Antiviral response and immunopathogenesis of interleukin 27 in COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with a high mortality rate. The clinical course is attributed to the severity of pneumonia and systemic complications. In COVID-19 patients and murine models of SARS-CoV-2 infection, the disease may be accompanied by excessive production of cytokines, leading to an accumulation of immune cells in affected organs such as lungs. Previous reports have shown that SARS-CoV-2 infection antagonizes interferon (IFN)-dependent antiviral response, thereby preventing the expression of IFN-stimulated genes (ISGs). Lower IFN levels have been linked to more-severe COVID-19. Interleukin 27 (IL27) is a heterodimeric cytokine composed of IL27p28 and EBI3 subunits, which induce both pro- and anti-inflammatory responses. Recently, we and others have reported that IL27 also induces a strong antiviral response in an IFN-independent manner. Here, we investigated transcription levels of both IL27 subunits in COVID-19 patients. The results show that SARS-CoV-2 infection modulates TLR1/2-MyD88 signaling in PBMCs and monocytes and induces NF-κB activation and expression of NF-κB-target genes that are dependent on a robust pro-inflammatory response, including EBI3; and activates IRF1 signaling which induces IL27p28 mRNA expression. The results suggest that IL27 induces a robust STAT1-dependent pro-inflammatory and antiviral response in an IFN-independent manner in COVID-derived PBMCs and monocytes as a function of a severe clinical course of COVID-19. Similar results were observed in macrophages stimulated with the SARS-CoV-2 spike protein. Thus, IL27 can trigger an antiviral response in the host, suggesting the possibility of novel therapeutics against SARS-CoV-2 infection in humans.

Cytokine Profiling in Different SARS-CoV-2 Genetic Variants.

This study is a successor of our previous work concerning changes in the chemokine profile in infection that are associated with different SARS-CoV-2 genetic variants. The goal of our study was to take into account both the virus and the host immune system by assessing concentrations of cytokines in patients infected with different SARS-CoV-2 variants (ancestral Wuhan strain, Alpha, Delta and Omicron). Our study was performed on 340 biological samples taken from COVID-19 patients and healthy donors in the timespan between May 2020 and April 2022. We performed genotyping of the virus in nasopharyngeal swabs, which was followed by assessment of cytokines' concentration in blood plasma. We noted that out of nearly 30 cytokines, only four showed stable elevation independently of the variant (IL-6, IL-10, IL-18 and IL-27), and we believe them to be 'constant' markers for COVID-19 infection. Cytokines that were studied as potential biomarkers lose their diagnostic value as the virus evolves, and the specter of potential targets for predictive models is narrowing. So far, only four cytokines (IL-6, IL-10, IL-18, and IL-27) showed a consistent rise in concentrations independently of the genetic variant of the virus. Although we believe our findings to be of scientific interest, we still consider them inconclusive; further investigation and comparison of immune responses to different variants of SARS-CoV-2 is required.

Impacts of IL-27 and IL-32 in the pathogenesis and outcome of COVID-19 associated mucormycosis.

Changes in the immune system participate in the pathogenesis and development of infectious diseases. Previous studies have indicated immune dysregulation in patients suffering from COVID-19 and mucormycosis. Therefore, this study investigated whether interleukin-27 (IL-27) and interleukin-32 (IL-32) levels may participate in the development and outcome of COVID-19 associated mucormycosis (CAM). The blood samples were obtained from 79 patients suffering from COVID-19 and mucormycosis and 25 healthy subjects. The serum samples were isolated from the whole blood and frequencies of some immune cells were measured by a cell counter. The levels of IL-27 and IL-32 were assessed by enzyme-linked immunosorbent assay. IL-27 and IL-32 levels were significantly lower in patients with COVID-19 and mucormycosis than healthy subjects (P < .05), although there was no significant difference in IL-27 between patients with COVID-19 and CAM. IL-27 level was significantly higher in severe COVID-19 survivors than dead cases (P < .01). Patients with CAM had significant increases in NLR compared to COVID-19 patients and healthy individuals (P < .0001-0.01). NLR was significantly associated with COVID-19 outcome (P < .05). Severe COVID-19 survivors had a significant reduction in NLR compared to non-survivors (P < .05). Changes in IL-27 and IL-32 levels may contribute to the pathogenesis of CAM. IL-27 may relate to the pathogenesis and outcomes of mucormycosis in COVID-19 patients.

