Predicting humoral responses to primary and booster SARS-CoV-2 mRNA vaccination in people living with HIV: a machine learning approach

BACKGROUND

SARS-CoV-2 mRNA vaccines are highly immunogenic in people living with HIV (PLWH) on effective antiretroviral therapy (ART). However, whether viro-immunologic parameters or other factors affect immune responses to vaccination is debated. This study aimed to develop a machine learning-based model able to predict the humoral response to mRNA vaccines in PLWH and to assess the impact of demographic and clinical variables on antibody production over time.

METHODS

Different machine learning algorithms have been compared in the setting of a longitudinal observational study involving 497 PLWH, after primary and booster SARS-CoV-2 mRNA vaccination. Both Generalized Linear Models and non-linear Models (Tree Regression and Random Forest) were trained and tested.

RESULTS

Non-linear algorithms showed better ability to predict vaccine-elicited humoral responses. The best-performing Random Forest model identified a few variables as more influential, within 39 clinical, demographic, and immunological factors. In particular, previous SARS-CoV-2 infection, BMI, CD4 T-cell count and CD4/CD8 ratio were positively associated with the primary cycle immunogenicity, yet their predictive value diminished with the administration of booster doses.

CONCLUSIONS

In the present work we have built a non-linear Random Forest model capable of accurately predicting humoral responses to SARS-CoV-2 mRNA vaccination, and identifying relevant factors that influence the vaccine response in PLWH. In clinical contexts, the application of this model provides promising opportunities for predicting individual vaccine responses, thus facilitating the development of vaccination strategies tailored for PLWH.

Primary HIV infection features colonic damage and neutrophil inflammation yet containment of microbial translocation

INTRODUCTION

Impairment of the gastrointestinal barrier leads to microbial translocation and peripheral immune activation, which are linked to disease progression. Data in the setting of primary HIV/SIV infection suggest that gut barrier damage is one of the first events of the pathogenic cascade, preceding mucosal immune dysfunction and microbial translocation. We assessed gut structure and immunity as well as microbial translocation in acutely and chronically-infected, combination antiretroviral therapy (cART)-naive individuals.

METHODS

Fifteen people with primary HIV infection (P-HIV) and 13 with chronic HIV infection (C-HIV) c-ART-naive participants were cross-sectionally studied. Gut biopsies were analysed in terms of gut reservoirs (total, integrated and unintegrated HIV DNA); tight junction proteins (E-cadherin, Zonula Occludens-1), CD4 + expression, neutrophil myeloperoxidase (histochemical staining); collagen deposition (Masson staining). Flow cytometry was used to assess γδ T-cell frequency (CD3 + panγδ+Vδ1+/Vδ2+). In plasma, we measured microbial translocation (LPS, sCD14, EndoCAb) and gut barrier function (I-FABP) markers (ELISA).

RESULTS

P-HIV displayed significantly higher tissue HIV DNA, yet neutrophil infiltration and collagen deposition in the gut were similar in the two groups. In contrast, microbial translocation markers were significantly lower in P-HIV compared with C-HIV. A trend to higher mucosal E-cadherin, and gut γδ T-cells was also observed in P-HIV.

CONCLUSION

Early HIV infection features higher HIV DNA in the gut, yet comparable mucosal alterations to those observed in chronic infection. In contrast, microbial translocation is contained in primary HIV infection, likely because of a partial preservation of E-cadherin and mucosal immune subsets, namely γδ T-cells.

Association between SARS-CoV-2 RNAemia, skewed T cell responses, inflammation, and severity in hospitalized COVID-19 people living with HIV

Severe COVID-19 outcomes have been reported in people living with HIV (PLWH), yet the underlying pathogenetic factors are largely unknown. We therefore aimed to assess SARS-CoV-2 RNAemia and plasma cytokines in PLWH hospitalized for COVID-19 pneumonia, exploring associations with magnitude and functionality of SARS-CoV-2-specific immune responses. Eighteen unvaccinated PLWH (16/18 on cART; median CD4 T cell count 361.5/μL; HIV-RNA<50 cp/mL in 15/18) and 18 age/sex-matched people without HIV were consecutively recruited at a median time of 10 days from symptoms onset. PLWH showed greater SARS-CoV-2 RNAemia, a distinct plasma cytokine profile, and worse respiratory function (lower PaO2/FiO2nadir), all correlating with skewed T cell responses (higher perforin production by cytotoxic T cells as well as fewer and less polyfunctional SARS-CoV-2-specific T cells), despite preserved humoral immunity. In conclusion, these data suggest a link between HIV-related T cell dysfunction and poor control over SARS-CoV-2 replication/dissemination that may in turn influence COVID-19 severity in PLWH.

