Interleukin-18 and tumor necrosis factor-α are elevated in solid organ transplant recipients with possible cytomegalovirus end-organ disease

Cytomegalovirus antigen-specific multi-cytokine immune responses in patients with rheumatic diseases under different cytomegalovirus infection status: A case-control study

OBJECTIVE

To explore Cytomegalovirus (CMV) antigen-specific multi-cytokine immune responses in patients with rheumatic disease (RD) under different CMV infection status.

METHODS

A total of 60 RD patients in our center from March 2023 to August 2023 were enrolled. The patients were divided into latent CMV infection and active CMV infection, the latter was classified as subclinical CMV infection or CMV disease based on presence or absence of symptoms related to CMV. Whole blood was collected and stimulated with QuantiFERON-CMV antigen. The levels of IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, IL-17 and CXCL-2 in supernatant were measured by Luminex Assays. The receiver operating characteristic curve was used to evaluate the diagnostic accuracy of cytokine for distinguishing different CMV infection status.

RESULTS

The proportion of patients with severe lymphopenia was lowest in the latent CMV infection group, while there were no significant differences in medication usage in different CMV infection status. After stimulation with QF-CMV antigens, the levels of IFN-γ, TNF-α and IL-2 in the CMV disease group were significantly lower than those in the latent CMV infection group. CMV antigen-specific IFN-γ, TNF-α levels and severe lymphopenia together provided the best discriminatory performance for distinguishing between latent and either active CMV infection patients (AUC = 0.854) or CMV disease patients (AUC = 0.935).

CONCLUSION

Noninvasive peripheral blood biomarkers (the combination of CMV antigen-specific IFN-γ, TNF-α levels and severe lymphopenia) may have the potential to diferentiate different status of CMV infection in RD population.

Interleukin-18 serum level before and after intralesional immunotherapy with tuberculin purified protein derivative in patients with cutaneous and genital warts

BACKGROUND

Several studies demonstrated the efficacy of intralesional purified protein derivative (PPD) immunotherapy in warts eradication. Nevertheless, the precise induced immune mechanisms are undetermined. Injected PPD is hypothesized to induce a delayed hypersensitivity reaction associated with cytokines release. Interleukin (IL)-18 has a major role in defense against viral infection via inducing interferon-γ release from T-helper 1 and natural killer (NK) cells. Moreover, IL-18 triggers Fas ligand expression on cytotoxic T cells and NK cells enhancing their cytotoxicity against virally infected cells.

AIM

The aim of this study was to assess the role of IL-18 in the response to intralesional PPD injection in patients with warts.

METHODS

The study included 25 patients with warts and 25 HCs. Patients underwent PPD skin test, and only patients with positive tests were included and received intralesional PPD injections starting 72 h after the test then every 2 weeks until wart clearance or a maximum of 3 sessions. Serum IL-18 level was measured via enzyme-linked immune-sorbent assay in patients (pre-treatment and 2 weeks after the last injection) and HCs.

RESULTS

After 3 sessions of injection, six (24%) patients were designated responders, nine (36%) patients showed partial response, and 10 (40%) patients were designated non-responders. Serum IL-18 level, post-treatment, was significantly higher than pre-treatment level (p = 0.025) and level in HCs (p = 0.036). Furthermore, the post-treatment level was significantly higher in responders than non-responders (p = 0.025).

CONCLUSION

IL-18 is probably implicated in the immune mechanisms induced by PPD injection that cause eradication of warts.

Interleukin-18 Binding Protein in Immune Regulation and Autoimmune Diseases

Natural soluble antagonist and decoy receptor on the surface of the cell membrane are evolving as crucial immune system regulators as these molecules are capable of recognizing, binding, and neutralizing (so-called inhibitors) their targeted ligands. Eventually, these soluble antagonists and decoy receptors terminate signaling by prohibiting ligands from connecting to their receptors on the surface of cell membrane. Interleukin-18 binding protein (IL-18BP) participates in regulating both Th1 and Th2 cytokines. IL-18BP is a soluble neutralizing protein belonging to the immunoglobulin (Ig) superfamily as it harbors a single Ig domain. The Ig domain is essential for its binding to the IL-18 ligand and holds partial homology to the IL-1 receptor 2 (IL-1R2) known as a decoy receptor of IL-1α and IL-1β. IL-18BP was defined as a unique soluble IL-18BP that is distinct from IL-18Rα and IL-18Rβ chain. IL-18BP is encoded by a separated gene, contains 8 exons, and is located at chr.11 q13.4 within the human genome. In this review, we address the difference in the biological activity of IL-18BP isoforms, in the immunity balancing Th1 and Th2 immune response, its critical role in autoimmune diseases, as well as current clinical trials of recombinant IL-18BP (rIL-18BP) or equivalent.

Herpesviruses and Inflammasomes: One Sensor Does Not Fit All

Herpesviruses are ubiquitous double-stranded DNA viruses that cause lifelong infections and are associated with a variety of diseases. While they have evolved multiple mechanisms to evade the immune system, they are all recognized by the innate immune system, which can lead to both localized and systemic inflammation. A more recently appreciated mechanism of herpesvirus innate immune activation is through inflammasome signaling. The inflammasome is an intracellular multiprotein complex that, when activated, leads to the release of proinflammatory cytokines, including IL-1β and IL-18, and activation of the inflammatory programed cell death pathway known as pyroptosis. Despite the herpesviruses sharing a similar structure, their mechanisms of inflammasome activation and the consequences of inflammasome activation in cases of virus-associated disease are not uniform. This review will highlight the similarities and differences among herpesviruses with regard to their mechanisms of inflammasome activation and impacts on diseases caused by herpesviruses. Furthermore, it will identify areas where additional studies are warranted to better understand the impact of this important innate immune signaling program on the pathogenesis of these common viruses.