Molecular monitoring of viral infections in immunocompromised patients in a large university hospital in Italy: reflections after thirteen years of real-life activity.

PURPOSE: This study aimed to investigate the prevalence and viral reactivations of clinical interest in the immunocompromised patient with particular focus on hematologic and solid organ transplant recipients. METHODS: Molecular screening data of CMV, EBV, JCV and BKV from 2011 to 2023 were analyzed. This extensive time span allowed the access to more than 100,000 samples from over 20,000 patients treated at Policlinico Umberto I. It was possible to temporally investigate patient attendance patterns, average age distribution, seasonality of infections, and positivity rates of the analyzed viruses. RESULTS: Between 2019 and 2022 a significant reduction in organ transplants performed and in the positive molecular detection of EBV, JCV and BKV was observed. Additionally, there has been a noteworthy decrease in CMV reactivations, with a reduction of up to 50% starting in 2019. A remarkable reduction of 39% in the rate of CMV viral reactivation has been also achieved in SOT between 2016 and 2023. CONCLUSION: The years following 2019 were profoundly impacted by the COVID-19 pandemic era. This period resulted in a substantial reduction in healthcare services and hospital visits. Furthermore, the introduction of the drug Letermovir in Italy in 2019 demonstrated remarkable efficacy, evidenced by a reduction in CMV reactivations. Additionally, the adoption of a novel clinical approach centered on personalized therapy facilitated improved management of immunocompromised patients.

Torque teno virus (TTV): A gentle spy virus of immune status, predictive marker of seroconversion to COVID-19 vaccine in kidney and lung transplant recipients.

To date, no comprehensive marker to monitor the immune status of patients is available. Given that Torque teno virus (TTV), a known human virome component, has previously been identified as a marker of immunocompetence, it was retrospectively investigated whether TTV viral load may also represent a marker of ability to develop antibody in response to COVID-19-BNT162B2 vaccine in solid organ transplant recipients (SOT). Specifically, 273 samples from 146 kidney and 26 lung transplant recipients after successive doses of vaccine were analyzed. An inverse correlation was observed within the TTV copy number and anti-Spike IgG antibody titer with a progressive decrease in viremia the further away from the transplant date. Analyzing the data obtained after the second dose, a significant difference in TTV copy number between responsive and nonresponsive patients was observed, considering a 5 log10 TTV copies/mL threshold to discriminate between the two groups. Moreover, for 86 patients followed in their response to the second and third vaccination doses a 6 log10 TTV copies/mL threshold was used to predict responsivity to the booster dose. Although further investigation is necessary, possibly extending the analysis to other patient categories, this study suggests that TTV can be used as a good marker of vaccine response in transplant patients.

SARS-COV-2 vaccination with BNT162B2 in renal transplant patients: Risk factors for impaired response and immunological implications.

Solid organ transplant patients are at a higher risk for poor CoronaVirus Disease-2019 (COVID-19)-related outcomes and have been included as a priority group in the vaccination strategy worldwide. We assessed the safety and efficacy of a two-dose vaccination cycle with mRNA-based COVID-19 vaccine (BNT162b2) among 82 kidney transplant outpatients followed in our center in Rome, Italy. After a median of 43 post-vaccine days, a SARS-CoV-2 anti-Spike seroprevalence of 52.4% (n = 43/82) was observed. No impact of the vaccination on antibody-mediated rejection or graft function was observed, and no significant safety concerns were reported. Moreover, no de novo HLA-donor-specific antibodies (DSA) were detected during the follow-up period. Only one patient with pre-vaccination HLA-DSA did not experience an increased intensity of the existing HLA-DSA. During the follow-up, only one infection (mild COVID-19) was observed in a patient after receiving the first vaccine dose. According to the multivariable logistic regression analysis, lack of seroconversion after two-dose vaccination independently associated with patient age ≥60 years (OR = 4.50; P = .02) and use of anti-metabolite as an immunosuppressant drug (OR = 5.26; P = .004). Among younger patients not taking anti-metabolites, the seroconversion rate was high (92.9%). Further larger studies are needed to assess the best COVID-19 vaccination strategy in transplanted patients.