Risk of COVID-19 in-hospital mortality in people living with HIV compared to general population according to age and CD4 strata: data from the ICONA network

OBJECTIVES

We aimed to study whether people living with HIV (PLWH) are at higher risk of in-hospital COVID-19 mortality compared to the general population (GenPop).

METHODS

This was a retrospective study in 19 Italian centers (February 2020 to November 2022) including hospitalized PLWH and GenPop with SARS-CoV-2 infection. The main outcome was in-hospital mortality. Competing risk analyses by Fine-Gray regression model were used to estimate the association between in-hospital mortality and HIV status/age.

RESULTS

A total of 7399 patients with COVID-19 were included, 239 (3.2%) PLWH, and 7160 (96.8%) GenPop. By day 40, in-hospital death occurred in 1283/7160 (17.9%) among GenPop and 34/239 (14.2%) among PLWH. After adjusting for potential confounders, compared to GenPop <65 years, a significantly higher risk of death was observed for GenPop ≥65 (adjusted subdistribution hazard ratio [aSHR] 1.79 [95% CI 1.39-2.31]), PLWH ≥65 (aSHR 2.16 [95% CI 1.15-4.04]), PLWH <65 with CD4 ≤200 (aSHR 9.69 [95% CI 5.50-17.07]) and PLWH <65 with CD4 201-350 (aSHR 4.37 [95% CI 1.79-10.63]), whereas no evidence for a difference for PLWH <65 with CD4 >350 (aSHR 1.11 [95% CI 0.41-2.99]).

CONCLUSIONS

In PLWH aged <65 years a CD4 ≤350 rather than HIV itself seems the driver for the observed higher risk of in-hospital mortality. We cannot however rule out that HIV infection per se is the risk factor in those aged ≥65 years.

SARS-CoV-2 mRNA Vaccine Response in People Living with HIV According to CD4 Count and CD4/CD8 Ratio

BACKGROUND

Our aim was to estimate the rates of not achieving a robust/above-average humoral response to the COVID-19 mRNA vaccine in people living with HIV (PLWH) who received ≥2 doses and to investigate the role of the CD4 and CD4/CD8 ratio in predicting the humoral response.

METHODS

We evaluated the humoral anti-SARS-CoV-2 response 1-month after the second and third doses of COVID-19 mRNA vaccine as a proportion of not achieving a robust/above-average response using two criteria: (i) a humoral threshold identified as a correlate of protection against SARS-CoV-2 (<90% vaccine efficacy): anti-RBD < 775 BAU/mL or anti-S < 298 BAU/mL, (ii) threshold of binding antibodies equivalent to average neutralization activity from the levels of binding (nAb titer < 1:40): anti-RBD < 870 BAU/mL or anti-S < 1591 BAU/mL. PLWH were stratified according to the CD4 count and CD4/CD8 ratio at first dose. Logistic regression was used to compare the probability of not achieving robust/above-average responses. A mixed linear model was used to estimate the mean anti-RBD titer at various time points across the exposure groups.

RESULTS

a total of 1176 PLWH were included. The proportions of participants failing to achieve a robust/above-average response were significantly higher in participants with a lower CD4 and CD4/CD8 ratio, specifically, a clearer gradient was observed for the CD4 count. The CD4 count was a better predictor of the humoral response of the primary cycle than ratio. The third dose was pivotal in achieving a robust/above-average humoral response, at least for PLWH with CD4 > 200 cells/mm3 and a ratio > 0.6.

CONCLUSIONS

A robust humoral response after a booster dose has not been reached by 50% of PLWH with CD4 < 200 cells mm3. In the absence of a validated correlate of protections in the Omicron era, the CD4 count remains the most solid marker to guide vaccination campaigns in PLWH.

Six-month immune responses to mRNA-1273 vaccine in combination antiretroviral therapy treated late presenter people with HIV according to previous SARS-CoV-2 infection

OBJECTIVE

Immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in people with HIV (PWH) with a history of late presentation (LP) and their durability have not been fully characterized.

