Compartmentalization of immunosenescence: a deeper look at the mucosa

Involvement of CD40-CD40L and ICOS-ICOSL in the development of chronic rhinosinusitis by targeting eosinophils

Background

Chronic rhinosinusitis (CRS), whose prevalence and pathogenesis are age-related, is characterized by nasal tissue eosinophil infiltration. CD40-CD40 ligand (CD40L) pathway involves in the eosinophil-mediated inflammation, and inducible co-stimulator (ICOS)-ICOS ligand (ICOSL) signal can strengthen CD40-CD40L interaction. Whether CD40-CD40L and ICOS-ICOSL have a role in the development of CRS remains unknown.

Objectives

The aim of this study is to investigate the association of CD40-CD40L and ICOS-ICOSL expression with CRS and underlying mechanisms.

Methods

Immunohistology detected the expression of CD40, CD40L, ICOS, and ICOSL. Immunofluorescence was performed to evaluate the co-localizations of CD40 or ICOSL with eosinophils. Correlations between CD40-CD40L and ICOS-ICOSL as well as clinical parameters were analyzed. Flow cytometry was used to explore the activation of eosinophils by CD69 expression and the CD40 and ICOSL expression on eosinophils.

Results

Compared with the non-eCRS subset, ECRS (eosinophilic CRS) subset showed significantly increased CD40, ICOS, and ICOSL expression. The CD40, CD40L, ICOS, and ICOSL expressions were all positively correlated with eosinophil infiltration in nasal tissues. CD40 and ICOSL were mainly expressed on eosinophils. ICOS expression was significantly correlated with the expression of CD40-CD40L, whereas ICOSL expression was correlated with CD40 expression. ICOS-ICOSL expression positively correlated with blood eosinophils count and disease severity. rhCD40L and rhICOS significantly enhanced the activation of eosinophils from patients with ECRS. Tumor necrosis factor-α (TNF-α) and interleukin-5 (IL-5) obviously upregulated CD40 expression on eosinophils, which was significantly inhibited by the p38 mitogen-activated protein kinase (MAPK) inhibitor.

Conclusions

Increased CD40-CD40L and ICOS-ICOSL expressions in nasal tissues are linked to eosinophils infiltration and disease severity of CRS. CD40-CD40L and ICOS-ICOSL signals enhance eosinophils activation of ECRS. TNF-α and IL-5 regulate eosinophils function by increasing CD40 expression partly via p38 MAPK activation in patients with CRS.

Histopathological Differences in Adult and Elderly Patients With Chronic Rhinosinusitis

BACKGROUND

Adult and elderly patients with chronic rhinosinusitis (CRS) undergo similar therapeutic management. Few studies have undertaken sinonasal tissue-level comparisons of these groups. This study examines histopathological differences between adults (>18, <65 years) and the elderly (≥65 years) with CRS, with the goal of optimizing medical management.

METHODS

In a retrospective cohort analysis, demographic factors, comorbidities, and a structured histopathological report of 13 variables were compared across adult and elderly patients with CRS who underwent functional endoscopic sinus surgery. These cohorts of adult and elderly patients included patients with and without nasal polyps (NP).

RESULTS

Three hundred adult (158 aCRSsNP, 142 aCRSwNP) and 77 elderly (38 eCRSsNP, 39 eCRSwNP) patients were analyzed. Mean age of the adult cohort was 44.4 ± 12.4 years, while that of the elderly cohort was 71.9 ± 5.9 years (P < .001). Significantly more adults compared to elderly individuals demonstrated a positive atopic status (79.7% vs 64.0%, P = .004). Elderly patients exhibited higher rates of comorbid diabetes mellitus than adult patients (21.6% vs 10.3%, P = .009). Adults exhibited more tissue eosinophilia (43.4% vs 28.6%, P = .012) and presence of eosinophil aggregates (25.0% vs 14.3%, P = .029) compared to elderly patients, regardless of NP status. Conversely, the elderly demonstrated significantly more fungal elements (11.7% vs 3.0%, P = .004), and trended toward increased overall inflammation (63.6% vs 55.3%, P = .118) and tissue neutrophilia (35.1% vs 27.3%, P = .117), compared to adults.

CONCLUSION

Sinonasal tissue of adult and elderly patients with CRS demonstrates clear histopathological differences. Patient comorbidities, in addition to histopathological characterizations, may provide further context for management optimization.

LEVEL OF EVIDENCE

2.

SHORT SUMMARY

Sinonasal tissue samples from adult and elderly patients with CRS demonstrate clear histopathological differences. These patient populations also exhibit unique comorbidities. These distinctions have the potential to inform and optimize management of this condition.