Quality of T-Cell Response to SARS-CoV-2 mRNA Vaccine in ART-Treated PLWH.

We investigated specific humoral and T-cell responses in people living with HIV (PLWH) before (T0), after two (T1) and after six months (T2) from the third dose of the BNT162b2 vaccine. Healthy donors (HD) were enrolled. The specific humoral response was present in most PLWH already after the second dose, but the third dose increased both the rate of response and its magnitude. Collectively, no significant differences were found in the percentage of responding T-cells between PLWH and HD. At T0, stratifying PLWH according to CD4 cell count, a lower percentage of responding T-cells in <200 cells/µL subgroup compared to >200 cells/µL one was observed. At T1, this parameter was comparable between the two subgroups, and the same result was found at T2. However, the pattern of co-expression of IFNγ, IL2 and TNFα in PLWH was characterized by a higher expression of TNFα, independently of CD4 cell count, indicating a persistent immunological signature despite successful ART. mRNA vaccination elicited a specific response in most PLWH, although the cellular one seems qualitatively inferior compared to HD. Therefore, an understanding of the T-cell quality dynamic is needed to determine the best vaccination strategy and, in general, the capability of immune response in ART-treated PLWH.

KSHV dysregulates bulk macroautophagy, mitophagy and UPR to promote endothelial to mesenchymal transition and CCL2 release, key events in viral-driven sarcomagenesis.

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of KS, an aggressive neoplasm that mainly occurs in immune-compromised patients. Spindle cells represent the main feature of this aggressive malignancy and arise from KSHV-infected endothelial cells undergoing endothelial to mesenchymal transition (EndMT), which changes their cytoskeletal composition and organization. As in epithelial to mesenchymal transition (EMT), EndMT is driven by transcription factors such as SNAI1 and ZEB1 and implies a cellular reprogramming mechanism regulated by several molecular pathways, particularly PI3K/AKT/MTOR. Here we found that KSHV activated MTOR and its targets 4EBP1 and ULK1 and reduced bulk macroautophagy and mitophagy to promote EndMT, activate ER stress/unfolded protein response (UPR), and increase the release of the pro-angiogenic and pro-inflammatory chemokine CCL2 by HUVEC cells. Our study suggests that the manipulation of macroautophagy, mitophagy and UPR and the interplay between the three could be a promising strategy to counteract EndMT, angiogenesis and inflammation, the key events of KSHV-driven sarcomagenesis.

Impact of HHV-6A and HHV-6B lytic infection on autophagy and endoplasmic reticulum stress.

Herpesviruses are known to manipulate autophagy to optimize their replication, counteract immune response and probably to promote tumourigenesis. This study explored, for the first time, the impact of human herpesvirus (HHV)-6 lytic infection on autophagy and demonstrated that HHV-6A and B (viruses sharing more than 80 % homology) differently affected this cellular process. Indeed, while HHV-6A (GS) infection of HSB2 cells promoted autophagy, HHV-6B (Z29) or the virus isolated from the serum of roseola infantum-affected patient-inhibited autophagy in Molt-3 cells or in PBMCs, respectively. Interestingly, the different behaviour of HHV-6A and B on the autophagic process was accompanied by different effects on endoplasmic reticulum stress, unfolded protein response and cell survival that was more strongly reduced by HHV-6B infection. We hypothesize that the ability to inhibit autophagy displayed by HHV-6B could be due to the fact that it contains gene homologues of those encoding for TRS1; the protein responsible for the block of autophagy by human cytomegalovirus. Understanding how HHV-6A/B infection regulates autophagy could be of particular interest, as it has been recently shown that this virus may be involved in Alzheimer's disease in which a dysregulation of autophagy may also play a role.

Early collection of saliva specimens from Bell's palsy patients: quantitative analysis of HHV-6, HSV-1, and VZV.