DESIGN

In this prospective, longitudinal study, we sought to assess T-cell and humoral responses to SARS-CoV-2 mRNA vaccination up to 6 months in LP-PWH on effective combination antiretroviral therapy (cART) as compared to HIV-negative healthcare workers (HCWs), and to evaluate whether previous SARS-CoV-2 infection modulates immune responses to vaccine.

METHODS

SARS-CoV-2 spike (S)-specific T-cell responses were determined by two complementary flow cytometry methodologies, namely activation-induced marker (AIM) assay and intracellular cytokine staining (ICS), whereas humoral responses were measured by ELISA [anti-receptor binding domain (RBD) antibodies) and receptor-binding inhibition assay (spike-ACE2 binding inhibition activity), before vaccination (T0), 1 month (T1) and 5 months (T2) after the second dose.

RESULTS

LP-PWH showed at T1 and T2 significant increase of: S-specific memory and circulating T follicular helper (cTfh) CD4 + T cells; polyfunctional Th1-cytokine (IFN-γ, TNF-α, IL-2)- and Th2-cytokine (IL-4)-producing S-specific CD4 + T cells; anti-RBD antibodies and spike-ACE2 binding inhibition activity. Immune responses to vaccine in LP-PWH were not inferior to HCWs overall, yet S-specific CD8 + T cells and spike-ACE2 binding inhibition activity correlated negatively with markers of immune recovery on cART. Interestingly, natural SARS-CoV-2 infection, while able to sustain S-specific antibody response, seems less efficacious in inducing a T-cell memory and in boosting immune responses to vaccine, possibly reflecting an enduring partial immunodeficiency.

CONCLUSIONS

Altogether, these findings support the need for additional vaccine doses in PWH with a history of advanced immune depression and poor immune recovery on effective cART.

Immunologic Interplay Between HIV/AIDS and COVID-19: Adding Fuel to the Flames?

PURPOSE OF REVIEW

HIV/AIDS and COVID-19 have been the major pandemics overwhelming our times. Given the enduring immune disfunction featuring people living with HIV (PLWH) despite combination antiretroviral therapy (cART), concerns for higher incidence and severity of SARS-CoV-2 infection as well as for suboptimal responses to the newly developed vaccines in this population arose early during the pandemics. Herein, we discuss the complex interplay between HIV and SARS-CoV-2, with a special focus on the immune responses to SARS-CoV-2 natural infection and vaccination in PLWH.

RECENT FINDINGS

Overall, current literature shows that COVID-19 severity and outcomes may be worse and immune responses to infection or vaccination lower in PLWH with poor CD4 + T-cell counts and/or uncontrolled HIV viremia. Data regarding the risk of post-acute sequelae of SARS-CoV-2 infection (PASC) among PLWH are extremely scarce, yet they seem to suggest a higher incidence of such condition. Scarce immunovirological control appears to be the major driver of weak immune responses to SARS-CoV-2 infection/vaccination and worse COVID-19 outcomes in PLWH. Therefore, such individuals should be prioritized for vaccination and should receive additional vaccine doses. Furthermore, given the potentially higher risk of developing long-term sequelae, PLWH who experienced COVID-19 should be ensured a more careful and prolonged follow-up.

Gut-dependent inflammation and alterations of the intestinal microbiota in individuals with perinatal HIV exposure and different HIV serostatus

OBJECTIVE

HIV-exposed infected (HEI) and uninfected (HEU) children represent the two possible outcomes of maternal HIV infection. Modifications of the intestinal microbiome have been linked to clinical vulnerability in both settings, yet whether HEI and HEU differ in terms of gut impairment and peripheral inflammation/activation is unknown.

DESIGN

We performed a cross-sectional, pilot study on fecal and plasma microbiome as well as plasma markers of gut damage, microbial translocation, inflammation and immune activation in HIV-infected and uninfected children born from an HIV-infected mother.

METHODS

Fecal and plasma microbiome were determined by means of 16S rDNA amplification with subsequent qPCR quantification. Plasma markers were quantified via ELISA.

RESULTS

Forty-seven HEI and 33 HEU children were consecutively enrolled. The two groups displayed differences in fecal beta-diversity and relative abundance, yet similar microbiome profiles in plasma as well as comparable gut damage and microbial translocation. In contrast, monocyte activation (sCD14) and systemic inflammation (IL-6) were significantly higher in HEI than HEU.

