single-center laboratory experience in Rome. The study retrospectively included 6565 subjects tested for SARS-CoV-2 at the Laboratory of Virology of Sapienza University Hospital in Rome from 6 March to 4 May. A total of 9995 clinical specimens were analyzed, including nasopharyngeal swabs, bronchoalveolar lavage fluids, gargle lavages, stools, pleural fluids, and cerebrospinal fluids. Positivity to SARS-CoV-2 was detected in 8% (527/6565) of individuals, increased with age, and was higher in male patients (P < .001). The number of new confirmed cases reached a peak on 18 March and then decreased. The virus was detected in respiratory samples, in stool and in pleural fluids, while none of gargle lavage or cerebrospinal fluid samples gave a positive result. This analysis allowed to gather comprehensive information on SARS-CoV-2 epidemiology in our area, highlighting positivity variations over time and in different sex and age group and the need for a continuous surveillance of the infection, mostly because the pandemic evolution remains unknown.

Analysis of type I IFN response and T cell activation in severe COVID-19/HIV-1 coinfection: A case report.

RATIONALE: Complex immune dysregulation in interferon (IFN) and T cell response has been observed in human immunodeficiency virus (HIV-1)-infected patients as well as in coronavirus disease-2019 (COVID-19) patients. However, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)/HIV-1 coinfection has been described in only few cases worldwide and no data are available on immunological outcomes in HIV-1-patients infected with SARS-CoV-2. Hence, this study aims to compare type I IFN response and T cell activation levels between a SARS-CoV-2/HIV-1-coinfected female patient and age-matched HIV-1-positive or uninfected women. PATIENT CONCERNS: A 52-year-old woman diagnosed with SARS-CoV-2/HIV-1 coinfection, ten HIV-1-positive women and five age-matched-healthy individuals were enrolled in this study. DIAGNOSES: SARS-CoV-2 infection caused severe pneumonia in the second week of illness in HIV-1-positive patient under protease inhibitors. Chest high-resolution computed tomography images of the SARS-CoV-2/HIV-1-coinfected patient showed bilateral ground-glass opacities. INTERVENTIONS: SARS-CoV-2/HIV-1-coinfected female patient under darunavir/cobicistat regimen received a 7-days hydroxychloroquine therapy. Analysis of IFNα/ß mRNA levels and CD4 and CD8 T cell (CD38, human leukocyte antigen-DR [HLA-DR], CD38 HLA-DR) frequencies were performed by RT/real-time PCR assays and flow cytometry, respectively. Median relative difference (MRD) was calculated for each immunological variable. For values greater than reference, MRD should be a positive number and for values that are smaller, MRD should be negative. OUTCOMES: The severe pneumonia observed in SARS-CoV-2/HIV-1-positive patient under protease inhibitors was reversed by a 7-days hydroxychloroquine therapy. At the end of treatment, on day 7, patient reported resolution of fever, normalization of respiratory rate (14 breaths/min), and improved oxygen arterial pressure with a FiO2 of 30%. MRD values for IFNα/ß and CD4 and CD8 T cells expressing CD38 and/or HLA-DR found in SARS-CoV-2-/HIV-1-coinfected woman were approximatively equal to 0 when refereed respectively to HIV-1-positive female patients [MRDs IFNα/ß: median -0.2545 (range: -0.5/0.1); T cells: median -0.11 (range: -0.8/1.3)] and ≥ 6 when referred to healthy individuals [MRDs IFNα/ß: median 28.45 (range: 15/41.9); T cells: median 10 (range 6/22)]. LESSONS: These results indicate that SARS-CoV-2 infection in HIV-1-positive female patient was associated with increased levels of IFNα/ß-mRNAs and T cell activation compared to healthy individuals.

High abundance of genus Prevotella is associated with dysregulation of IFN-I and T cell response in HIV-1-infected patients.