Predicting roles of IL-27 and IL-32 in determining the severity and outcome of COVID-19.

OBJECTIVE: Immune changes play fundamental roles in the pathogenesis and severity of coronavirus disease 2019 (COVID-19). Previous studies have revealed alterations in immune responses of patients with non-severe and severe COVID-19. Therefore, this study investigated whether interleukin-27 (IL-27) and interleukin-32 (IL-32) levels may be considered as predicting factors for determining the severity and outcome of COVID-19. METHODS: The blood samples were collected from 50 non-severe and severe patients infected with COVID-19 and 25 healthy subjects. The serum samples were isolated from the whole blood. The levels of IL-27 and IL-32 were measured by enzyme-linked immunosorbent assay and percentages of some immune cells were studied by cell counter. RESULTS: The levels of IL-27 and IL-32 were significantly higher in COVID-19 patients than healthy subjects (p < 0.0001-0.01). IL-27 was significantly reduced in severe COVID-19 patients who needed to undergo ICU therapy (p < 0.05). Disease severity was significantly associated with IL-27 level in patients with COVID-19 (p < 0.05), unlike IL-32 level. There was a significant association between IL-27 and IL-32 in participants (p < 0.0001, odds ratio (OR) = 0.9873; 95% confidence interval (CI) = 0.9998 to 1.000; p < 0.05, OR = 0.4462; 95% CI = 0.08,579 to 0.7802; p < 0.01, OR = 0.6640, 95% CI = 0.3007-0.8590). IL-27 level was significantly higher in the recovered subjects than dead cases (p < 0.0001). IL-27 and IL-32 levels in patients who had fever were significantly higher than those who did not have (p < 0.01-0.05), unlike patients who suffered from cough (p < 0.001-0.01). The IL-27 level in patients with non-severe COVID-19 was directly correlated with CRP value (p < 0.05, OR = 0.5,722,357, 95% CI = 0.06,807,176-0.8,435,928). IL-27 and IL-32 levels in non-severe patients were positively associated with NLR (p < 0.01, OR = 0.7292; 95% CI = 0.2809 to 0.9163; p < 0.01, OR = 0.6537, 95% CI = 0.1425-0.8896). Patients with severe COVID-19 had a significant increase in NLR (p < 0.0001-0.05). NLR was significantly correlated with the disease severity (p < 0.0001-0.05). Survivors had a significant reduction in NLR compared with those who succumbed to COVID-19 (p < 0.05). CONCLUSION: Change in IL-27 level along with the frequencies of some immune cells may serve as a predictor of the severity and outcome of COVID-19.

Role of Innate and Adaptive Cytokines in the Survival of COVID-19 Patients.

SARS-CoV-2 is a new coronavirus characterized by a high infection and transmission capacity. A significant number of patients develop inadequate immune responses that produce massive releases of cytokines that compromise their survival. Soluble factors are clinically and pathologically relevant in COVID-19 survival but remain only partially characterized. The objective of this work was to simultaneously study 62 circulating soluble factors, including innate and adaptive cytokines and their soluble receptors, chemokines and growth and wound-healing/repair factors, in severe COVID-19 patients who survived compared to those with fatal outcomes. Serum samples were obtained from 286 COVID-19 patients and 40 healthy controls. The 62 circulating soluble factors were quantified using a Luminex Milliplex assay. Results. The patients who survived had decreased levels of the following 30 soluble factors of the 62 studied compared to those with fatal outcomes, therefore, these decreases were observed for cytokines and receptors predominantly produced by the innate immune system-IL-1α, IL-1α, IL-18, IL-15, IL-12p40, IL-6, IL-27, IL-1Ra, IL-1RI, IL-1RII, TNFα, TGFα, IL-10, sRAGE, sTNF-RI and sTNF-RII-for the chemokines IL-8, IP-10, MCP-1, MCP-3, MIG and fractalkine; for the growth factors M-CSF and the soluble receptor sIL2Ra; for the cytokines involved in the adaptive immune system IFNγ, IL-17 and sIL-4R; and for the wound-repair factor FGF2. On the other hand, the patients who survived had elevated levels of the soluble factors TNFß, sCD40L, MDC, RANTES, G-CSF, GM-CSF, EGF, PDGFAA and PDGFABBB compared to those who died. Conclusions. Increases in the circulating levels of the sCD40L cytokine; MDC and RANTES chemokines; the G-CSF and GM-CSF growth factors, EGF, PDGFAA and PDGFABBB; and tissue-repair factors are strongly associated with survival. By contrast, large increases in IL-15, IL-6, IL-18, IL-27 and IL-10; the sIL-1RI, sIL1RII and sTNF-RII receptors; the MCP3, IL-8, MIG and IP-10 chemokines; the M-CSF and sIL-2Ra growth factors; and the wound-healing factor FGF2 favor fatal outcomes of the disease.