Bell's palsy is the most common cause of facial paralysis. Although it has been associated with diabetes mellitus, hypertension, pregnancy, and preeclampsia, the etiology of Bell's palsy remains unknown. The reactivation of latent herpes simplex virus (HSV) or varicella-zoster virus (VZV) with subsequent inflammation and entrapment of the facial nerve in the narrow labyrinthine segment has been implicated as a cause of facial paralysis, but the active role of these viruses in Bell's palsy is still discussed. This study quantified HSV-1 DNA, VZV DNA, and HHV-6 DNA in 95 saliva samples collected from patients within 48 hr from the onset of paralysis. HSV-1, VZV, and HHV-6 were detected in 13%, 3%, and 61% of patients, respectively. The detection rate did not differ significantly between patients and a control group of healthy donors. Interestingly, however, the value of HHV-6 DNA copies was significantly higher than that detected in healthy donors. In addition, the mean value of HHV-6 DNA recorded in patients who had at least a one grade improvement of palsy at the first visit was significantly lower than that detected in patients who showed no change in facial palsy grade or an increase of at least one grade. These findings call into question the role of HSV-1 and VZV in the etiology of Bell's palsy, and suggest that HHV-6 may be involved in the development of the disease or that the underlying disease mechanism might predispose patients to HHV-6 reactivation.

Anti-N SARS-CoV-2 assays for evaluation of natural viral infection.

BACKGROUND: The 2019 coronavirus (COVID-19) epidemic, required the development of different diagnostic tests. While reverse transcriptase real-time PCR (RT-PCR) remains the first-line test of choice in acute infection diagnosis, anti-N antibodies serological assays provide a valuable tool to differentiate natural SARS-CoV-2 immunological response from that induced by vaccination, thus the goal of our study was to evaluate three serological tests agreement for these antibodies detection. METHODS: Three anti-N different tests were examined in 74 sera from patients referred or not COVID infection: immunochromatographic rapid test (Panbio™ COVID-19 IgG/IgM Rapid Test Device Abbott, Germany), ELISA kit (NovaLisa® SARS-CoV-2 IgG and IgM NovaTech Immunodiagnostic GmbH, Germany) and ECLIA immunoassay (Elecsys® Anti-SARS-CoV-2 Roche Diagnostics, Manheim, Germany). RESULTS: Qualitative comparison of the three analytical methods revealed a moderate agreement between ECLIA immunoassay and immunochromatographic rapid test (Cohen kappa coefficient κ = 0.564). Correlation analysis indicated weak positive correlation between total Ig (IgT) detected by ECLIA immunoassay and IgG by ELISA test (p < 0.0001), the analysis of ECLIA IgT and IgM ELISA detected, showed no statistical correlation. CONCLUSION: Comparison between of three analytical systems available for anti-N SARS-CoV-2 IgG and IgM antibodies showed a general agreement when compared to detect total and G class immunoglobulins, while doubtful or discordant results have been highlighted for IgT and IgM class. Anyway, all the tests examined provide reliable results to assess the serological status of SARS-CoV-2 infected patients.

The inhibition of IRE1alpha/XBP1 axis prevents EBV-driven lymphomagenesis in NSG mice.

IMPORTANCE: The novelty of this study lies in the fact that it shows that IRE1 alpha endoribonuclease inhibition by 4µ8C was able to counteract Epstein-Barr virus-driven lymphomagenesis in NOD SCID gamma mice and prevent B-cell immortalization in vitro, unveiling that this drug may be a promising therapeutic approach to reduce the risk of post-transplant lymphoproliferative disorders (PTLD) onset in immune-deficient patients. This hypothesis is further supported by the fact that 4µ8C impaired the survival of PTLD-like cells derived from mice, meaning that it could be helpful also in the case in which there is the possibility that these malignancies have begun to arise.

EBV infection of primary colonic epithelial cells causes inflammation, DDR and autophagy dysregulation, effects that may predispose to IBD and carcinogenesis.

