Allergic rhinitis and allergic asthma are common illnesses that frequently occur together (Schatz and Rosenwasser 2014). Epidemiological studies have shown that between 85 and 95% of patients with asthma have allergic rhinitis (Sibbald and Rink 1991). The presence of rhinitis is also recognized as a major risk factor for the development of asthma (Compalati et al., 2010). Allergic asthma is differentiated from non-allergic asthma by the fact that the patients are sensitized to environmental allergens (Romanet-Manent et al., 2002). Patients with allergic asthma may have intermittent or persistent asthma and may or not be subject to exacerbations which, in some poorly controlled cases, may occur frequently (Khan 2014).

Allergic rhinitis and allergic asthma are both characterized by a Th2 immune response and airway hyper-responsiveness (AHR). However, Th2 immune responses are mainly related to mild and moderate asthma, while there is considerable evidence suggesting that Th17, IL17-A and IL17-F were correlated with more severe forms of asthma (Chesne et al., 2014). Nitric oxide (NO) and Metalloproteinase 9 (MMP-9) might also play a significant role in the physiopathology of allergic asthma and allergic rhinitis, as they appear to be linked with inflammation, bronchoconstriction and airways remodelling mechanisms (Lopuhaa et al., 2003; Oshita et al., 2003; Mori et al., 2012).

The hygiene hypothesis proposes that a low exposure to viral and bacterial antigens in early life result in a lack of regulation of the immune system which predispose to type 2 immune response linked to allergic diseases. This hypothesis might explain the increase in prevalence of asthma and other allergic diseases in industrialized countries and the inverse correlation between incidence of allergic diseases and exposure to helminths (Strachan 1989; Santiago Hda and Nutman 2016). Helminths might be linked to the prevention of allergies and asthma by modulating the imbalance between the effector cells, mainly Th2 cells but also Th1/Th17 cells and regulatory T cells (Treg) populations which has been reported to be reduced in peripheral blood mononuclear cells (PBMC) of asthmatic patients (Fernandes et al., 2019).

During a mouse model of ovalbumin (OVA)-induced asthma, the infection of the mice with the protoscoleces of the helminth Echinoccous granulosus sensu stricto (E.g.) (Vuitton et al., 2020) remarkably reduced the severity of OVA-induced airway inflammation by reducing eosinophil infiltration and mucus production in lung tissue and ameliorating AHR. Indeed, the infection also enhanced IL-10 production and down-regulated IL-5 and IL-17A production (Wang et al., 2014). Moreover, many studies has reported the in vitro and in vivo immunomodulatorry and anti-inflammatory effects of the laminated layer (LL), the outer layer of the hydatid cyst (Steers et al., 2001; Amri and Touil-Boukoffa 2015, Soufli et al., 2015; Benazzouz et al., 2021).

In this sense, the main objectives of our study was to investigate the immune-modulatory effect of Echinoccocus granulosus laminated layer on pro-inflammatory markers in PBMC from patients with allergic rhinitis and allergic asthma. This effect was also evaluated on NO, IL-17A and IL-10 production in relation with allergic asthma severity.