Comprehensive Profiling of Peripheral Immune Cells and Subsets in Patients with Intermittent Allergic Rhinitis Compared to Healthy Controls and After Treatment with Glucocorticoids

Histology-based blood leukocyte profiling reveals parallel Th2 and Th17 signatures in seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis (AR), a common condition in the westernized world, is suggested to be more immunologically complex than the archetypical 'Th2' inflammation. New approaches are needed to decode this complexity.

AIMS/OBJECTIVES

In this study, we explored a novel histology-based analysis for circulating blood leukocyte profiling in 16 patients with seasonal AR outside and during the pollen season.

MATERIAL AND METHODS

Leukocytes were purified with minimal ex-vivo artefacts, embedded into agarose-paraffin pellets for immunohistochemistry-based immune cell profiling. Blood leukocyte mapping was performed.

RESULTS

Samples collected during the pollen season had statistically increased eosinophils, neutrophils, monocytes, and CD8⁺ T-lymphocytes compared to the off-season baseline. In contrast, no change was observed for CD20⁺ B-lymphocytes and CD3⁺ T-lymphocytes. Subclassification of CD4⁺ T-helper cells demonstrated a parallel and significant expansion of Th2 and Th17-cells during the pollen season, while Th1-cells remained unchanged. Whereas absolute basophils numbers were unaltered, the basophil markers GATA2 and CPA3 increased during the pollen season.

CONCLUSIONS AND SIGNIFICANCE

This study introduces a novel and applicable method for systemic immune cell screening and provides further evidence of complex and parallel Th2 and Th17-immune signatures in seasonal AR. It also forwards GATA2 and CPA3 as potential biomarkers for ongoing allergic inflammation.

Allergic rhinitis, allergic contact dermatitis and disease comorbidity belong to separate entities with distinct composition of T-cell subsets, cytokines, immunoglobulins and autoantibodies

Background

Allergic rhinitis (AR) and allergic contact dermatitis (ACD) are prevalent allergic diseases and have significant impacts on patients’ daily life. Despite many studies on AR or ACD have been conducted separately, little is known about the immune responses in patients of AR combined with ACD and the interplay between AR and ACD. Our study compared various aspects of immune elements in patients with AR or/and ACD, aiming to characterize the immune responses in AR, ACD, and AR combined with ACD.

Methods

A total of 57 patients diagnosed with AR or/and ACD and 28 healthy volunteers were included. AR patients were further divided into seasonal AR (SAR) and perennial AR (PAR). All subjects’ blood samples were taken to assess the concentration of immunoglobulins, complement C3, C4, autoantibodies and cytokines in serum by immunoturbidimetry, ELISA or Luminex200 platform. Peripheral blood mononuclear cells (PBMCs) were subjected to the analysis of lymphocyte subpopulations by flow cytometry.

Results

It indicated that AR disease caused elevated levels of IgE, IgA, IgG, IgG4, as well as IL-4, IL-15, IL-8 and IL-6 in serum. AR patients possessed a decreased CD4/CD8 ratio and an increased proportion of memory CD4 + T-cell subset, with a skewed Th2 response and an enhanced CD8 + T-cell activation. Compared with patients with sole AR or ACD condition, AR + ACD patients presented with a significantly increased proportion of memory CD8 + T-cell subset and were prone to autoimmune disorders as indicated by the increased autoantibodies. The immune elements in patients with ACD only were least affected compared with those in other conditions. Additionally, seasonal or perennial AR patients exhibited different cytokine profiles and proportions of memory T-cell subsets.

Conclusions

In this study, we illuminated the respective characteristics of immune responses in AR, ACD, and AR combined with ACD. Meanwhile, we discovered that the PAR and SAR patients possessed different cytokine profiles and T-cell compartments. It suggested that these allergic conditions belong to different disease entities. Characterizing the detailed immune changes in these allergic diseases would help to develop proper treatments targeting particular immune elements in different allergic diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-022-00646-6.

Atopic respiratory diseases and IgE sensitization are associated with leukocyte subset concentrations in 14,440 blood donors

BACKGROUND AND AIMS

Allergic rhinitis (AR), allergic conjunctivitis (AC), and asthma are characterized by activation of the immune system. The aim of this study was to explore the long-term association between AR, AC, asthma, and specific immunoglobulin E (IgE) and blood platelet and leukocyte differential counts.

MATERIAL AND METHODS

In the Danish Blood Donor Study, 14,440 participants from Central Denmark Region had platelet and leukocyte differential counts available and completed a questionnaire regarding AR, AC, and asthma. Of these participants, 8485 were tested for IgE to inhalation allergens.