EBV is a gammaherpesvirus strongly associated to human cancer. The virus has been shown to play a role also in inflammatory diseases, including IBD, in the context of which colon cancer more frequently arise. In this study, we show for the first time that EBV infects primary colonic epithelial cells (HCoEpC), promotes pro-inflammatory cytokine secretion and activates molecular pathways bridging inflammation and cancer, such as ERK1/2. These effects, occurring in the course of the lytic phase of the viral life cycle, led to DDR and autophagy dysregulation. Such cellular responses, playing a key role in the maintenance of proteostasis and genome integrity, are essential to prevent carcinogenesis. Interestingly, we found that the use of the demethylating agent 5-AZA could counteract most of the effects induced by EBV infection in HCoEpC, suggesting that DNA hyper-methylation may strongly contribute to viral-driven inflammation and colon cancer predisposition.

Differential expression of Type I interferon and inflammatory genes in SARS-CoV-2-infected patients treated with monoclonal antibodies.

INTRODUCTION: Considering the reported efficacy of monoclonal antibodies (mAbs) directed against the Spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in reducing disease severity, the aim of this study was to investigate the innate immune response before and after mAbs treatment in 72 vaccinated and 31 unvaccinated SARS-CoV-2 patients. METHODS: The mRNA levels of IFN-I, IFN-related genes and cytokines were evaluated using RT/real-time quantitative PCR. RESULTS: Vaccinated patients showed increased rate of negative SARS-CoV-2 PCR tests on nasopharyngeal swab compared with unvaccinated ones after mAbs treatment (p = .002). Unvaccinated patients had lower IFN-α/ω and higher IFN-related genes (IFNAR1, IFNAR2, IRF9, ISG15, ISG56 and IFI27) and cytokines (IL-6, IL-10 and TGF-ß) mRNA levels compared to vaccinated individuals before mAbs (p < .05 for all genes). Increased IFN-α/ω, IFNAR1, IFNAR2 and IRF9 levels were observed in unvaccinated patients after mAbs treatment, while the mRNA expression ISGs and IL-10 were reduced in all patients. CONCLUSION: These data suggest that anti-S vaccinated patients have increased levels of innate immune genes compared to unvaccinated ones. Also, gene expression changes in IFN genes after mAbs administration are different according to the vaccination status of patients.

The dysregulation of autophagy and ER stress induced by HHV-6A infection activates pro-inflammatory pathways and promotes the release of inflammatory cytokines and cathepsin S by CNS cells.

HHV-6A is a neurotropic herpesvirus able to infect several CNS cells including astrocytes and primary neurons. Here we found that HHV-6A infection of astrocytoma cells, by reducing autophagy, increased ROS and induced ER stress, promoting the release of inflammatory cytokines such as IL-6 and IL-1ß and activating pathways such as STAT3, NF-kB and mTOR. Moreover, HHV-6A infection increased the production of CXCL13, a B lymphocyte attracting chemokine, whose recruitment in the CNS could further enhance neuroinflammation. Interestingly, HHV-6A also increased the release of cathepsin S by infected astrocytoma cells as well as by primary neurons. As this enzyme is involved in the degradation of MBP, this effect could contribute to the onset/progression of MS, a neurodegenerative disease that, besides inflammation, is characterized by a progressive demyelination process. In conclusion, this study unveils new molecular mechanisms through which HHV-6A may promote important aspects involved in several neurodegenerative diseases.

DNA damage triggers an interplay between wtp53 and c-Myc affecting lymphoma cell proliferation and Kaposi sarcoma herpesvirus replication.

The induction of DNA damage together with the interference with DNA repair represents a promising strategy in cancer treatment. Here we show that the PARP-1/2/3 inhibitor AZD2461 in combination with the CHK1 inhibitor UCN-01 altered the DNA damage response and reduced cell proliferation in PEL cells, an aggressive B cell lymphoma highly resistant to chemotherapies. AZD2461/UCN-01 combination activated p53/p21 and downregulated c-Myc in these cells, leading to a reduced expression level of RAD51, molecule involved in DNA repair. The effect of AZD2461/UCN-01 on c-Myc and p53/p21 was inter-dependent and, besides impairing cell proliferation, contributed to the activation of the replicative cycle of KSHV, carried in a latent state in PEL cells. Finally, we found that the pharmacological or genetic inhibition of p21 counteracted the viral lytic cycle activation and further reduced PEL cell proliferation, suggesting that it could induce a double beneficial effect in this setting. This study unveils that, therapeutic approaches, based on the induction of DNA damage and the reduction of DNA repair, could be used to successfully treat this malignant lymphoma.