OBJECTIVE: HIV-1-associated dysbiosis is most commonly characterized by overall decreased diversity, with abundance of the genus Prevotella, recently related to inflammatory responses. DESIGN: A pilot study including 10 antiretroviral therapy-treated HIV-1-infected men and 50 uninfected controls was performed to identify the main gut dysbiosis determinants (e.g. Prevotella enrichment), that may affect mucosal antiviral defenses and T cell immunity in HIV-1-infected individuals. METHODS: 16rRNA gene sequencing was applied to the HIV-1-infected individuals' fecal microbiota and compared with controls. Measurements of CD4 and CD8 T cell activation [CD38, human leukocyte antigen (HLA)-DR, CD38 HLA-DR] and frequencies of Th17, obtained from lamina propria lymphocytes isolated from five different intestinal sites, were performed by flow cytometry. IFNß, IFNAR1 and MxA gene expression level was evaluated by real-time PCR in lamina propria lymphocytes. Nonparametric t tests were used for statistical analysis. RESULTS: HIV-1-infected men had a significant fecal microbial communities' imbalance, including different levels of genera Faecalibacterium, Prevotella, Alistipes and Bacteroides, compared with controls. Notably, Prevotella abundance positively correlated with frequencies of CD4 T cells expressing CD38 or HLA-DR and coexpressing CD38 and HLA-DR (P < 0.05 for all these measures). The same trend was observed for the activated CD8 T cells. Moreover, Prevotella levels were inversely correlated with IFN-I genes (P < 0.05 for IFNß, IFNAR1 and MxA genes) and the frequencies of Th17 cells (P < 0.05). By contrast, no statistically significant correlations were observed for the remaining bacterial genera. CONCLUSION: Our findings suggest that Prevotella enrichment might affect gut mucosal IFN-I pathways and T cell response in HIV-1-infected patients, thus contributing to immune dysfunction.

Differential toll like receptor expression in cystic fibrosis patients' airways during rhinovirus infection.

OBJECTIVES: Since an inappropriate and sustained activation of TLRs may contribute to a chronic inflammatory response resulting in detrimental effects in cystic fibrosis (CF) patients, we sought to examine whether HRV infection might alter the respiratory expression of TLRs according to the microbiological status of CF patients. METHODS: Respiratory samples were collected from the respiratory tract of CF patients (n = 294) over a period of 12 months. In addition to the usual microbiological investigation, HRV-RNA detection and typing were performed by RT-PCR and sequencing. HRV viral load and TLRs levels were measured by RT-Real Time PCR. RESULTS: HRV-RNA was detected in 80 out of 515 respiratory samples (15.5%) with a similar rate in all age groups (0-10 years, 11-24 years, ≥ 25 years). Patients infected with different HRV A, B and C species exhibited higher levels of TLR2, TLR4 and TLR8 as compared to HRV negative patients. Moreover, the expression level of TLR2, TLR4 and TLR8 correlated with high level of HRV viral load. HRV positive patients co-colonized by Staphylococcus aureus or Pseudomonas aeruginosa showed also enhanced amounts of TLR2 and TLR2/4-mRNAs expression respectively. In the case of presence of both bacteria, TLR2, TLR4, TLR8 and TLR9 levels are elevated in positive HRV patients. CONCLUSIONS: TLRs, especially TLR2 and TLR4, increased in HRV positive CF individuals and varies according to the presence of S. aureus, P. aeruginosa and both bacteria.

Differential interferon gene expression in bronchiolitis caused by respiratory syncytial virus-A genotype ON1.

