Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent for coronavirus 2019 (COVID-19) pneumonia. Little is known about the kinetics, tissue distribution, cross-reactivity, and neutralization antibody response in patients with COVID-19. Two groups of patients with RT-PCR–confirmed COVID-19 were enrolled in this study: 12 severely ill patients in intensive care units who needed mechanical ventilation and 11 mildly ill patients in isolation wards. Serial clinical samples were collected for laboratory detection. Results showed that most of the severely ill patients had viral shedding in a variety of tissues for 20–40 days after onset of disease (8/12, 66.7%), while the majority of mildly ill patients had viral shedding restricted to the respiratory tract and had no detectable virus RNA 10 days after onset (9/11, 81.8%). Mildly ill patients showed significantly lower IgM response compared with that of the severe group. IgG responses were detected in most patients in both the severe and mild groups at 9 days after onset, and remained at a high level throughout the study. Antibodies cross-reactive to SARS-CoV and SARS-CoV-2 were detected in patients with COVID-19 but not in patients with MERS. High levels of neutralizing antibodies were induced after about 10 days after onset in both severely and mildly ill patients which were higher in the severe group. SARS-CoV-2 pseudotype neutralization test and focus reduction neutralization test with authentic virus showed consistent results. Sera from patients with COVID-19 inhibited SARS-CoV-2 entry. Sera from convalescent patients with SARS or Middle East respiratory syndrome (MERS) did not. Anti–SARS-CoV-2 S and N IgG levels exhibited a moderate correlation with neutralization titers in patients’ plasma. This study improves our understanding of immune response in humans after SARS-CoV-2 infection.

Influenza remains one of the major epidemic diseases worldwide, and rapid virus replication and collateral lung tissue damage caused by excessive pro-inflammatory host immune cell responses lead to high mortality rates. Thus, novel therapeutic agents that control influenza A virus (IAV) propagation and attenuate excessive pro-inflammatory responses are needed. Polysaccharide extract from Radix isatidis, a traditional Chinese herbal medicine, exerted potent anti-IAV activity against human seasonal influenza viruses (H1N1 and H3N2) and avian influenza viruses (H6N2 and H9N2) in vitro. The polysaccharides also significantly reduced the expression of pro-inflammatory cytokines (IL-6) and chemokines (IP-10, MIG, and CCL-5) stimulated by A/PR/8/34 (H1N1) at a range of doses (7.5 mg/mL, 15 mg/mL, and 30 mg/mL); however, they were only effective against progeny virus at a high dose. Similar activity was detected against inflammation induced by avian influenza virus H9N2. The polysaccharides strongly inhibited the protein expression of TLR-3 induced by PR8, suggesting that they impair the upregulation of pro-inflammatory factors induced by IAV by inhibiting activation of the TLR-3 signaling pathway. The polysaccharide extract from Radix isatidis root therefore has the potential to be used as an adjunct to antiviral therapy for the treatment of IAV infection.

Background: Anti-interferon-γ autoantibody (AIGA) positivity is an emerging immunodeficiency syndrome closely associated with intracellular infection in individuals without human immunodeficiency virus (HIV). However, the information on epidemiology, pathogen spectrum, and immunotherapy among these patients lack a systematic description of large data.Methods: This systematic literature review and multicenter retrospective study aimed to describe the pathogen spectrum and review treatment strategies among patients with AIGA positivity.Results: We included 810 HIV-negative patients with AIGA positivity infected with one or more intracellular pathogens. Excluding four teenagers, all the patients were adults. The most common pathogen was nontuberculous mycobacteria (NTM) (676/810, 83.5%). A total of 765 NTM isolates were identified in 676 patients with NTM, including 342 (44.7%) rapid-grower mycobacteria, 273 (35.7%) slow-grower mycobacteria, and 150 (19.6%) unidentified NTM subtype. Even with long-term and intensive antimicrobial treatments, 42.6% of patients with AIGA positivity had recurrence and/or persistent infection. Sixty-seven patients underwent immunoregulatory or immunosuppressive therapy, and most (60) achieved remission. The most common treatment strategy was rituximab (27/67, 40.3%) and cyclophosphamide (22/67, 32.8%), followed by cyclophosphamide combined with glucocorticoids (8/67, 11.9%).Conclusions: Intracellular pathogen was the most common infection in patients with AIGA positivity. The predominant infection phenotypes were NTM, varicella-zoster virus, Talaromyces marneffei, and Salmonella spp., with or without other opportunistic infections. AIGA immunotherapy, including rituximab or cyclophosphamide, has yielded good preliminary results in some cases.

Talaromyces marneffei is an emerging pathogen, and the number of infections in HIV-negative individuals is rapidly increasing. Nevertheless, there is no sufficient comprehensive report on this issue, and awareness needs to be raised among clinicians. We analyzed the differences in the clinical data of patients who are HIV-negative and HIV-positive with Talaromyces marneffei infection (TMI) from 2018 to 2022. A total of 848 patients were included, among whom 104 were HIV-negative. The obvious differences between the HIV-positive and HIV-negative groups were as follows: (i) the patients who are HIV-negative were older and more likely to exhibit cough and rash, (ii) the time in days from symptom onset to diagnosis among patients who are HIV-negative was longer, (iii) the laboratory findings and radiological presentations seemed more severe in patients who are HIV-negative, (iv) differences were observed regarding the underlying conditions and co-infection pathogens, and correlation analysis showed that correlations existed for many indicators, (v) and persistent infection was more likely to occur in patients who are HIV-negative. TMI in patients who are HIV-negative differs from that in patients who are HIV-positive in many aspects, and more investigations are needed. Clinicians should be more aware of TMI in patients who are HIV-negative.

Ban-Lan-Gen (BLG) is a traditional Chinese herbal medicine. It has been used for the prevention and treatment of virus-related respiratory diseases such as influenza virus infection. BLG contains some antiviral compounds, but few evidence-based clinical studies have been conducted to assess its efficacy against influenza. We assessed the effects of BLG (including efficacy and safety) on the treatment of seasonal influenza in an evidence-based clinical trial. We conducted a randomized, double-blinded, oseltamivir- and placebo-controlled, parallel-design clinical trial. A total of 177 subjects are going to be recruited after satisfying the criteria: (i) 18 to 65 years of age; (ii) illness onset within 36 h; (3) axillary temperature ≥38.0°C; and (iv) positive influenza (type A/B) virus test. Subjects will be assigned randomly into three groups in equal proportions: oseltamivir treatment, BLG granule treatment, and placebo treatment. Each group receives 5-day treatment and is followed up 1, 3, 5, 7 and 21 days later. Symptoms and patient compliance are recorded, and virus/serum viral antibodies tested. We will use the primary outcome, secondary outcome, and safety indicators to evaluate the efficacy and safety of BLG granules in the treatment of seasonal influenza. We have described the first clinical trial for treatment using a single herb against influenza A and B viruses in China. We will hold a large-scale clinical trial to comprehensively evaluate the effectiveness and safety of BLG against influenza infection based on the results of this pilot study. And this clinical trial will serve as an example for the study of other traditional herbal medicines in evidence-based clinical trials. This study has been registered at ClinicalTrials.gov: NCT02232945 (3 September 2014).