Heterogenous CD8+ T Cell Maturation and 'Polarization' in Acute and Convalescent COVID-19 Patients.

BACKGROUND: The adaptive antiviral immune response requires interaction between CD8+ T cells, dendritic cells, and Th1 cells for controlling SARS-CoV-2 infection, but the data regarding the role of CD8+ T cells in the acute phase of COVID-19 and post-COVID-19 syndrome are still limited. METHODS: . Peripheral blood samples collected from patients with acute COVID-19 (n = 71), convalescent subjects bearing serum SARS-CoV-2 N-protein-specific IgG antibodies (n = 51), and healthy volunteers with no detectable antibodies to any SARS-CoV-2 proteins (HC, n = 46) were analyzed using 10-color flow cytometry. RESULTS: Patients with acute COVID-19 vs. HC and COVID-19 convalescents showed decreased absolute numbers of CD8+ T cells, whereas the frequency of CM and TEMRA CD8+ T cells in acute COVID-19 vs. HC was elevated. COVID-19 convalescents vs. HC had increased naïve and CM cells, whereas TEMRA cells were decreased compared to HC. Cell-surface CD57 was highly expressed by the majority of CD8+ T cells subsets during acute COVID-19, but convalescents had increased CD57 on 'naïve', CM, EM4, and pE1 2-3 months post-symptom onset. CXCR5 expression was altered in acute and convalescent COVID-19 subjects, whereas the frequencies of CXCR3+ and CCR4+ cells were decreased in both patient groups vs. HC. COVID-19 convalescents had increased CCR6-expressing CD8+ T cells. Moreover, CXCR3+CCR6- Tc1 cells were decreased in patients with acute COVID-19 and COVID-19 convalescents, whereas Tc2 and Tc17 levels were increased compared to HC. Finally, IL-27 negatively correlated with the CCR6+ cells in acute COVID-19 patients. CONCLUSIONS: We described an abnormal CD8+ T cell profile in COVID-19 convalescents, which resulted in lower frequencies of effector subsets (TEMRA and Tc1), higher senescent state (upregulated CD57 on 'naïve' and memory cells), and higher frequencies of CD8+ T cell subsets expressing lung tissue and mucosal tissue homing molecules (Tc2, Tc17, and Tc17.1). Thus, our data indicate that COVID-19 can impact the long-term CD8+ T cell immune response.

B cells promote CD8 T cell primary and memory responses to subunit vaccines.

The relationship between B cells and CD4 T cells has been carefully studied, revealing a collaborative effort in which B cells promote the activation, differentiation, and expansion of CD4 T cells while the so-called "helper" cells provide signals to B cells, influencing their class switching and fate. Interactions between B cells and CD8 T cells are not as well studied, although CD8 T cells exhibit an accelerated contraction after certain infections in B-cell-deficient mice. Here, we find that B cells significantly enhance primary CD8 T cell responses after vaccination. Moreover, memory CD8 numbers and function are impaired in B-cell-deficient animals, leading to increased susceptibility to bacterial challenge. We also show that interleukin-27 production by B cells contributes to their impact on primary, but not memory, CD8 responses. Better understanding of the interactions between CD8 T cells and B cells may aid in the design of more effective future vaccine strategies.

Study on the Correlation between Interleukin-27 and CXCL10 in Pulmonary Tuberculosis.