Divergent age-related humoral correlates of protection against respiratory syncytial virus infection in older and young adults: a pilot, controlled, human infection challenge model

BACKGROUND

Respiratory viral infections are typically more severe in older adults. Older adults are more vulnerable to infection and do not respond effectively to vaccines due to a combination of immunosenescence, so-called inflamm-ageing, and accumulation of comorbidities. Although age-related changes in immune responses have been described, the causes of this enhanced respiratory disease in older adults remain poorly understood. We therefore performed volunteer challenge with respiratory syncytial virus (RSV) in groups of younger and older adult volunteers. The aim of this study was to establish the safety and tolerability of this model and define age-related clinical, virological, and immunological outcomes.

METHODS

In this human infection challenge pilot study, adults aged 18-55 years and 60-75 years were assessed for enrolment using protocol-defined inclusion and exclusion criteria. Symptoms were documented by self-completed diaries and viral load determined by quantitative PCR of nasal lavage. Peripheral blood B cell frequencies were measured by enzyme-linked immunospot and antibodies against pre-fusion and post-fusion, NP, and G proteins in the blood and upper respiratory tract were measured. The study was registered with ClinicalTrials.gov, NCT03728413.

FINDINGS

381 adults aged 60-75 years (older cohort) and 19 adults aged 18-55 years (young cohort) were assessed for enrolment using protocol-defined inclusion and exclusion criteria between Nov 12, 2018, and Feb 26, 2020. 12 healthy volunteers aged 60-75 years and 21 aged 18-55 years were inoculated intranasally with RSV Memphis-37. Nine (67%) of the 12 older volunteers became infected, developing mild-to-moderate upper respiratory tract symptoms that resolved without serious adverse events or sequelae. Viral load peaked on day 6 post-inoculation and symptoms peaked between days 6 and 8. Increases in circulating IgG-positive and IgA-positive antigen-specific plasmablasts, serum neutralising antibodies, and pre-F specific IgG were similar younger and older adults. However, in contrast to young participants, secretory IgA titres in older volunteers failed to increase during infection and, unlike serum IgG, did not correlate with protection.

INTERPRETATION

Better understanding of age-related differences in clinical outcomes and immune correlates of protection can overcome reduction in vaccine efficacy with advancing age. We identify correlates of protection in older adults, revealing previously unrecognised factors which might have implications for targeted vaccine discovery and drug development in this vulnerable group.

FUNDING

Medical Research Council and GlaxoSmithKline EMINENT Consortium.

Age-associated changes in chronic rhinosinusitis endotypes

BACKGROUND

Immunologic function in innate and adaptive immunity changes with the ageing process. Thus, age-related cytokine profiles in chronic rhinosinusitis (CRS) need to be investigated for precision medicine.

OBJECTIVE

The objective of this study was to characterize age-related changes in immunologic profiles according to CRS subtypes.

METHODS

Subjects in control (n = 29), CRS without nasal polyps (CRSsNP, n = 86), and CRS with nasal polyps (eosinophilic NP: ENP, n = 81; non-eosinophilic NP: NENP, n = 113) were enrolled in this study. Twenty markers for type 1/2/3 inflammation and other inflammatory processes were measured in homogenates of sinonasal tissues and statistically analysed.

RESULTS

In control tissues, type 2/3 and proinflammatory mediators showed an inverse correlation with age. CRSsNP and NENP showed an age-related increase in type 2 cytokines and a decline in type 3 cytokines. Interestingly, the age-related decrease in type 3 mediators was associated with those of CT scores in NENP. ENP showed an age-related increase in type 3 cytokines with type 2 mediators sustained at high levels. Smokers with ENP demonstrated age-associated increases in type 1/2/3 mediators as well as CT scores. These age-related patterns in each CRS were confirmed by statistically adjusting atopy status, smoking history, and disease duration.

CONCLUSION

Age-associated cytokine changes differed among CRS subtypes and control tissues. CRSsNP and NENP demonstrated a decline in type 3 mediators and increase in type 2 mediators, whereas type 3 mediators increased with age in ENP.

Relationships Between Ion Channels, Mitochondrial Functions and Inflammation in Human Aging

Aging is often associated with a loss of function. We believe aging to be more an adaptation to the various, and often continuous, stressors encountered during life in order to maintain overall functionality of the systems. The maladaptation of a system during aging may increase the susceptibility to diseases. There are basic cellular functions that may influence and/or are influenced by aging. Mitochondrial function is amongst these. Their presence in almost all cell types makes of these valuable targets for interventions to slow down or even reserve signs of aging. In this review, the role of mitochondria and essential physiological regulators of mitochondria and cellular functions, ion channels, will be discussed in the context of human aging. The origins of inflamm-aging, associated with poor clinical outcomes, will be linked to mitochondria and ion channel biology.