Bronchiolitis severity is determined by a complex interaction among viral replication and antiviral immunity. The current respiratory syncytial virus (RSV)-A, genotype ON1 demonstrated a high replicative capacity but seemed to be clinically less severe than the previously circulating RSV-A, NA1. To learn insights about ON1 innate immune response, we analyzed expression levels of type I/III interferon (IFN)-related genes in the respiratory mucosa of infants with RSV bronchiolitis. We enrolled RSV-positive bronchiolitis patients over 12 epidemic seasons at a university hospital in Rome. From nasopharyngeal washings' cells (46 positive to NA1, 47 to ON1 and 28 to RSV-B, genotype BA), the mRNA copy number of the type III IFN receptor (IFNLR1 and IL10RB subunits), and of the type I/III IFN-stimulated genes, MxA and ISG56, was calculated using the threshold cycle relative quantification method with respect to an invariant gene. Expression levels of type III IFN receptor subunits genes positively correlated to each other and did not differ in infants infected with different RSV genotypes. The ISGs levels also positively correlated between them but differed among groups. MxA levels were significantly higher in NA1-infected infants than in those with ON1 and BA; ISG56 expression was slightly higher in NA1 than in the other strains. Interestingly, a moderate negative correlation existed between viral load and both ISGs values in ON1-infected infants only. The reduced ISG levels elicited during infections with ON1 (and BA) may cause a weaker control of RSV replication and/or an inadequate host immune response which may impact the risk of respiratory sequelae.

Challenges in the management of HIV infection: update on the role of probiotic supplementation as a possible complementary therapeutic strategy for cART treated people living with HIV/AIDS.

Introduction: Recent insights show that gut-mucosal immunity and intestinal microbiota play a key role in the pathogenesis of HIV infection. Alterations in the composition of intestinal flora (dysbiosis) could be associated with an impaired intestinal epithelium barrier activity and an impaired mucosal immunity function, significantly contributing to microbial translocation which is considered a major driver of chronic immune activation. Areas covered: This article provides an overview on the novel trends in probiotic therapy application. A particular emphasis is addressed to the importance of probiotics as a novel strategy to attenuate or prevent gastrointestinal involvement and to improve gut-mucosal immunity in HIV-infected subjects. Therefore, opportunities, limits and methodological criticalities of supplementation with probiotic therapy are considered and analyzed. Expert opinion: Use of probiotics is emerging as a novel strategy to manage dysbiosis and gut-mucosal impairment, to reduce immune activation and to limit a number of non-AIDS-related disorders. However, despite the growing use of probiotic therapy, mechanisms by which oral bacteria intake exhibits its effects are strain-related and disease-specific, hence clinicians need to take these two factors into consideration when suggesting probiotic supplementation to HIV-infected patients.

Merkel Cell Polyomavirus DNA Detection in Respiratory Samples: Study of a Cohort of Patients Affected by Cystic Fibrosis.

BACKGROUND: The role of Merkel cell polyomavirus (MCPyV) as a respiratory pathogen is controversial, and it is still unclear in patients with cystic fibrosis (CF). The aim of this study was to define the MCPyV prevalence and epidemiology in CF patients in order to gain new insights into the association between MCPyV infection and respiratory diseases. METHODS: A one-year study was conducted testing oropharyngeal aspirate samples from 249 and 124 CF and non-CF patients, respectively. Detection of MCPyV was carried out by nested polymerase chain reaction (PCR). Moreover, a sequence alignment to examine viral capsid protein 1 (VP1) and a phylogenetic analysis were performed. RESULTS: MCPyV DNA was detected in 65 out of 249 samples analyzed CF (26%), a percentage that was higher than that recorded in non-CF patients (0.8%). There were no statistically significant differences in MCPyV prevalence according to gender, while there was a correlation between MCPyV detection and age. Interestingly, an association between the presence of MCPyV and the concurrent isolation of Staphylococcus aureus was found. Sequence analysis of MCPyV VP1 and phylogenetic analysis revealed a 99% homology with the published sequences of these viruses in GenBank. CONCLUSIONS: Detection of MCPyV in CF patient specimens pointed out a possible interaction between the virus and CF. Further studies are necessary to fully understand the involvement of MCPyV in the pathogenesis of respiratory disorders.