RESULTS

The prevalence of AR, AC, asthma, and IgE sensitization was 19%, 15%, 9%, and 29%, respectively. AR, AC, asthma, wheeze, and IgE sensitization was associated with increased blood eosinophil concentration even in IgE sensitized participants who did not report any allergy or asthma. The strongest associations were observed for participants with current disease. We found no differences in eosinophil concentration between months without symptoms and months with symptoms of AR and asthma.

CONCLUSION

AR, AC, asthma, wheezing, and IgE sensitization to inhalation allergens are associated with increased eosinophil concentration. This may reflect a persistent inflammation even in periods without symptomatic disease.

Reduced CD4+T Cell CXCR3 Expression in Patients With Allergic Rhinitis

While T cells are considered to play a primary role in IgE-mediated atopic diseases, little is known about the systemic variations of T cell subsets from patients with allergic rhinitis (AR). To elucidate the characteristics of peripheral T cells, we analyzed natural killer, B cell, and T cell populations, performed T cell subset construction, and assessed chemokine receptor and associated serum cytokine expression in 25 AR patients and 20 healthy controls. Our results revealed increased levels of CD4⁺T cells, serum interleukin (IL)-10, IL-6, and interferon (IFN)-γ, and reduced Th1 and Th17 subsets, identified by their chemokine receptors, in AR patients. These results suggest a systemic activation of T cell responses in AR. We further demonstrated that AR patients exhibit significantly reduced CD4⁺T cell CXCR3 expression, especially in patients with moderate-severe disease severity, demonstrating that CXCR3 is a potential key molecule that hinders the Th1/Th2 balance in AR pathology. Overall, systemic T cell activation occurred in AR patients and CXCR3 dramatically decreased in CD4⁺T cells, which may ultimately be used as a potential disease and/or therapeutic target.

The impact of allergen exposure and specific immunotherapy on circulating blood cells in allergic rhinitis

Allergic rhinitis (AR) is an IgE-mediated inflammatory disease of the nasal mucosa with well described local immune responses during allergen exposure. The frequent association of AR with general extra-nasal symptoms and other allergic conditions, such as conjunctivitis and asthma, however, support a more systemic disease impact. In addition to acute elevation of soluble inflammatory mediators in periphery blood, a growing number of studies have reported changes in circulating blood cells after specific nasal allergen challenge or environmental allergen exposure. These findings imply an involvement of specific blood leukocyte subsets, thrombocytes and recently, erythrocytes. This review summarizes the circulating blood cell dynamics associated with allergen exposure in AR subjects reported so far. Additionally, the impact of therapy, particularly allergen-specific immunotherapy (AIT), the only currently available causal treatment reducing AR-related symptoms, is further considered in this context.

Pregnancy alters the circulating B cell compartment in atopic asthmatic women, and transitional B cells are positively associated with the development of allergy manifestations in their progeny

PROBLEM

Maternal atopy is a risk factor for allergy. B cells are poorly studied in reproduction and atopy. We aimed to assess how pregnancy affects B cells in atopic women and whether B cells relate to allergic manifestations in offspring.

METHOD OF STUDY

Women with and without atopic asthma, pregnant and non-pregnant were enrolled for the study, and circulating B cells were evaluated by flow cytometry, using CD19, CD27, CD38, IgD, and IgM.

RESULTS

Compared to healthy non-pregnant, atopic asthmatic non-pregnant (ANP) women presented increased B cell counts, enlarged memory subsets, less transitional cells, and plasmablasts. Atopic asthmatic pregnant (AP) and healthy pregnant (HP) women showed similarities: reduced B cell counts and percentages, fewer memory cells, especially switched, and higher plasmablast percentages. Transitional B cell percentages were increased in AP women with allergic manifestations in their progeny.

CONCLUSION

Atopic asthmatic non-pregnant women have a distinctive B cell compartment. B cells change in pregnancy, similarly in AP and HP women. The recognition that AP women with allergy in their progeny have a typical immune profile may help, in the future, the adoption of preventive measures to avoid the manifestation of allergic diseases in their newborns.

Alterations on peripheral blood B cell subsets induced by allergic rhinitis

OBJECTIVES AND DESIGN

Here we evaluated whether allergic rhinitis to Dermatophagoides pteronyssinus induces alterations on circulating B cell subsets.