Objective: To investigate the correlation between interleukin-27 and CXCL10 and other cytokines in pulmonary tuberculosis and to further explore the related miRNAs through bioinformatics. Methods: Collect the lesion tissue and peripheral blood of pulmonary tuberculosis patients and the peripheral blood of healthy controls. Immunohistochemical staining and qRT-PCR were used to observe the expression of interleukin-27, CXCL9, CXCL10, and CXCL11. Then, predict the key miRNA, qRT-PCR was used to verify the expression of miRNA in the peripheral blood and evaluated the correlation between them. Results: Both immunohistochemical staining and qRT-PCR indicated that the expressions of IL-27, CXCL9, CXCL10, and CXCL11 were significantly increased in tuberculosis patients, and IL-27 was significantly correlated with CXCL10 (r = 0.68). Key molecules such as has-let-7b-5p, has-miR-30a-3p, and has-miR-320b were screened out. Among them, has-let-7b-5p was significantly downregulated, and has-miR-30a-3p was significantly upregulated; they were related to interleukin-27 and CXCL10. Conclusion: Our data shows that interleukin-27 and CXCL10 are significantly related in pulmonary tuberculosis, and has-let-7b-5p and has-miR-30a-3p are also related to interleukin-27 and CXCL10. It laid the foundation for subsequently exploiting the potential biomarkers in tuberculosis disease.

Serial measurement of cytokines strongly predict COVID-19 outcome.

PURPOSE: Cytokines are major mediators of COVID-19 pathogenesis and several of them are already being regarded as predictive markers for the clinical course and outcome of COVID-19 cases. A major pitfall of many COVID-19 cytokine studies is the lack of a benchmark sampling timing. Since cytokines and their relative change during an infectious disease course is quite dynamic, we evaluated the predictive value of serially measured cytokines for COVID-19 cases. METHODS: In this single-center, prospective study, a broad spectrum of cytokines were determined by multiplex ELISA assay in samples collected at admission and at the third day of hospitalization. Appropriateness of cytokine levels in predicting mortality were assessed by receiver-operating characteristic (ROC) analyses for both sampling times in paralel to conventional biomarkers. RESULTS: At both sampling points, higher levels of IL-6, IL-7, IL-10, IL-15, IL-27 IP-10, MCP-1, and GCSF were found to be more predictive for mortality (p<0.05). Some of these cytokines, such as IL-6, IL-10, IL-7 and GCSF, had higher sensitivity and specificity in predicting mortality. AUC values of IL-6, IL-10, IL-7 and GCSF were 0.85 (0.65 to 0.92), 0.88 (0.73 to 0.96), 0.80 (0.63 to 0.91) and 0.86 (0.70 to 0.95), respectively at hospital admission. Compared to hospital admission, on the 3rd day of hospitalization serum levels of IL-6 and, IL-10 decreased significantly in the survivor group, unlike the non-survivor group (IL-6, p = 0.015, and IL-10, p = 0.016). CONCLUSION: Our study results suggest that single-sample-based cytokine analyzes can be misleading and that cytokine levels measured serially at different sampling times provide a more precise and accurate estimate for the outcome of COVID-19 patients.

TLR7 Ligation Inhibits TLR8 Responsiveness in IL-27-Primed Human THP-1 Monocytes and Macrophages.

Regulation of proinflammatory cytokine expression is critical in the face of single-stranded RNA (ssRNA) virus infections. Many viruses, including coronavirus and influenza virus, wreak havoc on the control of cytokine expression, leading to the formation of detrimental cytokine storms. Understanding the regulation and interplay between inflammatory cytokines is critical to the identification of targets involved in controlling the induction of cytokine expression. In this study, we focused on how the antiviral cytokine interleukin-27 (IL-27) regulates signal transduction downstream of Toll-like receptor 7 (TLR7) and TLR8 ligation, which recognize endosomal single-stranded RNA. Given that IL-27 alters bacterial-sensing TLR expression on myeloid cells and can inhibit replication of single-stranded RNA viruses, we investigated whether IL-27 affects expression and function of TLR7 and TLR8. Analysis of IL-27-treated THP-1 monocytic cells and THP-1-derived macrophages revealed changes in mRNA and protein expression of TLR7 and TLR8. Although treatment with IL-27 enhanced TLR7 expression, only TLR8-mediated cytokine secretion was amplified. Furthermore, we demonstrated that imiquimod, a TLR7 agonist, inhibited cytokine and chemokine production induced by a TLR8 agonist, TL8-506. Delineating the immunomodulatory role of IL-27 on TLR7 and TLR8 responses provides insight into how myeloid cell TLR-mediated responses are regulated during virus infection.