CONCLUSION

In the setting of perinatal HIV infection, enduring immune activation and inflammation do not appear to be linked to alterations within the gut. Given that markers of activation and inflammation are independent predictors of HIV disease progression, future studies are needed to understand the underlying mechanisms of such processes and elaborate adjuvant therapies to reduce the clinical risk in individuals with perinatal HIV infection.

Gamma-Delta T-Cell Phenotype and Function in DAA-Treated HIV-HCV Co-Infected and HCV-Mono-Infected Subjects

HIV-HCV co-infected subjects are at risk of liver fibrosis which may be linked to immune imbalances. Direct-acting antivirals (DAAs) represent the mainstay of HCV treatment in co-infected individuals, yet their effects on immune cell populations playing a role in fibrogenesis is unknown. We assessed γδ T-cell phenotype and function, Treg and Th17 frequencies, as well as γ-globulins and B-cell activation in 47 HIV-HCV co-infected and 35 HCV mono-infected individuals prior to and following DAA treatment (SVR12). Γδ T-cell activation decreased in both groups yet persisted at higher levels in the HIV-HCV co-infected subjects. No differences were registered in terms of γδT-cell function. Of note, the Vδ2/Th17 ratio, inversely linked to liver damage, increased significantly in the two groups upon treatment, yet a negative correlation between the Vδ2/Th17 ratio and liver function enzymes was found in the co-infected subjects alone. B-cell activation and γ-globulin levels decreased in both settings, yet B-cell activation remained higher in the HIV-HCV co-infected individuals. In HIV-HCV co-infected and HCV mono-infected participants, the effect of DAA was limited to γδ T- and B-cell activation as well as γ-globulin concentrations and the Vδ2/Th17 ratio, with no changes in γδ T-cell function and Treg frequencies. Importantly, γδ T- and B-cell activation remained at higher levels in the co-infected individuals than in those with HCV mono-infection alone. The persistence of such alterations within these cell subsets may be associated with the risk of hepatic and extrahepatic complications.

Failure of CD4+ T-cell Recovery upon Virally-Effective cART: an Enduring Gap in the Understanding of HIV+ Immunological non-Responders

The introduction of cART in the treatment of HIV infection has significantly decreased morbidity and mortality by inducing suppression of viral replication and recovery of CD4+ T-cell counts. How- ever, about 30% of HIV-infected individuals fail to achieve normalization of CD4+ T-cell counts, de- spite antiretroviral therapy and complete suppression of the HIV load: these patients are referred to as "immunological non-responders". Several studies have shown an increased risk of clinical pro- gression to both AIDS and non-AIDS events as well as a higher mortality in these patients. The pathogenetic factors underlying this condition are multiple and none of these alone can exhaustive- ly explain the mechanism of incomplete immune reconstitution. In light of this, the purpose of the present review is to: i) describe in detail the pathogenetic mechanisms that contribute to scarce immune recovery; ii) discuss the higher morbidity and mortality which feature such a condition; iii) take stock of therapeutic strategies used in recent years for these patients.

Hallmarks of Severe COVID-19 Pathogenesis: A Pas de Deux Between Viral and Host Factors

Two years into Coronavirus Disease 2019 (COVID-19) pandemic, a comprehensive characterization of the pathogenesis of severe and critical forms of COVID-19 is still missing. While a deep dysregulation of both the magnitude and functionality of innate and adaptive immune responses have been described in severe COVID-19, the mechanisms underlying such dysregulations are still a matter of scientific debate, in turn hampering the identification of new therapies and of subgroups of patients that would most benefit from individual clinical interventions. Here we review the current understanding of viral and host factors that contribute to immune dysregulation associated with COVID-19 severity in the attempt to unfold and broaden the comprehension of COVID-19 pathogenesis and to define correlates of protection to further inform strategies of targeted therapeutic interventions.

Persistence of High Peripheral Activated CD8+ T-cells and Not a Low CD4:CD8 Ratio Predict cytologic HPV-Related Dysplasia in cART-Treated, HIV-Positive Subjects

Background

People with HIV are at increased risk of HPV-disease progression, given the persistence of immune activation and residual inflammation despite effective cART. Whether a low CD4:CD8 T-cell ratio, known to mirror peripheral immune dysfunction, associates with Squamous Intraepithelial Lesions (SIL) is unknown.

