Objective The aim of this study was to analyze the clinical, radiologic, and biological features associated with human herpesvirus 6 (HHV-6) encephalitis in immunocompetent and immunocompromised hosts to establish which clinical settings should prompt HHV-6 testing. Methods We performed a retrospective research in the virology database of Fondazione IRCCS Policlinico San Matteo (Pavia, Italy) for all patients who tested positive for HHV-6 DNA in the CSF and/or in blood from January 2008 to September 2018 and separately assessed the number of patients meeting the criteria for HHV-6 encephalitis in the group of immunocompetent and immunocompromised hosts. Results Of the 926 patients tested for HHV-6 during the period of interest, 45 met the study criteria. Among immunocompetent hosts (n = 17), HHV-6 encephalitis was diagnosed to 4 infants or children presenting with seizures or mild encephalopathy during primary HHV-6 infection (CSF/blood replication ratio <1. Conclusions The detection of a CSF/blood replication ratio >1 represented a specific feature of immunocompromised patients with HHV-6 encephalitis and could be of special help to establish a diagnosis of HHV-6 encephalitis in hematopoietic stem cell transplant recipients lacking radiologic evidence of limbic involvement.

The role of immunosuppression in SARS-CoV-2-related disease (COVID-19) is a matter of debate. We here describe the course and the outcome of COVID-19 in a cohort of patients undergoing treatment with calcineurin inhibitors. In this monocentric cohort study, data were collected from the COVID-19 outbreak in Italy up to 28 April 2020. Patients were followed at our hospital for solid organ transplantation or systemic rheumatic disorders (RMDs) and were on calcineurin inhibitor (CNI)-based therapy. Selected patients were referred from the North of Italy. The aim of our study was to evaluate the clinical course of COVID-19 in this setting. We evaluated 385 consecutive patients (220 males, 57%; median age 61 years, IQR 48–69); 331 (86%) received solid organ transplantation and 54 (14%) had a RMD. CNIs were the only immunosuppressant administered in 47 patients (12%). We identified 14 (4%) COVID-19 patients, all transplanted, mainly presenting with fever (86%) and diarrhea (71%). Twelve patients were hospitalized and two of them died, both with severe comorbidities. No patients developed acute respiratory distress syndrome or infectious complications. The surviving 10 patients are now fully recovered. The clinical course of COVID-19 patients on CNIs is generally mild, and the risk of superinfection seems low.

The development and persistence of SARS-CoV-2-specific immune response in immunocompetent (IC) and immunocompromised patients is crucial for long-term protection. Immune response to SARS-CoV-2 infection was analysed in 57 IC and 15 solid organ transplanted (TX) patients. Antibody responses were determined by ELISA and neutralization assay. T-cell response was determined by stimulation with peptide pools of the Spike, Envelope, Membrane, and Nucleocapsid proteins with a 20-h Activation Induced Marker (AIM) and 7-day lymphoproliferative assays. Antibody response was detected at similar levels in IC and TX patients. Anti-Spike IgG, IgA and neutralizing antibodies persisted for at least one year, while anti-Nucleocapsid IgG declined earlier. Patients with pneumonia developed higher antibody levels than patients with mild symptoms. Similarly, both rapid and proliferative T-cell responses were detected within the first two months after infection at comparable levels in IC and TX patients, and were higher in patients with pneumonia. T-cell response persisted for at least one year in both IC and TX patients. Spike, Membrane, and Nucleocapsid proteins elicited the major CD4⁺ and CD8⁺ T-cell responses, whereas the T-cell response to Envelope protein was negligible. After SARS-CoV-2 infection, antibody and T-cell responses develop rapidly and persist over time in both immunocompetent and transplanted patients.

The guidelines on ventilator-associated pneumonia (VAP) recommend an empiric therapy against methicillin-resistant Staphylococcus aureus (MRSA) according to its prevalence rate. Considering the MRSA and MSSA VAP prevalence over the last 9 years in our tertiary care hospital, we assessed the clinical value of the MRSA nasal-swab screening in either predicting or ruling out MRSA VAP. We extracted the data of 1461 patients with positive bronchoalveolar lavage (BAL). Regarding the MRSA nasal-swab screening, 170 patients were positive for MRSA or MSSA. Overall, MRSA had a high prevalence in our ICU. Despite the COVID-19 pandemic, there was a significant downward trend in MRSA prevalence, while MSSA remained steady over time. Having VAP due to MRSA did not have any impact on LOS and mortality. Finally, the MRSA nasal-swab testing demonstrated a very high negative predictive value for MRSA VAP. Our results suggested the potential value of a patient-centered approach to improve antibiotic stewardship.

The clinical course of COVID-19 in patients undergoing chronic immunosuppressive therapy is yet poorly known. We performed a monocentric cross-sectional study describing the clinical course of COVID-19 in a cohort of patients from northern Italy treated with calcineurin-inhibitors for organ transplantation or rheumatic diseases. Data were collected by phone call and clinical chart review between March 27^th- 31^st2020. COVID-19 related symptoms, rynopharingeal swab, therapeutic changes and outcome were assessed in 384 consecutive patients (57% males; median age 61 years, IQR 48-69). 331 patients (86%) received solid organ transplantation (kidney n=140, 36%, heart n=100, 26%, lung n=91, 24%) and 53 (14%) had a rheumatic disease. Calcineurin inhibitors were the only immunosuppressant administered in 46 patients (12%). 14 patients developed a “confirmed COVID-19” (swab positivity) and 14 a “clinical COVID-19” (only typical symptoms). Fever (75%) and diarrhoea (50%) were the most common symptoms. Fourteen patients were hospitalized and 11 have already been dismissed. No patient required start/changes of the O2 therapy or developed superinfection. Only one patient, with metastatic lung cancer, died. In conclusion, COVID-19 showed a mild course in our cohort, with low mortality. Calcineurin inhibitor-based immunosuppressive regimens appear safe in this context and should not be discontinued.

Cutaneous infections caused by dematiaceous fungi are rare in the general population but are increasingly recognized in solid organ transplant recipients as a consequence of prolonged immunosuppression. When Alternaria species are confirmed as the causative agents of a skin infection, the condition is referred to as alternariosis. These infections may clinically resemble bacterial or neoplastic lesions and require accurate diagnosis and individualized therapy. We report one case of cutaneous alternariosis in a kidney transplant recipient receiving tacrolimus-based immunosuppression. The patient was a 47-year-old woman who sustained minor trauma to her knee three months after transplantation. She developed an ulcerated, crusted lesion, which coincided with severe neutropenia. Histology, culture and molecular identification confirmed A. infectoria. Treatment included systemic azole therapy (voriconazole followed by isavuconazole) and surgical excision, resulting in resolution without recurrence. This case highlights the importance of early recognition of alternariosis in transplant recipients. Successful management typically requires combined surgical and systemic antifungal therapy, with careful monitoring of drug interactions and immunosuppressive levels to prevent toxicity or rejection.