Natural killer cells play an important role in virus infection control: Antiviral mechanism, subset expansion and clinical application.

With the global spread of coronavirus disease 2019 (COVID-19), the important role of natural killer (NK) cells in the control of various viral infections attracted more interest, via non-specific activation, such as antibody-dependent cell-mediated cytotoxicity (ADCC) and activating receptors, as well as specific activation, such as memory-like NK generation. In response to different viral infections, NK cells fight viruses in different ways, and different NK subsets proliferate. For instance, cytomegalovirus (CMV) induces NKG2C + CD57 + KIR+ NK cells to expand 3-6 months after hematopoietic stem cell transplantation (HSCT), but human immunodeficiency virus (HIV) induces KIR3DS1+/KIR3DL1 NK cells to expand in the acute phase of infection. However, the similarities and differences among these processes and their molecular mechanisms have not been fully discussed. In this article, we provide a summary and comparison of antiviral mechanisms, unique subset expansion and time periods in peripheral blood and tissues under different conditions of CMV, HIV, Epstein-Barr virus (EBV), COVID-19 and hepatitis B virus (HBV) infections. Accordingly, we also discuss current clinical NK-associated antiviral applications, including cell therapy and NK-related biological agents, and we state the progress and future prospects of NK cell antiviral treatment.

Vitamin D, smoking, EBV, and long-term cognitive performance in MS: 11-year follow-up of BENEFIT.

OBJECTIVE: To investigate whether vitamin D, smoking, and anti-Epstein-Barr virus (EBV) antibody concentrations predict long-term cognitive status and neuroaxonal injury in multiple sclerosis (MS). METHODS: This study was conducted among 278 patients with clinically isolated syndrome who participated in the clinical trial BENEFIT (Betaferon/Betaseron in Newly Emerging Multiple Sclerosis for Initial Treatment) and completed the 11-year assessment (BENEFIT-11). We measured serum 25-hydroxyvitamin-D (25(OH)D), cotinine (smoking biomarker), and anti-Epstein-Barr virus nuclear antigen 1 (EBNA-1) immunoglobulin G (IgG) at baseline and at months 6, 12, and 24 and examined whether these biomarkers contributed to predict Paced Auditory Serial Addition Test (PASAT)-3 scores and serum neurofilament light chain (NfL) concentrations at 11 years. Linear and logistic regression models were adjusted for sex, baseline age, treatment allocation, steroid treatment, multifocal symptoms, T2 lesions, and body mass index. RESULTS: Higher vitamin D predicted better, whereas smoking predicted worse cognitive performance. A 50-nmol/L higher mean 25(OH)D in the first 2 years was related to 65% lower odds of poorer PASAT performance at year 11 (95% confidence intervals [95% CIs]: 0.14-0.89). Standardized PASAT scores were lower in smokers and heavy smokers than nonsmokers (p trend = 0.026). Baseline anti-EBNA-1 IgG levels did not predict cognitive performance (p trend = 0.88). Associations with NfL concentrations at year 11 corroborated these findings-a 50-nmol/L higher mean 25(OH)D in the first 2 years was associated with 20% lower NfL (95% CI: -36% to 0%), whereas smokers had 20% higher NfL levels than nonsmokers (95% CI: 2%-40%). Anti-EBNA-1 antibodies were not associated with NfL. CONCLUSIONS: Lower vitamin D and smoking after clinical onset predicted worse long-term cognitive function and neuronal integrity in patients with MS.

Neutrophil-to-lymphocyte ratio as a prognostic marker in locally advanced nasopharyngeal carcinoma: A pooled analysis of two randomised controlled trials.