Methods

Retrospective cohort study on cART-treated HIV-positive subjects undergoing screening for HPV-related dysplasia (anal/cervical cytology and HPV genotyping). SIL was defined as the presence of either atypical squamous cells of undetermined significance (ASCUS), Low-grade SIL or High-grade SIL. Demographic and viro-immunological parameters (T-cell count, CD4:CD8 T-cell ratio, CD8+CD38+ T-cells percentage) at the time of screening were analyzed by Chi square, Mann Whitney test and multivariate logistic regression analysis.

Results

419 cART-treated subjects were included. Half of the patients had cervical/anal SIL. Individuals with SIL were more commonly males, MSM, co-infected with Treponema pallidum, treated with Integrase Inhibitors (INSTI)-based cART regimens and with a shorter time since HIV diagnosis and cART initiation than subjects with normal cytology. CD38+CD8+ T-cells percentage, but not the CD4:CD8 T-cell ratio, correlated with SIL. HPV infection, especially with multiple and high-risk genotypes, was confirmed associated with SIL. In multivariate analysis, the only factors independently associated with cervical/anal dysplasia were HPV infection and harbouring higher percentages of peripheral activated CD38+CD8+ T-cells.

Conclusions

HPV infection is the major driver of dysplasia in the setting of HIV infection. CD8+CD38+ T-cells also resulted an independent predictor of dysplasia in cART-treated subjects, while the CD4:CD8 T-cell ratio did not. In the setting of HIV-HPV co-infection, the CD4:CD8 T-cell ratio may not fully capture the alterations of HPV-specific immunity.

Female gender is associated with long COVID syndrome: a prospective cohort study

Objective

We explored the association between female gender and long COVID syndrome, defined as persistence of physical and/or psychological symptoms for more than 4 weeks after recovery from acute COVID-19 disease. The secondary aim was to identify predictors of long COVID syndrome by multivariable logistic regression analysis.

Methods

This was a single-centre prospective cohort study conducted at San Paolo Hospital in Milan, Italy. We enrolled adult patients who were evaluated at the post-COVID outpatient service of our Infectious Diseases Unit between 15 April 2020 and 15 December 2020. Participants were individuals who had clinically recovered from COVID-19 and in whom virological clearance had occurred. Previous infection by SARS-CoV-2 was microbiologically documented by positivity using a reverse-transcriptase polymerase chain reaction (RT-PCR) assay of nasopharyngeal swab. All enrolled patients underwent blood tests and a comprehensive medical examination at follow-up. Individuals were interviewed about resolved and persisting symptoms and were asked to fill in two questionnaires to allow assessment of the Hospital Anxiety and Depression symptoms (HADS) score and of the Impact of Event Scale–Revised (IES-R) score.

Results

A total of 377 patients were enrolled in the study. The median time from symtpom onset to virological clerance was 44 (37–53) days. A diagnosis of long COVID syndrome was made in 260/377 (69%) patients. The most common reported symptoms were fatigue (149/377, 39.5%), exertional dyspnoea (109/377, 28.9%), musculoskeletal pain (80/377, 21.2%) and “brain fog” (76/377, 20.2%). Anxiety symptoms were ascertained in 71/377 (18.8%) individuals, whereas 40/377 (10.6%) patients presented symptoms of depression. Post-traumatic stress disorder (defined by a pathological IES-R score) was diagnosed in one-third of patients (85/275, 31%). Female gender was independently associated with long COVID syndrome at multivariable analysis (AOR 3.3 vs. males, 95% CI 1.8–6.2, p < 0.0001). Advanced age (adjusted (A)OR 1.03 for 10 years older, 95% CI 1.01–1.05, p 0.01) and active smoking (AOR 0.19 for former smokers vs. active smokers, 95% CI 0.06–0.62, p 0.002) were also associated with a higher risk of long COVID, while no association was found between severity of disease and long COVID (AOR 0.67 for continuous positive airway pressure (CPAP)/non-invasive mechanical ventilation (NIMV)/orotracheal intubation (OTI) vs. no 02 therapy, 95% CI 0.29–1.55, p 0.85).

Discussion

Factors that were found to be associated with a higher risk of developing “long COVID” syndrome were female gender, older age and active smoking, but not severity of the acute disease. Individuals affected by SARS-CoV-2 infection with the aforementioned features should be early identified and involved in follow-up programmes.

