Analysis of the changes in Th9 cells and related cytokines in the peripheral blood of spontaneous urticaria patients

The Role of Crosstalk of Immune Cells in Pathogenesis of Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is defined as recurrent episodes of spontaneous wheal development and/or angioedema for more than six weeks and at least twice a week. The core link in the pathogenesis of CSU is the activation of mast cells, T cells, eosinophils, and other immune cells infiltrating around the small venules of the lesion. Increased vascular permeability, vasodilatation, and recruitment of inflammatory cells directly depend on mast cell mediators’ release. Complex regulatory systems tightly influence the critical roles of mast cells in the local microenvironment. The bias toward Th2 inflammation and autoantibodies derived from B cells, histamine expressed by basophils, and initiation of the extrinsic coagulation pathway by eosinophils or monocytes exerts powerful modulatory influences on mast cells. Cell-to-cell interactions between mast cells and eosinophils/T cells also are regulators of their function and may involve CSU’s pathomechanism. This review summarizes up-to-date knowledge regarding the crosstalk between mast cells and other immune cells, providing the impetus to develop new research concepts and treatment strategies for CSU.

Exhaled Nitric Oxide Level in Pharynx Angioedema

Airway inflammation is related to increased nitric oxide production. It can be assessed noninvasively with exhaled nitric oxide measurement. As airway inflammation was supposed to be present in chronic urticaria and angioedema patients we hypothesized increased exhaled nitric oxide in this group. Twenty-six symptomatic chronic urticaria patients with an acute episode of pharynx angioedema (17 women and 9 men, median age 35) were included in the study group. None of the patients reported a history of asthma, allergic rhinitis or cigarette smoking. The control group consisted of 29 non-smoking healthy subjects (19 women and 10 men, median age 22) without any history of atopy. Exhaled nitric oxide measurement was performed in all subjects. Exhaled nitric oxide levels in the angioedema group did not differ statistically significantly from those detected in healthy subjects (15.5 ppb and 17.0 ppb respectively). Our results indicate the lack of airway inflammation in chronic urticaria patients with pharynx angioedema.

Interleukin-9 in Immunopathology of Trypanosoma cruzi Experimental Infection

Chagas’ disease is a parasitosis caused by Trypanosoma cruzi, which affects approximately 8 million people worldwide. The balance between pro- and anti-inflammatory cytokines produced during immunological responses contributes to disease prognosis and progression. Parasite tissue persistence can induce chronic inflammatory stimuli, which can cause long-term tissue injury and fibrosis. Chronic Chagas’ patients exhibit increased levels of interleukin (IL)-9, an important cytokine in the regulation of inflammatory and fibrogenic processes. Data on the role of IL-9 in other pathologies are sometimes contradictory, and few studies have explored this cytokine’s influence in Chagas’ disease pathology. Hence, the aim of this study was to evaluate the role of IL-9 in the progression of T. cruzi infection in vivo and in vitro. In vitro infection demonstrated that IL-9 reduced the number of infected cells and decreased the multiplication of intracellular amastigotes in both C2C12 myoblasts and bone marrow-derived macrophages. In myoblasts, the increased production of nitric oxide (NO) was essential for reduced parasite multiplication, whereas macrophage responses resulted in increased IL-6 and reduced TGF-β levels, indicating that parasite growth restriction mechanisms induced by IL-9 were cell-type specific. Experimental infection of BALB/c mice with T. cruzi trypomastigotes of the Y strain implicated a major role of IL-9 during the chronic phase, as increased Th9 and Tc9 cells were detected among splenocytes; higher levels of IL-9 in these cell populations and increased cardiac IL-9 levels were detected compared to those of uninfected mice. Moreover, rIL9 treatment decreased serum IL-12, IL-6, and IL-10 levels and cardiac TNF-α levels, possibly attempting to control the inflammatory response. IL-9 neutralization increased cardiac fibrosis, synthesis of collagens I and III, and mastocyte recruitment in BALB/c heart tissue during the chronic phase. In conclusion, our data showed that IL-9 reduced the invasion and multiplication of T. cruzi in vitro, in both myoblasts and macrophages, favoring disease control through cell-specific mechanisms. In vivo, IL-9 was elevated during experimental chronic infection in BALB/c mice, and this cytokine played a protective role in the immunopathological response during this phase by controlling cardiac fibrosis and proinflammatory cytokine production.

The Pathogenesis of Chronic Spontaneous Urticaria: The Role of Infiltrating Cells

Chronic spontaneous urticaria is characterized by a perivascular non-necrotizing cellular infiltrate around small venules of the skin. It consists primarily of CD4(+) lymphocytes, a prominence of the T helper (Th)2 subtype but also Th1 cells, with Th17 cell-derived cytokines elevated in plasma. There are also neutrophils, eosinophils, basophils, and monocytes. Chemokines derived from mast cells and activated endothelial cells drive the process. Although the role of the cellular infiltrate has not previously been addressed, each constituent can contribute to the overall pathogenesis. It is of interest that CSU responds to corticosteroid, yet, short-term steroids do not affect autoimmunity or degranulation of mast cells, and act on margination of cells along the endothelium and chemotaxis to enter the surrounding dermis. In this review, we address each cell's contribution to the overall inflammatory response, as it is currently understood, with a view toward development of therapeutic options that impede the function of critical cells and/or their secretory products.

Role of IL-9 and IL-10 in the pathogenesis of chronic spontaneous urticaria through the JAK/STAT signalling pathway

This study investigated the role of interleukin (IL)-9 and IL-10 in the pathogenesis of chronic spontaneous urticaria (CSU). Autologous serum skin test and histamine release test were performed in CSU patients and normal subjects. Kunming mice were used to develop a mouse model for CSU. We induced IL-9 overexpression, IL-10 overexpression, and JAK/STAT pathway inhibition as well as a combination of all three conditions in CSU and control mice. Eosinophils in the skin tissues, inflammatory cytokine expression, and distribution of T lymphocyte subsets in peripheral blood of mice were detected. Expression patterns of IL-9, IL-10, STAT3, JAK2, and INF-γ in clinical samples and mice were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The positive rate of autologous serum skin test and the histamine release rate of CSU patients, compared with normal subjects, were apparently elevated. Compared with controls, mice with CSU experienced longer duration and higher frequency of pruritus and demonstrated enhanced levels of CD8⁺ , the ratio of CD4⁺ /CD8⁺ , number of eosinophils, and inflammatory cytokine expression in serum as well as activated JAK/STAT signalling pathway; at the same time, levels of CD4⁺ and INF-γ were reduced. This trend was found in CSU mice overexpressing IL-9 and IL-10 when compared with the CSU mice without treatment. In contrast, JAK/STAT inhibition reversed the above trend. Overall, our study suggests that IL-9 and IL-10 contribute to CSU development via activation of the JAK/STAT signalling pathway.