PURPOSE: To assess the prognostic value of neutrophil-to-lymphocyte ratio (NLR) in patients with International Union Against Cancer (UICC)-staged III/IVA,B nasopharyngeal carcinoma (NPC), who were enrolled into two randomised controlled trials of concurrent/adjuvant chemotherapy when added to radiotherapy (SQNP01), and induction chemotherapy when added to chemoradiotherapy (NCC0901). MATERIAL AND METHODS: A post hoc analysis of pooled cohorts from SQNP01 (N = 221) and NCC0901 (N = 172) was performed. We employed a threshold of pre-treatment NLR = 3.0 (median) to stratify patients. Survival outcomes were compared using log-rank test. Multivariable Cox regression analyses were performed to assess association between NLR and overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRFS). RESULTS: High NLR (≥3.0) was associated with advanced T-status (p = 0.002), N-status (p = 0.002), overall UICC stage (p = 0.004), and high pre-treatment Epstein-Barr virus DNA titre (p = 0.001). High NLR was not associated with OS (0.94 [0.67-1.32], p = 0.7), DFS (0.98 [0.73-1.33], p = 0.9), DMFS (1.02 [0.66-1.57], p = 0.9), and LRFS (1.37 [0.84-2.22], p = 0.2) on univariable and multivariable analyses, while conventional clinical indices (T-status, N-status, and overall UICC stage) were prognostic of clinical outcomes. High NLR also did not predict for a treatment effect with the experimental arms in both trials. CONCLUSION: Our pooled analyses that were confined to a homogenous patient population of locally advanced NPC do not suggest that NLR adds prognostic value to conventional clinical indices in identifying patients with unfavourable disease.

Effect of high dose vitamin C on Epstein-Barr viral infection.

Background Many natural compounds were tested for the ability to suppress viral replication. The present manuscript details an analysis of high dose vitamin C therapy on patients with EBV infection. Material and Methods The data were obtained from the patient history database at the Riordan Clinic. Among people in our database who were treated with intravenous vitamin C (7.5 g to 50 g infusions) between 1997 and 2006, 178 patients showed elevated levels of EBV EA IgG (range 25 to 211 AU) and 40 showed elevated levels of EBV VCA IgM (range 25 to 140 AU). Most of these patients had a diagnosis of chronic fatigue syndrome, with the rest being diagnosed as having mononucleosis, fatigue, or EBV infection. Results Our data provide evidence that high dose intravenous vitamin C therapy has a positive effect on disease duration and reduction of viral antibody levels. Plasma levels of ascorbic acid and vitamin D were correlated with levels of antibodies to EBV. We found an inverse correlation between EBV VCA IgM and vitamin C in plasma in patients with mononucleosis and CFS meaning that patients with high levels of vitamin C tended to have lower levels of antigens in the acute state of disease. In addition, a relation was found between vitamin D levels and EBV EA IgG with lower levels of EBV early antigen IgG for higher levels of vitamin D. Conclusions The clinical study of ascorbic acid and EBV infection showed the reduction in EBV EA IgG and EBV VCA IgM antibody levels over time during IVC therapy that is consistent with observations from the literature that millimolar levels of ascorbate hinder viral infection and replication in vitro.

Immunomodulatory effects of blood transfusions: the synergic role of soluble HLA Class I free heavy-chain molecules detectable in blood components.

BACKGROUND: Over the past decades, the weight of the published literature demonstrates that blood transfusions can induce clinically significant immunosuppression in recipients. Several studies showed significant improved clinical outcomes in the patients receiving leukoreduced transfusions, compared with control patients who received nonleukoreduced transfusions. Moreover, the immunosuppressive potential of blood products grows with the time of their storage and becomes highest in nonleukoreduced blood products stored for a long time. STUDY DESIGN AND METHODS: The interest was previously focused on the determination of immunomodulatory soluble molecules such as soluble HLA Class I (sHLA-I) and soluble Fas ligand (sFasL) in different blood components and on the evaluation of their immunomodulatory activities. On this basis, whether soluble beta2-microglobulin free HLA Class I heavy chains (sHLA-beta2fHC) could be detected and immunochemically characterized in different blood components was evaluated. Immunomodulatory activity of detectable sHLA-beta2fHC molecules was evaluated by apoptosis inducing capacity in interleukin-2-activated antigen-specific cytotoxic T lymphocytes (CTL). RESULTS: Double-determinant immunoenzymatic assay indicates that sHLA-beta2fHC levels in red blood cells stored for up to 30 days and in random-donor platelets are significantly (p < 0.001) higher than in other blood components, and the immunochemical characterization suggests that the major source of sHLA-beta2fHC molecules might be the residual white cells that undergo membrane damage during storage. Finally, allogeneic CD8+ CTL apoptosis induction confirmed biofunctionality of sHLA-beta2fHC molecules. CONCLUSION: These data are comparable with those previously reported dealing with contaminant soluble molecules in allogeneic and autologous blood components, suggesting that sHLA-beta2fHC molecules could contribute to the immunosuppressive effects of blood transfusions.