Functional immune reconstitution early after allogeneic haematopoietic cell transplantation: A comparison of pre- and post-transplantation cytokine responses in stimulated whole blood

Differences in toll-like receptor ligand-induced cytokine concentrations before and after solid organ transplantation: A prospective, observational cohort study in a clinical setting

Reliable methods to assess immune function after solid organ transplantation (SOT) are needed to guide dosing of immunosuppression. We hypothesized that toll-like receptor ligand-induced cytokine concentrations would decrease post-transplantation due to the use of immunosuppressive medication. Furthermore, we hypothesized that induced cytokine concentrations pre-transplantation would be higher in recipients with episodes of acute rejection post-transplantation due to underlying immunological dispositions. We aimed to investigate toll-like receptor ligand-induced cytokine concentrations by TruCulture©, a standardized immunoassay, in SOT recipients before and 3 months after SOT and explored associations with methylprednisolone-treated acute rejections. We conducted a prospective, observational cohort study including 123 participants (67 liver, 32 kidney and 24 lung transplant recipients). Whole blood was stimulated for 22 h with: (A) Lipopolysaccharide (LPS), (B) Resiquimod, (C) Polyinosinic:polycytidylic acid (Poly I:C) and (D) a blank control. Cytokine concentrations (TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-12p40, IL-17A, IFN-α and IFN-γ) were measured by Luminex. 30 participants developed methylprednisolone-treated acute rejection at a median of 9 days (IQR 5-17) post-SOT. We found that all induced cytokine concentrations decreased post-SOT except from LPS-induced and Poly I:C-induced IL-10. The induced cytokine concentration pre-transplantation did not differ in recipients with or without acute rejection. In conclusion, the induced cytokine concentrations decreased for all stimuli post-SOT, except the anti-inflammatory cytokine IL-10. Importantly, recipients developing early acute rejection did not differ in induced cytokine concentrations pre-SOT. Thus, the use of a standardized assay in SOT is feasible in a clinical setting and may provide important information on the immune function post-SOT.

Distinct Immune Reconstitution Profiles Captured by Immune Functional Assays at 6 Months Post Allogeneic Hematopoietic Stem Cell Transplantation

Immune reconstitution after allogeneic-hematopoietic-stem-cell transplantation (allo-HSCT) is a complex and individual process. In this cross-sectional study, whole-blood (WB) immune functional assay (IFA) was used to characterize immune function by assessing immune-related gene/pathway alterations. The usefulness of this tool in the context of infection, 6 months after transplantation, was evaluated. Sixty allo-HSCT recipients at 6 months after transplantation and 10 healthy volunteers (HV) were included. WB was stimulated in standardized TruCulture tubes using lipopolysaccharides and Staphylococcal enterotoxin B. Gene expression was quantified using a custom 144-gene panel using NanoString nCounter technology and analyzed using Ingenuity Pathway Analysis. The relationships between immune function and clinical characteristics, immune cell counts, and post-transplantation infections were assessed. Allo-HSCT recipients were able to activate similar networks of the innate and adaptive immune response compared to HV, with, nevertheless, a lower intensity. A reduced number and a lower expression of genes associated with immunoregulatory and inflammatory processes were observed in allo-HSCT recipients. The use of immunosuppressive treatments was associated with a protracted immune reconstitution revealed by transcriptomic immunoprofiling. No difference in immune cell counts was observed among patients receiving or not receiving immunosuppressive treatments using a large immunophenotyping panel. Moreover, the expression of a set of genes, including CCL3/CCL4, was significantly lower in patients with Herpesviridae reactivation (32%, 19/60), which once again was not identified using classical immune cell counts. Transcriptional IFA revealed the heterogeneity among allo-HSCT recipients with a reduced immune function, a result that could not be captured by circulating immune cell counts. This highlights the potential added value of this tool for the personalized care of immunocompromised patients.

Innate immune function during antineoplastic treatment is associated with 12-months survival in non-small cell lung cancer

Introduction

The immune system has proven to be a key player in the progression as well as containment of cancer with new treatment strategies based on immunotherapy targeting this interaction. Assessing immune function could reveal critical information about the immune response to therapeutic interventions, revealing predictive biomarkers for tailored care and precision medicine.

Methods

We investigated immune function in 37 patients with inoperable non-small cell lung cancer (NSCLC) undergoing treatment with PD-L1 immune checkpoint inhibitor (ICI), chemotherapy (CT) or chemo-radiotherapy (CT/RT). Blood samples before (day 0) and during therapy (day 7, 21 and 80) were investigated by a standardized immunoassay, TruCulture®.

Results

Outcomes revealed a developing innate immune response induced by both immunotherapy and chemotherapy. NSCLC-patients displayed evidence of chronic innate immune activation and exhaustion prior to treatment. This pattern was particularly pronounced during treatment in patients dying within 12-months follow-up. Compared to treatment with CT, ICI demonstrated a higher ex vivo-stimulated release of proinflammatory cytokines.

Discussion

These preliminary findings may pave the way for tailored treatment and immune-monitoring.

Early stimulated immune responses predict clinical disease severity in hospitalized COVID-19 patients

Background

The immune pathogenesis underlying the diverse clinical course of COVID-19 is poorly understood. Currently, there is an unmet need in daily clinical practice for early biomarkers and improved risk stratification tools to help identify and monitor COVID-19 patients at risk of severe disease.