Predictors of low ovarian reserve in cART-treated women living with HIV

Ovarian dysfunction and lower circulating anti-Müllerian hormone (AMH) feature women living with HIV (WLWH). Because treated human immunodeficiency virus (HIV) infection is characterized by a pro-inflammatory/oxidative phenotype resulting in residual comorbidity, we sought to investigate possible associations between plasma AMH and markers of inflammation, immune activation/senescence/exhaustion, oxidative stress as well as comorbidities in a cohort of combined anti-retroviral therapy (cART)-treated WLWH versus age-matched HIV-uninfected, healthy women.Eighty WLWH on effective cART aged 25 to 50 years and 66 age-matched healthy women were enrolled. We measured: plasma AMH, IL-6, reactive oxygen species modulator 1 (ROMO1) (ELISA); plasma tumor necrosis factor α, IL-10, soluble vascular cell adhesion molecule 1, osteopontin (Luminex); CD4/CD8 activation (CD38/CD69), apoptosis (CD95), exhaustion (PD1), maturation (CD45RA/CD45R0/CD127/CCR7), recent thymic emigrants (CD31/CD103) (flow cytometry). Mann Whitney and chi-squared tests were used. Univariate and multivariate logistic regression analyses were used to assess factors associated with low AMH (≤1 ng/mL).Compared to healthy women, WLWH were more frequently non-Caucasian, drug/alcohol abusers, with history of late menarche, lower hormonal contraceptive use, with higher gravidity and lower parity. WLWH showed significantly lower AMH (P = .004) as well as higher ROMO1 (P = .0003) and tumor necrosis factor α (P < .0001). The multivariate analyses revealed ROMO1 (adjusted odds ratio [AOR]: 1.42, P = .03) and HIV infection (AOR: 8.1, P = .0001) as independently associated with low AMH. The logistic regression model with both HIV status and ROMO1 (a marker of oxidative stress) confirmed HIV as the only predictor of low AMH (AOR: 17, P = .0003).Despite effective cART, WLWH showed lower AMH compared to age-matched peers, indicating pre-mature ovarian ageing. Both HIV and oxidative stress are independently associated with low AMH, emphasizing the impact of HIV-associated oxidative stress on reproductive aging.

Declining Mortality Rate of Hospitalised Patients in the Second Wave of the COVID-19 Epidemics in Italy: Risk Factors and the Age-Specific Patterns

BACKGROUND

Mortality rate from COVID-19 in Italy is among the world's highest. We aimed to ascertain whether there was any reduction of in-hospital mortality in patients hospitalised for COVID-19 in the second-wave period (October 2020-January 2021) compared to the first one (February-May 2020); further, we verified whether there were clusters of hospitalised patients who particularly benefitted from reduced mortality rate.

METHODS

Data collected related to in-patients' demographics, clinical, laboratory, therapies and outcome. Primary end-point was time to in-hospital death. Factors associated were evaluated by uni- and multivariable analyses. A flow diagram was created to determine the rate of in-hospital death according to individual and disease characteristics.

RESULTS

A total of 1561 patients were included. The 14-day cumulative incidence of in-hospital death by competing risk regression was of 24.8% (95% CI: 21.3-28.5) and 15.9% (95% CI: 13.7-18.2) in the first and second wave. We observed that the highest relative reduction of death from first to second wave (more than 47%) occurred mainly in the clusters of patients younger than 70 years.

CONCLUSIONS

Progress in care and supporting therapies did affect population over 70 years to a lesser extent. Preventive and vaccination campaigns should focus on individuals whose risk of death from COVID-19 remains high.

A Quantitative Estimate of the Expected Shortening of the Median Isolation Period of Patients With COVID-19 After the Adoption of a Symptom-Based Strategy

A long period of isolation was observed in patients hospitalized for COVID-19 in Milan over March-September 2020 (45; IQR: 37–54 days). A significantly shorter period would have been observed by the application of May-WHO (22, IQR: 17–30 days, P < 0.001) and October-Italian (26, IQR: 21–34 days, P < 0.001) Guidelines. The adoption of the new symptom-based criteria is likely to lead to a significant reduction in the length of the isolation period with potential social, economic and psychological benefits, particularly in the younger population with mild/moderate disease and no comorbidities. In our opinion, the release from isolation after 21 days from symptoms onset, even without a PCR diagnostic test, in most cases seems the most adequate strategy that could balance precautions to prevent SARS CoV-2 transmission and unnecessary prolonged isolation or overuse of diagnostic testing.

Long-Term Suppressive cART Is Not Sufficient to Restore Intestinal Permeability and Gut Microbiota Compositional Changes

Background: We explored the long-term effects of cART on markers of gut damage, microbial translocation, and paired gut/blood microbiota composition, with a focus on the role exerted by different drug classes.