MATERIALS AND METHODS

Circulating B cell subsets and isotype expression on antigen-experienced B cells from allergic patients under conventional pharmacological treatment (NO-SIT, n = 15) and under subcutaneous immunotherapy (SCIT, n = 33), and non-allergic subjects (NC, n = 25) were analyzed by flow cytometry.

RESULTS

In allergic patients, we found a significant decrease in IgM(+) and IgG(+) memory B cells and an increase in IgA(+) memory B cells. Additionally, the numbers of circulating IgA(+) plasmablasts in allergic patients were also increased, while those cells expressing IgM were reduced.

CONCLUSIONS

Allergic patients have a disturbed B cell subsets distribution which seems to underlie rhinitis pathogenesis and remain unchanged after SCIT.

Comprehensive assessment of proteins regulated by dexamethasone reveals novel effects in primary human peripheral blood mononuclear cells

Inflammation is a physiological process involved in many diseases. Monitoring proteins involved in regulatory effects may help to improve our understanding of inflammation. We have analyzed proteome alterations induced in peripheral blood mononuclear cells (PBMCs) upon inflammatory activation in great detail using high-resolution mass spectrometry. Moreover, the activated cells were treated with dexamethasone to investigate their response to this antiphlogistic drug. From a total of 6886 identified proteins, 469 proteins were significantly regulated upon inflammatory activation. Data are available via ProteomeXchange with identifiers PXD001415-23. Most of these proteins were counter-regulated by dexamethasone, with some exceptions concerning members of the interferon-induced protein family. To confirm some of these results, we performed targeted MRM analyses of selected peptides. The inflammation-induced upregulation of proteins such as IL-1β, IL-6, CXCL2, and GROα was confirmed, however, with strong quantitative interindividual differences. Furthermore, the inability of dexamethasone to downregulate inflammation-induced proteins such as PTX3 and TSG6 was clearly demonstrated. In conclusion, the relation of cell function as well as drug-induced modulation thereof was successfully mapped to proteomes, suggesting targeted analysis as a novel and powerful drug evaluation method. Although most consequences of dexamethasone were found to be compatible with the expected mode of action, some unexpected but significant observations may be related to adverse effects.

DNA methylation changes separate allergic patients from healthy controls and may reflect altered CD4+ T-cell population structure

Altered DNA methylation patterns in CD4⁺ T-cells indicate the importance of epigenetic mechanisms in inflammatory diseases. However, the identification of these alterations is complicated by the heterogeneity of most inflammatory diseases. Seasonal allergic rhinitis (SAR) is an optimal disease model for the study of DNA methylation because of its well-defined phenotype and etiology. We generated genome-wide DNA methylation (N_patients = 8, N_controls = 8) and gene expression (N_patients = 9, N_controls = 10) profiles of CD4⁺ T-cells from SAR patients and healthy controls using Illumina's HumanMethylation450 and HT-12 microarrays, respectively. DNA methylation profiles clearly and robustly distinguished SAR patients from controls, during and outside the pollen season. In agreement with previously published studies, gene expression profiles of the same samples failed to separate patients and controls. Separation by methylation (N_patients = 12, N_controls = 12), but not by gene expression (N_patients = 21, N_controls = 21) was also observed in an in vitro model system in which purified PBMCs from patients and healthy controls were challenged with allergen. We observed changes in the proportions of memory T-cell populations between patients (N_patients = 35) and controls (N_controls = 12), which could explain the observed difference in DNA methylation. Our data highlight the potential of epigenomics in the stratification of immune disease and represents the first successful molecular classification of SAR using CD4⁺ T cells.

T-cells, a type of white blood cell, are an important part of the immune-system in humans. T-cells allow us to adapt our immune-response to the various infectious agents we encounter during life. However, T-cells can also cause disease when they target the body's own cells, e.g. Psoriasis, or when they react to a harmless particle or ‘antigen’, i.e. allergy. Much evidence supports an environmental, or ‘epigenetic’, component to allergy. Surprisingly, although allergy is viewed as a T-cell disease with an epigenetic component, no studies have identified epigenetic differences between healthy individuals and allergic individuals. Using a state-of-the-art genome-wide approach, we found that we could clearly and robustly separate allergic patients from healthy controls. It is often assumed that these changes reflect changes in DNA methylation in a given type of cell; however such differences can also result from different mixtures of T-cell subtypes in the samples. Indeed, we found that allergic patients had different proportions of T-cell sub-types compared to healthy controls. These changes in T-cell proportions may explain the difference in DNA methylation profile we observed between patients and controls. Our study is the first successful molecular classification of allergy using CD4⁺ T cells.