Methods

We performed longitudinal assessment of stimulated immune responses in 30 patients hospitalized with COVID-19. We used the TruCulture whole-blood ligand-stimulation assay applying standardized stimuli to activate distinct immune pathways, allowing quantification of cytokine responses. We further characterized immune cell subsets by flow cytometry and used this deep immunophenotyping data to map the course of clinical disease within and between patients.

Results

Here we demonstrate impairments in innate immune response pathways at time of COVID-19 hospitalization that are associated with the development of severe disease. We show that these impairments are transient in those discharged from hospital, as illustrated by functional and cellular immune reconstitution. Specifically, we identify lower levels of LPS-stimulated IL-1β, and R848-stimulated IL-12 and IL-17A, at hospital admission to be significantly associated with increasing COVID-19 disease severity during hospitalization. Furthermore, we propose a stimulated immune response signature for predicting risk of developing severe or critical COVID-19 disease at time of hospitalization, to validate in larger cohorts.

Conclusions

We identify early impairments in innate immune responses that are associated with subsequent COVID-19 disease severity. Our findings provide basis for early identification of patients at risk of severe disease which may have significant implications for the early management of patients hospitalized with COVID-19.

Improved induced innate immune response after cART initiation in people with HIV

Introduction

Impairment of the innate immune function may contribute to the increased risk of bacterial and viral infections in people with HIV (PWH). In this study we aimed to investigate the induced innate immune responses in PWH prior to and after initiation of combinational antiretroviral therapy (cART). Furthermore, we aimed to investigate if the induced innate immune responses before initiation of cART were associated with CD4+ T-cell recovery one year after initiating cART.

Material and method

The induced innate immune response was assessed by the TruCulture^® whole blood technique in 32 PWH before cART initiation and after 1, 6 and 12 months. To mimic bacterial and viral infections we used a panel of three stimuli (lipopolysaccharide (LPS), resiquimod (R848), and polyinosinic:polycytidylic acid (Poly I:C)) to stimulate the extracellular Toll-like receptor (TLR) 4 and the intracellular TLR7/8 and TLR3, respectively. The following cytokine responses were analyzed by Luminex 200: Tumor Necrosis Factor (TNF)-α, Interleukin (IL)-1b, IL-6, IL-8, IL-10, IL-12p40, IL17A, Interferon (IFN)-α, and IFN-γ.

Results

At baseline PWH with nadir CD4+ T-cell count <350 cell/µL had lower levels of LPS-, R848-, and Poly I:C-induced IL-6 and IFN-γ, LPS- and R848-induced TNF-α and IL-12, LPS induced IL-1b, and R848-induced IL-10 than PWH with nadir CD4+ T-cell count >350 cells/µL. The majority (>50%) had induced cytokine concentrations below the reference intervals at baseline which was most pronounced for the LPS- and Poly I:C-induced responses. The induced responses in the whole population improved after 12 months of cART, and more PWH had induced cytokine concentrations within the reference intervals after 12 months. However, the majority of PWH still had LPS-induced INF-α, INF-γ and Poly I:C-induced TNF-α and IL-6 below the reference interval. The induced innate immune responses before cART initiation were not associated with the CD4+ T-cell recovery after 12 months of cART.

Conclusion

The innate immune response was impaired in PWH, with a more pronounced impairment in PWH with low nadir CD4+ T-cell count. Initiation of cART improved the innate immune response, but compared to the reference intervals, some impairment remained in PWH without viral replication.

The Induced Immune Response in Patients With Infectious Spondylodiscitis: A Prospective Observational Cohort Study

Introduction

Infectious spondylodiscitis is a rare infection of the intervertebral disc and the adjacent vertebral bodies that often disseminates and requires long-term antibiotic therapy. Immunologic profiling of patients with infectious spondylodiscitis could allow for a personalized medicine strategy. We aimed to examine the induced immune response in patients with infectious spondylodiscitis during and after antibiotic therapy. Furthermore, we explored potential differences in the induced immune response depending on the causative pathogen and the dissemination of the disease.

Methods

This was a prospective observational cohort study that enrolled patients with infectious spondylodiscitis between February 2018 and August 2020. A blood sample was collected at baseline, after four to six weeks of antibiotic therapy (during antibiotic therapy), and three to seven months after end of antibiotic therapy (post-infection). The induced immune response was assessed using the standardized functional immune assay TruCulture^®. We used a panel of three immune cell stimuli (lipopolysaccharide, Resiquimod and polyinosinic:polycytodylic acid) and an unstimulated control. For each stimulus, the induced immune response was assessed by measuring the released concentration of Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p40, IL-17A, Interferon-γ (IFN-γ) and Tumor necrosis factor-α (TNF-α) in pg/mL.

Results

In total, 49 patients with infectious spondylodiscitis were included. The induced immune responses were generally lower than references at baseline, but the cytokine release increased in patients after treatment with antibiotic therapy. Post-infection, most of the released cytokine concentrations were within the reference range. No significant differences in the induced immune responses based on stratification according to the causative pathogen or dissemination of disease were found.

Conclusion

We found lower induced immune responses in patients with infectious spondylodiscitis at baseline. However, post-infection, the immune function normalized, indicating that an underlying immune deficiency is not a prominent factor for spondylodiscitis. We did not find evidence to support the use of induced immune responses as a tool for prediction of the causative pathogen or disease dissemination, and other methods should be explored to guide optimal treatment of patients with infectious spondylodiscitis.