Susceptibility towards Chickenpox, Measles and Rubella among Healthcare Workers at a Teaching Hospital in Rome.

Immunization is the best protection against chickenpox, measles and rubella. It is important to identify and immunize susceptible healthcare workers to prevent and control hospital infections. Our aim was to estimate the susceptibility level of healthcare workers at a Teaching Hospital in Rome concerning these diseases and the factors associated to the susceptibility. Methods: a cross sectional study was carried out at the Department of Occupational Medicine of the Umberto I General Hospital of Rome. Participants were recruited during routine occupational health surveillance. As far as inclusion criteria, the following professionals were considered: doctors, nurses, laboratory technicians and other health professionals. Concerning the exclusion criteria, patients with HIV, cancer and diseases of the immune system, and acute illness or fever more than 38.5 °C, were not included in the study. A blood sample was tested for the presence of antibodies against measles, rubella and chicken pox. Results: 1106 healthcare professionals were involved in the study (41.8% nurses, 30.4% doctors, 12.3% laboratory technicians, 15.1% other health professionals): 25 (2.3%), 73 (6.6%) and 35 (3.2%) of these were susceptible to measles, rubella and chicken pox, respectively. The only variable associated with susceptibility of measles was age (p < 0.001). Furthermore, there was evidence of an association between various susceptibilities, particularly between measles and chickenpox (OR: 4.38). Conclusion: this study showed that even if the majority of our healthcare professionals are immunized for MRV, it is necessary not to underestimate the seronegativity of non-immune ones. All health professionals should be vaccinated to ensure safety for patients, especially the weakest.

Multiple sclerosis-disease modifying therapies affect humoral and T-cell response to mRNA COVID-19 vaccine.

Background: The mRNA vaccines help protect from COVID-19 severity, however multiple sclerosis (MS) disease modifying therapies (DMTs) might affect the development of humoral and T-cell specific response to vaccination. Methods: The aim of the study was to evaluate humoral and specific T-cell response, as well as B-cell activation and survival factors, in people with MS (pwMS) under DMTs before (T0) and after two months (T1) from the third dose of vaccine, comparing the obtained findings to healthy donors (HD). All possible combinations of intracellular IFNγ, IL2 and TNFα T-cell production were evaluated, and T-cells were labelled "responding T-cells", those cells that produced at least one of the three cytokines of interest, and "triple positive T-cells", those cells that produced simultaneously all the three cytokines. Results: The cross-sectional evaluation showed no significant differences in anti-S antibody titers between pwMS and HD at both time-points. In pwMS, lower percentages of responding T-cells at T0 (CD4: p=0.0165; CD8: p=0.0022) and triple positive T-cells at both time-points compared to HD were observed (at T0, CD4: p=0.0007 and CD8: p=0.0703; at T1, CD4: p=0.0422 and CD8: p=0.0535). At T0, pwMS showed higher plasma levels of APRIL, BAFF and CD40L compared to HD (p<0.0001, p<0.0001 and p<0.0001, respectively) and at T1, plasma levels of BAFF were still higher in pwMS compared to HD (p=0.0022).According to DMTs, at both T0 and T1, lower anti-S antibody titers in the depleting/sequestering-out compared to the enriching-in pwMS subgroup were found (p=0.0410 and p=0.0047, respectively) as well as lower percentages of responding CD4+ T-cells (CD4: p=0.0394 and p=0.0004, respectively). Moreover, the depleting/sequestering-out subgroup showed higher percentages of IFNγ-IL2-TNFα+ T-cells at both time-points, compared to the enriching-in subgroup in which a more heterogeneous cytokine profile was observed (at T0 CD4: p=0.0187; at T0 and T1 CD8: p =0.0007 and p =0.0077, respectively). Conclusion: In pwMS, humoral and T-cell response to vaccination seems to be influenced by the different DMTs. pwMS under depleting/sequestering-out treatment can mount cellular responses even in the presence of a low positive humoral response, although the cellular response seems qualitatively inferior compared to HD. An understanding of T-cell quality dynamic is needed to determine the best vaccination strategy and in general the capability of immune response in pwMS under different DMT.