Methods: We enrolled 41 cART naïve HIV-infected subjects, undergoing blood and fecal sampling prior to cART (T0) and after 12 (T12) and 24 (T24) months of therapy. Fifteen HIV-uninfected individuals were enrolled as controls. We analyzed: (i) T-cell homeostasis (flow cytometry); (ii) microbial translocation (sCD14, EndoCab, 16S rDNA); (iii) intestinal permeability and damage markers (LAC/MAN, I-FABP, fecal calprotectin); (iv) plasma and fecal microbiota composition (alpha- and beta-diversity, relative abundance); (v) functional metagenome predictions (PICRUSt).

Results: Twelve and twenty four-month successful cART resulted in a rise in EndoCAb (p = 0.0001) and I-FABP (p = 0.039) vis-à-vis stable 16S rDNA, sCD14, calprotectin and LAC/MAN, along with reduced immune activation in the periphery. Furthermore, cART did not lead to substantial modifications of microbial composition in both plasma and feces and metabolic metagenome predictions. The stratification according to cART regimens revealed a feeble effect on microbiota composition in patients on NNRTI-based or INSTI-based regimens, but not PI-based regimens.

Conclusions: We hereby show that 24 months of viro-immunological effective cART, while containing peripheral hyperactivation, exerts only minor effects on the gastrointestinal tract. Persistent alteration of plasma markers indicative of gut structural and functional impairment seemingly parallels enduring fecal dysbiosis, irrespective of drug classes, with no effect on metabolic metagenome predictions.

The importance of patients' case-mix for the correct interpretation of the hospital fatality rate in COVID-19 disease

OBJECTIVE

We aimed to document data on the epidemiology and factors associated with clinical course leading to death of patients hospitalised with COVID-19.

METHODS

Prospective observational cohort study on patients hospitalised with COVID-19 disease in February-24th/May-17th 2020 in Milan, Italy. Uni-multivariable Cox regression analyses were performed. Death's percentage by two-weeks' intervals according to age and disease severity was analysed.

RESULTS

A total of 174/539 (32.3%) patients died in hospital over 8228 person-day follow-up; the 14-day Kaplan-Meier probability of death was 29.5% (95%CI: 25.5-34.0). Older age, burden of comorbidities, COVID-19 disease severity, inflammatory markers at admission were independent predictors of increased risk, while several drug-combinations were predictors of reduced risk of in-hospital death. The highest fatality rate, 36.5%, occurred during the 2nd-3rd week of March, when 55.4% of patients presented with severe disease, while a second peak, by the end of April, was related to the admission of older patients (55% ≥80 years) with less severe disease, 30% coming from long-term care facilities.

CONCLUSIONS

The unusual fatality rate in our setting is likely to be related to age and the clinical conditions of our patients. These findings may be useful to better allocate resources of the national healthcare system, in case of re-intensification of COVID-19 epidemics.

Disappearance of Electrocardiographic Abnormalities Associated with the Arrhythmic Pattern of a Barlow Disease After Surgical Mitral Valve Repair

We describe the case of a 46-year old female with a Barlow's disease (MVP) characterized by systolic curling of posterior left ventricular (LV) wall + significant mitral annular disjunction + complex ventricular arrhythmias + syncope + inverted T waves in inferolateral leads in whom a successful surgical mitral valve rapair determined the disappearance not only of the echocardiographic but also the electrocar-diographic abnormalities (in particular the inferolateral T waves inversion on basal electrocardiogram and the complex basal arrhythmic pattern). This case demonstrates that electrocardiographic abnormalities may disappear after the surgical correction of the mechanical stretch imposed on the inferior LV free wall by the prolapsing mitral valve leaflets. Electrocardiographic changes remain an important and easy marker to recognize for the identification of a high-risk subgroup of MVP patients.

Glyoxalase I polymorphism: gene frequencies in two Italian populations

The gene frequencies for human red cell glyoxalase I have been determined in 1,222 unrelated subjects from two areas of Central Italy (Rome and Viareggio). No significant difference has been found between the two samples. Therefore the data have been pooled. The cumulative GLO1 gene frequency estimate is 0.376 +/- 0.010. This gene frequency is comparable to that reported for another sample from Rome and very similar to that found in Naples while it is significantly lower than those reported for Northern Italy (Milan and Genoa) and for the Northern European Caucasian populations studied so far.