Infectious risk in multiple sclerosis patients treated with disease-modifying therapies: A three-year observational cohort study.

BACKGROUND: The disease-modifying therapies (DMTs) largely used in multiple sclerosis (MS) may result in higher infectious risk. OBJECTIVE: We aimed to investigate the infectious risk in DMT-treated MS patients. METHODS: MS patients were evaluated for infectious risk before starting, switching or during DMT. RESULTS: In this three-year observational cohort study 174 MS patients were enrolled. Among them, 18 patients were anti-HBc + and 19 patients were QuantiFERON®-TB Gold In-Tube (QFT) + . No patients with anti-HBc + showed a detectable HBV-DNA and all started DMT. Among QTB + patients, 17 latent TB infections (LTBIs) and 2 active TB infections (TBIs) were identified. After one month of LTBI prophylaxis or TB treatment, respectively, all patients started DMTs.Overall, 149 started DMTs. During DMTs, one ocrelizumab-treated patient with anti-HBc + developed HBV reactivation and six patients (3 on natalizumab, 2 on ocrelizumab and 1 on IFN-ß) showed reactivation of HSV-1, with detectable plasma DNA. Finally, 1 cladribine-treated patient experienced VZV reactivation. All the reactivations of latent infections have been successfully treated. CONCLUSION: Screening of infectious diseases in DMT candidate MS patients helps to mitigate the infectious risk. During DMTs, a regular assessment of infectious risk allows to avoid discontinuing MS therapy and guarantees a higher degree of safety.

Evaluation of Immunogenicity to Three Doses of the SARS-CoV-2 BNT162b2 mRNA Vaccine in Lung Transplant Patients.

The aim of the study was to explore the humoral and T-cell response in lung transplant (LuT) patients. Two-time points were considered, before (T0) and after (Tpost) the third dose of the BNT162b2 mRNA vaccine, comparing LuT with healthy donors (HD). LuT patients showed a lower serologic response against SARS-CoV-2 compared with HD at both time-points (p = 0.0001 and p = 0.0011, respectively). A lower percentage of IFNγ+orIL2+orTNFα+CD4+ and CD8+ T-cells LuT patients was observed in LuT patients compared with HD at T0 (CD4+: p = 0.0001; CD8+: p = 0.0005) and Tpost (CD4+: p = 0.0028; CD8+: p = 0.0114), as well as in the percentage of IFNγ+IL2+TNFα+CD4+ T-cells (T0: p = 0.0247; Tpost: p = 0.0367). Finally, at Tpost, a lower percentage of IFNγ+IL2+TNFα+ CD8+ T-cells in LuT patients compared with HD was found (p = 0.0147). LuT patients were stratified according to the lowest cut-off value for the detection of a humoral response (4.81 BAU/mL) at T0, into responder (R) and non-responder (NR) groups. In the R group, no differences in the percentage of IFNγ+or IL2+orTNFα+ and IFNγ+IL2+TNFα+CD4+ and CD8+ T-cells compared with HD at both time-points were observed. Otherwise, in the NR group, lower percentages of IFNγ+IL2+TNFα+CD4+ T-cells compared with the R group (T0: p = 0.0159; Tpost: p = 0.0159), as well as compared with the HD, at both time-points, were observed (T0: p = 0.0064; Tpost: p = 0.0064). These data seem to confirm that some LuT patients can mount cellular responses even in the absence of a positive humoral response (>33.8 BAU/mL), although this cellular response is dysfunctional and partially detrimental.

Viral Acute Anterior Uveitis: Clinical Signs Useful for Differential Diagnosis.

Purpose: To assess the frequency of clinical signs in patients with viral acute anterior uveitis (AAU), and their ability to differentiate viral versus non-viral AAU.Methods: 168 patients with AAU, including 84 with presumed viral etiology, were evaluated. Sensitivity, specificity, area under the curve (AUC), positive and negative predictive value were calculated for each clinical sign. The model built with these parameters was tested on a validation group comprising 66 patients with AAU.Results: The most useful clinical signs were unilaterality (sensitivity: 98.8%, specificity: 57.1%), intraocular pressure (IOP) ≥24 mmHg (sensitivity: 68.7%, specificity: 91.7%), and the association between the two (sensitivity: 68.7%, specificity: 95.2%). In the validation group, the model built with these parameters presented AUC of 0.939. Adding iris atrophy AUC increased to 0.97. Considering these signs, it was possible to diagnose viral uveitis in 93.9% of the patients.Conclusion: Unilaterality, IOP≥24 mmHg and iris atrophy are significant predictors of possible viral etiology in AAU.

The cross-talk between STAT1/STAT3 and ROS up-regulates PD-L1 and promotes the release of pro-inflammatory/immune suppressive cytokines in primary monocytes infected by HHV-6B.

Programmed death ligand 1 (PD-L1) up-regulation on antigen presenting cells induces T cell dysfunction, strongly impairing immune response. Human Herpesviruses (HHV) 6B is a ß-herpesvirus that, although displays a higher tropism for T cells, can infect other immune cells including monocytes and dendritic cells (DCs) and neuronal cells. We have previously shown that HHV-6B infection of primary monocytes reduced autophagy and induced Endoplasmic Reticulum (ER) stress/ Unfolded Protein Response (UPR), impairing their survival and differentiation into DCs. In this study, we found that PD-L1 expression was up-regulated by HHV-6B on the surface of infected monocytes and that its extracellular release also increased, effects known to lead to an impairment of anti-viral immune response. At molecular level, PD-L1 up-regulation correlated with the activation of a positive regulatory circuit between the increase of intracellular ROS and the activation of STAT1 and STAT3 induced by HHV-6B, accompanied by a high release of pro-inflammatory/immune suppressive cytokines. In conclusion, this study unveils new strategies put in place by HHV-6B to induce immune dysfunction and the underlying molecular pathways that could be targeted to counteract such immune suppressive effects.

Human herpesvirus-8-positive primary effusion lymphoma in HIV-negative patients: Single institution case series with a multidisciplinary characterization.

BACKGROUND: Primary effusion lymphoma (PEL) is a very rare non-Hodgkin lymphoma caused by human herpesvirus-8 (HHV8) that grows in liquid phase within body cavities. The diagnosis of PEL is based on cytology but requires confirmatory ancillary tests. PEL occurs mainly in association with HIV infection. This study describes 9 cases of PEL in HIV-negative patients and compares their characteristics with 10 HIV-associated cases of PEL diagnosed at a single institution in Italy between 1995 and 2019. METHODS: Clinical records were reviewed for demographic data, comorbidities, laboratory abnormalities, and outcome. PEL samples were evaluated for cytomorphology, immunophenotype, immunoglobulin (IG)/T cell receptor (TR) rearrangements, and HHV8 and Epstein-Barr virus (EBV) viral loads in effusion supernatants. RESULTS: HIV-unrelated PEL occurred in 8 elderly patients (7 men, 1 woman) and 1 young adult with primary antibody deficiency. Cytology revealed HHV8-positive lymphoma cells lacking B/T cell antigens and exhibiting 2 cell patterns (polymorphous or monotonous). IG was clonally rearranged in all cases; aberrant TRG occurred in 2 cases. Effusion supernatants had more than 106 HHV8 DNA copies per mL and variable loads of EBV DNA. Compared with HIV-associated PEL, the HIV-negative cohort was characterized by older age, less frequent association with Kaposi sarcoma and/or multicentric Castleman disease, comparable but less abnormal laboratory parameters, and a nonsignificant survival benefit. PEL cases with low apoptosis were associated with better prognosis. CONCLUSION: To the best of our knowledge, our case series of HIV-unrelated PEL is the largest thus far, expands the spectrum of cytological findings, and supports the need for a multidisciplinary approach in the diagnostic workup.